* Add a primop to return the context of a string.

(e.g. "${somePkg}/bin/foo"), store the original derivation
  expression in the context.

Makefile.am

@@ -1,17 +1,11 @@
 SUBDIRS = externals src scripts corepkgs doc misc tests
 EXTRA_DIST = substitute.mk nix.spec nix.spec.in bootstrap.sh \
-  svn-revision nix.conf.example NEWS
+  nix.conf.example NEWS version
 
 include ./substitute.mk
 
 nix.spec: nix.spec.in
 
-rpm: nix.spec dist
-	rpm $(EXTRA_RPM_FLAGS) -ta $(distdir).tar.gz
-
-relname:
-	echo -n $(distdir) > relname
-
 install-data-local: init-state
 	$(INSTALL) -d $(DESTDIR)$(sysconfdir)/nix
 	$(INSTALL_DATA) $(srcdir)/nix.conf.example $(DESTDIR)$(sysconfdir)/nix
@@ -35,22 +29,18 @@ init-state:
 	$(INSTALL) $(INIT_FLAGS) -d $(DESTDIR)$(localstatedir)/nix/profiles
 	$(INSTALL) $(INIT_FLAGS) -d $(DESTDIR)$(localstatedir)/nix/gcroots
 	$(INSTALL) $(INIT_FLAGS) -d $(DESTDIR)$(localstatedir)/nix/temproots
-	$(INSTALL) $(INIT_FLAGS) $(GROUP_WRITABLE) -d $(DESTDIR)$(localstatedir)/nix/gcroots/tmp
-	$(INSTALL) $(INIT_FLAGS) $(GROUP_WRITABLE) -d $(DESTDIR)$(localstatedir)/nix/gcroots/channels
 	ln -sfn $(localstatedir)/nix/profiles $(DESTDIR)$(localstatedir)/nix/gcroots/profiles
 	$(INSTALL) $(INIT_FLAGS) -d $(DESTDIR)$(localstatedir)/nix/userpool
-	$(INSTALL) $(INIT_FLAGS) -m 1777 -d $(DESTDIR)$(storedir)
+	-$(INSTALL) $(INIT_FLAGS) -m 1777 -d $(DESTDIR)$(storedir)
 	$(INSTALL) $(INIT_FLAGS) $(GROUP_WRITABLE) -d $(DESTDIR)$(localstatedir)/nix/manifests
 	ln -sfn $(localstatedir)/nix/manifests $(DESTDIR)$(localstatedir)/nix/gcroots/manifests
 
 else
+
 init-state:
+
 endif
 
-svn-revision:
-	svnversion . > svn-revision
-
-all-local: NEWS
-
-NEWS: doc/manual/NEWS.txt
+NEWS:
+	$(MAKE) -C doc/manual NEWS.txt
 	cp $(srcdir)/doc/manual/NEWS.txt NEWS

configure.ac

@@ -1,21 +1,8 @@
-AC_INIT(nix, 0.12)
+AC_INIT(nix, m4_esyscmd([echo -n $(cat ./version)$VERSION_SUFFIX]))
 AC_CONFIG_SRCDIR(README)
 AC_CONFIG_AUX_DIR(config)
 AM_INIT_AUTOMAKE([dist-bzip2 foreign])
 
-# Change to `1' to produce a `stable' release (i.e., the `preREVISION'
-# suffix is not added).
-STABLE=0
-
-# Put the revision number in the version.
-if test "$STABLE" != "1"; then
-    if REVISION=`test -d $srcdir/.svn && svnversion -n $srcdir 2> /dev/null`; then
-        VERSION=${VERSION}pre${REVISION}
-    elif REVISION=`cat $srcdir/svn-revision 2> /dev/null`; then
-        VERSION=${VERSION}pre${REVISION}
-    fi
-fi
-
 AC_DEFINE_UNQUOTED(NIX_VERSION, ["$VERSION"], [Nix version.])
 
 AC_CANONICAL_HOST
@@ -63,17 +50,39 @@ AC_DEFINE_UNQUOTED(SYSTEM, ["$system"], [platform identifier (`cpu-os')])
 test "$localstatedir" = '${prefix}/var' && localstatedir=/nix/var
 
 
-# Windows-specific stuff.
-if test "$sys_name" = "cygwin"; then
-    # We cannot delete open files.
-    AC_DEFINE(CANNOT_DELETE_OPEN_FILES, 1, [Whether it is impossible to delete open files.])
+# Whether to produce a statically linked binary.  On Cygwin, this is
+# the default: dynamically linking against the ATerm DLL does work,
+# except that it requires the ATerm "lib" directory to be in $PATH, as
+# Windows doesn't have anything like an RPATH embedded in executable.
+# Since this is kind of annoying, we use static libraries for now.
 
-    # Shared libraries don't work, currently.
+AC_ARG_ENABLE(static-nix, AC_HELP_STRING([--enable-static-nix],
+  [produce statically linked binaries]),
+  static_nix=$enableval, static_nix=no)
+
+if test "$sys_name" = cygwin; then
+   static_nix=yes
+fi
+
+if test "$static_nix" = yes; then
     AC_DISABLE_SHARED
     AC_ENABLE_STATIC
 fi
 
 
+# Windows-specific stuff.
+if test "$sys_name" = "cygwin"; then
+    # We cannot delete open files.
+    AC_DEFINE(CANNOT_DELETE_OPEN_FILES, 1, [Whether it is impossible to delete open files.])
+fi
+
+# Solaris-specific stuff.
+if test "$sys_name" = "sunos"; then
+    # Solaris requires -lsocket -lnsl for network functions
+    ADDITIONAL_NETWORK_LIBS="-lsocket -lnsl"
+    AC_SUBST(ADDITIONAL_NETWORK_LIBS)
+fi
+
 AC_PROG_CC
 AC_PROG_CXX
 
@@ -85,8 +94,7 @@ AC_PROG_LIBTOOL
 
 
 # Use 64-bit file system calls so that we can support files > 2 GiB.
-CFLAGS="-D_FILE_OFFSET_BITS=64 $CFLAGS"
-CXXFLAGS="-D_FILE_OFFSET_BITS=64 $CXXFLAGS"
+AC_SYS_LARGEFILE
 
 
 # Check for pubsetbuf.
@@ -103,6 +111,8 @@ AC_LANG_POP(C++)
 
 # Check for chroot support (requires chroot() and bind mounts).
 AC_CHECK_FUNCS([chroot])
+AC_CHECK_FUNCS([unshare])
+AC_CHECK_HEADERS([sched.h], [], [], [])
 AC_CHECK_HEADERS([sys/param.h], [], [], [])
 AC_CHECK_HEADERS([sys/mount.h], [], [],
 [#ifdef HAVE_SYS_PARAM_H
@@ -111,12 +121,17 @@ AC_CHECK_HEADERS([sys/mount.h], [], [],
 ])
 
 
-# Check for <locale>
+# Check for <locale>.
 AC_LANG_PUSH(C++)
 AC_CHECK_HEADERS([locale], [], [], [])
 AC_LANG_POP(C++)
 
 
+# Check whether we have the personality() syscall, which allows us to
+# do i686-linux builds on x86_64-linux machines.
+AC_CHECK_HEADERS([sys/personality.h])
+
+
 AC_DEFUN([NEED_PROG],
 [
 AC_PATH_PROG($1, $2)
@@ -130,7 +145,6 @@ NEED_PROG(bash, bash)
 NEED_PROG(patch, patch)
 AC_PATH_PROG(xmllint, xmllint, false)
 AC_PATH_PROG(xsltproc, xsltproc, false)
-AC_PATH_PROG(jing, jing, false) # needed because xmllint --relaxng seems broken
 AC_PATH_PROG(w3m, w3m, false)
 AC_PATH_PROG(flex, flex, false)
 AC_PATH_PROG(bison, bison, false)
@@ -179,31 +193,6 @@ AC_ARG_WITH(store-dir, AC_HELP_STRING([--with-store-dir=PATH],
   storedir=$withval, storedir='/nix/store')
 AC_SUBST(storedir)
 
-AC_ARG_ENABLE(old-db-compat, AC_HELP_STRING([--disable-old-db-compat],
-  [disable support for converting from old Berkeley DB-based Nix stores]),
-  old_db_compat=$enableval, old_db_compat=yes)
-AM_CONDITIONAL(OLD_DB_COMPAT, test "$old_db_compat" = "yes")
-
-AC_ARG_WITH(bdb, AC_HELP_STRING([--with-bdb=PATH],
-  [prefix of Berkeley DB (for Nix <= 0.11 compatibility)]),
-  bdb=$withval, bdb=)
-AM_CONDITIONAL(HAVE_BDB, test -n "$bdb")
-if test -z "$bdb"; then
-  bdb_lib='-L${top_builddir}/externals/inst-bdb/lib -ldb_cxx'
-  bdb_include='-I${top_builddir}/externals/inst-bdb/include'
-else
-  bdb_lib="-L$bdb/lib -ldb_cxx"
-  bdb_include="-I$bdb/include"
-fi
-if test "$old_db_compat" = "no"; then
-  bdb_lib=
-  bdb_include=
-else
-  AC_DEFINE(OLD_DB_COMPAT, 1, [Whether to support converting from old Berkeley DB-based Nix stores.])
-fi
-AC_SUBST(bdb_lib)
-AC_SUBST(bdb_include)
-
 AC_ARG_WITH(aterm, AC_HELP_STRING([--with-aterm=PATH],
   [prefix of CWI ATerm library]),
   aterm=$withval, aterm=)
@@ -250,7 +239,7 @@ else
   bzip2_include="-I$bzip2/include"
   bzip2_bin="$bzip2/bin"
   bzip2_bin_test="$bzip2/bin"
-fi   
+fi
 AC_SUBST(bzip2_lib)
 AC_SUBST(bzip2_include)
 AC_SUBST(bzip2_bin)
@@ -272,15 +261,24 @@ AC_CHECK_FUNCS([setresuid setreuid lchown])
 
 # Nice to have, but not essential.
 AC_CHECK_FUNCS([strsignal])
+AC_CHECK_FUNCS([posix_fallocate])
 
 
-# This is needed if ATerm, Berkeley DB or bzip2 are static libraries,
+# This is needed if ATerm or bzip2 are static libraries,
 # and the Nix libraries are dynamic.
 if test "$(uname)" = "Darwin"; then
     LDFLAGS="-all_load $LDFLAGS"
 fi
 
 
+if test "$static_nix" = yes; then
+    # `-all-static' has to be added at the end of configure, because
+    # the C compiler doesn't know about -all-static (it's filtered out
+    # by libtool, but configure doesn't use libtool).
+    LDFLAGS="-all-static $LDFLAGS"
+fi
+
+
 AM_CONFIG_HEADER([config.h])
 AC_CONFIG_FILES([Makefile
    externals/Makefile

corepkgs/channels/unpack.sh.in

@@ -8,9 +8,15 @@ inputs=($inputs)
 for ((n = 0; n < ${#inputs[*]}; n += 2)); do
     channelName=${inputs[n]}
     channelTarball=${inputs[n+1]}
+    
     echo "unpacking channel $channelName"
+    
     @bunzip2@ < $channelTarball | @tar@ xf -
 
+    if test -e */channel-name; then
+        channelName="$(@coreutils@/cat */channel-name)"
+    fi
+
     nr=1
     attrName=$(echo $channelName | @tr@ -- '- ' '__')
     dirName=$attrName

doc/manual/Makefile.am

@@ -6,7 +6,12 @@ XSLTPROC = $(xsltproc) $(xmlflags) \
  --param xref.with.number.and.title 1 \
  --param toc.section.depth 3 \
  --param admon.style \'\' \
- --param callout.graphics.extension \'.gif\'
+ --param callout.graphics.extension \'.gif\' \
+ --param contrib.inline.enabled 0
+
+dblatex_opts = \
+ -P doc.collab.show=0 \
+ -P latex.output.revhistory=0
 
 # Note: we use GIF for now, since the PNGs shipped with Docbook aren't
 # transparent.
@@ -29,13 +34,9 @@ MANUAL_SRCS = manual.xml introduction.xml installation.xml \
  conf-file.xml release-notes.xml \
  style.css images
 
+# Note: RelaxNG validation requires xmllint >= 2.7.4.
 manual.is-valid: $(MANUAL_SRCS) version.txt
-#	$(XMLLINT) --xinclude $< | $(XMLLINT) --noout --nonet --relaxng $(docbookrng)/docbook.rng -
-	if test "$(jing)" != "false"; then \
-		$(XMLLINT) --xinclude $< | $(jing) $(docbookrng)/docbook.rng /dev/fd/0; \
-	else \
-		echo "Not validating."; \
-	fi
+	$(XMLLINT) --noout --nonet --xinclude --noxincludenode --relaxng $(docbookrng)/docbook.rng $<
 	touch $@
 
 version.txt:
@@ -50,7 +51,7 @@ manual.html: $(MANUAL_SRCS) manual.is-valid images
 
 manual.pdf: $(MANUAL_SRCS) manual.is-valid images
 	if test "$(dblatex)" != ""; then \
-		$(dblatex) manual.xml; \
+		$(dblatex) $(dblatex_opts) manual.xml; \
 	else \
 		echo "Please install dblatex and rerun configure."; \
 		exit 1; \
@@ -79,10 +80,14 @@ all-local: manual.html NEWS.html NEWS.txt
 install-data-local: manual.html
 	$(INSTALL) -d $(DESTDIR)$(docdir)/manual
 	$(INSTALL_DATA) manual.html $(DESTDIR)$(docdir)/manual
+	ln -sf manual.html $(DESTDIR)$(docdir)/manual/index.html
 	$(INSTALL_DATA) style.css $(DESTDIR)$(docdir)/manual
 	cp -r images $(DESTDIR)$(docdir)/manual/images
 	$(INSTALL) -d $(DESTDIR)$(docdir)/manual/figures
 	$(INSTALL_DATA) $(FIGURES) $(DESTDIR)$(docdir)/manual/figures
+	$(INSTALL) -d $(DESTDIR)$(docdir)/release-notes
+	$(INSTALL_DATA) NEWS.html $(DESTDIR)$(docdir)/release-notes/index.html
+	$(INSTALL_DATA) style.css $(DESTDIR)$(docdir)/release-notes/
 
 images:
 	mkdir images

doc/manual/builtins.xml

@@ -77,18 +77,8 @@ attrValues = attrs: map (name: builtins.getAttr name attrs) (builtins.attrNames
 if builtins ? getEnv then builtins.getEnv "PATH" else ""</programlisting>
 
     This allows a Nix expression to fall back gracefully on older Nix
-    installations that don’t have the desired built-in function.
-    However, in that case you should not write
-
-<programlisting>
-if builtins ? getEnv then __getEnv "PATH" else ""</programlisting>
-
-    This Nix expression will trigger an “undefined variable” error on
-    older Nix versions since <function>__getEnv</function> doesn’t
-    exist.  <literal>builtins.getEnv</literal>, on the other hand, is
-    safe since <literal>builtins</literal> always exists and attribute
-    selection is lazy, so it’s only performed if the test
-    succeeds.</para></listitem>
+    installations that don’t have the desired built-in
+    function.</para></listitem>
 
   </varlistentry>
 
@@ -334,6 +324,16 @@ x: x + 456</programlisting>
   </varlistentry>
 
   
+  <varlistentry><term><function>builtins.intersectAttrs</function>
+  <replaceable>e1</replaceable> <replaceable>e2</replaceable></term>
+
+    <listitem><para>Return an attribute set consisting of the
+    attributes in the set <replaceable>e2</replaceable> that also
+    exist in the set <replaceable>e1</replaceable>.</para></listitem>
+
+  </varlistentry>
+        
+    
   <varlistentry><term><function>builtins.isAttrs</function>
   <replaceable>e</replaceable></term>
 
@@ -364,6 +364,36 @@ x: x + 456</programlisting>
   </varlistentry>
 
   
+  <varlistentry><term><function>builtins.isString</function>
+  <replaceable>e</replaceable></term>
+
+    <listitem><para>Return <literal>true</literal> if
+    <replaceable>e</replaceable> evaluates to a string, and
+    <literal>false</literal> otherwise.</para></listitem>
+
+  </varlistentry>
+
+  
+  <varlistentry><term><function>builtins.isInt</function>
+  <replaceable>e</replaceable></term>
+
+    <listitem><para>Return <literal>true</literal> if
+    <replaceable>e</replaceable> evaluates to a int, and
+    <literal>false</literal> otherwise.</para></listitem>
+
+  </varlistentry>
+
+  
+  <varlistentry><term><function>builtins.isBool</function>
+  <replaceable>e</replaceable></term>
+
+    <listitem><para>Return <literal>true</literal> if
+    <replaceable>e</replaceable> evaluates to a bool, and
+    <literal>false</literal> otherwise.</para></listitem>
+
+  </varlistentry>
+
+  
   <varlistentry><term><function>isNull</function>
   <replaceable>e</replaceable></term>
 

doc/manual/conf-file.xml

@@ -233,7 +233,17 @@ build-use-chroot = /dev /proc /bin</programlisting>
     <filename>configure</filename> at build time.</para></listitem>
 
   </varlistentry>
-  
+
+
+  <varlistentry><term><literal>fsync-metadata</literal></term>
+
+    <listitem><para>If set to <literal>true</literal>, changes to the
+    Nix store metadata (in <filename>/nix/var/nix/db</filename>) are
+    synchronously flushed to disk.  This improves robustness in case
+    of system crashes, but reduces performance.  The default is
+    <literal>false</literal>.</para></listitem>
+
+  </varlistentry>
     
 </variablelist>
 

doc/manual/env-common.xml

@@ -151,12 +151,12 @@ $ mount -o bind /mnt/otherdisk/nix /nix</screen>
   <para>On the basis of this information, and whatever persistent
   state the build hook keeps about other machines and their current
   load, it has to decide what to do with the build.  It should print
-  out on file descriptor 3 one of the following responses (terminated
-  by a newline, <literal>"\n"</literal>):
+  out on standard error one of the following responses (terminated by
+  a newline, <literal>"\n"</literal>):
 
   <variablelist>
 
-    <varlistentry><term><literal>decline</literal></term>
+    <varlistentry><term><literal># decline</literal></term>
 
       <listitem><para>The build hook is not willing or able to perform
       the build; the calling Nix process should do the build itself,
@@ -164,7 +164,7 @@ $ mount -o bind /mnt/otherdisk/nix /nix</screen>
 
     </varlistentry>
 
-    <varlistentry><term><literal>postpone</literal></term>
+    <varlistentry><term><literal># postpone</literal></term>
 
       <listitem><para>The build hook cannot perform the build now, but
       can do so in the future (e.g., because all available build slots
@@ -174,7 +174,7 @@ $ mount -o bind /mnt/otherdisk/nix /nix</screen>
 
     </varlistentry>
 
-    <varlistentry><term><literal>accept</literal></term>
+    <varlistentry><term><literal># accept</literal></term>
 
       <listitem><para>The build hook has accepted the
       build.</para></listitem>
@@ -185,37 +185,12 @@ $ mount -o bind /mnt/otherdisk/nix /nix</screen>
 
   </para>
 
-  <para>If the build hook accepts the build, it is possible that it is
-  no longer necessary to do the build because some other process has
-  performed the build in the meantime.  To prevent races, the hook
-  must read from file descriptor 4 a single line that tells it whether
-  to continue:
-
-  <variablelist>
-
-    <varlistentry><term><literal>cancel</literal></term>
-
-      <listitem><para>The build has already been done, so the hook
-      should exit.</para></listitem>
-
-    </varlistentry>
-  
-    <varlistentry><term><literal>okay</literal></term>
-
-      <listitem><para>The hook should proceed with the build.  At this
-      point, the calling Nix process has acquired locks on the output
-      path, so no other Nix process will perform the
-      build.</para></listitem>
-
-    </varlistentry>
-
-  </variablelist>
-
-  </para>
-
-  <para>If the hook has been told to proceed, Nix will store in the
-  hook’s current directory a number of text files that contain
-  information about the derivation:
+  <para>After sending <literal># accept</literal>, the hook should
+  read one line from standard input, which will be the string
+  <literal>okay</literal>.  It can then proceed with the build.
+  Before sending <literal>okay</literal>, Nix will store in the hook’s
+  current directory a number of text files that contain information
+  about the derivation:
 
   <variablelist>
 
@@ -255,7 +230,9 @@ $ mount -o bind /mnt/otherdisk/nix /nix</screen>
   <para>The hook should copy the inputs to the remote machine,
   register the validity of the inputs, perform the remote build, and
   copy the outputs back to the local machine.  An exit code other than
-  <literal>0</literal> indicates that the hook has failed.</para>
+  <literal>0</literal> indicates that the hook has failed.  An exit
+  code equal to 100 means that the remote build failed (as opposed to,
+  e.g., a network error).</para>
 
   </listitem>
 

doc/manual/installation.xml

@@ -107,13 +107,6 @@ you can use <command>configure</command>'s
 <option>--with-aterm</option> and <option>--with-bzip2</option>
 options to point to their respective locations.</para>
 
-<para>If you want to be able to upgrade Nix stores from before version
-0.12pre12020, you need Sleepycat's Berkeley DB version version 4.5.
-(Other versions may not have compatible database formats.).  Berkeley
-DB 4.5 is included in the Nix source distribution.  If you do not need
-this ability, you can build Nix with the
-<option>--disable-old-db-compat</option> configure option.</para>
-
 </section>
 
 
@@ -140,16 +133,25 @@ $ ./bootstrap</screen>
 <para>The installation path can be specified by passing the
 <option>--prefix=<replaceable>prefix</replaceable></option> to
 <command>configure</command>.  The default installation directory is
-<filename>/nix</filename>.  You can change this to any location you
-like.  You must have write permission to the
+<filename>/usr/local</filename>.  You can change this to any location
+you like.  You must have write permission to the
 <replaceable>prefix</replaceable> path.</para>
 
-<warning><para>It is best <emphasis>not</emphasis> to change the
-installation prefix from its default, since doing so makes it
-impossible to use pre-built binaries from the standard Nixpkgs
-channels.</para></warning>
+<para>Nix keeps its <emphasis>store</emphasis> (the place where
+packages are stored) in <filename>/nix/store</filename> by default.
+This can be changed using
+<option>--with-store-dir=<replaceable>path</replaceable></option>.</para>
 
-<para>If you want to rebuilt the documentation, pass the full path to
+<warning><para>It is best <emphasis>not</emphasis> to change the Nix
+store from its default, since doing so makes it impossible to use
+pre-built binaries from the standard Nixpkgs channels — that is, all
+packages will need to be built from source.</para></warning>
+
+<para>Nix keeps state (such as its database and log files) in
+<filename>/nix/var</filename> by default.  This can be changed using
+<option>--localstatedir=<replaceable>path</replaceable></option>.</para>
+
+<para>If you want to rebuild the documentation, pass the full path to
 the DocBook RELAX NG schemas and to the DocBook XSL stylesheets using
 the
 <option>--with-docbook-rng=<replaceable>path</replaceable></option>
@@ -160,27 +162,26 @@ options.</para>
 </section>
 
 
-<section><title>Installing from RPMs</title>
+<section><title>Installing a binary distribution</title>
 
-<para>RPM packages of Nix can be downloaded from <link
-xlink:href="http://nixos.org/" />.  These RPMs should work for most
-fairly recent releases of SuSE and Red Hat Linux.  They have been
-known to work work on SuSE Linux 8.1 and 9.0, and Red Hat 9.0.  In
-fact, it should work on any RPM-based Linux distribution based on
-<literal>glibc</literal> 2.3 or later.</para>
-
-<para>Once downloaded, the RPMs can be installed or upgraded using
-<command>rpm -U</command>.  For example,
+<para>RPM and Deb packages of Nix for a number of different versions
+of Fedora, openSUSE, Debian and Ubuntu can be downloaded from <link
+xlink:href="http://nixos.org/" />.  Once downloaded, the RPMs can be
+installed or upgraded using <command>rpm -U</command>.  For example,
 
 <screen>
-$ rpm -U nix-0.5pre664-1.i386.rpm</screen>
+$ rpm -U nix-0.13pre18104-1.i386.rpm</screen>
+
+Likewise, for a Deb package:
+
+<screen>
+$ dpkg -i nix_0.13pre18104-1_amd64.deb</screen>
 
 </para>
 
-<para>The RPMs install into the directory <filename>/nix</filename>.
-Nix can be uninstalled using <command>rpm -e nix</command>.  After
-this it will be necessary to manually remove the Nix store and other
-auxiliary data:
+<para>Nix can be uninstalled using <command>rpm -e nix</command> or
+<command>dpkg -r nix</command>.  After this you should manually remove
+the Nix store and other auxiliary data, if desired:
 
 <screen>
 $ rm -rf /nix/store
@@ -191,6 +192,7 @@ $ rm -rf /nix/var</screen>
 </section>
 
 
+<!-- TODO: should be updated
 <section><title>Upgrading Nix through Nix</title>
 
 <para>You can install the latest stable version of Nix through Nix
@@ -203,6 +205,7 @@ installation</link> by clicking on the package links at <link
 xlink:href="http://nixos.org/releases/full-index-nix.html" />.</para>
 
 </section>
+-->
 
 
 <section><title>Security</title>

doc/manual/introduction.xml

@@ -320,7 +320,7 @@ overview of NixOS is given in the HotOS XI paper <citetitle
 xlink:href="http://www.st.ewi.tudelft.nl/~dolstra/pubs/hotos-final.pdf">Purely
 Functional System Configuration Management</citetitle>.  The Nix
 homepage has <link
-xlink:href="http://nix.cs.uu.nl/docs/papers.html">an up-to-date list
+xlink:href="http://nixos.org/docs/papers.html">an up-to-date list
 of Nix-related papers</link>.</para>
 
 <para>Nix is the subject of Eelco Dolstra’s PhD thesis <citetitle

doc/manual/manual.xml

@@ -17,6 +17,7 @@
         <orgname>Delft University of Technology</orgname>
         <orgdiv>Department of Software Technology</orgdiv>
       </affiliation>
+      <contrib>Author</contrib>
     </author>
 
     <copyright>
@@ -25,10 +26,11 @@
       <year>2006</year>
       <year>2007</year>
       <year>2008</year>
+      <year>2009</year>
       <holder>Eelco Dolstra</holder>
     </copyright>
 
-    <date>November 2008</date>
+    <date>September 2009</date>
     
   </info>
 
@@ -49,68 +51,29 @@
     
     <section>
       <title>Main commands</title>
-      <section xml:id="sec-nix-env">
-        <title>nix-env</title>
-        <xi:include href="nix-env.xml" />
-      </section>
-      <section xml:id="sec-nix-instantiate">
-        <title>nix-instantiate</title>
-        <xi:include href="nix-instantiate.xml" />
-      </section>
-      <section xml:id="sec-nix-store">
-        <title>nix-store</title>
-        <xi:include href="nix-store.xml" />
-      </section>
+      <xi:include href="nix-env.xml" />
+      <xi:include href="nix-instantiate.xml" />
+      <xi:include href="nix-store.xml" />
     </section>
     
     <section>
       <title>Utilities</title>
-      <section xml:id="sec-nix-build">
-        <title>nix-build</title>
-        <xi:include href="nix-build.xml" />
-      </section>
-      <section xml:id="sec-nix-channel">
-        <title>nix-channel</title>
-        <xi:include href="nix-channel.xml" />
-      </section>
-      <section xml:id="sec-nix-collect-garbage">
-        <title>nix-collect-garbage</title>
-        <xi:include href="nix-collect-garbage.xml" />
-      </section>
-      <section xml:id="sec-nix-copy-closure">
-        <title>nix-copy-closure</title>
-        <xi:include href="nix-copy-closure.xml" />
-      </section>
-      <section xml:id="sec-nix-hash">
-        <title>nix-hash</title>
-        <xi:include href="nix-hash.xml" />
-      </section>
-      <section xml:id="sec-nix-install-package">
-        <title>nix-install-package</title>
-        <xi:include href="nix-install-package.xml" />
-      </section>
-      <section xml:id="sec-nix-prefetch-url">
-        <title>nix-prefetch-url</title>
-        <xi:include href="nix-prefetch-url.xml" />
-      </section>
-      <section xml:id="sec-nix-pull">
-        <title>nix-pull</title>
-        <xi:include href="nix-pull.xml" />
-      </section>
-      <section xml:id="sec-nix-push">
-        <title>nix-push</title>
-        <xi:include href="nix-push.xml" />
-      </section>
-      <section xml:id="sec-nix-worker">
-        <title>nix-worker</title>
-        <xi:include href="nix-worker.xml" />
-      </section>
+      <xi:include href="nix-build.xml" />
+      <xi:include href="nix-channel.xml" />
+      <xi:include href="nix-collect-garbage.xml" />
+      <xi:include href="nix-copy-closure.xml" />
+      <xi:include href="nix-hash.xml" />
+      <xi:include href="nix-install-package.xml" />
+      <xi:include href="nix-prefetch-url.xml" />
+      <xi:include href="nix-pull.xml" />
+      <xi:include href="nix-push.xml" />
+      <xi:include href="nix-worker.xml" />
     </section>
-    
+
   </appendix>
 
   <xi:include href="troubleshooting.xml" />
-  <xi:include href="bugs.xml" />
+  <!-- <xi:include href="bugs.xml" /> -->
   <xi:include href="glossary.xml" />
 
   <appendix>

doc/manual/nix-build.xml

@@ -1,6 +1,7 @@
 <refentry xmlns="http://docbook.org/ns/docbook"
           xmlns:xlink="http://www.w3.org/1999/xlink"
-          xmlns:xi="http://www.w3.org/2001/XInclude">
+          xmlns:xi="http://www.w3.org/2001/XInclude"
+          xml:id="sec-nix-build">
 
 <refmeta>
   <refentrytitle>nix-build</refentrytitle>

doc/manual/nix-channel.xml

@@ -1,6 +1,7 @@
 <refentry xmlns="http://docbook.org/ns/docbook"
           xmlns:xlink="http://www.w3.org/1999/xlink"
-          xmlns:xi="http://www.w3.org/2001/XInclude">
+          xmlns:xi="http://www.w3.org/2001/XInclude"
+          xml:id="sec-nix-channel">
   
 <refmeta>
   <refentrytitle>nix-channel</refentrytitle>

doc/manual/nix-collect-garbage.xml

@@ -1,6 +1,7 @@
 <refentry xmlns="http://docbook.org/ns/docbook"
           xmlns:xlink="http://www.w3.org/1999/xlink"
-          xmlns:xi="http://www.w3.org/2001/XInclude">
+          xmlns:xi="http://www.w3.org/2001/XInclude"
+          xml:id="sec-nix-collect-garbage">
   
 <refmeta>
   <refentrytitle>nix-collect-garbage</refentrytitle>

doc/manual/nix-copy-closure.xml

@@ -1,6 +1,7 @@
 <refentry xmlns="http://docbook.org/ns/docbook"
           xmlns:xlink="http://www.w3.org/1999/xlink"
-          xmlns:xi="http://www.w3.org/2001/XInclude">
+          xmlns:xi="http://www.w3.org/2001/XInclude"
+          xml:id="sec-nix-copy-closure">
 
 <refmeta>
   <refentrytitle>nix-copy-closure</refentrytitle>

doc/manual/nix-env.xml

@@ -1,6 +1,7 @@
 <refentry xmlns="http://docbook.org/ns/docbook"
           xmlns:xlink="http://www.w3.org/1999/xlink"
-          xmlns:xi="http://www.w3.org/2001/XInclude">
+          xmlns:xi="http://www.w3.org/2001/XInclude"
+          xml:id="sec-nix-env">
   
 <refmeta>
   <refentrytitle>nix-env</refentrytitle>

doc/manual/nix-hash.xml

@@ -1,6 +1,7 @@
 <refentry xmlns="http://docbook.org/ns/docbook"
           xmlns:xlink="http://www.w3.org/1999/xlink"
-          xmlns:xi="http://www.w3.org/2001/XInclude">
+          xmlns:xi="http://www.w3.org/2001/XInclude"
+          xml:id="sec-nix-hash">
   
 <refmeta>
   <refentrytitle>nix-hash</refentrytitle>

doc/manual/nix-install-package.xml

@@ -1,6 +1,7 @@
 <refentry xmlns="http://docbook.org/ns/docbook"
           xmlns:xlink="http://www.w3.org/1999/xlink"
-          xmlns:xi="http://www.w3.org/2001/XInclude">
+          xmlns:xi="http://www.w3.org/2001/XInclude"
+          xml:id="sec-nix-install-package">
   
 <refmeta>
   <refentrytitle>nix-install-package</refentrytitle>

doc/manual/nix-instantiate.xml

@@ -1,6 +1,7 @@
 <refentry xmlns="http://docbook.org/ns/docbook"
           xmlns:xlink="http://www.w3.org/1999/xlink"
-          xmlns:xi="http://www.w3.org/2001/XInclude">
+          xmlns:xi="http://www.w3.org/2001/XInclude"
+          xml:id="sec-nix-instantiate">
   
 <refmeta>
   <refentrytitle>nix-instantiate</refentrytitle>

doc/manual/nix-lang-ref.xml

@@ -178,100 +178,5 @@
     </productionset>
     
   </sect1>
-  
-
-
-  <sect1>
-    <title>Semantics</title>
-
-
-    
-    <sect2>
-      <title>Built-in functions</title>
-
-      <para>
-        The Nix language provides the following built-in function
-        (<quote>primops</quote>):
-      </para>
-
-      <variablelist>
-
-        <varlistentry>
-          <term><function>import</function>
-          <replaceable>e</replaceable></term>
-          <listitem>
-            <para>
-              Evaluates the expression <replaceable>e</replaceable>,
-              which must yield a path value.  The Nix expression
-              stored at this path in the file system is then read,
-              parsed, and evaluated.  Returns the result of the
-              evaluation of the Nix expression just read.
-            </para>
-
-            <para>
-              Example: <literal>import ./foo.nix</literal> evaluates
-              the expression stored in <filename>foo.nix</filename>
-              (in the directory containing the expression in which the
-              <function>import</function> occurs).
-            </para>
-          </listitem>
-        </varlistentry>
-
-        <varlistentry>
-          <term><function>derivation</function>
-          <replaceable>e</replaceable></term>
-          <listitem>
-            <para>
-              Evaluates the expression <replaceable>e</replaceable>,
-              which must yield an attribute set.  [...]
-            </para>
-          </listitem>
-        </varlistentry>
-
-        <varlistentry>
-          <term><function>baseNameOf</function>
-          <replaceable>e</replaceable></term>
-          <listitem>
-            <para>
-              Evaluates the expression <replaceable>e</replaceable>,
-              which must yield a string value, and returns a string
-              representing its <emphasis>base name</emphasis>.  This
-              is the substring following the last path separator
-              (<literal>/</literal>).
-            </para>
-
-            <para>
-              Example: <literal>baseNameOf "/foo/bar"</literal>
-              returns <literal>"bar"</literal>, and
-              <literal>baseNameOf "/foo/bar/"</literal> returns
-              <literal>""</literal>.
-            </para>
-          </listitem>
-        </varlistentry>
-
-        <varlistentry>
-          <term><function>toString</function>
-          <replaceable>e</replaceable></term>
-          <listitem>
-            <para>
-              Evaluates the expression <replaceable>e</replaceable>
-              and coerces it into a string, if possible.  Only
-              strings, paths, and URIs can be so coerced.
-            </para>
-
-            <para>
-              Example: <literal>toString
-              http://www.cs.uu.nl/</literal> returns
-              <literal>"http://www.cs.uu.nl/"</literal>.
-            </para>
-          </listitem>
-        </varlistentry>
-            
-      </variablelist>
-
-    </sect2>
-
-  </sect1>
-  
 
 </appendix>

doc/manual/nix-prefetch-url.xml

@@ -1,6 +1,7 @@
 <refentry xmlns="http://docbook.org/ns/docbook"
           xmlns:xlink="http://www.w3.org/1999/xlink"
-          xmlns:xi="http://www.w3.org/2001/XInclude">
+          xmlns:xi="http://www.w3.org/2001/XInclude"
+          xml:id="sec-nix-prefetch-url">
   
 <refmeta>
   <refentrytitle>nix-prefetch-url</refentrytitle>

doc/manual/nix-pull.xml

@@ -1,6 +1,7 @@
 <refentry xmlns="http://docbook.org/ns/docbook"
           xmlns:xlink="http://www.w3.org/1999/xlink"
-          xmlns:xi="http://www.w3.org/2001/XInclude">
+          xmlns:xi="http://www.w3.org/2001/XInclude"
+          xml:id="sec-nix-pull">
 
 <refmeta>
   <refentrytitle>nix-pull</refentrytitle>

doc/manual/nix-push.xml

@@ -1,6 +1,7 @@
 <refentry xmlns="http://docbook.org/ns/docbook"
           xmlns:xlink="http://www.w3.org/1999/xlink"
-          xmlns:xi="http://www.w3.org/2001/XInclude">
+          xmlns:xi="http://www.w3.org/2001/XInclude"
+          xml:id="sec-nix-push">
 
 <refmeta>
   <refentrytitle>nix-push</refentrytitle>

doc/manual/nix-store.xml

@@ -1,6 +1,7 @@
 <refentry xmlns="http://docbook.org/ns/docbook"
           xmlns:xlink="http://www.w3.org/1999/xlink"
-          xmlns:xi="http://www.w3.org/2001/XInclude">
+          xmlns:xi="http://www.w3.org/2001/XInclude"
+          xml:id="sec-nix-store">
 
 <refmeta>
   <refentrytitle>nix-store</refentrytitle>
@@ -212,8 +213,6 @@ linkend="sec-nix-build"><command>nix-build</command></link> does.</para>
   </group>
   <arg><option>--max-freed</option> <replaceable>bytes</replaceable></arg>
   <arg><option>--max-links</option> <replaceable>nrlinks</replaceable></arg>
-  <arg><option>--max-atime</option> <replaceable>atime</replaceable></arg>
-  <arg><option>--use-atime</option></arg>
 </cmdsynopsis>
 
 </refsection>
@@ -291,42 +290,6 @@ options control what gets deleted and in what order:
     
   </varlistentry>
 
-  <varlistentry><term><option>--max-atime</option> <replaceable>atime</replaceable></term>
-  
-    <listitem><para>Only delete a store path if its last-accessed time
-    is less than <replaceable>atime</replaceable>.  This allows you to
-    garbage-collect only packages that haven’t been used recently.
-    The time is expressed as the number of seconds in the Unix epoch,
-    i.e., since 1970-01-01 00:00:00 UTC.  An easy way to convert to
-    this format is <literal>date +%s -d "<replaceable>date
-    specification</replaceable>"</literal>.</para>
-
-    <para>For directories, the last-accessed time is the highest
-    last-accessed time of any regular file in the directory (or in any
-    of its subdirectories).  That is, the <literal>atime</literal>
-    field maintained by the filesystem is ignored for directories.
-    This is because operations such as rebuilding the
-    <command>locate</command> database tend to update the
-    <literal>atime</literal> values of all directories, so they’re not
-    a useful indicator of whether a package was recently used.</para>
-
-    <para>Note that <command>nix-store --optimise</command> reads all
-    regular files in the Nix store, and so causes all last-accessed
-    times to be set to the present time.  This makes
-    <option>--max-atime</option> ineffective (for a while at
-    least).</para></listitem>
-    
-  </varlistentry>
-
-  <varlistentry><term><option>--use-atime</option></term>
-
-    <listitem><para>Delete store paths in order of ascending
-    last-accessed time.  This is useful in conjunction with the other
-    options to delete only the least recently used
-    packages.</para></listitem>
-
-  </varlistentry>
-  
 </variablelist>
 
 </para>
@@ -357,13 +320,6 @@ deleting `/nix/store/kq82idx6g0nyzsp2s14gfsc38npai7lf-cairo-1.0.4.tar.gz.drv'
 
 </para>
 
-<para>To delete unreachable paths not accessed in the last two months:
-
-<screen>
-$ nix-store --gc -v --max-atime $(date +%s -d "2 months ago")</screen>
-
-</para>
-
 <para>To delete at least 100 MiBs of unreachable paths:
 
 <screen>
@@ -448,6 +404,7 @@ error: cannot delete path `/nix/store/zq0h41l75vlb4z45kzgjjmsjxvcv1qk7-mesa-6.4'
     <arg choice='plain'><option>--tree</option></arg>
     <arg choice='plain'><option>--binding</option> <replaceable>name</replaceable></arg>
     <arg choice='plain'><option>--hash</option></arg>
+    <arg choice='plain'><option>--roots</option></arg>
   </group>
   <arg><option>--use-output</option></arg>
   <arg><option>-u</option></arg>
@@ -630,12 +587,20 @@ query is applied to the target of the symlink.</para>
   <varlistentry><term><option>--hash</option></term>
   
     <listitem><para>Prints the SHA-256 hash of the contents of the
-    store path <replaceable>paths</replaceable>.  Since the hash is
+    store paths <replaceable>paths</replaceable>.  Since the hash is
     stored in the Nix database, this is a fast
     operation.</para></listitem>
 
   </varlistentry>
 
+  <varlistentry><term><option>--roots</option></term>
+  
+    <listitem><para>Prints the garbage collector roots that point,
+    directly or indirectly, at the store paths
+    <replaceable>paths</replaceable>.</para></listitem>
+
+  </varlistentry>
+
 </variablelist>
 
 </refsection>
@@ -713,6 +678,18 @@ $ gv graph.ps</screen>
 
 </para>
 
+<para>Show every garbage collector root that points to a store path
+that depends on <command>svn</command>:
+
+<screen>
+$ nix-store -q --roots $(which svn)
+/nix/var/nix/profiles/default-81-link
+/nix/var/nix/profiles/default-82-link
+/nix/var/nix/profiles/per-user/eelco/profile-97-link
+</screen>
+
+</para>
+
 </refsection>
 
 

doc/manual/nix-worker.xml

@@ -1,6 +1,7 @@
 <refentry xmlns="http://docbook.org/ns/docbook"
           xmlns:xlink="http://www.w3.org/1999/xlink"
-          xmlns:xi="http://www.w3.org/2001/XInclude">
+          xmlns:xi="http://www.w3.org/2001/XInclude"
+          xml:id="sec-nix-worker">
 
 <refmeta>
   <refentrytitle>nix-worker</refentrytitle>

doc/manual/opt-common-syn.xml

@@ -24,6 +24,7 @@
 <arg><option>--fallback</option></arg>
 <arg><option>--readonly-mode</option></arg>
 <arg><option>--log-type</option> <replaceable>type</replaceable></arg>
+<arg><option>--show-trace</option></arg>
 <sbr />
 
 </nop>

doc/manual/opt-common.xml

@@ -251,14 +251,14 @@
 
 <programlisting>
 { # The system (e.g., `i686-linux') for which to build the packages.
-  system ? __currentSystem
+  system ? builtins.currentSystem
   <replaceable>...</replaceable>
 }: <replaceable>...</replaceable></programlisting>
 
   So if you call this Nix expression (e.g., when you do
   <literal>nix-env -i <replaceable>pkgname</replaceable></literal>),
   the function will be called automatically using the value <link
-  linkend='builtin-currentSystem'><literal>__currentSystem</literal></link>
+  linkend='builtin-currentSystem'><literal>builtins.currentSystem</literal></link>
   for the <literal>system</literal> argument.  You can override this
   using <option>--arg</option>, e.g., <literal>nix-env -i
   <replaceable>pkgname</replaceable> --arg system
@@ -305,6 +305,14 @@
 </varlistentry>
 
 
+<varlistentry><term><option>--show-trace</option></term>
+  
+  <listitem><para>Causes Nix to print out a stack trace in case of Nix
+  expression evaluation errors.</para></listitem>
+  
+</varlistentry>
+
+
 </variablelist>
 
 

doc/manual/package-management.xml

@@ -331,7 +331,7 @@ default profile, respectively.  If the profile doesn’t exist, it will
 be created automatically.  You should be careful about storing a
 profile in another location than the <filename>profiles</filename>
 directory, since otherwise it might not be used as a root of the
-garbage collector (see section <xref linkend='sec-garbage-collection'
+garbage collector (see <xref linkend='sec-garbage-collection'
 />).</para>
 
 <para>All <command>nix-env</command> operations work on the profile
@@ -507,19 +507,16 @@ click on it, and it will be installed with all the necessary
 dependencies.</para>
 
 <para>For instance, you can go to <link
-xlink:href="http://nixos.org/releases/nixpkgs/nixpkgs-unstable/" /> —
-or to any older release of Nix Packages — and click on any link for
-the individual packages for your platform (say, <link
-xlink:href='http://nix.cs.uu.nl/dist/nix/nixpkgs-0.10pre6622/pkgs/subversion-1.4.0-i686-linux.nixpkg'><literal>subversion-1.4.0</literal>
-for <literal>i686-linux</literal></link>).  The first time you do
-this, your browser will ask what to do with
-<literal>application/nix-package</literal> files.  You should open
-them with <filename>/nix/bin/nix-install-package</filename>.  This
-will open a window that asks you to confirm that you want to install
-the package.  When you answer <literal>Y</literal>, the package and
-all its dependencies will be installed.  This is a binary deployment
-mechanism — you get packages pre-compiled for the selected platform
-type.</para>
+xlink:href="http://hydra.nixos.org/jobset/nixpkgs/trunk/channel/latest"
+/> and click on any link for the individual packages for your
+platform.  The first time you do this, your browser will ask what to
+do with <literal>application/nix-package</literal> files.  You should
+open them with <filename>/nix/bin/nix-install-package</filename>.
+This will open a window that asks you to confirm that you want to
+install the package.  When you answer <literal>Y</literal>, the
+package and all its dependencies will be installed.  This is a binary
+deployment mechanism — you get packages pre-compiled for the selected
+platform type.</para>
 
 <para>You can also install <literal>application/nix-package</literal>
 files from the command line directly.  See <xref

doc/manual/quick-start.xml

@@ -1,5 +1,6 @@
 <chapter xmlns="http://docbook.org/ns/docbook"
-         xmlns:xlink="http://www.w3.org/1999/xlink">
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="chap-quick-start">
 
 <title>Quick Start</title>
 
@@ -10,9 +11,9 @@ to the following chapters.</para>
 
 <orderedlist>
 
-<listitem><para>Download a source tarball or RPM from <link
-xlink:href='http://nixos.org/'/>.  Build source
-distributions using the regular sequence:
+<listitem><para>Download a source tarball, RPM or Deb from <link
+xlink:href='http://nixos.org/'/>.  Build source distributions using
+the regular sequence:
         
 <screen>
 $ tar xvfj nix-<replaceable>version</replaceable>.tar.bz2
@@ -20,13 +21,21 @@ $ ./configure
 $ make
 $ make install <lineannotation>(as root)</lineannotation></screen>
 
-This will install Nix in <filename>/nix</filename>.  You shouldn't
-change the prefix if at all possible since that will make it
-impossible to use pre-built binaries from the Nixpkgs channel and
-other channels.  Alternatively, you could grab an RPM if you're on an
-RPM-based system.  You should also add
-<filename>/nix/etc/profile.d/nix.sh</filename> to your
-<filename>~/.bashrc</filename> (or some other login
+This will install the Nix binaries in <filename>/usr/local</filename>
+and keep the Nix store and other state in <filename>/nix</filename>.
+You can change the former by specifying
+<option>--prefix=<replaceable>path</replaceable></option>.  The
+location of the store can be changed using
+<option>--with-store-dir=<replaceable>path</replaceable></option>.
+However, you shouldn't change the store location, if at all possible,
+since that will make it impossible to use pre-built binaries from the
+Nixpkgs channel and other channels.  The location of the state can be
+changed using
+<option>--localstatedir=<replaceable>path</replaceable>.</option></para></listitem>
+
+<listitem><para>You should add
+<filename><replaceable>prefix</replaceable>/etc/profile.d/nix.sh</filename>
+to your <filename>~/.bashrc</filename> (or some other login
 file).</para></listitem>
 
 <listitem><para>Subscribe to the Nix Packages channel.
@@ -99,7 +108,7 @@ numbers).</para></listitem>
 
 <listitem><para>You can also install specific packages directly from
 your web browser.  For instance, you can go to <link
-xlink:href="http://nix.cs.uu.nl/dist/nix/nixpkgs-unstable-latest/" />
+xlink:href="http://hydra.nixos.org/jobset/nixpkgs/trunk/channel/latest" />
 and click on any link for the individual packages for your platform.
 Associate <literal>application/nix-package</literal> with the program
 <filename>/nix/bin/nix-install-package</filename>.  A window should

doc/manual/release-notes.xml

@@ -6,6 +6,151 @@
 
 
 
+<!--==================================================================-->
+
+<section xml:id="ssec-relnotes-0.14"><title>Release 0.14 (TBA)</title>
+
+<para>This release has the following improvements:</para>
+
+<itemizedlist>
+
+  <listitem>
+    <para>The garbage collector now starts deleting garbage much
+    faster than before.  It no longer determines liveness of all paths
+    in the store, but does so on demand.</para>
+  </listitem>
+
+  <listitem>
+    <para>Added a new operation, <command>nix-store --query
+    --roots</command>, that shows the garbage collector roots that
+    directly or indirectly point to the given store paths.</para>
+  </listitem>
+
+  <listitem>
+    <para>Removed support for converting Berkeley DB-based Nix
+    databases to the new schema.</para>
+  </listitem>
+
+  <listitem>
+    <para>Removed the <option>--use-atime</option> and
+    <option>--max-atime</option> garbage collector options.  They were
+    not very useful in practice.</para>
+  </listitem>
+
+  <listitem>
+    <para>A few bug fixes.</para>
+  </listitem>
+
+</itemizedlist>
+
+</section>
+
+
+<!--==================================================================-->
+
+<section xml:id="ssec-relnotes-0.13"><title>Release 0.13 (November 5,
+2009)</title>
+
+<para>This is primarily a bug fix release.  It has some new
+features:</para>
+
+<itemizedlist>
+
+  <listitem>
+    <para>Syntactic sugar for writing nested attribute sets.  Instead of
+
+<programlisting>
+{
+  foo = {
+    bar = 123;
+    xyzzy = true;
+  };
+  a = { b = { c = "d"; }; };
+}
+</programlisting>
+
+    you can write
+
+<programlisting>
+{
+  foo.bar = 123;
+  foo.xyzzy = true;
+  a.b.c = "d";
+}
+</programlisting>
+
+    This is useful, for instance, in NixOS configuration files.</para>
+    
+  </listitem>
+
+  <listitem>
+    <para>Support for Nix channels generated by Hydra, the Nix-based
+    continuous build system.  (Hydra generates NAR archives on the
+    fly, so the size and hash of these archives isn’t known in
+    advance.)</para>
+  </listitem>
+
+  <listitem>
+    <para>Support <literal>i686-linux</literal> builds directly on
+    <literal>x86_64-linux</literal> Nix installations.  This is
+    implemented using the <function>personality()</function> syscall,
+    which causes <command>uname</command> to return
+    <literal>i686</literal> in child processes.</para>
+  </listitem>
+  
+  <listitem>
+    <para>Various improvements to the <literal>chroot</literal>
+    support.  Building in a <literal>chroot</literal> works quite well
+    now.</para>
+  </listitem>
+
+  <listitem>
+    <para>Nix no longer blocks if it tries to build a path and another
+    process is already building the same path.  Instead it tries to
+    build another buildable path first.  This improves
+    parallelism.</para>
+  </listitem>
+
+  <listitem>
+    <para>Support for large (> 4 GiB) files in NAR archives.</para>
+  </listitem>
+    
+  <listitem>
+    <para>Various (performance) improvements to the remote build
+    mechanism.</para>
+  </listitem>
+    
+  <listitem>
+    <para>New primops: <varname>builtins.addErrorContext</varname> (to
+    add a string to stack traces — useful for debugging),
+    <varname>builtins.isBool</varname>,
+    <varname>builtins.isString</varname>,
+    <varname>builtins.isInt</varname>,
+    <varname>builtins.intersectAttrs</varname>.</para>
+  </listitem>
+
+  <listitem>
+    <para>OpenSolaris support (Sander van der Burg).</para>
+  </listitem>
+
+  <listitem>
+    <para>Stack traces are no longer displayed unless the
+    <option>--show-trace</option> option is used.</para>
+  </listitem>
+
+  <listitem>
+    <para>The scoping rules for <literal>inherit
+    (<replaceable>e</replaceable>) ...</literal> in recursive
+    attribute sets have changed.  The expression
+    <replaceable>e</replaceable> can now refer to the attributes
+    defined in the containing set.</para>
+  </listitem>
+
+</itemizedlist>
+
+</section>
+
+
 <!--==================================================================-->
 
 <section xml:id="ssec-relnotes-0.12"><title>Release 0.12 (November 20,

doc/manual/writing-nix-expressions.xml

@@ -1106,7 +1106,7 @@ used in the Nix expression for Subversion.</para>
     incompatibility might occur.</para>
   </callout>
 
-  <callout arearefs='ex-subversion-nix-co-2'>
+  <callout arearefs='ex-subversion-nix-co-3'>
     <para>This assertion says that in order for Subversion to have SSL
     support (so that it can access <literal>https</literal> URLs), an
     OpenSSL library must be passed.  Additionally, it says that
@@ -1432,7 +1432,7 @@ command-line argument.  See <xref linkend='sec-standard-environment'
   inputs.</para></listitem>
 
   <listitem><para>After the build, Nix sets the last-modified
-  timestamp on all files in the build result to 0 (00:00:00 1/1/1970
+  timestamp on all files in the build result to 1 (00:00:01 1/1/1970
   UTC), sets the group to the default group, and sets the mode of the
   file to 0444 or 0555 (i.e., read-only, with execute permission
   enabled if the file was originally executable).  Note that possible

externals/Makefile.am

@@ -1,46 +1,3 @@
-# Berkeley DB
-
-DB = db-4.5.20
-
-if OLD_DB_COMPAT
-
-$(DB).tar.gz:
-	@echo "Nix requires Berkeley DB to build."
-	@echo "Please download version 4.5.20 from"
-	@echo "  http://download-east.oracle.com/berkeley-db/db-4.5.20.tar.gz"
-	@echo "and place it in the externals/ directory."
-	false
-
-$(DB): $(DB).tar.gz
-	gunzip < $(srcdir)/$(DB).tar.gz | tar xvf -
-	(cd $(DB) && $(patch) -p1) < $(srcdir)/bdb-cygwin.patch
-
-have-db:
-	$(MAKE) $(DB)
-	touch have-db
-
-if HAVE_BDB
-build-db:
-else
-build-db: have-db
-	(pfx=`pwd` && \
-	cd $(DB)/build_unix && \
-	CC="$(CC)" CXX="$(CXX)" CFLAGS="$(CFLAGS)" CXXFLAGS="$(CXXFLAGS)" \
-	 ../dist/configure --prefix=$$pfx/inst-bdb \
-	 --enable-cxx --disable-shared --disable-cryptography \
-         --disable-replication --disable-verify && \
-	$(MAKE) && \
-	$(MAKE) install_include install_lib)
-	touch build-db
-endif
-
-else
-
-build-db:
-
-endif
-
-
 # CWI ATerm
 
 ATERM = aterm-2.4.2-fixes-r2
@@ -48,7 +5,7 @@ ATERM = aterm-2.4.2-fixes-r2
 $(ATERM).tar.bz2:
 	@echo "Nix requires the CWI ATerm library to build."
 	@echo "Please download version 2.4.2-fixes-r2 from"
-	@echo "  http://losser.st-lab.cs.uu.nl/~eelco/dist/aterm-2.4.2-fixes-r2.tar.bz2"
+	@echo "  http://nixos.org/tarballs/aterm-2.4.2-fixes-r2.tar.bz2"
 	@echo "and place it in the externals/ directory."
 	false
 
@@ -107,11 +64,10 @@ install:
 endif
 
 
-all: build-db build-aterm build-bzip2
+all: build-aterm build-bzip2
 
-EXTRA_DIST = $(DB).tar.gz $(ATERM).tar.bz2 $(BZIP2).tar.gz \
-  bdb-cygwin.patch
+EXTRA_DIST = $(ATERM).tar.bz2 $(BZIP2).tar.gz
 
 ext-clean:
-	$(RM) -f have-db build-db have-aterm build-aterm have-bzip2 build-bzip2
-	$(RM) -rf $(DB) $(ATERM) $(BZIP2)
+	$(RM) -f have-aterm build-aterm have-bzip2 build-bzip2
+	$(RM) -rf $(ATERM) $(BZIP2)

externals/bdb-cygwin.patch

@@ -1,22 +0,0 @@
-diff -rc db-4.5.20-orig/os/os_flock.c db-4.5.20/os/os_flock.c
-*** db-4.5.20-orig/os/os_flock.c	2006-10-13 12:36:12.000000000 +0200
---- db-4.5.20/os/os_flock.c	2006-10-13 12:40:11.000000000 +0200
-***************
-*** 30,35 ****
---- 30,44 ----
-  
-  	DB_ASSERT(dbenv, F_ISSET(fhp, DB_FH_OPENED) && fhp->fd != -1);
-  
-+ #ifdef __CYGWIN__
-+ 	/*
-+ 	 * Windows file locking interferes with read/write operations, so we
-+ 	 * map the ranges to an area past the end of the file.
-+ 	 */
-+ 	DB_ASSERT(dbenv, offset < (off_t) 1 << 62);
-+ 	offset += (off_t) 1 << 62;
-+ #endif
-+ 
-  	fl.l_start = offset;
-  	fl.l_len = 1;
-  	fl.l_type = acquire ? F_WRLCK : F_UNLCK;
-Only in db-4.5.20/os: os_flock.c~

misc/emacs/nix-mode.el

@@ -76,10 +76,10 @@ The hook `nix-mode-hook' is run when Nix mode is started.
     ("\\<baseNameOf\\>" . font-lock-builtin-face)
     ("\\<toString\\>" . font-lock-builtin-face)
     ("\\<isNull\\>" . font-lock-builtin-face)
-    ("\\<\\([a-zA-Z_][a-zA-Z0-9_']*\\)[ \t]*="
-     (1 font-lock-variable-name-face nil nil))
     ("[a-zA-Z][a-zA-Z0-9\\+-\\.]*:[a-zA-Z0-9%/\\?:@&=\\+\\$,_\\.!~\\*'-]+"
      . font-lock-constant-face)
+    ("\\<\\([a-zA-Z_][a-zA-Z0-9_'\.]*\\)[ \t]*="
+     (1 font-lock-variable-name-face nil nil))
     ("[a-zA-Z0-9._\\+-]*\\(/[a-zA-Z0-9._\\+-]+\\)+"
      . font-lock-constant-face)
     ))

misc/vim/syntax/nix.vim

@@ -21,12 +21,14 @@ syn match nixFuncArg "\zs\w\+\ze\s*:"
 syn region nixStringParam start=+\${+ end=+}+
 syn region nixMultiLineComment start=+/\*+ skip=+\\"+ end=+\*/+
 syn match  nixEndOfLineComment "#.*$"
-syn region nixString      start=+"+ skip=+\\"+ end=+"+ contains=nixStringParam
+syn region nixStringIndented start=+''+ skip=+'''\|''${\|"+ end=+''+ contains=nixStringParam
+syn region nixString         start=+"+ skip=+\\"+ end=+"+ contains=nixStringParam
 
 hi def link nixKeyword       Keyword
 hi def link nixConditional   Conditional
 hi def link nixBrace         Special
 hi def link nixString        String
+hi def link nixStringIndented String
 hi def link nixBuiltin       Special
 hi def link nixStringParam   Macro
 hi def link nixMultiLineComment Comment

nix.conf.example

@@ -154,21 +154,17 @@
 #build-chroot-dirs = /dev /dev/pts /proc
 
 
-### Option `system'
+### Option `build-cache-failure'
 #
-# This option specifies the canonical Nix system name of the current
-# installation, such as `i686-linux' or `powerpc-darwin'.  Nix can
-# only build derivations whose `system' attribute equals the value
-# specified here.  In general, it never makes sense to modify this
-# value from its default, since you can use it to `lie' about the
-# platform you are building on (e.g., perform a Mac OS build on a
-# Linux machine; the result would obviously be wrong).  It only makes
-# sense if the Nix binaries can run on multiple platforms, e.g.,
-# `universal binaries' that run on `powerpc-darwin' and `i686-darwin'.
-#
-# It defaults to the canonical Nix system name detected by `configure'
-# at build time.
+# If this option is enabled, Nix will do negative caching; that is, it
+# will remember failed builds, and won't attempt to try to build them
+# again if you ask for it.  Negative caching is disabled by default
+# because Nix cannot distinguish between permanent build errors (e.g.,
+# a syntax error in a source file) and transient build errors (e.g., a
+# full disk), as they both cause the builder to return a non-zero exit
+# code.  You can clear the cache by doing `rm -f
+# /nix/var/nix/db/failed/*'.
 #
 # Example:
-#   system = i686-darwin
-#system =
+#   build-cache-failure = true
+#build-cache-failure = false

release.nix

@@ -0,0 +1,209 @@
+{ nixpkgs ? ../nixpkgs }:
+
+let
+
+  jobs = rec {
+
+
+    tarball =
+      { nix ? {outPath = ./.; rev = 1234;}
+      , officialRelease ? false
+      }:
+
+      with import nixpkgs {};
+
+      releaseTools.sourceTarball {
+        name = "nix-tarball";
+        version = builtins.readFile ./version;
+        src = nix;
+        inherit officialRelease;
+
+        buildInputs =
+          [ curl bison flex2533 perl libxml2 libxslt w3m bzip2
+            tetex dblatex nukeReferences
+          ];
+
+        configureFlags = ''
+          --with-docbook-rng=${docbook5}/xml/rng/docbook
+          --with-docbook-xsl=${docbook5_xsl}/xml/xsl/docbook
+          --with-xml-flags=--nonet
+        '';
+
+        # Include the ATerm and Bzip2 tarballs in the distribution.
+        preConfigure = ''
+          stripHash ${aterm242fixes.src}
+          cp -pv ${aterm242fixes.src} externals/$strippedName
+
+          stripHash ${bzip2.src}
+          cp -pv ${bzip2.src} externals/$strippedName
+
+          # TeX needs a writable font cache.
+          export VARTEXFONTS=$TMPDIR/texfonts
+        '';
+
+        preDist = ''
+          make -C doc/manual install prefix=$out
+          
+          make -C doc/manual manual.pdf prefix=$out
+          cp doc/manual/manual.pdf $out/manual.pdf
+
+          # The PDF containes filenames of included graphics (see
+          # http://www.tug.org/pipermail/pdftex/2007-August/007290.html).
+          # This causes a retained dependency on dblatex, which Hydra
+          # doesn't like (the output of the tarball job is distributed
+          # to Windows and Macs, so there should be no Linux binaries
+          # in the closure).
+          nuke-refs $out/manual.pdf
+          
+          echo "doc manual $out/share/doc/nix/manual" >> $out/nix-support/hydra-build-products
+          echo "doc-pdf manual $out/manual.pdf" >> $out/nix-support/hydra-build-products
+          echo "doc release-notes $out/share/doc/nix/release-notes" >> $out/nix-support/hydra-build-products
+        '';
+      };
+
+
+    build =
+      { tarball ? jobs.tarball {}
+      , system ? "i686-linux"
+      }:
+
+      with import nixpkgs {inherit system;};
+
+      releaseTools.nixBuild {
+        name = "nix";
+        src = tarball;
+
+        buildInputs = [curl perl bzip2 openssl];
+
+        configureFlags = ''
+          --disable-init-state
+          --with-aterm=${aterm242fixes} --with-bzip2=${bzip2}
+        '';
+      };
+
+
+    /*
+    static =
+      { tarball ? jobs.tarball {}
+      , system ? "i686-linux"
+      }:
+
+      with import nixpkgs {inherit system;};
+
+      releaseTools.binaryTarball {
+        name = "nix-static-tarball";
+        src = tarball;
+
+        buildInputs = [curl perl bzip2];
+
+        configureFlags = ''
+          --disable-init-state
+          --with-aterm=${aterm242fixes} --with-bzip2=${bzip2}
+          --enable-static-nix
+        '';
+      };
+    */
+
+      
+    coverage =
+      { tarball ? jobs.tarball {}
+      }:
+
+      with import nixpkgs {};
+
+      releaseTools.coverageAnalysis {
+        name = "nix-build";
+        src = tarball;
+
+        buildInputs = [
+          curl perl bzip2 openssl
+          # These are for "make check" only:
+          graphviz libxml2 libxslt
+        ];
+
+        configureFlags = ''
+          --disable-init-state --disable-shared
+          --with-aterm=${aterm242fixes} --with-bzip2=${bzip2}
+        '';
+
+        lcovFilter = ["*/boost/*" "*-tab.*"];
+
+        # We call `dot', and even though we just use it to
+        # syntax-check generated dot files, it still requires some
+        # fonts.  So provide those.
+        FONTCONFIG_FILE = texFunctions.fontsConf;
+      };
+
+      
+    rpm_fedora5i386 = makeRPM_i686 (diskImages: diskImages.fedora5i386) 10;
+    rpm_fedora9i386 = makeRPM_i686 (diskImages: diskImages.fedora9i386) 20;
+    rpm_fedora9x86_64 = makeRPM_x86_64 (diskImages: diskImages.fedora9x86_64) 20;
+    rpm_fedora10i386 = makeRPM_i686 (diskImages: diskImages.fedora10i386) 30;
+    rpm_fedora10x86_64 = makeRPM_x86_64 (diskImages: diskImages.fedora10x86_64) 30;
+    rpm_fedora11i386 = makeRPM_i686 (diskImages: diskImages.fedora11i386) 40;
+    rpm_fedora11x86_64 = makeRPM_x86_64 (diskImages: diskImages.fedora11x86_64) 40;
+    rpm_fedora12i386 = makeRPM_i686 (diskImages: diskImages.fedora12i386) 50;
+    rpm_fedora12x86_64 = makeRPM_x86_64 (diskImages: diskImages.fedora12x86_64) 50;
+    rpm_opensuse103i386 = makeRPM_i686 (diskImages: diskImages.opensuse103i386) 40;
+    rpm_opensuse110i386 = makeRPM_i686 (diskImages: diskImages.opensuse110i386) 50;
+    rpm_opensuse110x86_64 = makeRPM_x86_64 (diskImages: diskImages.opensuse110x86_64) 50;
+
+    
+    deb_debian40i386 = makeDeb_i686 (diskImages: diskImages.debian40i386) 40;
+    deb_debian40x86_64 = makeDeb_x86_64 (diskImages: diskImages.debian40x86_64) 40;
+    deb_debian50i386 = makeDeb_i686 (diskImages: diskImages.debian50i386) 50;
+    deb_debian50x86_64 = makeDeb_x86_64 (diskImages: diskImages.debian50x86_64) 50;
+    deb_ubuntu804i386 = makeDeb_i686 (diskImages: diskImages.ubuntu804i386) 20;
+    deb_ubuntu804x86_64 = makeDeb_x86_64 (diskImages: diskImages.ubuntu804x86_64) 20;
+    deb_ubuntu810i386 = makeDeb_i686 (diskImages: diskImages.ubuntu810i386) 30;
+    deb_ubuntu810x86_64 = makeDeb_x86_64 (diskImages: diskImages.ubuntu810x86_64) 30;
+    deb_ubuntu904i386 = makeDeb_i686 (diskImages: diskImages.ubuntu904i386) 40;
+    deb_ubuntu904x86_64 = makeDeb_x86_64 (diskImages: diskImages.ubuntu904x86_64) 40;
+    deb_ubuntu910i386 = makeDeb_i686 (diskImages: diskImages.ubuntu910i386) 50;
+    deb_ubuntu910x86_64 = makeDeb_x86_64 (diskImages: diskImages.ubuntu910x86_64) 50;
+
+
+  };
+
+
+  makeRPM_i686 = makeRPM "i686-linux";
+  makeRPM_x86_64 = makeRPM "x86_64-linux";
+
+  makeRPM = 
+    system: diskImageFun: prio:
+    { tarball ? jobs.tarball {}
+    }:
+
+    with import nixpkgs {inherit system;};
+
+    releaseTools.rpmBuild rec {
+      name = "nix-rpm-${diskImage.name}";
+      src = tarball;
+      diskImage = diskImageFun vmTools.diskImages;
+      memSize = 1024;
+      meta = { schedulingPriority = toString prio; };
+    };
+
+
+  makeDeb_i686 = makeDeb "i686-linux";
+  makeDeb_x86_64 = makeDeb "x86_64-linux";
+  
+  makeDeb =
+    system: diskImageFun: prio:
+    { tarball ? jobs.tarball {}
+    }:
+
+    with import nixpkgs {inherit system;};
+
+    releaseTools.debBuild {
+      name = "nix-deb";
+      src = tarball;
+      diskImage = diskImageFun vmTools.diskImages;
+      memSize = 1024;
+      meta = { schedulingPriority = toString prio; };
+      configureFlags = "--sysconfdir=/etc";
+      debRequires = ["curl"];
+    };
+
+
+in jobs

scripts/build-remote.pl.in

@@ -3,6 +3,7 @@
 use strict;
 use Fcntl ':flock';
 use English '-no_match_vars';
+use IO::Handle;
 
 # General operation:
 #
@@ -23,16 +24,12 @@ use English '-no_match_vars';
 
 my $loadIncreased = 0;
 
-my $amWilling = shift @ARGV;
-my $localSystem = shift @ARGV;
-my $neededSystem = shift @ARGV;
-my $drvPath = shift @ARGV;
+my ($amWilling, $localSystem, $neededSystem, $drvPath, $maxSilentTime) = @ARGV;
+$maxSilentTime = 0 unless defined $maxSilentTime;
 
 sub sendReply {
     my $reply = shift;
-    open OUT, ">&3" or die;
-    print OUT "$reply\n";
-    close OUT;
+    print STDERR "# $reply\n";
 }
 
 sub decline {
@@ -47,30 +44,25 @@ mkdir $currentLoad, 0777 or die unless -d $currentLoad;
 my $conf = $ENV{"NIX_REMOTE_SYSTEMS"};
 decline if !defined $conf || ! -e $conf;
 
-# Decline if the local system can do the build.
-decline if $amWilling && ($localSystem eq $neededSystem);
-
-
-# Otherwise find a willing remote machine.
-my %machines;
-my %systemTypes;
-my %sshKeys;
-my %maxJobs;
-my %curJobs;
+my $canBuildLocally = $amWilling && ($localSystem eq $neededSystem);
 
 
 # Read the list of machines.
+my @machines;
 open CONF, "< $conf" or die;
 
 while (<CONF>) {
     chomp;
     s/\#.*$//g;
     next if /^\s*$/;
-    /^\s*(\S+)\s+(\S+)\s+(\S+)\s+(\d+)\s*$/ or die;
-    $machines{$1} = "";
-    $systemTypes{$1} = $2;
-    $sshKeys{$1} = $3;
-    $maxJobs{$1} = $4;
+    /^\s*(\S+)\s+(\S+)\s+(\S+)\s+(\d+)(\s+([0-9\.]+))?\s*$/ or die;
+    push @machines,
+        { hostName => $1
+        , systemTypes => [split(/,/, $2)]
+        , sshKeys => $3
+        , maxJobs => $4
+        , speedFactor => 1.0 * ($6 || 1)
+        };
 }
 
 close CONF;
@@ -82,35 +74,56 @@ open MAINLOCK, ">>$mainLock" or die;
 flock(MAINLOCK, LOCK_EX) or die;
 
 
-# Find a suitable system.
+sub openSlotLock {
+    my ($machine, $slot) = @_;
+    my $slotLockFn = "$currentLoad/" . (join '+', @{$machine->{systemTypes}}) . "-" . $machine->{hostName} . "-$slot";
+    my $slotLock = new IO::Handle;
+    open $slotLock, ">>$slotLockFn" or die;
+    return $slotLock;
+}
+    
+
+# Find all machine that can execute this build, i.e., that support
+# builds for the given platform and are not at their job limit.
 my $rightType = 0;
-my $machine;
-LOOP: foreach my $cur (keys %machines) {
-    if ($neededSystem eq $systemTypes{$cur}) {
+my @available = ();
+LOOP: foreach my $cur (@machines) {
+    if (grep { $neededSystem eq $_ } @{$cur->{systemTypes}}) {
         $rightType = 1;
 
-        # We have a machine of the right type.  Try to get a lock on
-        # one of the machine's lock files.
+        # We have a machine of the right type.  Determine the load on
+        # the machine.
         my $slot = 0;
-        while ($slot < $maxJobs{$cur}) {
-            my $slotLock = "$currentLoad/$cur-$slot";
-            open SLOTLOCK, ">>$slotLock" or die;
-            if (flock(SLOTLOCK, LOCK_EX | LOCK_NB)) {
-                $machine = $cur;
-                last LOOP;
-            }                
-            close SLOTLOCK;
+        my $load = 0;
+        my $free;
+        while ($slot < $cur->{maxJobs}) {
+            my $slotLock = openSlotLock($cur, $slot);
+            if (flock($slotLock, LOCK_EX | LOCK_NB)) {
+                $free = $slot unless defined $free;
+                flock($slotLock, LOCK_UN) or die;
+            } else {
+                $load++;
+            }
+            close $slotLock;
             $slot++;
         }
+
+        push @available, { machine => $cur, load => $load, free => $free }
+            if $load < $cur->{maxJobs};
     }
 }
 
-close MAINLOCK;
+if (defined $ENV{NIX_DEBUG_HOOK}) {
+    print STDERR "load on " . $_->{machine}->{hostName} . " = " . $_->{load} . "\n"
+        foreach @available;
+}
 
 
-# Didn't find one?
-if (!defined $machine) {
-    if ($rightType) {
+# Didn't find any available machine?  Then decline or postpone.
+if (scalar @available == 0) {
+    # Postpone if we have a machine of the right type, except if the
+    # local system can and wants to do the build.
+    if ($rightType && !$canBuildLocally) {
         sendReply "postpone";
         exit 0;
     } else {
@@ -118,21 +131,52 @@ if (!defined $machine) {
     }
 }
 
-# Yes we did, accept.
+
+# Prioritise the available machines as follows:
+# - First by load divided by speed factor, rounded to the nearest
+#   integer.  This causes fast machines to be preferred over slow
+#   machines with similar loads.
+# - Then by speed factor.
+# - Finally by load.
+sub lf { my $x = shift; return int($x->{load} / $x->{machine}->{speedFactor} + 0.4999); }
+@available = sort
+    { lf($a) <=> lf($b)
+          || $b->{machine}->{speedFactor} <=> $a->{machine}->{speedFactor}
+          || $a->{load} <=> $b->{load}
+    } @available;
+
+
+# Select the best available machine and lock a free slot.
+my $selected = $available[0]; 
+my $machine = $selected->{machine};
+
+my $slotLock = openSlotLock($machine, $selected->{free});
+flock($slotLock, LOCK_EX | LOCK_NB) or die;
+utime undef, undef, $slotLock;
+
+close MAINLOCK;
+
+
+# Tell Nix we've accepted the build.
 sendReply "accept";
-open IN, "<&4" or die;
-my $x = <IN>;
+if (defined $ENV{NIX_DEBUG_HOOK}) {
+    my $hostName = $machine->{hostName};
+    my $sp = $machine->{speedFactor};
+    print STDERR "building `$drvPath' on `$hostName' - $sp - " . $selected->{free} . "\n";
+    sleep 10;
+    exit 0;
+}
+my $x = <STDIN>;
 chomp $x;
-#print "got $x\n";  
-close IN;
 
 if ($x ne "okay") {
     exit 0;
 }
 
 
-# Do the actual job.
-print "BUILDING REMOTE: $drvPath on $machine\n";
+# Do the actual build.
+my $hostName = $machine->{hostName};
+print STDERR "building `$drvPath' on `$hostName'\n";
 
 # Make sure that we don't get any SSH passphrase or host key popups -
 # if there is any problem it should fail, not do something
@@ -141,10 +185,10 @@ $ENV{"DISPLAY"} = "";
 $ENV{"SSH_PASSWORD_FILE="} = "";
 $ENV{"SSH_ASKPASS="} = "";
 
-my $sshOpts = "-i $sshKeys{$machine} -x";
+my $sshOpts = "-i " . $machine->{sshKeys} . " -x";
 
 # Hack to support Cygwin: if we login without a password, we don't
-# have exactly the same right as when we do.  This causes the
+# have exactly the same rights as when we do.  This causes the
 # Microsoft C compiler to fail with certain flags:
 #
 #   http://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?FeedbackID=99676
@@ -154,8 +198,8 @@ my $sshOpts = "-i $sshKeys{$machine} -x";
 # password.  (It only calls this command when there is no controlling
 # terminal, but Nix ensures that is is the case.  When doing this
 # manually, use setsid(1).)
-if ($sshKeys{$machine} =~ /^password:/) {
-    my $passwordFile = $sshKeys{$machine};
+if ($machine->{sshKeys} =~ /^password:/) {
+    my $passwordFile = $machine->{sshKeys};
     $passwordFile =~ s/^password://;
     $sshOpts = "ssh -x";
     $ENV{"SSH_PASSWORD_FILE"} = $passwordFile;
@@ -173,36 +217,40 @@ $inputs =~ s/\n/ /g;
 my $outputs = `cat outputs`; die if ($? != 0);
 $outputs =~ s/\n/ /g;
 
-print "COPYING INPUTS...\n";
+print "copying inputs...\n";
 
 my $maybeSign = "";
 $maybeSign = "--sign" if -e "/nix/etc/nix/signing-key.sec";
 
-system("NIX_SSHOPTS=\"$sshOpts\" nix-copy-closure $machine $maybeSign $drvPath $inputs") == 0
-    or die "cannot copy inputs to $machine: $?";
+system("NIX_SSHOPTS=\"$sshOpts\" @bindir@/nix-copy-closure $hostName $maybeSign $drvPath $inputs") == 0
+    or die "cannot copy inputs to $hostName: $?";
 
-print "BUILDING...\n";
+print "building...\n";
 
-system("ssh $sshOpts $machine 'nix-store -rvvK $drvPath'") == 0
-    or die "remote build on $machine failed: $?";
+my $buildFlags = "--max-silent-time $maxSilentTime";
 
-print "REMOTE BUILD DONE: $drvPath on $machine\n";
+# `-tt' forces allocation of a pseudo-terminal.  This is required to
+# make the remote nix-store process receive a signal when the
+# connection dies.  Without it, the remote process might continue to
+# run indefinitely (that is, until it next tries to write to
+# stdout/stderr).
+if (system("ssh -tt $sshOpts $hostName 'nix-store --realise $buildFlags $drvPath > /dev/null'") != 0) {
+    # If we couldn't run ssh or there was an ssh problem (indicated by
+    # exit code 255), then we return exit code 1; otherwise we assume
+    # that the builder failed, which we indicated to Nix using exit
+    # code 100.  It's important to distinguish between the two because
+    # the first is a transient failure and the latter is permanent.
+    my $res = $? == -1 || ($? >> 8) == 255 ? 1 : 100;
+    print STDERR "build of `$drvPath' on `$hostName' failed with exit code $?\n";
+    exit $res;
+}
+
+print "build of `$drvPath' on `$hostName' succeeded\n";
 
 foreach my $output (split '\n', $outputs) {
     my $maybeSignRemote = "";
     $maybeSignRemote = "--sign" if $UID != 0;
     
-    system("ssh $sshOpts $machine 'nix-store --export $maybeSignRemote $output' > dump") == 0
-	or die "cannot copy $output from $machine: $?";
-
-    # This doesn't work yet, since the caller has a lock on the output
-    # path.  We should move towards lock-free invocation of build
-    # hooks and substitutes.
-    #system("nix-store --import < dump") == 0
-    #    or die "cannot import $output: $?";
-
-    # Hack: skip the first 8 bytes (the nix-store --export next
-    # archive marker).  The archive follows.
-    system("(dd bs=1 count=8 of=/dev/null && cat) < dump | nix-store --restore $output") == 0
-	or die "cannot restore $output: $?";
+    system("ssh $sshOpts $hostName 'nix-store --export $maybeSignRemote $output' | @bindir@/nix-store --import > /dev/null") == 0
+	or die "cannot copy $output from $hostName: $?";
 }

scripts/download-using-manifests.pl.in

@@ -9,7 +9,7 @@ my $binDir = $ENV{"NIX_BIN_DIR"} || "@bindir@";
 
 STDOUT->autoflush(1);
 
-my $manifestDir = "@localstatedir@/nix/manifests";
+my $manifestDir = ($ENV{"NIX_MANIFESTS_DIR"} or "@localstatedir@/nix/manifests");
 my $logFile = "@localstatedir@/log/nix/downloads";
 
 
@@ -19,10 +19,15 @@ my %localPaths;
 my %patches;
 
 for my $manifest (glob "$manifestDir/*.nixmanifest") {
-    if (readManifest($manifest, \%narFiles, \%localPaths, \%patches) < 3) {
+    my $version = readManifest($manifest, \%narFiles, \%localPaths, \%patches);
+    if ($version < 3) {
         print STDERR "you have an old-style manifest `$manifest'; please delete it\n";
         exit 1;
     }
+    if ($version >= 10) {
+        print STDERR "manifest `$manifest' is too new; please delete it or upgrade Nix\n";
+        exit 1;
+    }
 }
 
 
@@ -185,13 +190,11 @@ while ($queueFront < scalar @queue) {
                 $format = "" if $baseHashAlgo eq "md5";
                 my $hash = `$binDir/nix-hash --type '$baseHashAlgo' $format "$patch->{basePath}"`;
                 chomp $hash;
-#                print "  MY HASH is $hash\n";
                 if ($hash ne $baseHash) {
                     print LOGFILE "$$ rejecting $patch->{basePath}\n";
                     next;
                 }
             }
-#            print "  PATCH from $patch->{basePath}\n";
             addToQueue $patch->{basePath};
             addEdge $patch->{basePath}, $u, $patch->{size}, "patch", $patch;
         }
@@ -199,10 +202,12 @@ while ($queueFront < scalar @queue) {
         # Add NAR file edges to the start node.
         my $narFileList = $narFiles{$u};
         foreach my $narFile (@{$narFileList}) {
-#            print "  NAR from $narFile->{url}\n";
-            addEdge "start", $u, $narFile->{size}, "narfile", $narFile;
+            # !!! how to handle files whose size is not known in advance?
+            # For now, assume some arbitrary size (1 MB).
+            addEdge "start", $u, ($narFile->{size} || 1000000), "narfile", $narFile;
             if ($u eq $targetPath) {
-                print LOGFILE "$$ full-download-would-be $narFile->{size}\n";
+                my $size = $narFile->{size} || -1;
+                print LOGFILE "$$ full-download-would-be $size\n";
             }
         }
 
@@ -228,8 +233,6 @@ while (scalar @todo > 0) {
 
     my $u_ = $graph{$u};
 
-#    print "IN $u $u_->{d}\n";
-
     foreach my $edge (@{$u_->{edges}}) {
         my $v_ = $graph{$edge->{end}};
         if ($v_->{d} > $u_->{d} + $edge->{weight}) {
@@ -237,7 +240,6 @@ while (scalar @todo > 0) {
             # Store the edge; to edge->start is actually the
             # predecessor.
             $v_->{pred} = $edge; 
-#            print "  RELAX $edge->{end} $v_->{d}\n";
         }
     }
 }
@@ -259,20 +261,18 @@ while ($cur ne "start") {
 my $curStep = 1;
 my $maxStep = scalar @path;
 
-sub downloadFile {
-    my $url = shift;
-    my ($hashAlgo, $hash) = parseHash(shift);
+sub downloadFile { 
+    my $url = shift; 
     $ENV{"PRINT_PATH"} = 1;
     $ENV{"QUIET"} = 1;
-    $ENV{"NIX_HASH_ALGO"} = $hashAlgo;
-    my ($hash2, $path) = `$binDir/nix-prefetch-url '$url' '$hash'`;
+    my ($hash, $path) = `$binDir/nix-prefetch-url '$url'`;
     die "download of `$url' failed" unless $? == 0;
-    chomp $hash2;
     chomp $path;
-    die "hash mismatch, expected $hash, got $hash2" if $hash ne $hash2;
     return $path;
 }
 
+my $finalNarHash;
+
 while (scalar @path > 0) {
     my $edge = pop @path;
     my $u = $edge->{start};
@@ -302,7 +302,7 @@ while (scalar @path > 0) {
 
         # Download the patch.
         print "  downloading patch...\n";
-        my $patchPath = downloadFile "$patch->{url}", "$patch->{hash}";
+        my $patchPath = downloadFile "$patch->{url}";
 
         # Apply the patch to the NAR archive produced in step 1 (for
         # the already present path) or a later step (for patch sequences).
@@ -320,17 +320,20 @@ while (scalar @path > 0) {
             system("$binDir/nix-store --restore $v < $tmpNar2") == 0
                 or die "cannot unpack $tmpNar2 into `$v'";
         }
+
+        $finalNarHash = $patch->{narHash};
     }
 
     elsif ($edge->{type} eq "narfile") {
         my $narFile = $edge->{info};
         print "downloading `$narFile->{url}' into `$v'\n";
 
-        print LOGFILE "$$ narfile $narFile->{url} $narFile->{size} $v\n";
+        my $size = $narFile->{size} || -1;
+        print LOGFILE "$$ narfile $narFile->{url} $size $v\n";
         
         # Download the archive.
         print "  downloading archive...\n";
-        my $narFilePath = downloadFile "$narFile->{url}", "$narFile->{hash}";
+        my $narFilePath = downloadFile "$narFile->{url}";
 
         if ($curStep < $maxStep) {
             # The archive will be used a base to a patch.
@@ -342,11 +345,36 @@ while (scalar @path > 0) {
             system("@bunzip2@ < '$narFilePath' | $binDir/nix-store --restore '$v'") == 0
                 or die "cannot unpack `$narFilePath' into `$v'";
         }
+
+        $finalNarHash = $narFile->{narHash};
     }
 
     $curStep++;
 }
 
 
+# Make sure that the hash declared in the manifest matches what we
+# downloaded and unpacked.
+
+if (defined $finalNarHash) {
+    my ($hashAlgo, $hash) = parseHash $finalNarHash;
+
+    # The hash in the manifest can be either in base-16 or base-32.
+    # Handle both.
+    my $extraFlag =
+        ($hashAlgo eq "sha256" && length($hash) != 64)
+        ? "--base32" : "";
+    
+    my $hash2 = `@bindir@/nix-hash --type $hashAlgo $extraFlag $targetPath`
+        or die "cannot compute hash of path `$targetPath'";
+    chomp $hash2;
+    
+    die "hash mismatch in downloaded path $targetPath; expected $hash, got $hash2"
+        if $hash ne $hash2;
+} else {
+    die "cannot check integrity of the downloaded path since its hash is not known";
+}
+
+
 print LOGFILE "$$ success\n";
 close LOGFILE;

scripts/nix-build.in

@@ -12,6 +12,7 @@ my $outLink;
 my $drvLink;
 
 my $dryRun = 0;
+my $verbose = 0;
 
 my @instArgs = ();
 my @buildArgs = ();
@@ -77,7 +78,7 @@ EOF
 
     elsif ($arg eq "--attr" or $arg eq "-A") {
         $n++;
-        die "$0: `--attr' requires an argument\n" unless $n < scalar @ARGV;
+        die "$0: `$arg' requires an argument\n" unless $n < scalar @ARGV;
         push @instArgs, ("--attr", $ARGV[$n]);
     }
 
@@ -87,7 +88,21 @@ EOF
         $n += 2;
     }
 
-    elsif ($arg eq "--max-jobs" or $arg eq "-j" or $arg eq "--max-silent-time") {
+    elsif ($arg eq "--log-type") {
+        $n++;
+        die "$0: `$arg' requires an argument\n" unless $n < scalar @ARGV;
+        push @instArgs, ($arg, $ARGV[$n]);
+        push @buildArgs, ($arg, $ARGV[$n]);
+    }
+
+    elsif ($arg eq "--option") {
+        die "$0: `$arg' requires two arguments\n" unless $n + 2 < scalar @ARGV;
+        push @instArgs, ($arg, $ARGV[$n + 1], $ARGV[$n + 2]);
+        push @buildArgs, ($arg, $ARGV[$n + 1], $ARGV[$n + 2]);
+        $n += 2;
+    }
+
+    elsif ($arg eq "--max-jobs" or $arg eq "-j" or $arg eq "--max-silent-time" or $arg eq "--log-type") {
         $n++;
         die "$0: `$arg' requires an argument\n" unless $n < scalar @ARGV;
         push @buildArgs, ($arg, $ARGV[$n]);
@@ -98,6 +113,16 @@ EOF
         $dryRun = 1;
     }
     
+    elsif ($arg eq "--show-trace") {
+        push @instArgs, $arg;
+    }
+    
+    elsif ($arg eq "--verbose" or substr($arg, 0, 2) eq "-v") {
+        push @buildArgs, $arg;
+        push @instArgs, $arg;
+        $verbose = 1;
+    }
+    
     elsif (substr($arg, 0, 1) eq "-") {
         push @buildArgs, $arg;
     }
@@ -128,11 +153,14 @@ foreach my $expr (@exprs) {
     # !!! would prefer the perl 5.8.0 pipe open feature here.
     my $pid = open(DRVPATHS, "-|") || exec "$binDir/nix-instantiate", "--add-root", $drvLink, "--indirect", @instArgs, $expr;
     while (<DRVPATHS>) {chomp; push @drvPaths, $_;}
-    close DRVPATHS or exit 1;
+    if (!close DRVPATHS) {
+        die "nix-instantiate killed by signal " . ($? & 127) . "\n" if ($? & 127);
+        exit 1;
+    }
 
     foreach my $drvPath (@drvPaths) {
         my $target = readlink $drvPath or die "cannot read symlink `$drvPath'";
-        print STDERR "store derivation is $target\n";
+        print STDERR "derivation is $target\n" if $verbose;
     }
 
     # Build.
@@ -140,7 +168,10 @@ foreach my $expr (@exprs) {
     $pid = open(OUTPATHS, "-|") || exec "$binDir/nix-store", "--add-root", $outLink, "--indirect", "-rv",
         @buildArgs, @drvPaths;
     while (<OUTPATHS>) {chomp; push @outPaths, $_;}
-    close OUTPATHS or exit 1;
+    if (!close OUTPATHS) {
+        die "nix-store killed by signal " . ($? & 127) . "\n" if ($? & 127);
+        exit 1;
+    }
 
     next if $dryRun;
 

scripts/nix-channel.in

@@ -78,6 +78,9 @@ sub removeChannel {
 sub update {
     readChannels;
 
+    # Create the manifests directory if it doesn't exist.
+    mkdir "$stateDir/manifests", 0755 unless -e "$stateDir/manifests";
+
     # Do we have write permission to the manifests directory?  If not,
     # then just skip pulling the manifest and just download the Nix
     # expressions.  If the user is a non-privileged user in a
@@ -85,11 +88,6 @@ sub update {
     # source.
     if (-W "$stateDir/manifests") {
 
-        # Remove all the old manifests.
-        for my $manifest (glob "$stateDir/manifests/*.nixmanifest") {
-            unlink $manifest or die "cannot remove `$manifest': $!";
-        }
-
         # Pull cache manifests.
         foreach my $url (@channels) {
             #print "pulling cache manifest from `$url'\n";
@@ -125,15 +123,13 @@ sub update {
 
     my $rootFile = "$rootsDir/per-user/$userName/channels";
     
-    # Instantiate the Nix expression.
+    # Build the Nix expression.
     print "unpacking channel Nix expressions...\n";
-    my $storeExpr = `@bindir@/nix-instantiate --add-root '$rootFile'.tmp @datadir@/nix/corepkgs/channels/unpack.nix --argstr system @system@ --arg inputs '$inputs'`
-        or die "cannot instantiate Nix expression";
-    chomp $storeExpr;
-
-    # Build the resulting derivation.
-    my $outPath = `@bindir@/nix-store --add-root '$rootFile' -r '$storeExpr'`
-        or die "cannot realise store expression";
+    my $outPath = `\\
+        @bindir@/nix-build --out-link '$rootFile' --drv-link '$rootFile'.tmp \\
+        @datadir@/nix/corepkgs/channels/unpack.nix \\
+        --argstr system @system@ --arg inputs '$inputs'`
+        or die "cannot unpack the channels";
     chomp $outPath;
 
     unlink "$rootFile.tmp";

scripts/nix-copy-closure.in

@@ -55,30 +55,18 @@ while (@ARGV) {
 if ($toMode) { # Copy TO the remote machine.
 
     my @allStorePaths;
-    my %storePathsSeen;
 
-    foreach my $storePath (@storePaths) {
-        # $arg might be a symlink to the store, so resolve it.
-        my $storePath2 = (`$binDir/nix-store --query --resolve '$storePath'`
-            or die "cannot resolve `$storePath'");
-        chomp $storePath2;
-
-        # Get the closure of this path.
-        my $pid = open(READ,
-            "$binDir/nix-store --query --requisites '$storePath2'|") or die;
+    # Get the closure of this path.
+    my $pid = open(READ, "$binDir/nix-store --query --requisites @storePaths|") or die;
     
-        while (<READ>) {
-            chomp;
-            die "bad: $_" unless /^\//;
-            if (!defined $storePathsSeen{$_}) {
-                push @allStorePaths, $_;
-                $storePathsSeen{$_} = 1;
-            }
-        }
-
-        close READ or die "nix-store failed: $?";
+    while (<READ>) {
+        chomp;
+        die "bad: $_" unless /^\//;
+        push @allStorePaths, $_;
     }
 
+    close READ or die "nix-store failed: $?";
+
 
     # Ask the remote host which paths are invalid.
     open(READ, "ssh @sshOpts $sshHost nix-store --check-validity --print-invalid @allStorePaths|");
@@ -111,15 +99,11 @@ else { # Copy FROM the remote machine.
         "ssh @sshOpts $sshHost nix-store --query --requisites @storePaths|") or die;
     
     my @allStorePaths;
-    my %storePathsSeen;
 
     while (<READ>) {
         chomp;
         die "bad: $_" unless /^\//;
-        if (!defined $storePathsSeen{$_}) {
-            push @allStorePaths, $_;
-            $storePathsSeen{$_} = 1;
-        }
+        push @allStorePaths, $_;
     }
 
     close READ or die "nix-store on remote machine `$sshHost' failed: $?";

scripts/nix-http-export.cgi.in

@@ -12,7 +12,8 @@ needed_path="?$QUERY_STRING"
 needed_path="${needed_path#*[?&]needed_path=}"
 needed_path="${needed_path%%&*}"
 #needed_path="$(echo $needed_path  | ./unhttp)"
-needed_path="$(echo $needed_path  | sed -e 's/%2B/+/g; s/%3D/=/g')"
+needed_path="${needed_path//%2B/+}"
+needed_path="${needed_path//%3D/=}"
 
 echo needed_path: "$needed_path" >&2
 

scripts/nix-install-package.in

@@ -123,6 +123,11 @@ if ($interactive) {
 }
 
 
+# Store the manifest in the temporary directory so that we don't
+# pollute /nix/var/nix/manifests.
+$ENV{NIX_MANIFESTS_DIR} = $tmpDir;
+
+
 print "\nPulling manifests...\n";
 system("$binDir/nix-pull", $manifestURL) == 0
     or barf "nix-pull failed: $?";

scripts/nix-prefetch-url.in

@@ -60,7 +60,7 @@ removeTempDir() {
 
 
 doDownload() {
-    @curl@ $cacheFlags --fail -# --location --max-redirs 20 --disable-epsv \
+    @curl@ $cacheFlags --fail --location --max-redirs 20 --disable-epsv \
         --cookie-jar $tmpPath/cookies "$url" -o $tmpFile
 }
 

scripts/nix-pull.in

@@ -8,21 +8,22 @@ my $tmpDir = tempdir("nix-pull.XXXXXX", CLEANUP => 1, TMPDIR => 1)
     or die "cannot create a temporary directory";
 
 my $binDir = $ENV{"NIX_BIN_DIR"} || "@bindir@";
-
-my $libexecDir = $ENV{"NIX_LIBEXEC_DIR"};
-$libexecDir = "@libexecdir@" unless defined $libexecDir;
-
-my $stateDir = $ENV{"NIX_STATE_DIR"};
-$stateDir = "@localstatedir@/nix" unless defined $stateDir;
-
-my $storeDir = $ENV{"NIX_STORE_DIR"};
-$storeDir = "@storedir@" unless defined $storeDir;
+my $libexecDir = ($ENV{"NIX_LIBEXEC_DIR"} or "@libexecdir@");
+my $storeDir = ($ENV{"NIX_STORE_DIR"} or "@storedir@");
+my $stateDir = ($ENV{"NIX_STATE_DIR"} or "@localstatedir@/nix");
+my $manifestDir = ($ENV{"NIX_MANIFESTS_DIR"} or "$stateDir/manifests");
 
 
 # Prevent access problems in shared-stored installations.
 umask 0022;
 
 
+# Create the manifests directory if it doesn't exist.
+if (! -e $manifestDir) {
+    mkdir $manifestDir, 0755 or die "cannot create directory `$manifestDir'";
+}
+
+
 # Process the URLs specified on the command line.
 my %narFiles;
 my %localPaths;
@@ -50,7 +51,7 @@ sub processURL {
 
     # First see if a bzipped manifest is available.
     if (system("@curl@ --fail --silent --head '$url'.bz2 > /dev/null") == 0) {
-        print "obtaining list of Nix archives at `$url.bz2'...\n";
+        print "fetching list of Nix archives at `$url.bz2'...\n";
         my $bzipped = downloadFile "$url.bz2";
 
         $manifest = "$tmpDir/MANIFEST";
@@ -68,10 +69,11 @@ sub processURL {
         print "obtaining list of Nix archives at `$url'...\n";
         $manifest = downloadFile $url;
     }
+
+    my $version = readManifest($manifest, \%narFiles, \%localPaths, \%patches);
     
-    if (readManifest($manifest, \%narFiles, \%localPaths, \%patches) < 3) {
-        die "`$url' is not manifest or it is too old (i.e., for Nix <= 0.7)\n";
-    }
+    die "`$url' is not a manifest or it is too old (i.e., for Nix <= 0.7)\n" if $version < 3;
+    die "manifest `$url' is too new\n" if $version >= 5;
 
     if ($skipWrongStore) {
         foreach my $path (keys %narFiles) {
@@ -90,11 +92,31 @@ sub processURL {
     my $hash = `$binDir/nix-hash --flat '$manifest'`
         or die "cannot hash `$manifest'";
     chomp $hash;
+
+    my $urlFile = "$manifestDir/$baseName-$hash.url";
+    open URL, ">$urlFile" or die "cannot create `$urlFile'";
+    print URL "$url";
+    close URL;
     
-    my $finalPath = "$stateDir/manifests/$baseName-$hash.nixmanifest";
-    
-    system("@coreutils@/ln", "-sfn", "$manifest", "$finalPath") == 0
+    my $finalPath = "$manifestDir/$baseName-$hash.nixmanifest";
+
+    unlink $finalPath if -e $finalPath;
+        
+    symlink("$manifest", "$finalPath")
         or die "cannot link `$finalPath to `$manifest'";
+
+    # Delete all old manifests downloaded from this URL.
+    for my $urlFile2 (glob "$manifestDir/*.url") {
+        next if $urlFile eq $urlFile2;
+        open URL, "<$urlFile2" or die;
+        my $url2 = <URL>;
+        chomp $url2;
+        close URL;
+        next unless $url eq $url2;
+        my $base = $urlFile2; $base =~ s/.url$//;
+        unlink "${base}.url";
+        unlink "${base}.nixmanifest";
+    }
 }
 
 while (@ARGV) {

scripts/nix-push.in

@@ -128,7 +128,7 @@ while (<READ>) {
 close READ or die "nix-instantiate failed: $?";
 
 
-# Realise the store expressions.
+# Build the derivations.
 print STDERR "creating archives...\n";
 
 my @narPaths;
@@ -140,12 +140,7 @@ while (scalar @tmp > 0) {
     my @tmp2 = @tmp[0..$n - 1];
     @tmp = @tmp[$n..scalar @tmp - 1];
 
-    # Note: we disable build hooks because of the impure path
-    # reference (see above).  Even if that is fixed, using a hook
-    # probably wouldn't make that much sense; pumping lots of data
-    # around just to compress them won't gain that much.
-    $ENV{"NIX_BUILD_HOOK"} = "";
-    my $pid = open(READ, "$binDir/nix-store --no-build-hook --realise @tmp2|")
+    my $pid = open(READ, "$binDir/nix-store --realise @tmp2|")
         or die "cannot run nix-store";
     while (<READ>) {
         chomp;

scripts/readmanifest.pm.in

@@ -2,10 +2,7 @@ use strict;
 
 
 sub addPatch {
-    my $patches = shift;
-    my $storePath = shift;
-    my $patch = shift;
-    my $allowConflicts = shift;
+    my ($patches, $storePath, $patch) = @_;
 
     $$patches{$storePath} = []
         unless defined $$patches{$storePath};
@@ -14,15 +11,9 @@ sub addPatch {
 
     my $found = 0;
     foreach my $patch2 (@{$patchList}) {
-        if ($patch2->{url} eq $patch->{url}) {
-            if ($patch2->{hash} eq $patch->{hash}) {
-                $found = 1 if ($patch2->{basePath} eq $patch->{basePath});
-            } else {
-                die "conflicting hashes for URL $patch->{url}, " .
-                    "namely $patch2->{hash} and $patch->{hash}"
-                    unless $allowConflicts;
-            }
-        }
+        $found = 1 if
+            $patch2->{url} eq $patch->{url} &&
+            $patch2->{basePath} eq $patch->{basePath};
     }
     
     push @{$patchList}, $patch if !$found;
@@ -32,12 +23,7 @@ sub addPatch {
 
 
 sub readManifest {
-    my $manifest = shift;
-    my $narFiles = shift;
-    my $localPaths = shift;
-    my $patches = shift;
-    my $allowConflicts = shift;
-    $allowConflicts = 0 unless defined $allowConflicts;
+    my ($manifest, $narFiles, $localPaths, $patches) = @_;
 
     open MANIFEST, "<$manifest"
         or die "cannot open `$manifest': $!";
@@ -98,15 +84,7 @@ sub readManifest {
 
                     my $found = 0;
                     foreach my $narFile (@{$narFileList}) {
-                        if ($narFile->{url} eq $url) {
-                            if ($narFile->{hash} eq $hash) {
-                                $found = 1;
-                            } else {
-                                die "conflicting hashes for URL $url, " .
-                                    "namely $narFile->{hash} and $hash"
-                                    unless $allowConflicts;
-                            }
-                        }
+                        $found = 1 if $narFile->{url} eq $url;
                     }
                     if (!$found) {
                         push @{$narFileList},
@@ -124,7 +102,7 @@ sub readManifest {
                         , basePath => $basePath, baseHash => $baseHash
                         , narHash => $narHash, patchType => $patchType
                         , hashAlgo => $hashAlgo
-                        }, $allowConflicts;
+                        };
                 }
 
                 elsif ($type eq "localPath") {
@@ -171,12 +149,8 @@ sub readManifest {
 }
 
 
-sub writeManifest
-{
-    my $manifest = shift;
-    my $narFiles = shift;
-    my $patches = shift;
-    my $copySources = shift;
+sub writeManifest {
+    my ($manifest, $narFiles, $patches) = @_;
 
     open MANIFEST, ">$manifest.tmp"; # !!! check exclusive
 
@@ -190,9 +164,9 @@ sub writeManifest
             print MANIFEST "{\n";
             print MANIFEST "  StorePath: $storePath\n";
             print MANIFEST "  NarURL: $narFile->{url}\n";
-            print MANIFEST "  Hash: $narFile->{hash}\n";
+            print MANIFEST "  Hash: $narFile->{hash}\n" if defined $narFile->{hash};
             print MANIFEST "  NarHash: $narFile->{narHash}\n";
-            print MANIFEST "  Size: $narFile->{size}\n";
+            print MANIFEST "  Size: $narFile->{size}\n" if defined $narFile->{size};
             print MANIFEST "  References: $narFile->{references}\n"
                 if defined $narFile->{references} && $narFile->{references} ne "";
             print MANIFEST "  Deriver: $narFile->{deriver}\n"

src/boost/Makefile.am

@@ -1,6 +1,6 @@
 SUBDIRS = format
 
-pkginclude_HEADERS = assert.hpp checked_delete.hpp format.hpp \
+nobase_pkginclude_HEADERS = assert.hpp checked_delete.hpp format.hpp \
  shared_ptr.hpp weak_ptr.hpp throw_exception.hpp \
  enable_shared_from_this.hpp \
  detail/shared_count.hpp detail/workaround.hpp

src/libexpr/Makefile.am

@@ -8,7 +8,7 @@ libexpr_la_SOURCES = \
 pkginclude_HEADERS = \
  nixexpr.hh eval.hh parser.hh lexer-tab.hh parser-tab.hh \
  get-drvs.hh attr-path.hh expr-to-xml.hh common-opts.hh \
- names.hh
+ names.hh nixexpr-ast.hh
 
 libexpr_la_LIBADD = ../libutil/libutil.la ../libstore/libstore.la \
  ../boost/format/libformat.la
@@ -19,7 +19,7 @@ BUILT_SOURCES = nixexpr-ast.cc nixexpr-ast.hh \
 EXTRA_DIST = lexer.l parser.y nixexpr-ast.def nixexpr-ast.cc
 
 AM_CXXFLAGS = \
- -I$(srcdir)/.. ${bdb_include} ${aterm_include} \
+ -I$(srcdir)/.. ${aterm_include} \
  -I$(srcdir)/../libutil -I$(srcdir)/../libstore
 AM_CFLAGS = \
  ${aterm_include}

src/libexpr/eval.cc

@@ -23,6 +23,8 @@ EvalState::EvalState()
     initNixExprHelpers();
 
     addPrimOps();
+
+    allowUnsafeEquality = getEnv("NIX_NO_UNSAFE_EQ", "") == "";
 }
 
 
@@ -240,7 +242,7 @@ LocalNoInline(Expr updateAttrs(Expr e1, Expr e2))
 }
 
 
-string evalString(EvalState & state, Expr e, PathSet & context)
+string evalString(EvalState & state, Expr e, ATermList & context)
 {
     e = evalExpr(state, e);
     string s;
@@ -252,11 +254,10 @@ string evalString(EvalState & state, Expr e, PathSet & context)
 
 string evalStringNoCtx(EvalState & state, Expr e)
 {
-    PathSet context;
+    ATermList context;
     string s = evalString(state, e, context);
-    if (!context.empty())
-        throw EvalError(format("the string `%1%' is not allowed to refer to a store path (such as `%2%')")
-            % s % *(context.begin()));
+    if (context != ATempty)
+        throw EvalError(format("the string `%1%' is not allowed to refer to a store path") % s);
     return s;
 }
 
@@ -310,7 +311,7 @@ ATermList flattenList(EvalState & state, Expr e)
 }
 
 
-string coerceToString(EvalState & state, Expr e, PathSet & context,
+string coerceToString(EvalState & state, Expr e, Context & context,
     bool coerceMore, bool copyToStore)
 {
     e = evalExpr(state, e);
@@ -341,7 +342,7 @@ string coerceToString(EvalState & state, Expr e, PathSet & context,
                 % path % dstPath);
         }
 
-        context.insert(dstPath);
+        context.set(toATerm(dstPath), makeNull());
         return dstPath;
     }
         
@@ -349,7 +350,13 @@ string coerceToString(EvalState & state, Expr e, PathSet & context,
     if (matchAttrs(e, es)) {
         Expr e2 = queryAttr(e, "outPath");
         if (!e2) throwTypeError("cannot coerce an attribute set (except a derivation) to a string");
-        return coerceToString(state, e2, context, coerceMore, copyToStore);
+        /* !!! hacky */
+        ATermList c;
+        string s = evalString(state, e2, c);
+        Context c2; matchContext(c, c2);
+        foreach (Context::const_iterator, i, c2)
+            context.set(i->key, e);
+        return s;
     }
 
     if (coerceMore) {
@@ -383,9 +390,9 @@ string coerceToString(EvalState & state, Expr e, PathSet & context,
 static ATerm concatStrings(EvalState & state, ATermVector & args,
     string separator = "")
 {
-    if (args.empty()) return makeStr("", PathSet());
+    if (args.empty()) return makeStr("", ATempty);
     
-    PathSet context;
+    Context context;
     std::ostringstream s;
 
     /* If the first element is a path, then the result will also be a
@@ -401,7 +408,7 @@ static ATerm concatStrings(EvalState & state, ATermVector & args,
         s << coerceToString(state, *i, context, false, !isPath);
     }
 
-    if (isPath && !context.empty())
+    if (isPath && context.size() != 0)
         throw EvalError(format("a string that refers to a store path cannot be appended to a path, in `%1%'")
             % s.str());
     
@@ -411,7 +418,7 @@ static ATerm concatStrings(EvalState & state, ATermVector & args,
 }
 
 
-Path coerceToPath(EvalState & state, Expr e, PathSet & context)
+Path coerceToPath(EvalState & state, Expr e, Context & context)
 {
     string path = coerceToString(state, e, context, false, false);
     if (path == "" || path[0] != '/')
@@ -598,7 +605,7 @@ LocalNoInline(Expr evalPlusConcat(EvalState & state, Expr e))
                     "concatenation of a derivation and a path is deprecated; "
                     "you should write `drv + \"%1%\"' instead of `drv + %1%'")
                 % aterm2String(p));
-            PathSet context;
+            Context context;
             return makeStr(
                 coerceToString(state, makeSelect(e1, toATerm("outPath")), context)
                 + aterm2String(p), context);
@@ -644,6 +651,48 @@ LocalNoInline(Expr evalOpConcat(EvalState & state, Expr e1, Expr e2))
 }
 
 
+/* Implementation of the `==' and `!=' operators. */
+LocalNoInline(bool areEqual(EvalState & state, Expr e1, Expr e2))
+{
+    e1 = evalExpr(state, e1);
+    e2 = evalExpr(state, e2);
+
+    /* We cannot test functions/primops for equality, and we currently
+       don't support testing equality between attribute sets or lists
+       - that would have to be a deep equality test to be sound. */
+    AFun sym1 = ATgetAFun(e1);
+    AFun sym2 = ATgetAFun(e2);
+
+    if (sym1 != sym2) return false;
+
+    /* Functions are incomparable. */
+    if (sym1 == symFunction || sym1 == symPrimOp) return false;
+
+    if (!state.allowUnsafeEquality && sym1 == symAttrs)
+        throw EvalError("comparison of attribute sets is not implemented");
+
+    /* !!! This allows comparisons of infinite data structures to
+       succeed, such as `let x = [x]; in x == x'.  This is
+       undesirable, since equivalent (?) terms such as `let x = [x]; y
+       = [y]; in x == y' don't terminate. */
+    if (e1 == e2) return true;
+    
+    if (sym1 == symList) {
+        ATermList es1; matchList(e1, es1);
+        ATermList es2; matchList(e2, es2);
+        if (ATgetLength(es1) != ATgetLength(es2)) return false;
+        ATermIterator i(es1), j(es2);
+        while (*i) {
+            if (!areEqual(state, *i, *j)) return false;
+            ++i; ++j;
+        }
+        return true;
+    }
+    
+    return false;
+}
+
+
 static char * deepestStack = (char *) -1; /* for measuring stack usage */
 
 
@@ -707,12 +756,10 @@ Expr evalExpr2(EvalState & state, Expr e)
        However, we don't want to make (==) strict, because that would
        make operations like `big_derivation == null' very slow (unless
        we were to evaluate them side-by-side). */
-    if (matchOpEq(e, e1, e2))
-        return makeBool(evalExpr(state, e1) == evalExpr(state, e2));
-
-    if (matchOpNEq(e, e1, e2))
-        return makeBool(evalExpr(state, e1) != evalExpr(state, e2));
-
+    if (matchOpEq(e, e1, e2)) return makeBool(areEqual(state, e1, e2));
+        
+    if (matchOpNEq(e, e1, e2)) return makeBool(!areEqual(state, e1, e2));
+        
     /* Negation. */
     if (matchOpNot(e, e1))
         return makeBool(!evalBool(state, e1));

src/libexpr/eval.hh

@@ -38,6 +38,8 @@ struct EvalState
     unsigned int nrEvaluated;
     unsigned int nrCached;
 
+    bool allowUnsafeEquality;
+
     EvalState();
 
     void addPrimOps();
@@ -59,7 +61,7 @@ Expr evalFile(EvalState & state, const Path & path);
 Expr strictEvalExpr(EvalState & state, Expr e);
 
 /* Specific results. */
-string evalString(EvalState & state, Expr e, PathSet & context);
+string evalString(EvalState & state, Expr e, ATermList & context);
 string evalStringNoCtx(EvalState & state, Expr e);
 int evalInt(EvalState & state, Expr e);
 bool evalBool(EvalState & state, Expr e);
@@ -72,13 +74,13 @@ ATermList flattenList(EvalState & state, Expr e);
 /* String coercion.  Converts strings, paths and derivations to a
    string.  If `coerceMore' is set, also converts nulls, integers,
    booleans and lists to a string. */
-string coerceToString(EvalState & state, Expr e, PathSet & context,
+string coerceToString(EvalState & state, Expr e, Context & context,
     bool coerceMore = false, bool copyToStore = true);
 
 /* Path coercion.  Converts strings, paths and derivations to a path.
    The result is guaranteed to be an canonicalised, absolute path.
    Nothing is copied to the store. */
-Path coerceToPath(EvalState & state, Expr e, PathSet & context);
+Path coerceToPath(EvalState & state, Expr e, Context & context);
 
 /* Automatically call a function for which each argument has a default
    value or has a binding in the `args' map.  Note: result is a call,

src/libexpr/expr-to-xml.cc

@@ -23,12 +23,12 @@ static XMLAttrs singletonAttrs(const string & name, const string & value)
 typedef set<Expr> ExprSet;
 
 
-static void printTermAsXML(Expr e, XMLWriter & doc, PathSet & context,
+static void printTermAsXML(Expr e, XMLWriter & doc, Context & context,
     ExprSet & drvsSeen);
 
 
 static void showAttrs(const ATermMap & attrs, XMLWriter & doc,
-    PathSet & context, ExprSet & drvsSeen)
+    Context & context, ExprSet & drvsSeen)
 {
     StringSet names;
     for (ATermMap::const_iterator i = attrs.begin(); i != attrs.end(); ++i)
@@ -65,7 +65,7 @@ static void printPatternAsXML(Pattern pat, XMLWriter & doc)
 }
 
 
-static void printTermAsXML(Expr e, XMLWriter & doc, PathSet & context,
+static void printTermAsXML(Expr e, XMLWriter & doc, Context & context,
     ExprSet & drvsSeen)
 {
     XMLAttrs attrs;
@@ -144,7 +144,7 @@ static void printTermAsXML(Expr e, XMLWriter & doc, PathSet & context,
 }
 
 
-void printTermAsXML(Expr e, std::ostream & out, PathSet & context)
+void printTermAsXML(Expr e, std::ostream & out, Context & context)
 {
     XMLWriter doc(true, out);
     XMLOpenElement root(doc, "expr");

src/libexpr/expr-to-xml.hh

@@ -9,7 +9,7 @@
 
 namespace nix {
 
-void printTermAsXML(Expr e, std::ostream & out, PathSet & context);
+void printTermAsXML(Expr e, std::ostream & out, Context & context);
     
 }
 

src/libexpr/get-drvs.cc

@@ -17,7 +17,7 @@ string DrvInfo::queryDrvPath(EvalState & state) const
         if (a && matchPath(evalExpr(state, a), t))
             return aterm2String(t);
         
-        PathSet context;
+        Context context;
         (string &) drvPath = a ? coerceToPath(state, a, context) : "";
     }
     return drvPath;
@@ -29,7 +29,7 @@ string DrvInfo::queryOutPath(EvalState & state) const
     if (outPath == "") {
         Expr a = attrs->get(toATerm("outPath"));
         if (!a) throw TypeError("output path missing");
-        PathSet context;
+        Context context;
         (string &) outPath = coerceToPath(state, a, context);
     }
     return outPath;
@@ -49,32 +49,56 @@ MetaInfo DrvInfo::queryMetaInfo(EvalState & state) const
     for (ATermMap::const_iterator i = attrs2.begin(); i != attrs2.end(); ++i) {
         Expr e = evalExpr(state, i->value);
         string s;
-        PathSet context;
-        if (matchStr(e, s, context))
-            meta[aterm2String(i->key)] = s;
-        /* For future compatibility, ignore attribute values that are
-           not strings. */
+        ATermList context;
+        MetaValue value;
+        int n;
+        ATermList es;
+        if (matchStr(e, s, context)) {
+            value.type = MetaValue::tpString;
+            value.stringValue = s;
+            meta[aterm2String(i->key)] = value;
+        } else if (matchInt(e, n)) {
+            value.type = MetaValue::tpInt;
+            value.intValue = n;
+            meta[aterm2String(i->key)] = value;
+        } else if (matchList(e, es)) {
+            value.type = MetaValue::tpStrings;
+            for (ATermIterator j(es); j; ++j)
+                value.stringValues.push_back(evalStringNoCtx(state, *j));
+            meta[aterm2String(i->key)] = value;
+        }
     }
 
     return meta;
 }
 
 
-string DrvInfo::queryMetaInfo(EvalState & state, const string & name) const
+MetaValue DrvInfo::queryMetaInfo(EvalState & state, const string & name) const
 {
     /* !!! evaluates all meta attributes => inefficient */
-    MetaInfo meta = queryMetaInfo(state);
-    MetaInfo::iterator i = meta.find(name);
-    return i == meta.end() ? "" : i->second;
+    return queryMetaInfo(state)[name];
 }
 
 
 void DrvInfo::setMetaInfo(const MetaInfo & meta)
 {
     ATermMap metaAttrs;
-    for (MetaInfo::const_iterator i = meta.begin(); i != meta.end(); ++i)
-        metaAttrs.set(toATerm(i->first),
-            makeAttrRHS(makeStr(i->second), makeNoPos()));
+    foreach (MetaInfo::const_iterator, i, meta) {
+        Expr e;
+        switch (i->second.type) {
+            case MetaValue::tpInt: e = makeInt(i->second.intValue); break;
+            case MetaValue::tpString: e = makeStr(i->second.stringValue); break;
+            case MetaValue::tpStrings: {
+                ATermList es = ATempty;
+                foreach (Strings::const_iterator, j, i->second.stringValues)
+                    es = ATinsert(es, makeStr(*j));
+                e = makeList(ATreverse(es));
+                break;
+            }
+            default: abort();
+        }
+        metaAttrs.set(toATerm(i->first), makeAttrRHS(e, makeNoPos()));
+    }
     attrs->set(toATerm("meta"), makeAttrs(metaAttrs));
 }
 

src/libexpr/get-drvs.hh

@@ -12,7 +12,16 @@
 namespace nix {
 
 
-typedef std::map<string, string> MetaInfo;
+struct MetaValue
+{
+    enum { tpNone, tpString, tpStrings, tpInt } type;
+    string stringValue;
+    Strings stringValues;
+    int intValue;
+};
+
+
+typedef std::map<string, MetaValue> MetaInfo;
 
 
 struct DrvInfo
@@ -34,7 +43,7 @@ public:
     string queryDrvPath(EvalState & state) const;
     string queryOutPath(EvalState & state) const;
     MetaInfo queryMetaInfo(EvalState & state) const;
-    string queryMetaInfo(EvalState & state, const string & name) const;
+    MetaValue queryMetaInfo(EvalState & state, const string & name) const;
 
     void setDrvPath(const string & s)
     {

src/libexpr/nixexpr-ast.def

@@ -45,6 +45,8 @@ Int | int | Expr |
 Str | string ATermList | Expr |
 Str | string | Expr | ObsoleteStr
 
+ContextElem | string Expr | ContextElem |
+
 # Internal to the parser, doesn't occur in ASTs.
 IndStr | string | Expr |
 
@@ -70,6 +72,7 @@ Bool | ATermBool | Expr |
 Null | | Expr |
 
 Bind | string Expr Pos | ATerm |
+BindAttrPath | ATermList Expr Pos | ATerm | # desugared during parsing
 Bind | string Expr | ATerm | ObsoleteBind
 Inherit | Expr ATermList Pos | ATerm |
 

src/libexpr/nixexpr.cc

@@ -19,7 +19,7 @@ string showPos(ATerm pos)
     if (matchNoPos(pos)) return "undefined position";
     if (!matchPos(pos, path, line, column))
         throw badTerm("position expected", pos);
-    return (format("`%1%', line %2%") % aterm2String(path) % line).str();
+    return (format("`%1%:%2%:%3%'") % aterm2String(path) % line % column).str();
 }
     
 
@@ -336,25 +336,47 @@ Expr makeBool(bool b)
 }
 
 
-bool matchStr(Expr e, string & s, PathSet & context)
+bool matchStr(Expr e, string & s, ATermList & context)
 {
-    ATermList l;
     ATerm s_;
-
-    if (!matchStr(e, s_, l)) return false;
-
+    if (!matchStr(e, s_, context)) return false;
     s = aterm2String(s_);
-
-    for (ATermIterator i(l); i; ++i)
-        context.insert(aterm2String(*i));
-
     return true;
 }
 
 
-Expr makeStr(const string & s, const PathSet & context)
+bool matchStr(Expr e, string & s, Context & context)
 {
-    return makeStr(toATerm(s), toATermList(context));
+    ATermList c;
+    if (!matchStr(e, s, c)) return false;
+    matchContext(c, context);
+    return true;
+}
+
+
+Expr makeStr(const string & s, ATermList context)
+{
+    return makeStr(toATerm(s), context);
+}
+
+
+Expr makeStr(const string & s, const Context & context)
+{
+    ATermList l = ATempty;
+    /* !!! should define a canonical ordering of context elements. */
+    foreach (Context::const_iterator, i, context)
+        l = ATinsert(l, makeContextElem(i->key, i->value));
+    return makeStr(s, l);
+}
+
+
+void matchContext(ATermList context, Context & result)
+{
+    for (ATermIterator i(context); i; ++i) {
+        ATerm s, e;
+        if (!matchContextElem(*i, s, e)) abort();
+        result.set(s, e);
+    }
 }
 
 
@@ -380,7 +402,7 @@ string showType(Expr e)
 
 string showValue(Expr e)
 {
-    PathSet context;
+    ATermList context;
     string s;
     ATerm s2;
     int i;

src/libexpr/nixexpr.hh

@@ -11,6 +11,7 @@ namespace nix {
 
 
 MakeError(EvalError, Error)
+MakeError(ParseError, Error)
 MakeError(AssertionError, EvalError)
 MakeError(ThrownError, AssertionError)
 MakeError(Abort, EvalError)
@@ -25,6 +26,7 @@ typedef ATerm DefaultValue;
 typedef ATerm Pos;
 typedef ATerm Pattern;
 typedef ATerm ATermBool;
+typedef ATerm ContextElem;
 
 
 /* A STL vector of ATerms.  Should be used with great care since it's
@@ -103,11 +105,18 @@ Expr canonicaliseExpr(Expr e);
 Expr makeBool(bool b);
 
 
-/* Manipulation of Str() nodes.  Note: matchStr() does not clear
-   context!  */
-bool matchStr(Expr e, string & s, PathSet & context);
+/* Manipulation of Str() nodes. */
+typedef ATermMap Context;
 
-Expr makeStr(const string & s, const PathSet & context = PathSet());
+bool matchStr(Expr e, string & s, ATermList & context);
+
+bool matchStr(Expr e, string & s, Context & context);
+
+Expr makeStr(const string & s, ATermList context = ATempty);
+
+Expr makeStr(const string & s, const Context & context);
+
+void matchContext(ATermList context, Context & result);
 
 
 /* Showing types, values. */

src/libexpr/parser.y

@@ -25,6 +25,7 @@
     
 #include "parser-tab.hh"
 #include "lexer-tab.hh"
+#define YYSTYPE YYSTYPE // workaround a bug in Bison 2.4
 
 #include "nixexpr.hh"
 #include "nixexpr-ast.hh"
@@ -43,28 +44,128 @@ struct ParseData
     Path path;
     string error;
 };
+ 
 
-
-static Expr fixAttrs(int recursive, ATermList as)
+static string showAttrPath(ATermList attrPath)
 {
-    ATermList bs = ATempty, cs = ATempty;
-    ATermList * is = recursive ? &cs : &bs;
+    string s;
+    for (ATermIterator i(attrPath); i; ++i) {
+        if (!s.empty()) s += '.';
+        s += aterm2String(*i);
+    }
+    return s;
+}
+ 
+
+struct Tree
+{
+    Expr leaf; ATerm pos; bool recursive;
+    typedef std::map<ATerm, Tree> Children;
+    Children children;
+    Tree() { leaf = 0; recursive = true; }
+};
+
+
+static ATermList buildAttrs(const Tree & t, ATermList & nonrec)
+{
+    ATermList res = ATempty;
+    for (Tree::Children::const_reverse_iterator i = t.children.rbegin();
+         i != t.children.rend(); ++i)
+        if (!i->second.recursive)
+            nonrec = ATinsert(nonrec, makeBind(i->first, i->second.leaf, i->second.pos));
+        else
+            res = ATinsert(res, i->second.leaf
+                ? makeBind(i->first, i->second.leaf, i->second.pos)
+                : makeBind(i->first, makeAttrs(buildAttrs(i->second, nonrec)), makeNoPos()));
+    return res;
+}
+ 
+
+static Expr fixAttrs(bool recursive, ATermList as)
+{
+    Tree attrs;
+
     for (ATermIterator i(as); i; ++i) {
-        ATermList names;
-        Expr src;
-        ATerm pos;
+        ATermList names, attrPath; Expr src, e; ATerm name, pos;
+
         if (matchInherit(*i, src, names, pos)) {
             bool fromScope = matchScope(src);
             for (ATermIterator j(names); j; ++j) {
-                Expr rhs = fromScope ? makeVar(*j) : makeSelect(src, *j);
-                *is = ATinsert(*is, makeBind(*j, rhs, pos));
+                if (attrs.children.find(*j) != attrs.children.end()) 
+                    throw ParseError(format("duplicate definition of attribute `%1%' at %2%")
+                        % showAttrPath(ATmakeList1(*j)) % showPos(pos));
+                Tree & t(attrs.children[*j]);
+                t.leaf = fromScope ? makeVar(*j) : makeSelect(src, *j);
+                t.pos = pos;
+                if (recursive && fromScope) t.recursive = false;
             }
-        } else bs = ATinsert(bs, *i);
+        }
+
+        else if (matchBindAttrPath(*i, attrPath, e, pos)) {
+
+            Tree * t(&attrs);
+            
+            for (ATermIterator j(attrPath); j; ) {
+                name = *j; ++j;
+                if (t->leaf) throw ParseError(format("attribute set containing `%1%' at %2% already defined at %3%")
+                    % showAttrPath(attrPath) % showPos(pos) % showPos (t->pos));
+                t = &(t->children[name]);
+            }
+
+            if (t->leaf)
+                throw ParseError(format("duplicate definition of attribute `%1%' at %2% and %3%")
+                    % showAttrPath(attrPath) % showPos(pos) % showPos (t->pos));
+            if (!t->children.empty())
+                throw ParseError(format("duplicate definition of attribute `%1%' at %2%")
+                    % showAttrPath(attrPath) % showPos(pos));
+
+            t->leaf = e; t->pos = pos;
+        }
+
+        else abort(); /* can't happen */
     }
-    if (recursive)
-        return makeRec(bs, cs);
-    else
-        return makeAttrs(bs);
+
+    ATermList nonrec = ATempty;
+    ATermList rec = buildAttrs(attrs, nonrec);
+        
+    return recursive ? makeRec(rec, nonrec) : makeAttrs(rec);
+}
+
+
+static void checkPatternVars(ATerm pos, ATermMap & map, Pattern pat)
+{
+    ATerm name;
+    ATermList formals;
+    Pattern pat1, pat2;
+    ATermBool ellipsis;
+    if (matchVarPat(pat, name)) {
+        if (map.get(name))
+            throw ParseError(format("duplicate formal function argument `%1%' at %2%")
+                % aterm2String(name) % showPos(pos));
+        map.set(name, name);
+    }
+    else if (matchAttrsPat(pat, formals, ellipsis)) { 
+        for (ATermIterator i(formals); i; ++i) {
+            ATerm d1;
+            if (!matchFormal(*i, name, d1)) abort();
+            if (map.get(name))
+                throw ParseError(format("duplicate formal function argument `%1%' at %2%")
+                    % aterm2String(name) % showPos(pos));
+            map.set(name, name);
+        }
+    }
+    else if (matchAtPat(pat, pat1, pat2)) {
+        checkPatternVars(pos, map, pat1);
+        checkPatternVars(pos, map, pat2);
+    }
+    else abort();
+}
+
+
+static void checkPatternVars(ATerm pos, Pattern pat)
+{
+    ATermMap map;
+    checkPatternVars(pos, map, pat);
 }
 
 
@@ -146,7 +247,7 @@ static Expr stripIndentation(ATermList es)
         /* Remove the last line if it is empty and consists only of
            spaces. */
         if (n == 1) {
-            unsigned int p = s2.find_last_of('\n');
+            string::size_type p = s2.find_last_of('\n');
             if (p != string::npos && s2.find_first_not_of(' ', p + 1) == string::npos)
                 s2 = string(s2, 0, p + 1);
         }
@@ -217,7 +318,7 @@ static void freeAndUnprotect(void * p)
 %type <t> start expr expr_function expr_if expr_op
 %type <t> expr_app expr_select expr_simple bind inheritsrc formal
 %type <t> pattern pattern2
-%type <ts> binds ids expr_list string_parts ind_string_parts
+%type <ts> binds ids attrpath expr_list string_parts ind_string_parts
 %type <formals> formals
 %token <t> ID INT STR IND_STR PATH URI
 %token IF THEN ELSE ASSERT WITH LET IN REC INHERIT EQ NEQ AND OR IMPL
@@ -244,13 +345,13 @@ expr: expr_function;
 
 expr_function
   : pattern ':' expr_function
-    { $$ = makeFunction($1, $3, CUR_POS); }
+    { checkPatternVars(CUR_POS, $1); $$ = makeFunction($1, $3, CUR_POS); }
   | ASSERT expr ';' expr_function
     { $$ = makeAssert($2, $4, CUR_POS); }
   | WITH expr ';' expr_function
     { $$ = makeWith($2, $4, CUR_POS); }
   | LET binds IN expr_function
-    { $$ = makeSelect(fixAttrs(1, ATinsert($2, makeBind(toATerm("<let-body>"), $4, CUR_POS))), toATerm("<let-body>")); }
+    { $$ = makeSelect(fixAttrs(true, ATinsert($2, makeBindAttrPath(ATmakeList1(toATerm("<let-body>")), $4, CUR_POS))), toATerm("<let-body>")); }
   | expr_if
   ;
 
@@ -305,12 +406,12 @@ expr_simple
   /* Let expressions `let {..., body = ...}' are just desugared
      into `(rec {..., body = ...}).body'. */
   | LET '{' binds '}'
-    { $$ = makeSelect(fixAttrs(1, $3), toATerm("body")); }
+    { $$ = makeSelect(fixAttrs(true, $3), toATerm("body")); }
   | REC '{' binds '}'
-    { $$ = fixAttrs(1, $3); }
+    { $$ = fixAttrs(true, $3); }
   | '{' binds '}'
-    { $$ = fixAttrs(0, $2); }
-  | '[' expr_list ']' { $$ = makeList($2); }
+    { $$ = fixAttrs(false, $2); }
+  | '[' expr_list ']' { $$ = makeList(ATreverse($2)); }
   ;
 
 string_parts
@@ -341,8 +442,8 @@ binds
   ;
 
 bind
-  : ID '=' expr ';'
-    { $$ = makeBind($1, $3, CUR_POS); }
+  : attrpath '=' expr ';'
+    { $$ = makeBindAttrPath(ATreverse($1), $3, CUR_POS); }
   | INHERIT inheritsrc ids ';'
     { $$ = makeInherit($2, $3, CUR_POS); }
   ;
@@ -354,16 +455,18 @@ inheritsrc
 
 ids: ids ID { $$ = ATinsert($1, $2); } | { $$ = ATempty; };
 
+attrpath
+  : attrpath '.' ID { $$ = ATinsert($1, $3); }
+  | ID { $$ = ATmakeList1($1); }
+  ;
+
 expr_list
-  : expr_select expr_list { $$ = ATinsert($2, $1); }
-    /* yes, this is right-recursive, but it doesn't matter since
-       otherwise we would need ATreverse which requires unbounded
-       stack space */
+  : expr_list expr_select { $$ = ATinsert($1, $2); }
   | { $$ = ATempty; }
   ;
 
 formals
-  : formal ',' formals /* idem - right recursive */
+  : formal ',' formals /* !!! right recursive */
     { $$.formals = ATinsert($3.formals, $1); $$.ellipsis = $3.ellipsis; }
   | formal
     { $$.formals = ATinsert(ATempty, $1); $$.ellipsis = false; }
@@ -392,84 +495,6 @@ formal
 namespace nix {
       
 
-static void checkAttrs(ATermMap & names, ATermList bnds)
-{
-    for (ATermIterator i(bnds); i; ++i) {
-        ATerm name;
-        Expr e;
-        ATerm pos;
-        if (!matchBind(*i, name, e, pos)) abort(); /* can't happen */
-        if (names.get(name))
-            throw EvalError(format("duplicate attribute `%1%' at %2%")
-                % aterm2String(name) % showPos(pos));
-        names.set(name, name);
-    }
-}
-
-
-static void checkPatternVars(ATerm pos, ATermMap & map, Pattern pat)
-{
-    ATerm name;
-    ATermList formals;
-    Pattern pat1, pat2;
-    ATermBool ellipsis;
-    if (matchVarPat(pat, name)) {
-        if (map.get(name))
-            throw EvalError(format("duplicate formal function argument `%1%' at %2%")
-                % aterm2String(name) % showPos(pos));
-        map.set(name, name);
-    }
-    else if (matchAttrsPat(pat, formals, ellipsis)) { 
-        for (ATermIterator i(formals); i; ++i) {
-            ATerm d1;
-            if (!matchFormal(*i, name, d1)) abort();
-            if (map.get(name))
-                throw EvalError(format("duplicate formal function argument `%1%' at %2%")
-                    % aterm2String(name) % showPos(pos));
-            map.set(name, name);
-        }
-    }
-    else if (matchAtPat(pat, pat1, pat2)) {
-        checkPatternVars(pos, map, pat1);
-        checkPatternVars(pos, map, pat2);
-    }
-    else abort();
-}
-
-
-static void checkAttrSets(ATerm e)
-{
-    ATerm pat, body, pos;
-    if (matchFunction(e, pat, body, pos)) {
-        ATermMap map(16);
-        checkPatternVars(pos, map, pat);
-    }
-
-    ATermList bnds;
-    if (matchAttrs(e, bnds)) {
-        ATermMap names(ATgetLength(bnds));
-        checkAttrs(names, bnds);
-    }
-    
-    ATermList rbnds, nrbnds;
-    if (matchRec(e, rbnds, nrbnds)) {
-        ATermMap names(ATgetLength(rbnds) + ATgetLength(nrbnds));
-        checkAttrs(names, rbnds);
-        checkAttrs(names, nrbnds);
-    }
-    
-    if (ATgetType(e) == AT_APPL) {
-        int arity = ATgetArity(ATgetAFun(e));
-        for (int i = 0; i < arity; ++i)
-            checkAttrSets(ATgetArgument(e, i));
-    }
-
-    else if (ATgetType(e) == AT_LIST)
-        for (ATermIterator i((ATermList) e); i; ++i)
-            checkAttrSets(*i);
-}
-
-
 static Expr parse(EvalState & state,
     const char * text, const Path & path,
     const Path & basePath)
@@ -484,16 +509,14 @@ static Expr parse(EvalState & state,
     int res = yyparse(scanner, &data);
     yylex_destroy(scanner);
     
-    if (res) throw EvalError(data.error);
+    if (res) throw ParseError(data.error);
 
     try {
         checkVarDefs(state.primOps, data.result);
     } catch (Error & e) {
-        throw EvalError(format("%1%, in `%2%'") % e.msg() % path);
+        throw ParseError(format("%1%, in `%2%'") % e.msg() % path);
     }
     
-    checkAttrSets(data.result);
-
     return data.result;
 }
 

src/libexpr/primops.cc

@@ -93,16 +93,17 @@ static Expr prim_currentTime(EvalState & state, const ATermVector & args)
    argument. */ 
 static Expr prim_import(EvalState & state, const ATermVector & args)
 {
-    PathSet context;
+    Context context;
     Path path = coerceToPath(state, args[0], context);
 
-    for (PathSet::iterator i = context.begin(); i != context.end(); ++i) {
-        assert(isStorePath(*i));
-        if (!store->isValidPath(*i))
+    foreach (Context::const_iterator, i, context) {
+        Path p = aterm2String(i->key);
+        assert(isStorePath(p));
+        if (!store->isValidPath(p))
             throw EvalError(format("cannot import `%1%', since path `%2%' is not valid")
-                % path % *i);
-        if (isDerivation(*i))
-            store->buildDerivations(singleton<PathSet>(*i));
+                % path % p);
+        if (isDerivation(p))
+            store->buildDerivations(singleton<PathSet>(p));
     }
 
     return evalFile(state, path);
@@ -125,6 +126,27 @@ static Expr prim_isFunction(EvalState & state, const ATermVector & args)
     return makeBool(matchFunction(e, pat, body, pos));
 }
 
+/* Determine whether the argument is an Int. */
+static Expr prim_isInt(EvalState & state, const ATermVector & args)
+{
+    int i;
+    return makeBool(matchInt(evalExpr(state, args[0]), i));
+}
+
+/* Determine whether the argument is an String. */
+static Expr prim_isString(EvalState & state, const ATermVector & args)
+{
+    string s;
+    ATermList context;
+    return makeBool(matchStr(evalExpr(state, args[0]), s, context));
+}
+
+/* Determine whether the argument is an Bool. */
+static Expr prim_isBool(EvalState & state, const ATermVector & args)
+{
+    ATermBool b;
+    return makeBool(matchBool(evalExpr(state, args[0]), b));
+}
 
 static Expr prim_genericClosure(EvalState & state, const ATermVector & args)
 {
@@ -176,7 +198,7 @@ static Expr prim_genericClosure(EvalState & state, const ATermVector & args)
 
 static Expr prim_abort(EvalState & state, const ATermVector & args)
 {
-    PathSet context;
+    ATermList context;
     throw Abort(format("evaluation aborted with the following error message: `%1%'") %
         evalString(state, args[0], context));
 }
@@ -184,12 +206,42 @@ static Expr prim_abort(EvalState & state, const ATermVector & args)
 
 static Expr prim_throw(EvalState & state, const ATermVector & args)
 {
-    PathSet context;
-    throw ThrownError(format("user-thrown exception: `%1%'") %
+    ATermList context;
+    throw ThrownError(format("user-thrown exception: %1%") %
         evalString(state, args[0], context));
 }
 
 
+static Expr prim_addErrorContext(EvalState & state, const ATermVector & args)
+{
+    ATermList context;
+    try {
+        return evalExpr(state, args[1]);
+    } catch (Error & e) {
+        e.addPrefix(format("%1%\n") %
+            evalString(state, args[0], context));
+        throw;
+    }
+}
+
+/* Try evaluating the argument. Success => {success=true; value=something;}, 
+ * else => {success=false; value=false;} */
+static Expr prim_tryEval(EvalState & state, const ATermVector & args)
+{
+    ATermMap res = ATermMap();
+    try {
+        Expr val = evalExpr(state, args[0]);
+        res.set(toATerm("value"), makeAttrRHS(val, makeNoPos()));
+        res.set(toATerm("success"), makeAttrRHS(eTrue, makeNoPos()));
+    } catch (AssertionError & e) {
+        printMsg(lvlDebug, format("tryEval caught an error: %1%: %2%") % e.prefix() % e.msg());
+        res.set(toATerm("value"), makeAttrRHS(eFalse, makeNoPos()));
+        res.set(toATerm("success"), makeAttrRHS(eFalse, makeNoPos()));
+    }
+    return makeAttrs(res);
+}
+
+
 /* Return an environment variable.  Use with care. */
 static Expr prim_getEnv(EvalState & state, const ATermVector & args)
 {
@@ -205,7 +257,12 @@ static Expr prim_getEnv(EvalState & state, const ATermVector & args)
 static Expr prim_trace(EvalState & state, const ATermVector & args)
 {
     Expr e = evalExpr(state, args[0]);
-    printMsg(lvlError, format("trace: %1%") % e);
+    string s;
+    ATermList context;
+    if (matchStr(e, s, context))
+        printMsg(lvlError, format("trace: %1%") % s);
+    else
+        printMsg(lvlError, format("trace: %1%") % e);
     return evalExpr(state, args[1]);
 }
 
@@ -215,6 +272,14 @@ static Expr prim_trace(EvalState & state, const ATermVector & args)
  *************************************************************/
 
 
+static bool isFixedOutput(const Derivation & drv)
+{
+    return drv.outputs.size() == 1 &&
+        drv.outputs.begin()->first == "out" &&
+        drv.outputs.begin()->second.hash != "";
+}
+
+
 /* Returns the hash of a derivation modulo fixed-output
    subderivations.  A fixed-output derivation is a derivation with one
    output (`out') for which an expected hash and hash algorithm are
@@ -227,35 +292,29 @@ static Expr prim_trace(EvalState & state, const ATermVector & args)
    function, we do not want to rebuild everything depending on it
    (after all, (the hash of) the file being downloaded is unchanged).
    So the *output paths* should not change.  On the other hand, the
-   *derivation store expression paths* should change to reflect the
-   new dependency graph.
+   *derivation paths* should change to reflect the new dependency
+   graph.
 
    That's what this function does: it returns a hash which is just the
-   of the derivation ATerm, except that any input store expression
+   hash of the derivation ATerm, except that any input derivation
    paths have been replaced by the result of a recursive call to this
-   function, and that for fixed-output derivations we return
-   (basically) its outputHash. */
+   function, and that for fixed-output derivations we return a hash of
+   its output path. */
 static Hash hashDerivationModulo(EvalState & state, Derivation drv)
 {
     /* Return a fixed hash for fixed-output derivations. */
-    if (drv.outputs.size() == 1) {
+    if (isFixedOutput(drv)) {
         DerivationOutputs::const_iterator i = drv.outputs.begin();
-        if (i->first == "out" &&
-            i->second.hash != "")
-        {
-            return hashString(htSHA256, "fixed:out:"
-                + i->second.hashAlgo + ":"
-                + i->second.hash + ":"
-                + i->second.path);
-        }
+        return hashString(htSHA256, "fixed:out:"
+            + i->second.hashAlgo + ":"
+            + i->second.hash + ":"
+            + i->second.path);
     }
 
     /* For other derivations, replace the inputs paths with recursive
        calls to this function.*/
     DerivationInputs inputs2;
-    for (DerivationInputs::iterator i = drv.inputDrvs.begin();
-         i != drv.inputDrvs.end(); ++i)
-    {
+    foreach (DerivationInputs::const_iterator, i, drv.inputDrvs) {
         Hash h = state.drvHashes[i->first];
         if (h.type == htUnknown) {
             Derivation drv2 = derivationFromPath(i->first);
@@ -302,10 +361,9 @@ static Expr prim_derivationStrict(EvalState & state, const ATermVector & args)
     /* Build the derivation expression by processing the attributes. */
     Derivation drv;
     
-    PathSet context;
+    Context context;
 
-    string outputHash;
-    string outputHashAlgo;
+    string outputHash, outputHashAlgo;
     bool outputHashRecursive = false;
 
     for (ATermMap::const_iterator i = attrs.begin(); i != attrs.end(); ++i) {
@@ -364,13 +422,40 @@ static Expr prim_derivationStrict(EvalState & state, const ATermVector & args)
     /* Everything in the context of the strings in the derivation
        attributes should be added as dependencies of the resulting
        derivation. */
-    for (PathSet::iterator i = context.begin(); i != context.end(); ++i) {
-        debug(format("derivation uses `%1%'") % *i);
-        assert(isStorePath(*i));
-        if (isDerivation(*i))
-            drv.inputDrvs[*i] = singleton<StringSet>("out");
+    foreach (Context::const_iterator, i, context) {
+        Path path = aterm2String(i->key);
+        
+        /* Paths marked with `=' denote that the path of a derivation
+           is explicitly passed to the builder.  Since that allows the
+           builder to gain access to every path in the dependency
+           graph of the derivation (including all outputs), all paths
+           in the graph must be added to this derivation's list of
+           inputs to ensure that they are available when the builder
+           runs. */
+        if (path.at(0) == '=') {
+            path = string(path, 1);
+            PathSet refs; computeFSClosure(path, refs);
+            foreach (PathSet::iterator, j, refs) {
+                drv.inputSrcs.insert(*j);
+                if (isDerivation(*j))
+                    drv.inputDrvs[*j] = singleton<StringSet>("out");
+            }
+        }
+
+        /* See prim_unsafeDiscardOutputDependency. */
+        bool useDrvAsSrc = false;
+        if (path.at(0) == '~') {
+            path = string(path, 1);
+            useDrvAsSrc = true;
+        }
+
+        assert(isStorePath(path));
+
+        debug(format("derivation uses `%1%'") % path);
+        if (!useDrvAsSrc && isDerivation(path))
+            drv.inputDrvs[path] = singleton<StringSet>("out");
         else
-            drv.inputSrcs.insert(*i);
+            drv.inputSrcs.insert(path);
     }
             
     /* Do we have all required attributes? */
@@ -380,6 +465,7 @@ static Expr prim_derivationStrict(EvalState & state, const ATermVector & args)
         throw EvalError("required attribute `system' missing");
 
     /* If an output hash was given, check it. */
+    Path outPath;
     if (outputHash == "")
         outputHashAlgo = "";
     else {
@@ -398,6 +484,7 @@ static Expr prim_derivationStrict(EvalState & state, const ATermVector & args)
                 % outputHash % outputHashAlgo);
         string s = outputHash;
         outputHash = printHash(h);
+        outPath = makeFixedOutputPath(outputHashRecursive, ht, h, drvName);
         if (outputHashRecursive) outputHashAlgo = "r:" + outputHashAlgo;
     }
 
@@ -413,13 +500,12 @@ static Expr prim_derivationStrict(EvalState & state, const ATermVector & args)
        have an empty value.  This ensures that changes in the set of
        output names do get reflected in the hash. */
     drv.env["out"] = "";
-    drv.outputs["out"] =
-        DerivationOutput("", outputHashAlgo, outputHash);
+    drv.outputs["out"] = DerivationOutput("", outputHashAlgo, outputHash);
         
     /* Use the masked derivation expression to compute the output
        path. */
-    Path outPath = makeStorePath("output:out",
-        hashDerivationModulo(state, drv), drvName);
+    if (outPath == "")
+        outPath = makeStorePath("output:out", hashDerivationModulo(state, drv), drvName);
 
     /* Construct the final derivation store expression. */
     drv.env["out"] = outPath;
@@ -440,9 +526,9 @@ static Expr prim_derivationStrict(EvalState & state, const ATermVector & args)
     /* !!! assumes a single output */
     ATermMap outAttrs(2);
     outAttrs.set(toATerm("outPath"),
-        makeAttrRHS(makeStr(outPath, singleton<PathSet>(drvPath)), makeNoPos()));
+        makeAttrRHS(makeStr(outPath, ATmakeList1(makeContextElem(toATerm(drvPath), makeNull()))), makeNoPos()));
     outAttrs.set(toATerm("drvPath"),
-        makeAttrRHS(makeStr(drvPath, singleton<PathSet>(drvPath)), makeNoPos()));
+        makeAttrRHS(makeStr(drvPath, ATmakeList1(makeContextElem(toATerm("=" + drvPath), makeNull()))), makeNoPos()));
 
     return makeAttrs(outAttrs);
 }
@@ -476,7 +562,7 @@ static Expr prim_derivationLazy(EvalState & state, const ATermVector & args)
 /* Convert the argument to a path.  !!! obsolete? */
 static Expr prim_toPath(EvalState & state, const ATermVector & args)
 {
-    PathSet context;
+    Context context;
     string path = coerceToPath(state, args[0], context);
     return makeStr(canonPath(path), context);
 }
@@ -492,22 +578,23 @@ static Expr prim_toPath(EvalState & state, const ATermVector & args)
    corner cases. */
 static Expr prim_storePath(EvalState & state, const ATermVector & args)
 {
-    PathSet context;
+    Context context;
     Path path = canonPath(coerceToPath(state, args[0], context));
     if (!isInStore(path))
         throw EvalError(format("path `%1%' is not in the Nix store") % path);
-    if (!store->isValidPath(path))
-        throw EvalError(format("store path `%1%' is not valid") % path);
-    context.insert(toStorePath(path));
+    Path path2 = toStorePath(path);
+    if (!store->isValidPath(path2))
+        throw EvalError(format("store path `%1%' is not valid") % path2);
+    context.set(toATerm(path2), makeNull());
     return makeStr(path, context);
 }
 
 
 static Expr prim_pathExists(EvalState & state, const ATermVector & args)
 {
-    PathSet context;
+    Context context;
     Path path = coerceToPath(state, args[0], context);
-    if (!context.empty())
+    if (context.size() != 0)
         throw EvalError(format("string `%1%' cannot refer to other paths") % path);
     return makeBool(pathExists(path));
 }
@@ -517,7 +604,7 @@ static Expr prim_pathExists(EvalState & state, const ATermVector & args)
    following the last slash. */
 static Expr prim_baseNameOf(EvalState & state, const ATermVector & args)
 {
-    PathSet context;
+    Context context;
     return makeStr(baseNameOf(coerceToString(state, args[0], context)), context);
 }
 
@@ -527,7 +614,7 @@ static Expr prim_baseNameOf(EvalState & state, const ATermVector & args)
    of the argument. */
 static Expr prim_dirOf(EvalState & state, const ATermVector & args)
 {
-    PathSet context;
+    Context context;
     Expr e = evalExpr(state, args[0]); ATerm dummy;
     bool isPath = matchPath(e, dummy);
     Path dir = dirOf(coerceToPath(state, e, context));
@@ -538,9 +625,9 @@ static Expr prim_dirOf(EvalState & state, const ATermVector & args)
 /* Return the contents of a file as a string. */
 static Expr prim_readFile(EvalState & state, const ATermVector & args)
 {
-    PathSet context;
+    Context context;
     Path path = coerceToPath(state, args[0], context);
-    if (!context.empty())
+    if (context.size() != 0)
         throw EvalError(format("string `%1%' cannot refer to other paths") % path);
     return makeStr(readFile(path));
 }
@@ -557,7 +644,7 @@ static Expr prim_readFile(EvalState & state, const ATermVector & args)
 static Expr prim_toXML(EvalState & state, const ATermVector & args)
 {
     std::ostringstream out;
-    PathSet context;
+    Context context;
     printTermAsXML(strictEvalExpr(state, args[0]), out, context);
     return makeStr(out.str(), context);
 }
@@ -567,16 +654,19 @@ static Expr prim_toXML(EvalState & state, const ATermVector & args)
    as an input by derivations. */
 static Expr prim_toFile(EvalState & state, const ATermVector & args)
 {
-    PathSet context;
+    ATermList context;
     string name = evalStringNoCtx(state, args[0]);
     string contents = evalString(state, args[1], context);
 
     PathSet refs;
 
-    for (PathSet::iterator i = context.begin(); i != context.end(); ++i) {
-        if (isDerivation(*i))
+    Context context2; matchContext(context, context2);
+    foreach (Context::const_iterator, i, context2) {
+        Path path = aterm2String(i->key);
+        if (path.at(0) == '=') path = string(path, 1);
+        if (isDerivation(path))
             throw EvalError(format("in `toFile': the file `%1%' cannot refer to derivation outputs") % name);
-        refs.insert(*i);
+        refs.insert(path);
     }
     
     Path storePath = readOnlyMode
@@ -587,7 +677,7 @@ static Expr prim_toFile(EvalState & state, const ATermVector & args)
        result, since `storePath' itself has references to the paths
        used in args[1]. */
     
-    return makeStr(storePath, singleton<PathSet>(storePath));
+    return makeStr(storePath, ATmakeList1(makeContextElem(toATerm(storePath), makeNull())));
 }
 
 
@@ -624,18 +714,18 @@ struct FilterFromExpr : PathFilter
 
 static Expr prim_filterSource(EvalState & state, const ATermVector & args)
 {
-    PathSet context;
+    Context context;
     Path path = coerceToPath(state, args[1], context);
-    if (!context.empty())
+    if (context.size() != 0)
         throw EvalError(format("string `%1%' cannot refer to other paths") % path);
 
     FilterFromExpr filter(state, args[0]);
 
     Path dstPath = readOnlyMode
-        ? computeStorePathForPath(path, false, false, "", filter).first
-        : store->addToStore(path, false, false, "", filter);
+        ? computeStorePathForPath(path, true, htSHA256, filter).first
+        : store->addToStore(path, true, htSHA256, filter);
 
-    return makeStr(dstPath, singleton<PathSet>(dstPath));
+    return makeStr(dstPath, ATmakeList1(makeContextElem(toATerm(dstPath), makeNull())));
 }
 
 
@@ -658,7 +748,7 @@ static Expr prim_attrNames(EvalState & state, const ATermVector & args)
     ATermList list = ATempty;
     for (StringSet::const_reverse_iterator i = names.rbegin();
          i != names.rend(); ++i)
-        list = ATinsert(list, makeStr(*i, PathSet()));
+        list = ATinsert(list, makeStr(*i));
 
     return makeList(list);
 }
@@ -737,6 +827,70 @@ static Expr prim_isAttrs(EvalState & state, const ATermVector & args)
 }
 
 
+/* Return the right-biased intersection of two attribute sets as1 and
+   as2, i.e. a set that contains every attribute from as2 that is also
+   a member of as1. */
+static Expr prim_intersectAttrs(EvalState & state, const ATermVector & args)
+{
+    ATermMap as1, as2;
+    queryAllAttrs(evalExpr(state, args[0]), as1, true);
+    queryAllAttrs(evalExpr(state, args[1]), as2, true);
+
+    ATermMap res;
+    foreach (ATermMap::const_iterator, i, as2)
+        if (as1[i->key]) res.set(i->key, i->value);
+
+    return makeAttrs(res);
+}
+
+
+static void attrsInPattern(ATermMap & map, Pattern pat)
+{
+    ATerm name;
+    ATermList formals;
+    Pattern pat1, pat2;
+    ATermBool ellipsis;
+    if (matchAttrsPat(pat, formals, ellipsis)) { 
+        for (ATermIterator i(formals); i; ++i) {
+            ATerm def;
+            if (!matchFormal(*i, name, def)) abort();
+            map.set(name, makeAttrRHS(makeBool(def != constNoDefaultValue), makeNoPos()));
+        }
+    }
+    else if (matchAtPat(pat, pat1, pat2)) {
+        attrsInPattern(map, pat1);
+        attrsInPattern(map, pat2);
+    }
+}
+
+
+/* Return a set containing the names of the formal arguments expected
+   by the function `f'.  The value of each attribute is a Boolean
+   denoting whether has a default value.  For instance,
+
+      functionArgs ({ x, y ? 123}: ...)
+   => { x = false; y = true; }
+
+   "Formal argument" here refers to the attributes pattern-matched by
+   the function.  Plain lambdas are not included, e.g.
+
+      functionArgs (x: ...)
+   => { }
+*/
+static Expr prim_functionArgs(EvalState & state, const ATermVector & args)
+{
+    Expr f = evalExpr(state, args[0]);
+    ATerm pat, body, pos;
+    if (!matchFunction(f, pat, body, pos))
+        throw TypeError("`functionArgs' required a function");
+    
+    ATermMap as;
+    attrsInPattern(as, pat);
+
+    return makeAttrs(as);
+}
+
+
 /*************************************************************
  * Lists
  *************************************************************/
@@ -849,7 +1003,7 @@ static Expr prim_lessThan(EvalState & state, const ATermVector & args)
    `"/nix/store/whatever..."'. */
 static Expr prim_toString(EvalState & state, const ATermVector & args)
 {
-    PathSet context;
+    Context context;
     string s = coerceToString(state, args[0], context, true, false);
     return makeStr(s, context);
 }
@@ -863,7 +1017,7 @@ static Expr prim_substring(EvalState & state, const ATermVector & args)
 {
     int start = evalInt(state, args[0]);
     int len = evalInt(state, args[1]);
-    PathSet context;
+    Context context;
     string s = coerceToString(state, args[2], context);
 
     if (start < 0) throw EvalError("negative start position in `substring'");
@@ -874,7 +1028,7 @@ static Expr prim_substring(EvalState & state, const ATermVector & args)
 
 static Expr prim_stringLength(EvalState & state, const ATermVector & args)
 {
-    PathSet context;
+    Context context;
     string s = coerceToString(state, args[0], context);
     return makeInt(s.size());
 }
@@ -882,9 +1036,42 @@ static Expr prim_stringLength(EvalState & state, const ATermVector & args)
 
 static Expr prim_unsafeDiscardStringContext(EvalState & state, const ATermVector & args)
 {
-    PathSet context;
+    Context context;
     string s = coerceToString(state, args[0], context);
-    return makeStr(s, PathSet());
+    return makeStr(s);
+}
+
+
+/* Sometimes we want to pass a derivation path (i.e. pkg.drvPath) to a
+   builder without causing the derivation to be built (for instance,
+   in the derivation that builds NARs in nix-push, when doing
+   source-only deployment).  This primop marks the string context so
+   that builtins.derivation adds the path to drv.inputSrcs rather than
+   drv.inputDrvs. */
+static Expr prim_unsafeDiscardOutputDependency(EvalState & state, const ATermVector & args)
+{
+    Context context;
+    string s = coerceToString(state, args[0], context);
+
+    Context context2;
+    foreach (Context::const_iterator, i, context) {
+        Path p = aterm2String(i->key);
+        if (p.at(0) == '=') p = "~" + string(p, 1);
+        context2.set(toATerm(p), i->value);
+    }
+    
+    return makeStr(s, context2);
+}
+
+
+static Expr prim_queryStringContext(EvalState & state, const ATermVector & args)
+{
+    Context context;
+    string s = coerceToString(state, args[0], context);
+    ATermList l = ATempty;
+    foreach (Context::const_iterator, i, context)
+        l = ATinsert(l, i->value);
+    return makeList(l);
 }
 
 
@@ -898,18 +1085,6 @@ static Expr prim_exprToString(EvalState & state, const ATermVector & args)
 }
 
 
-static Expr prim_stringToExpr(EvalState & state, const ATermVector & args)
-{
-    /* !!! this can introduce arbitrary garbage terms in the
-       evaluator! */;
-    string s;
-    PathSet l;
-    if (!matchStr(evalExpr(state, args[0]), s, l))
-        throw EvalError("stringToExpr needs string argument!");
-    return ATreadFromString(s.c_str());
-}
-
-
 /*************************************************************
  * Versions
  *************************************************************/
@@ -955,15 +1130,19 @@ void EvalState::addPrimOps()
     addPrimOp("import", 1, prim_import);
     addPrimOp("isNull", 1, prim_isNull);
     addPrimOp("__isFunction", 1, prim_isFunction);
+    addPrimOp("__isString", 1, prim_isString);
+    addPrimOp("__isInt", 1, prim_isInt);
+    addPrimOp("__isBool", 1, prim_isBool);
     addPrimOp("__genericClosure", 1, prim_genericClosure);
     addPrimOp("abort", 1, prim_abort);
     addPrimOp("throw", 1, prim_throw);
+    addPrimOp("__addErrorContext", 2, prim_addErrorContext);
+    addPrimOp("__tryEval", 1, prim_tryEval);
     addPrimOp("__getEnv", 1, prim_getEnv);
     addPrimOp("__trace", 2, prim_trace);
-    
+
     // Expr <-> String
     addPrimOp("__exprToString", 1, prim_exprToString);
-    addPrimOp("__stringToExpr", 1, prim_stringToExpr);
 
     // Derivations
     addPrimOp("derivation!", 1, prim_derivationStrict);
@@ -989,6 +1168,8 @@ void EvalState::addPrimOps()
     addPrimOp("__isAttrs", 1, prim_isAttrs);
     addPrimOp("removeAttrs", 2, prim_removeAttrs);
     addPrimOp("__listToAttrs", 1, prim_listToAttrs);
+    addPrimOp("__intersectAttrs", 2, prim_intersectAttrs);
+    addPrimOp("__functionArgs", 1, prim_functionArgs);
 
     // Lists
     addPrimOp("__isList", 1, prim_isList);
@@ -1009,6 +1190,8 @@ void EvalState::addPrimOps()
     addPrimOp("__substring", 3, prim_substring);
     addPrimOp("__stringLength", 1, prim_stringLength);
     addPrimOp("__unsafeDiscardStringContext", 1, prim_unsafeDiscardStringContext);
+    addPrimOp("__unsafeDiscardOutputDependency", 1, prim_unsafeDiscardOutputDependency);
+    addPrimOp("__queryStringContext", 1, prim_queryStringContext);
 
     // Versions
     addPrimOp("__parseDrvName", 1, prim_parseDrvName);

src/libmain/Makefile.am

@@ -1,6 +1,10 @@
 pkglib_LTLIBRARIES = libmain.la
 
-libmain_la_SOURCES = shared.cc shared.hh
+libmain_la_SOURCES = shared.cc
+
+libmain_la_LIBADD = ../libstore/libstore.la
+
+pkginclude_HEADERS = shared.hh
 
 AM_CXXFLAGS = \
  -DNIX_STORE_DIR=\"$(storedir)\" \

src/libmain/shared.cc

@@ -87,18 +87,6 @@ static void setLogType(string lt)
 }
 
 
-unsigned long long getIntArg(const string & opt,
-    Strings::iterator & i, const Strings::iterator & end)
-{
-    ++i;
-    if (i == end) throw UsageError(format("`%1%' requires an argument") % opt);
-    long long n;
-    if (!string2Int(*i, n) || n < 0)
-        throw UsageError(format("`%1%' requires a non-negative integer") % opt);
-    return n;
-}
-
-
 void initDerivationsHelpers();
 
 
@@ -125,6 +113,9 @@ RemoveTempRoots::~RemoveTempRoots()
 }
 
 
+static bool showTrace = false;
+
+
 /* Initialize and reorder arguments, then call the actual argument
    processor. */
 static void initAndRun(int argc, char * * argv)
@@ -138,7 +129,6 @@ static void initAndRun(int argc, char * * argv)
     nixConfDir = canonPath(getEnv("NIX_CONF_DIR", NIX_CONF_DIR));
     nixLibexecDir = canonPath(getEnv("NIX_LIBEXEC_DIR", NIX_LIBEXEC_DIR));
     nixBinDir = canonPath(getEnv("NIX_BIN_DIR", NIX_BIN_DIR));
-    nixChrootsDir = canonPath(getEnv("NIX_CHROOTS_DIR", nixStateDir + "/chroots"));
 
     string subs = getEnv("NIX_SUBSTITUTERS", "default");
     if (subs == "default") {
@@ -153,23 +143,29 @@ static void initAndRun(int argc, char * * argv)
     maxSilentTime = queryIntSetting("build-max-silent-time", 0);
 
     /* Catch SIGINT. */
-    struct sigaction act, oact;
+    struct sigaction act;
     act.sa_handler = sigintHandler;
     sigfillset(&act.sa_mask);
     act.sa_flags = 0;
-    if (sigaction(SIGINT, &act, &oact))
+    if (sigaction(SIGINT, &act, 0))
         throw SysError("installing handler for SIGINT");
-    if (sigaction(SIGTERM, &act, &oact))
+    if (sigaction(SIGTERM, &act, 0))
         throw SysError("installing handler for SIGTERM");
-    if (sigaction(SIGHUP, &act, &oact))
+    if (sigaction(SIGHUP, &act, 0))
         throw SysError("installing handler for SIGHUP");
 
     /* Ignore SIGPIPE. */
     act.sa_handler = SIG_IGN;
     act.sa_flags = 0;
-    if (sigaction(SIGPIPE, &act, &oact))
+    if (sigaction(SIGPIPE, &act, 0))
         throw SysError("ignoring SIGPIPE");
 
+    /* Reset SIGCHLD to its default. */
+    act.sa_handler = SIG_DFL;
+    act.sa_flags = 0;
+    if (sigaction(SIGCHLD, &act, 0))
+        throw SysError("resetting SIGCHLD");
+
     /* There is no privacy in the Nix system ;-)  At least not for
        now.  In particular, store objects should be readable by
        everybody.  This prevents nasty surprises when using a shared
@@ -193,7 +189,7 @@ static void initAndRun(int argc, char * * argv)
     for (Strings::iterator i = args.begin(); i != args.end(); ++i) {
         string arg = *i;
         if (string(arg, 0, 4) == "-at-") ;
-        else if (arg.length() > 2 && arg[0] == '-' && arg[1] != '-') {
+        else if (arg.length() > 2 && arg[0] == '-' && arg[1] != '-' && !isdigit(arg[1])) {
             for (unsigned int j = 1; j < arg.length(); j++)
                 if (isalpha(arg[j]))
                     remaining.push_back((string) "-" + arg[j]);
@@ -237,13 +233,22 @@ static void initAndRun(int argc, char * * argv)
         else if (arg == "--fallback")
             tryFallback = true;
         else if (arg == "--max-jobs" || arg == "-j")
-            maxBuildJobs = getIntArg(arg, i, args.end());
+            maxBuildJobs = getIntArg<unsigned int>(arg, i, args.end());
         else if (arg == "--readonly-mode")
             readOnlyMode = true;
         else if (arg == "--max-silent-time")
-            maxSilentTime = getIntArg(arg, i, args.end());
+            maxSilentTime = getIntArg<unsigned int>(arg, i, args.end());
         else if (arg == "--no-build-hook")
             useBuildHook = false;
+        else if (arg == "--show-trace")
+            showTrace = true;
+        else if (arg == "--option") {
+            ++i; if (i == args.end()) throw UsageError("`--option' requires two arguments");
+            string name = *i;
+            ++i; if (i == args.end()) throw UsageError("`--option' requires two arguments");
+            string value = *i;
+            overrideSetting(name, tokenizeString(value));
+        }
         else remaining.push_back(arg);
     }
 
@@ -359,7 +364,9 @@ int main(int argc, char * * argv)
             % e.what() % programId);
         return 1;
     } catch (BaseError & e) {
-        printMsg(lvlError, format("error: %1%") % e.msg());
+        printMsg(lvlError, format("error: %1%%2%") % (showTrace ? e.prefix() : "") % e.msg());
+        if (e.prefix() != "" && !showTrace)
+            printMsg(lvlError, "(use `--show-trace' to show detailed location information)");
         return 1;
     } catch (std::exception & e) {
         printMsg(lvlError, format("error: %1%") % e.what());

src/libmain/shared.hh

@@ -22,22 +22,30 @@ extern std::string programId;
 
 namespace nix {
 
+MakeError(UsageError, nix::Error);
+
 /* Ugh.  No better place to put this. */
 Path makeRootName(const Path & gcRoot, int & counter);
 void printGCWarning();
 
 void printMissing(const PathSet & paths);
 
-unsigned long long getIntArg(const string & opt,
-    Strings::iterator & i, const Strings::iterator & end);
+template<class N> N getIntArg(const string & opt,
+    Strings::iterator & i, const Strings::iterator & end)
+{
+    ++i;
+    if (i == end) throw UsageError(format("`%1%' requires an argument") % opt);
+    N n;
+    if (!string2Int(*i, n))
+        throw UsageError(format("`%1%' requires an integer argument") % opt);
+    return n;
+}
 
 /* Whether we're running setuid. */
 extern bool setuidMode;
 
 extern volatile ::sig_atomic_t blockInt;
 
-MakeError(UsageError, nix::Error);
-
 struct RemoveTempRoots 
 {
     ~RemoveTempRoots();    

src/libstore/Makefile.am

@@ -2,22 +2,22 @@ pkglib_LTLIBRARIES = libstore.la
 
 libstore_la_SOURCES = \
   store-api.cc local-store.cc remote-store.cc derivations.cc build.cc misc.cc \
-  globals.cc db.cc references.cc pathlocks.cc gc.cc upgrade-schema.cc \
+  globals.cc references.cc pathlocks.cc gc.cc \
   optimise-store.cc
 
 pkginclude_HEADERS = \
   store-api.hh local-store.hh remote-store.hh derivations.hh misc.hh \
-  globals.hh db.hh references.hh pathlocks.hh \
+  globals.hh references.hh pathlocks.hh \
   worker-protocol.hh
 
-libstore_la_LIBADD = ../libutil/libutil.la ../boost/format/libformat.la
+libstore_la_LIBADD = ../libutil/libutil.la ../boost/format/libformat.la @ADDITIONAL_NETWORK_LIBS@
 
 BUILT_SOURCES = derivations-ast.cc derivations-ast.hh
 
 EXTRA_DIST = derivations-ast.def derivations-ast.cc
 
 AM_CXXFLAGS = -Wall \
- -I$(srcdir)/.. ${bdb_include} ${aterm_include} -I$(srcdir)/../libutil
+ -I$(srcdir)/.. ${aterm_include} -I$(srcdir)/../libutil
 
 derivations-ast.cc derivations-ast.hh: ../aterm-helper.pl derivations-ast.def
 	$(perl) $(srcdir)/../aterm-helper.pl derivations-ast.hh derivations-ast.cc < $(srcdir)/derivations-ast.def

src/libstore/db.cc

@@ -1,474 +0,0 @@
-#include "config.h"
-
-#ifdef OLD_DB_COMPAT
-
-#include "db.hh"
-#include "util.hh"
-#include "pathlocks.hh"
-
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <fcntl.h>
-#include <errno.h>
-
-#include <memory>
-
-#include <db_cxx.h>
-
-
-namespace nix {
-
-
-/* Wrapper class to ensure proper destruction. */
-class DestroyDbc 
-{
-    Dbc * dbc;
-public:
-    DestroyDbc(Dbc * _dbc) : dbc(_dbc) { }
-    ~DestroyDbc() { dbc->close(); /* close() frees dbc */ }
-};
-
-
-class DestroyDbEnv
-{
-    DbEnv * dbenv;
-public:
-    DestroyDbEnv(DbEnv * _dbenv) : dbenv(_dbenv) { }
-    ~DestroyDbEnv() {
-        if (dbenv) {
-            if (dbenv->get_DB_ENV()) dbenv->close(0);
-            delete dbenv;
-        }
-    }
-    void release() { dbenv = 0; };
-};
-
-
-static void rethrow(DbException & e)
-{
-    throw Error(e.what());
-}
-
-
-Transaction::Transaction()
-    : txn(0)
-{
-}
-
-
-Transaction::Transaction(Database & db)
-    : txn(0)
-{
-    begin(db);
-}
-
-
-Transaction::~Transaction()
-{
-    if (txn) abort();
-}
-
-
-void Transaction::begin(Database & db)
-{
-    assert(txn == 0);
-    db.requireEnv();
-    try {
-        db.env->txn_begin(0, &txn, 0);
-    } catch (DbException e) { rethrow(e); }
-}
-
-
-void Transaction::commit()
-{
-    if (!txn) throw Error("commit called on null transaction");
-    debug(format("committing transaction %1%") % (void *) txn);
-    DbTxn * txn2 = txn;
-    txn = 0;
-    try {
-        txn2->commit(0);
-    } catch (DbException e) { rethrow(e); }
-}
-
-
-void Transaction::abort()
-{
-    if (!txn) throw Error("abort called on null transaction");
-    debug(format("aborting transaction %1%") % (void *) txn);
-    DbTxn * txn2 = txn;
-    txn = 0;
-    try {
-        txn2->abort();
-    } catch (DbException e) { rethrow(e); }
-}
-
-
-void Transaction::moveTo(Transaction & t)
-{
-    if (t.txn) throw Error("target txn already exists");
-    t.txn = txn;
-    txn = 0;
-}
-
-
-void Database::requireEnv()
-{
-    checkInterrupt();
-    if (!env) throw Error("database environment is not open "
-        "(maybe you don't have sufficient permission?)");
-}
-
-
-Db * Database::getDb(TableId table)
-{
-    if (table == 0)
-        throw Error("database table is not open "
-            "(maybe you don't have sufficient permission?)");
-    std::map<TableId, Db *>::iterator i = tables.find(table);
-    if (i == tables.end())
-        throw Error("unknown table id");
-    return i->second;
-}
-
-
-Database::Database()
-    : env(0)
-    , nextId(1)
-{
-}
-
-
-Database::~Database()
-{
-    close();
-}
-
-
-void openEnv(DbEnv * & env, const string & path, u_int32_t flags)
-{
-    try {
-        createDirs(path);
-    } catch (SysError & e) {
-        if (e.errNo == EPERM || e.errNo == EACCES)
-            throw DbNoPermission(format("cannot create the Nix database in `%1%'") % path);
-        else
-            throw;
-    }
-        
-    try {
-        env->open(path.c_str(),
-            DB_INIT_LOCK | DB_INIT_LOG | DB_INIT_MPOOL | DB_INIT_TXN |
-            DB_CREATE | flags,
-            0666);
-    } catch (DbException & e) {
-        printMsg(lvlError, format("environment open failed: %1%") % e.what());
-        throw;
-    }
-}
-
-
-static int my_fsync(int fd)
-{
-    return 0;
-}
-
-
-static void errorPrinter(const DbEnv * env, const char * errpfx, const char * msg)
-{
-    printMsg(lvlError, format("Berkeley DB error: %1%") % msg);
-}
-
-
-static void messagePrinter(const DbEnv * env, const char * msg)
-{
-    printMsg(lvlError, format("Berkeley DB message: %1%") % msg);
-}
-
-
-void Database::open2(const string & path, bool removeOldEnv)
-{
-    if (env) throw Error(format("environment already open"));
-
-    debug(format("opening database environment"));
-
-
-    /* Create the database environment object. */
-    DbEnv * env = new DbEnv(0);
-    DestroyDbEnv deleteEnv(env);
-
-    env->set_errcall(errorPrinter);
-    env->set_msgcall(messagePrinter);
-    if (getEnv("NIX_DEBUG_DB_REGISTER") == "1")
-        env->set_verbose(DB_VERB_REGISTER, 1);
-    env->set_verbose(DB_VERB_RECOVERY, 1);
-    
-    /* Smaller log files. */
-    env->set_lg_bsize(32 * 1024); /* default */
-    env->set_lg_max(256 * 1024); /* must be > 4 * lg_bsize */
-    
-    /* Write the log, but don't sync.  This protects transactions
-       against application crashes, but if the system crashes, some
-       transactions may be undone.  An acceptable risk, I think. */
-    env->set_flags(DB_TXN_WRITE_NOSYNC | DB_LOG_AUTOREMOVE, 1);
-    
-    /* Increase the locking limits.  If you ever get `Dbc::get: Cannot
-       allocate memory' or similar, especially while running
-       `nix-store --verify', just increase the following number, then
-       run db_recover on the database to remove the existing DB
-       environment (since changes only take effect on new
-       environments). */
-    env->set_lk_max_locks(10000);
-    env->set_lk_max_lockers(10000);
-    env->set_lk_max_objects(10000);
-    env->set_lk_detect(DB_LOCK_DEFAULT);
-    
-    /* Dangerous, probably, but from the docs it *seems* that BDB
-       shouldn't sync when DB_TXN_WRITE_NOSYNC is used, but it still
-       fsync()s sometimes. */
-    db_env_set_func_fsync(my_fsync);
-
-    
-    if (removeOldEnv) {
-        printMsg(lvlError, "removing old Berkeley DB database environment...");
-        env->remove(path.c_str(), DB_FORCE);
-        return;
-    }
-
-    openEnv(env, path, DB_REGISTER | DB_RECOVER);
-
-    deleteEnv.release();
-    this->env = env;
-}
-
-
-void Database::open(const string & path)
-{
-    try {
-
-        open2(path, false);
-        
-    } catch (DbException e) {
-        
-        if (e.get_errno() == DB_VERSION_MISMATCH) {
-            /* Remove the environment while we are holding the global
-               lock.  If things go wrong there, we bail out.
-               !!! argh, we abolished the global lock :-( */
-            open2(path, true);
-
-            /* Try again. */
-            open2(path, false);
-
-            /* Force a checkpoint, as per the BDB docs. */
-            env->txn_checkpoint(DB_FORCE, 0, 0);
-
-            printMsg(lvlError, "database succesfully upgraded to new version");
-        }
-
-#if 0        
-        else if (e.get_errno() == DB_RUNRECOVERY) {
-            /* If recovery is needed, do it. */
-            printMsg(lvlError, "running recovery...");
-            open2(path, false, true);
-        }
-#endif        
-        
-        else
-            rethrow(e);
-    }
-}
-
-
-void Database::close()
-{
-    if (!env) return;
-
-    /* Close the database environment. */
-    debug(format("closing database environment"));
-
-    try {
-
-        for (std::map<TableId, Db *>::iterator i = tables.begin();
-             i != tables.end(); )
-        {
-            std::map<TableId, Db *>::iterator j = i;
-            ++j;
-            closeTable(i->first);
-            i = j;
-        }
-
-        /* Do a checkpoint every 128 kilobytes, or every 5 minutes. */
-        env->txn_checkpoint(128, 5, 0);
-        
-        env->close(0);
-
-    } catch (DbException e) { rethrow(e); }
-
-    delete env;
-
-    env = 0;
-}
-
-
-TableId Database::openTable(const string & tableName, bool sorted)
-{
-    requireEnv();
-    TableId table = nextId++;
-
-    try {
-
-        Db * db = new Db(env, 0);
-
-        try {
-            db->open(0, tableName.c_str(), 0, 
-                sorted ? DB_BTREE : DB_HASH,
-                DB_CREATE | DB_AUTO_COMMIT, 0666);
-        } catch (...) {
-            delete db;
-            throw;
-        }
-
-        tables[table] = db;
-
-    } catch (DbException e) { rethrow(e); }
-
-    return table;
-}
-
-
-void Database::closeTable(TableId table)
-{
-    try {
-        Db * db = getDb(table);
-        db->close(DB_NOSYNC);
-        delete db;
-        tables.erase(table);
-    } catch (DbException e) { rethrow(e); }
-}
-
-
-void Database::deleteTable(const string & table)
-{
-    try {
-        env->dbremove(0, table.c_str(), 0, DB_AUTO_COMMIT);
-    } catch (DbException e) { rethrow(e); }
-}
-
-
-bool Database::queryString(const Transaction & txn, TableId table, 
-    const string & key, string & data)
-{
-    checkInterrupt();
-
-    try {
-        Db * db = getDb(table);
-
-        Dbt kt((void *) key.c_str(), key.length());
-        Dbt dt;
-
-        int err = db->get(txn.txn, &kt, &dt, 0);
-        if (err) return false;
-
-        if (!dt.get_data())
-            data = "";
-        else
-            data = string((char *) dt.get_data(), dt.get_size());
-    
-    } catch (DbException e) { rethrow(e); }
-
-    return true;
-}
-
-
-bool Database::queryStrings(const Transaction & txn, TableId table, 
-    const string & key, Strings & data)
-{
-    string d;
-    if (!queryString(txn, table, key, d))
-        return false;
-    data = unpackStrings(d);
-    return true;
-}
-
-
-void Database::setString(const Transaction & txn, TableId table,
-    const string & key, const string & data)
-{
-    checkInterrupt();
-    try {
-        Db * db = getDb(table);
-        Dbt kt((void *) key.c_str(), key.length());
-        Dbt dt((void *) data.c_str(), data.length());
-        db->put(txn.txn, &kt, &dt, 0);
-    } catch (DbException e) { rethrow(e); }
-}
-
-
-void Database::setStrings(const Transaction & txn, TableId table,
-    const string & key, const Strings & data, bool deleteEmpty)
-{
-    if (deleteEmpty && data.size() == 0)
-        delPair(txn, table, key);
-    else
-        setString(txn, table, key, packStrings(data));
-}
-
-
-void Database::delPair(const Transaction & txn, TableId table,
-    const string & key)
-{
-    checkInterrupt();
-    try {
-        Db * db = getDb(table);
-        Dbt kt((void *) key.c_str(), key.length());
-        db->del(txn.txn, &kt, 0);
-        /* Non-existence of a pair with the given key is not an
-           error. */
-    } catch (DbException e) { rethrow(e); }
-}
-
-
-void Database::enumTable(const Transaction & txn, TableId table,
-    Strings & keys, const string & keyPrefix)
-{
-    try {
-        Db * db = getDb(table);
-
-        Dbc * dbc;
-        db->cursor(txn.txn, &dbc, 0);
-        DestroyDbc destroyDbc(dbc);
-
-        Dbt kt, dt;
-        u_int32_t flags = DB_NEXT;
-
-        if (!keyPrefix.empty()) {
-            flags = DB_SET_RANGE;
-            kt = Dbt((void *) keyPrefix.c_str(), keyPrefix.size());
-        }
-
-        while (dbc->get(&kt, &dt, flags) != DB_NOTFOUND) {
-            checkInterrupt();
-            string data((char *) kt.get_data(), kt.get_size());
-            if (!keyPrefix.empty() &&
-                string(data, 0, keyPrefix.size()) != keyPrefix)
-                break;
-            keys.push_back(data);
-            flags = DB_NEXT;
-        }
-
-    } catch (DbException e) { rethrow(e); }
-}
-
- 
-void Database::clearTable(const Transaction & txn, TableId table)
-{
-    try {
-        Db * db = getDb(table);
-        u_int32_t count;
-        db->truncate(txn.txn, &count, 0);
-    } catch (DbException e) { rethrow(e); }
-}
-
-
-}
-
-#endif

src/libstore/db.hh

@@ -1,107 +0,0 @@
-#ifndef __DB_H
-#define __DB_H
-
-#include "types.hh"
-
-#include <map>
-
-
-/* Defined externally. */
-class DbTxn;
-class DbEnv;
-class Db;
-
-
-namespace nix {
-
-
-class Database;
-
-
-class Transaction
-{
-    friend class Database;
-
-private:
-    DbTxn * txn;
-    
-public:
-    Transaction();
-    Transaction(Database & _db);
-    ~Transaction();
-
-    void begin(Database & db);
-    void abort();
-    void commit();
-
-    void moveTo(Transaction & t);
-};
-
-
-#define noTxn Transaction()
-
-
-typedef unsigned int TableId; /* table handles */
-
-
-class Database
-{
-    friend class Transaction;
-
-private:
-    DbEnv * env;
-
-    TableId nextId;
-    std::map<TableId, Db *> tables;
-
-    void requireEnv();
-
-    Db * getDb(TableId table);
-
-    void open2(const string & path, bool removeOldEnv);
-    
-public:
-    Database();
-    ~Database();
-    
-    void open(const string & path);
-    void close();
-
-    TableId openTable(const string & table, bool sorted = false);
-    void closeTable(TableId table);
-    void deleteTable(const string & table);
-
-    bool queryString(const Transaction & txn, TableId table, 
-        const string & key, string & data);
-
-    bool queryStrings(const Transaction & txn, TableId table, 
-        const string & key, Strings & data);
-
-    void setString(const Transaction & txn, TableId table,
-        const string & key, const string & data);
-
-    void setStrings(const Transaction & txn, TableId table,
-        const string & key, const Strings & data,
-        bool deleteEmpty = true);
-
-    void delPair(const Transaction & txn, TableId table,
-        const string & key);
-
-    void enumTable(const Transaction & txn, TableId table,
-        Strings & keys, const string & keyPrefix = "");
-
-    void clearTable(const Transaction & txn, TableId table);
-};
-
-
-class DbNoPermission : public Error
-{
-public:
-    DbNoPermission(const format & f) : Error(f) { };
-};
-
- 
-}
-
-
-#endif /* !__DB_H */

src/libstore/derivations.cc

@@ -21,8 +21,7 @@ Path writeDerivation(const Derivation & drv, const string & name)
 {
     PathSet references;
     references.insert(drv.inputSrcs.begin(), drv.inputSrcs.end());
-    for (DerivationInputs::const_iterator i = drv.inputDrvs.begin();
-         i != drv.inputDrvs.end(); ++i)
+    foreach (DerivationInputs::const_iterator, i, drv.inputDrvs)
         references.insert(i->first);
     /* Note that the outputs of a derivation are *not* references
        (that can be missing (of course) and should not necessarily be

src/libstore/derivations.hh

@@ -1,7 +1,7 @@
 #ifndef __DERIVATIONS_H
 #define __DERIVATIONS_H
 
-typedef struct _ATerm * ATerm;
+#include <aterm1.h>
 
 #include "hash.hh"
 

src/libstore/gc.cc

@@ -7,6 +7,7 @@
 
 #include <functional>
 #include <queue>
+#include <algorithm>
 
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -247,9 +248,7 @@ static void readTempRoots(PathSet & tempRoots, FDs & fds)
     Strings tempRootFiles = readDirectory(
         (format("%1%/%2%") % nixStateDir % tempRootsDir).str());
 
-    for (Strings::iterator i = tempRootFiles.begin();
-         i != tempRootFiles.end(); ++i)
-    {
+    foreach (Strings::iterator, i, tempRootFiles) {
         Path path = (format("%1%/%2%/%3%") % nixStateDir % tempRootsDir % *i).str();
 
         debug(format("reading temporary root file `%1%'") % path);
@@ -328,7 +327,7 @@ static void findRoots(const Path & path, bool recurseSymlinks,
 
         if (S_ISDIR(st.st_mode)) {
             Strings names = readDirectory(path);
-            for (Strings::iterator i = names.begin(); i != names.end(); ++i)
+            foreach (Strings::iterator, i, names)
                 findRoots(path + "/" + *i, recurseSymlinks, deleteStale, roots);
         }
 
@@ -399,11 +398,11 @@ static void addAdditionalRoots(PathSet & roots)
 
     Strings paths = tokenizeString(result, "\n");
     
-    for (Strings::iterator i = paths.begin(); i != paths.end(); ++i) {
+    foreach (Strings::iterator, i, paths) {
         if (isInStore(*i)) {
             Path path = toStorePath(*i);
             if (roots.find(path) == roots.end() && store->isValidPath(path)) {
-                debug(format("found additional root `%1%'") % path);
+                debug(format("got additional root `%1%'") % path);
                 roots.insert(path);
             }
         }
@@ -421,8 +420,7 @@ static void dfsVisit(const PathSet & paths, const Path & path,
     if (store->isValidPath(path))
         store->queryReferences(path, references);
     
-    for (PathSet::iterator i = references.begin();
-         i != references.end(); ++i)
+    foreach (PathSet::iterator, i, references)
         /* Don't traverse into paths that don't exist.  That can
            happen due to substitutes for non-existent paths. */
         if (*i != path && paths.find(*i) != paths.end())
@@ -436,156 +434,224 @@ Paths topoSortPaths(const PathSet & paths)
 {
     Paths sorted;
     PathSet visited;
-    for (PathSet::const_iterator i = paths.begin(); i != paths.end(); ++i)
+    foreach (PathSet::const_iterator, i, paths)
         dfsVisit(paths, *i, visited, sorted);
     return sorted;
 }
 
 
-static time_t lastFileAccessTime(const Path & path)
-{
-    checkInterrupt();
-    
-    struct stat st;
-    if (lstat(path.c_str(), &st) == -1)
-        throw SysError(format("statting `%1%'") % path);
-
-    if (S_ISDIR(st.st_mode)) {
-        time_t last = 0;
-	Strings names = readDirectory(path);
-	for (Strings::iterator i = names.begin(); i != names.end(); ++i) {
-            time_t t = lastFileAccessTime(path + "/" + *i);
-            if (t > last) last = t;
-        }
-        return last;
-    }
-
-    else if (S_ISLNK(st.st_mode)) return 0;
-
-    else return st.st_atime;
-}
-
-
 struct GCLimitReached { };
 
 
-void LocalStore::gcPath(const GCOptions & options, GCResults & results, 
-    const Path & path)
+struct LocalStore::GCState
 {
-    results.paths.insert(path);
+    GCOptions options;
+    GCResults & results;
+    PathSet roots;
+    PathSet tempRoots;
+    PathSet deleted;
+    PathSet live;
+    PathSet busy;
+    bool gcKeepOutputs;
+    bool gcKeepDerivations;
 
-    if (!pathExists(path)) return;
-                
-#ifndef __CYGWIN__
-    AutoCloseFD fdLock;
-        
-    /* Only delete a lock file if we can acquire a write lock on it.
-       That means that it's either stale, or the process that created
-       it hasn't locked it yet.  In the latter case the other process
-       will detect that we deleted the lock, and retry (see
-       pathlocks.cc). */
-    if (path.size() >= 5 && string(path, path.size() - 5) == ".lock") {
-        fdLock = openLockFile(path, false);
-        if (fdLock != -1 && !lockFile(fdLock, ltWrite, false)) {
-            debug(format("skipping active lock `%1%'") % path);
-            return;
-        }
-    }
-#endif
+    bool drvsIndexed;
+    typedef std::multimap<string, Path> DrvsByName;
+    DrvsByName drvsByName; // derivation paths hashed by name attribute
 
-    /* Okay, it's safe to delete. */
-    unsigned long long bytesFreed, blocksFreed;
-    deleteFromStore(path, bytesFreed, blocksFreed);
-    results.bytesFreed += bytesFreed;
-    results.blocksFreed += blocksFreed;
-
-    if (results.bytesFreed > options.maxFreed) {
-        printMsg(lvlInfo, format("deleted more than %1% bytes; stopping") % options.maxFreed);
-        throw GCLimitReached();
-    }
-
-    if (options.maxLinks) {
-        struct stat st;
-        if (stat(nixStore.c_str(), &st) == -1)
-            throw SysError(format("statting `%1%'") % nixStore);
-        if (st.st_nlink < options.maxLinks) {
-            printMsg(lvlInfo, format("link count on the store has dropped below %1%; stopping") % options.maxLinks);
-            throw GCLimitReached();
-        }
-    }
-
-#ifndef __CYGWIN__
-    if (fdLock != -1)
-        /* Write token to stale (deleted) lock file. */
-        writeFull(fdLock, (const unsigned char *) "d", 1);
-#endif
-}
-
-
-void LocalStore::gcPathRecursive(const GCOptions & options,
-    GCResults & results, PathSet & done, const Path & path)
-{
-    if (done.find(path) != done.end()) return;
-    done.insert(path);
-
-    startNest(nest, lvlDebug, format("looking at `%1%'") % path);
-        
-    /* Delete all the referrers first.  They must be garbage too,
-       since if they were live, then the current path would also be
-       live.  Note that deleteFromStore() below still makes sure that
-       the referrer set has become empty, just in case.  (However that
-       doesn't guard against deleting top-level paths that are only
-       reachable from GC roots.) */
-    PathSet referrers;
-    if (isValidPath(path))
-        queryReferrers(path, referrers);
-    foreach (PathSet::iterator, i, referrers)
-        if (*i != path) gcPathRecursive(options, results, done, *i);
-
-    printMsg(lvlInfo, format("deleting `%1%'") % path);
-            
-    gcPath(options, results, path);
-}
-
-
-struct CachingAtimeComparator : public std::binary_function<Path, Path, bool> 
-{
-    std::map<Path, time_t> cache;
-
-    time_t lookup(const Path & p)
+    GCState(GCResults & results_) : results(results_), drvsIndexed(false)
     {
-        std::map<Path, time_t>::iterator i = cache.find(p);
-        if (i != cache.end()) return i->second;
-        debug(format("computing atime of `%1%'") % p);
-        cache[p] = lastFileAccessTime(p);
-        assert(cache.find(p) != cache.end());
-        return cache[p];
-    }
-        
-    bool operator () (const Path & p1, const Path & p2)
-    {
-        return lookup(p2) < lookup(p1);
     }
 };
 
 
-string showTime(const string & format, time_t t)
+static bool doDelete(GCOptions::GCAction action)
 {
-    char s[128];
-    strftime(s, sizeof s, format.c_str(), localtime(&t));
-    return string(s);
+    return action == GCOptions::gcDeleteDead
+        || action == GCOptions::gcDeleteSpecific;
+}
+
+
+bool LocalStore::isActiveTempFile(const GCState & state,
+    const Path & path, const string & suffix)
+{
+    return hasSuffix(path, suffix)
+        && state.tempRoots.find(string(path, 0, path.size() - suffix.size())) != state.tempRoots.end();
+}
+
+
+/* Return all the derivations in the Nix store that have `path' as an
+   output.  This function assumes that derivations have the same name
+   as their outputs. */
+PathSet LocalStore::findDerivers(GCState & state, const Path & path)
+{
+    PathSet derivers;
+
+    Path deriver = queryDeriver(path);
+    if (deriver != "") derivers.insert(deriver);
+
+    if (!state.drvsIndexed) {
+        Paths entries = readDirectory(nixStore);
+        foreach (Paths::iterator, i, entries)
+            if (isDerivation(*i))
+                state.drvsByName.insert(std::pair<string, Path>(
+                        getNameOfStorePath(*i), nixStore + "/" + *i));
+        state.drvsIndexed = true;
+    }
+    
+    string name = getNameOfStorePath(path);
+
+    // Urgh, I should have used Haskell...
+    std::pair<GCState::DrvsByName::iterator, GCState::DrvsByName::iterator> range =
+        state.drvsByName.equal_range(name);
+
+    for (GCState::DrvsByName::iterator i = range.first; i != range.second; ++i)
+        if (isValidPath(i->second)) {
+            Derivation drv = derivationFromPath(i->second);
+            foreach (DerivationOutputs::iterator, j, drv.outputs)
+                if (j->second.path == path) derivers.insert(i->second);
+        }
+
+    return derivers;
+}
+
+    
+bool LocalStore::tryToDelete(GCState & state, const Path & path)
+{
+    if (!pathExists(path)) return true;
+    if (state.deleted.find(path) != state.deleted.end()) return true;
+    if (state.live.find(path) != state.live.end()) return false;
+
+    startNest(nest, lvlDebug, format("considering whether to delete `%1%'") % path);
+
+    if (state.roots.find(path) != state.roots.end()) {
+        printMsg(lvlDebug, format("cannot delete `%1%' because it's a root") % path);
+        goto isLive;
+    }
+
+    if (isValidPath(path)) {
+
+        /* Recursively try to delete the referrers of this path.  If
+           any referrer can't be deleted, then this path can't be
+           deleted either. */
+        PathSet referrers;
+        queryReferrers(path, referrers);
+        foreach (PathSet::iterator, i, referrers)
+            if (*i != path && !tryToDelete(state, *i)) {
+                printMsg(lvlDebug, format("cannot delete `%1%' because it has live referrers") % path);
+                goto isLive;
+            }
+
+        /* If gc-keep-derivations is set and this is a derivation,
+           then don't delete the derivation if any of the outputs are
+           live. */
+        if (state.gcKeepDerivations && isDerivation(path)) {
+            Derivation drv = derivationFromPath(path);
+            foreach (DerivationOutputs::iterator, i, drv.outputs)
+                if (!tryToDelete(state, i->second.path)) {
+                    printMsg(lvlDebug, format("cannot delete derivation `%1%' because its output is alive") % path);
+                    goto isLive;
+                }
+        }
+
+        /* If gc-keep-derivations and gc-keep-outputs are both set,
+           it's possible that the path has already been deleted (due
+           to the recursion below), so bail out. */
+        if (!pathExists(path)) return true;
+
+        /* If gc-keep-outputs is set, then don't delete this path if
+           its deriver is not garbage.  !!! Nix does not reliably
+           store derivers, so we have to look at all derivations to
+           determine which of them derive `path'.  Since this makes
+           the garbage collector very slow to start on large Nix
+           stores, here we just look for all derivations that have the
+           same name as `path' (where the name is the part of the
+           filename after the hash, i.e. the `name' attribute of the
+           derivation).  This is somewhat hacky: currently, the
+           deriver of a path always has the same name as the output,
+           but this might change in the future. */
+        if (state.gcKeepOutputs) {
+            PathSet derivers = findDerivers(state, path);
+            foreach (PathSet::iterator, deriver, derivers) {
+                /* Break an infinite recursion if gc-keep-derivations
+                   and gc-keep-outputs are both set by tentatively
+                   assuming that this path is garbage.  This is a safe
+                   assumption because at this point, the only thing
+                   that can prevent it from being garbage is the
+                   deriver.  Since tryToDelete() works "upwards"
+                   through the dependency graph, it won't encouter
+                   this path except in the call to tryToDelete() in
+                   the gc-keep-derivation branch. */
+                state.deleted.insert(path);
+                if (!tryToDelete(state, *deriver)) {
+                    state.deleted.erase(path);
+                    printMsg(lvlDebug, format("cannot delete `%1%' because its deriver `%2%' is alive") % path % *deriver);
+                    goto isLive;
+                }
+            }
+        }
+    }
+
+    else {
+
+        /* A lock file belonging to a path that we're building right
+           now isn't garbage. */
+        if (isActiveTempFile(state, path, ".lock")) return false;
+
+        /* Don't delete .chroot directories for derivations that are
+           currently being built. */
+        if (isActiveTempFile(state, path, ".chroot")) return false;
+
+    }
+
+    /* The path is garbage, so delete it. */
+    if (doDelete(state.options.action)) {
+        printMsg(lvlInfo, format("deleting `%1%'") % path);
+
+        unsigned long long bytesFreed, blocksFreed;
+        deleteFromStore(path, bytesFreed, blocksFreed);
+        state.results.bytesFreed += bytesFreed;
+        state.results.blocksFreed += blocksFreed;
+
+        if (state.options.maxFreed && state.results.bytesFreed > state.options.maxFreed) {
+            printMsg(lvlInfo, format("deleted more than %1% bytes; stopping") % state.options.maxFreed);
+            throw GCLimitReached();
+        }
+
+        if (state.options.maxLinks) {
+            struct stat st;
+            if (stat(nixStore.c_str(), &st) == -1)
+                throw SysError(format("statting `%1%'") % nixStore);
+            if (st.st_nlink < state.options.maxLinks) {
+                printMsg(lvlInfo, format("link count on the store has dropped below %1%; stopping") % state.options.maxLinks);
+                throw GCLimitReached();
+            }
+        }
+        
+    } else
+        printMsg(lvlTalkative, format("would delete `%1%'") % path);
+    
+    state.deleted.insert(path);
+    if (state.options.action != GCOptions::gcReturnLive)
+        state.results.paths.insert(path);
+    return true;
+
+ isLive:
+    state.live.insert(path);
+    if (state.options.action == GCOptions::gcReturnLive)
+        state.results.paths.insert(path);
+    return false;
 }
 
 
 void LocalStore::collectGarbage(const GCOptions & options, GCResults & results)
 {
-    bool gcKeepOutputs =
-        queryBoolSetting("gc-keep-outputs", false);
-    bool gcKeepDerivations =
-        queryBoolSetting("gc-keep-derivations", true);
-    int gcKeepOutputsThreshold = 
-        queryIntSetting ("gc-keep-outputs-threshold", defaultGcLevel);
-
+    GCState state(results);
+    state.options = options;    
+    
+    state.gcKeepOutputs = queryBoolSetting("gc-keep-outputs", false);
+    state.gcKeepDerivations = queryBoolSetting("gc-keep-derivations", true);
+    
     /* Acquire the global GC root.  This prevents
        a) New roots from being added.
        b) Processes from creating new temporary root files. */
@@ -596,207 +662,60 @@ void LocalStore::collectGarbage(const GCOptions & options, GCResults & results)
     printMsg(lvlError, format("finding garbage collector roots..."));
     Roots rootMap = options.ignoreLiveness ? Roots() : nix::findRoots(true);
 
-    PathSet roots;
-    for (Roots::iterator i = rootMap.begin(); i != rootMap.end(); ++i)
-        roots.insert(i->second);
+    foreach (Roots::iterator, i, rootMap) state.roots.insert(i->second);
 
     /* Add additional roots returned by the program specified by the
        NIX_ROOT_FINDER environment variable.  This is typically used
        to add running programs to the set of roots (to prevent them
        from being garbage collected). */
     if (!options.ignoreLiveness)
-        addAdditionalRoots(roots);
-
-    if (options.action == GCOptions::gcReturnRoots) {
-        results.paths = roots;
-        return;
-    }
-
-    /* Determine the live paths which is just the closure of the
-       roots under the `references' relation. */
-    printMsg(lvlError, format("computing live paths..."));
-    PathSet livePaths;
-    for (PathSet::const_iterator i = roots.begin(); i != roots.end(); ++i)
-        computeFSClosure(canonPath(*i), livePaths);
-
-    if (gcKeepDerivations) {
-        for (PathSet::iterator i = livePaths.begin();
-             i != livePaths.end(); ++i)
-        {
-            /* Note that the deriver need not be valid (e.g., if we
-               previously ran the collector with `gcKeepDerivations'
-               turned off). */
-            Path deriver = queryDeriver(*i);
-            if (deriver != "" && isValidPath(deriver))
-                computeFSClosure(deriver, livePaths);
-        }
-    }
-
-    if (gcKeepOutputs) {
-        /* Hmz, identical to storePathRequisites in nix-store. */
-        for (PathSet::iterator i = livePaths.begin();
-             i != livePaths.end(); ++i)
-            if (isDerivation(*i)) {
-                Derivation drv = derivationFromPath(*i);
-
-		string gcLevelStr = drv.env["__gcLevel"];
-		int gcLevel;
-		if (!string2Int(gcLevelStr, gcLevel))
-		    gcLevel = defaultGcLevel;
-		
-		if (gcLevel >= gcKeepOutputsThreshold)    
-		    for (DerivationOutputs::iterator j = drv.outputs.begin();
-                         j != drv.outputs.end(); ++j)
-			if (isValidPath(j->second.path))
-			    computeFSClosure(j->second.path, livePaths);
-            }
-    }
-
-    if (options.action == GCOptions::gcReturnLive) {
-        results.paths = livePaths;
-        return;
-    }
+        addAdditionalRoots(state.roots);
 
     /* Read the temporary roots.  This acquires read locks on all
        per-process temporary root files.  So after this point no paths
        can be added to the set of temporary roots. */
-    PathSet tempRoots;
     FDs fds;
-    readTempRoots(tempRoots, fds);
-
-    /* Close the temporary roots.  Note that we *cannot* do this in
-       readTempRoots(), because there we may not have all locks yet,
-       meaning that an invalid path can become valid (and thus add to
-       the references graph) after we have added it to the closure
-       (and computeFSClosure() assumes that the presence of a path
-       means that it has already been closed). */
-    PathSet tempRootsClosed;
-    for (PathSet::iterator i = tempRoots.begin(); i != tempRoots.end(); ++i)
-        if (isValidPath(*i))
-            computeFSClosure(*i, tempRootsClosed);
-        else
-            tempRootsClosed.insert(*i);
+    readTempRoots(state.tempRoots, fds);
+    state.roots.insert(state.tempRoots.begin(), state.tempRoots.end());
 
     /* After this point the set of roots or temporary roots cannot
        increase, since we hold locks on everything.  So everything
-       that is not currently in in `livePaths' or `tempRootsClosed'
-       can be deleted. */
-    
-    /* Read the Nix store directory to find all currently existing
-       paths and filter out all live paths. */
-    printMsg(lvlError, format("reading the Nix store..."));
-    PathSet storePaths;
-    
-    if (options.action != GCOptions::gcDeleteSpecific) {
-        Paths entries = readDirectory(nixStore);
-        foreach (Paths::iterator, i, entries) {
-            Path path = canonPath(nixStore + "/" + *i);
-            if (livePaths.find(path) == livePaths.end() &&
-                tempRootsClosed.find(path) == tempRootsClosed.end())
-                storePaths.insert(path);
-        }
-    }
+       that is not reachable from `roots'. */
+
+    /* Now either delete all garbage paths, or just the specified
+       paths (for gcDeleteSpecific). */
+
+    if (options.action == GCOptions::gcDeleteSpecific) {
 
-    else {
         foreach (PathSet::iterator, i, options.pathsToDelete) {
             assertStorePath(*i);
-            storePaths.insert(*i);
-            if (livePaths.find(*i) != livePaths.end())
+            if (!tryToDelete(state, *i))
                 throw Error(format("cannot delete path `%1%' since it is still alive") % *i);
-            if (tempRootsClosed.find(*i) != tempRootsClosed.end())
-                throw Error(format("cannot delete path `%1%' since it is temporarily in use") % *i);
-        }
-    }
-
-    if (options.action == GCOptions::gcReturnDead) {
-        results.paths.insert(storePaths.begin(), storePaths.end());
-        return;
-    }
-
-    /* Delete all dead store paths (or until one of the stop
-       conditions is reached). */
-
-    PathSet done;
-    try {
-
-        if (!options.useAtime) {
-            /* Delete the paths, respecting the partial ordering
-               determined by the references graph. */
-            printMsg(lvlError, format("deleting garbage..."));
-            foreach (PathSet::iterator, i, storePaths)
-                gcPathRecursive(options, results, done, *i);
-        }
-
-        else {
-
-            /* Delete in order of ascending last access time, still
-               maintaining the partial ordering of the reference
-               graph.  Note that we can't use a topological sort for
-               this because that takes time O(V+E), and in this case
-               E=O(V^2) (i.e. the graph is dense because of the edges
-               due to the atime ordering).  So instead we put all
-               deletable paths in a priority queue (ordered by atime),
-               and after deleting a path, add additional paths that
-               have become deletable to the priority queue. */
-
-            CachingAtimeComparator atimeComp;
-
-            /* Create a priority queue that orders paths by ascending
-               atime.  This is why C++ needs type inferencing... */
-            std::priority_queue<Path, vector<Path>, binary_function_ref_adapter<CachingAtimeComparator> > prioQueue =
-                std::priority_queue<Path, vector<Path>, binary_function_ref_adapter<CachingAtimeComparator> >(binary_function_ref_adapter<CachingAtimeComparator>(&atimeComp));
-
-           /* Initially put the paths that are invalid or have no
-              referrers into the priority queue. */
-            printMsg(lvlError, format("finding deletable paths..."));
-            foreach (PathSet::iterator, i, storePaths) {
-                checkInterrupt();
-                /* We can safely delete a path if it's invalid or
-                   it has no referrers.  Note that all the invalid
-                   paths will be deleted in the first round. */
-                if (isValidPath(*i)) {
-                    if (queryReferrersNoSelf(*i).empty()) prioQueue.push(*i);
-                } else prioQueue.push(*i);
-            }
-
-            debug(format("%1% initially deletable paths") % prioQueue.size());
-
-            /* Now delete everything in the order of the priority
-               queue until nothing is left. */
-            printMsg(lvlError, format("deleting garbage..."));
-            while (!prioQueue.empty()) {
-                checkInterrupt();
-                Path path = prioQueue.top(); prioQueue.pop();
-
-                if (options.maxAtime != (time_t) -1 &&
-                    atimeComp.lookup(path) > options.maxAtime)
-                    continue;
-                
-                printMsg(lvlInfo, format("deleting `%1%' (last accessed %2%)") % path % showTime("%F %H:%M:%S", atimeComp.lookup(path)));
-
-                PathSet references;
-                if (isValidPath(path)) references = queryReferencesNoSelf(path);
-
-                gcPath(options, results, path);
-
-                /* For each reference of the current path, see if the
-                   reference has now become deletable (i.e. is in the
-                   set of dead paths and has no referrers left).  If
-                   so add it to the priority queue. */
-                foreach (PathSet::iterator, i, references) {
-                    if (storePaths.find(*i) != storePaths.end() &&
-                        queryReferrersNoSelf(*i).empty())
-                    {
-                        debug(format("path `%1%' has become deletable") % *i);
-                        prioQueue.push(*i);
-                    }
-                }
-            }
-            
         }
         
-    } catch (GCLimitReached & e) {
-    }
+    } else {
+        
+        printMsg(lvlError, format("reading the Nix store..."));
+        Paths entries = readDirectory(nixStore);
+
+        /* Randomise the order in which we delete entries to make the
+           collector less biased towards deleting paths that come
+           alphabetically first (e.g. /nix/store/000...).  This
+           matters when using --max-freed etc. */
+        vector<Path> entries_(entries.begin(), entries.end());
+        random_shuffle(entries_.begin(), entries_.end());
+
+        if (doDelete(state.options.action))
+            printMsg(lvlError, format("deleting garbage..."));
+        else
+            printMsg(lvlError, format("determining live/dead paths..."));
+    
+        try {
+            foreach (vector<Path>::iterator, i, entries_)
+                tryToDelete(state, canonPath(nixStore + "/" + *i));
+        } catch (GCLimitReached & e) {
+        }
+    }        
 }
 
 

src/libstore/globals.cc

@@ -16,7 +16,6 @@ string nixDBPath = "/UNINIT";
 string nixConfDir = "/UNINIT";
 string nixLibexecDir = "/UNINIT";
 string nixBinDir = "/UNINIT";
-string nixChrootsDir = "/UNINIT";
 
 bool keepFailed = false;
 bool keepGoing = false;
@@ -25,7 +24,7 @@ Verbosity buildVerbosity = lvlInfo;
 unsigned int maxBuildJobs = 1;
 bool readOnlyMode = false;
 string thisSystem = "unset";
-unsigned int maxSilentTime = 0;
+time_t maxSilentTime = 0;
 Paths substituters;
 bool useBuildHook = true;
 bool printBuildTrace = false;
@@ -35,6 +34,9 @@ static bool settingsRead = false;
 
 static std::map<string, Strings> settings;
 
+/* Overriden settings. */
+std::map<string, Strings> settingsCmdline;
+
 
 string & at(Strings & ss, unsigned int n)
 {
@@ -74,6 +76,8 @@ static void readSettings()
         advance(i, 2);
         settings[name] = Strings(i, tokens.end());
     };
+
+    settings.insert(settingsCmdline.begin(), settingsCmdline.end());
     
     settingsRead = true;
 }
@@ -119,6 +123,13 @@ unsigned int queryIntSetting(const string & name, unsigned int def)
 }
 
 
+void overrideSetting(const string & name, const Strings & value)
+{
+    if (settingsRead) settings[name] = value;
+    settingsCmdline[name] = value;
+}
+
+
 void reloadSettings()
 {
     settingsRead = false;

src/libstore/globals.hh

@@ -35,12 +35,6 @@ extern string nixLibexecDir;
 /* nixBinDir is the directory where the main programs are stored. */
 extern string nixBinDir;
 
-/* nixChrootsDir is the directory where we create chroot environments
-   (when chroot builds are enabled).  We don't put these under /tmp to
-   prevent "rm -rf /tmp" from recursing into /nix/store via the bind
-   mounts in the chroots. */
-extern string nixChrootsDir;
-
 
 /* Misc. global flags. */
 
@@ -71,7 +65,7 @@ extern string thisSystem;
 /* The maximum time in seconds that a builer can go without producing
    any output on stdout/stderr before it is killed.  0 means
    infinity. */
-extern unsigned int maxSilentTime;
+extern time_t maxSilentTime;
 
 /* The substituters.  There are programs that can somehow realise a
    store path without building, e.g., by downloading it or copying it
@@ -107,6 +101,8 @@ bool queryBoolSetting(const string & name, bool def);
 
 unsigned int queryIntSetting(const string & name, unsigned int def);
 
+void overrideSetting(const string & name, const Strings & value);
+
 void reloadSettings();
 
     

src/libstore/local-store.cc

@@ -16,6 +16,7 @@
 #include <utime.h>
 #include <fcntl.h>
 #include <errno.h>
+#include <stdio.h>
 
 
 namespace nix {
@@ -47,6 +48,21 @@ LocalStore::LocalStore()
     
     if (readOnlyMode) return;
 
+    /* Create missing state directories if they don't already exist. */
+    createDirs(nixStore);
+    createDirs(nixDBPath + "/info");
+    createDirs(nixDBPath + "/referrer");
+    createDirs(nixDBPath + "/failed");
+    Path profilesDir = nixStateDir + "/profiles";
+    createDirs(nixStateDir + "/profiles");
+    createDirs(nixStateDir + "/temproots");
+    Path gcRootsDir = nixStateDir + "/gcroots";
+    if (!pathExists(gcRootsDir)) {
+        createDirs(gcRootsDir);
+        if (symlink(profilesDir.c_str(), (gcRootsDir + "/profiles").c_str()) == -1)
+            throw SysError(format("creating symlink to `%1%'") % profilesDir);
+    }
+  
     checkStoreNotSymlink();
 
     try {
@@ -62,10 +78,7 @@ LocalStore::LocalStore()
         printMsg(lvlError, "waiting for the big Nix store lock...");
         lockFile(globalLock, ltRead, true);
     }
-
-    createDirs(nixDBPath + "/info");
-    createDirs(nixDBPath + "/referrer");
-
+    
     int curSchema = getSchema();
     if (curSchema > nixSchemaVersion)
         throw Error(format("current Nix store schema is version %1%, but I only support %2%")
@@ -76,6 +89,8 @@ LocalStore::LocalStore()
     }
     if (curSchema == 1) throw Error("your Nix store is no longer supported");
     if (curSchema < nixSchemaVersion) upgradeStore12();
+
+    doFsync = queryBoolSetting("fsync-metadata", false);
 }
 
 
@@ -85,8 +100,8 @@ LocalStore::~LocalStore()
         flushDelayedUpdates();
 
         foreach (RunningSubstituters::iterator, i, runningSubstituters) {
-            i->second.toBuf.reset();
-            i->second.to.reset();
+            i->second.to.close();
+            i->second.from.close();
             i->second.pid.wait(true);
         }
                 
@@ -108,23 +123,6 @@ int LocalStore::getSchema()
 }
 
 
-void copyPath(const Path & src, const Path & dst, PathFilter & filter)
-{
-    debug(format("copying `%1%' to `%2%'") % src % dst);
-
-    /* Dump an archive of the path `src' into a string buffer, then
-       restore the archive to `dst'.  This is not a very good method
-       for very large paths, but `copyPath' is mainly used for small
-       files. */ 
-
-    StringSink sink;
-    dumpPath(src, sink, filter);
-
-    StringSource source(sink.s);
-    restorePath(dst, source);
-}
-
-
 void canonicalisePathMetaData(const Path & path, bool recurse)
 {
     checkInterrupt();
@@ -167,7 +165,7 @@ void canonicalisePathMetaData(const Path & path, bool recurse)
         if (st.st_mtime != 0) {
             struct utimbuf utimbuf;
             utimbuf.actime = st.st_atime;
-            utimbuf.modtime = 0;
+            utimbuf.modtime = 1; /* 1 second into the epoch */
             if (utime(path.c_str(), &utimbuf) == -1) 
                 throw SysError(format("changing modification time of `%1%'") % path);
         }
@@ -176,7 +174,7 @@ void canonicalisePathMetaData(const Path & path, bool recurse)
 
     if (recurse && S_ISDIR(st.st_mode)) {
         Strings names = readDirectory(path);
-	for (Strings::iterator i = names.begin(); i != names.end(); ++i)
+	foreach (Strings::iterator, i, names)
 	    canonicalisePathMetaData(path + "/" + *i, true);
     }
 }
@@ -213,13 +211,20 @@ static Path referrersFileFor(const Path & path)
 }
 
 
+static Path failedFileFor(const Path & path)
+{
+    string baseName = baseNameOf(path);
+    return (format("%1%/failed/%2%") % nixDBPath % baseName).str();
+}
+
+
 static Path tmpFileForAtomicUpdate(const Path & path)
 {
     return (format("%1%/.%2%.%3%") % dirOf(path) % getpid() % baseNameOf(path)).str();
 }
 
 
-static void appendReferrer(const Path & from, const Path & to, bool lock)
+void LocalStore::appendReferrer(const Path & from, const Path & to, bool lock)
 {
     Path referrersFile = referrersFileFor(from);
     
@@ -234,6 +239,8 @@ static void appendReferrer(const Path & from, const Path & to, bool lock)
     
     string s = " " + to;
     writeFull(fd, (const unsigned char *) s.c_str(), s.size());
+
+    if (doFsync) fdatasync(fd);
 }
 
 
@@ -264,6 +271,8 @@ void LocalStore::rewriteReferrers(const Path & path, bool purge, PathSet referre
     
     writeFull(fd, (const unsigned char *) s.c_str(), s.size());
 
+    if (doFsync) fdatasync(fd);
+    
     fd.close(); /* for Windows; can't rename open file */
 
     if (rename(tmpFile.c_str(), referrersFile.c_str()) == -1)
@@ -332,6 +341,8 @@ void LocalStore::registerValidPath(const ValidPathInfo & info, bool ignoreValidi
             appendReferrer(*i, info.path, false);
     }
 
+    assert(info.hash.type == htSHA256);
+
     string s = (format(
         "Hash: sha256:%1%\n"
         "References: %2%\n"
@@ -342,7 +353,7 @@ void LocalStore::registerValidPath(const ValidPathInfo & info, bool ignoreValidi
 
     /* Atomically rewrite the info file. */
     Path tmpFile = tmpFileForAtomicUpdate(infoFile);
-    writeFile(tmpFile, s);
+    writeFile(tmpFile, s, doFsync);
     if (rename(tmpFile.c_str(), infoFile.c_str()) == -1)
         throw SysError(format("cannot rename `%1%' to `%2%'") % tmpFile % infoFile);
 
@@ -350,6 +361,20 @@ void LocalStore::registerValidPath(const ValidPathInfo & info, bool ignoreValidi
 }
 
 
+void LocalStore::registerFailedPath(const Path & path)
+{
+    /* Write an empty file in the .../failed directory to denote the
+       failure of the builder for `path'. */
+    writeFile(failedFileFor(path), "");
+}
+
+
+bool LocalStore::hasPathFailed(const Path & path)
+{
+    return pathExists(failedFileFor(path));
+}
+
+
 Hash parseHashField(const Path & path, const string & s)
 {
     string::size_type colon = s.find(':');
@@ -364,13 +389,16 @@ Hash parseHashField(const Path & path, const string & s)
 }
 
 
-ValidPathInfo LocalStore::queryPathInfo(const Path & path)
+ValidPathInfo LocalStore::queryPathInfo(const Path & path, bool ignoreErrors)
 {
     ValidPathInfo res;
     res.path = path;
 
     assertStorePath(path);
 
+    if (!isValidPath(path))
+        throw Error(format("path `%1%' is not valid") % path);
+
     std::map<Path, ValidPathInfo>::iterator lookup = pathInfoCache.find(path);
     if (lookup != pathInfoCache.end()) return lookup->second;
     
@@ -383,9 +411,13 @@ ValidPathInfo LocalStore::queryPathInfo(const Path & path)
     /* Parse it. */
     Strings lines = tokenizeString(info, "\n");
 
-    for (Strings::iterator i = lines.begin(); i != lines.end(); ++i) {
-        unsigned int p = i->find(':');
-        if (p == string::npos) continue; /* bad line */
+    foreach (Strings::iterator, i, lines) {
+        string::size_type p = i->find(':');
+        if (p == string::npos) {
+            if (!ignoreErrors)
+                throw Error(format("corrupt line in `%1%': %2%") % infoFile % *i);
+            continue; /* bad line */
+        }
         string name(*i, 0, p);
         string value(*i, p + 2);
         if (name == "References") {
@@ -394,7 +426,12 @@ ValidPathInfo LocalStore::queryPathInfo(const Path & path)
         } else if (name == "Deriver") {
             res.deriver = value;
         } else if (name == "Hash") {
-            res.hash = parseHashField(path, value);
+            try {
+                res.hash = parseHashField(path, value);
+            } catch (Error & e) {
+                if (!ignoreErrors) throw;
+                printMsg(lvlError, format("cannot parse hash field in `%1%': %2%") % infoFile % e.msg());
+            }
         } else if (name == "Registered-At") {
             int n = 0;
             string2Int(value, n);
@@ -411,7 +448,22 @@ bool LocalStore::isValidPath(const Path & path)
     /* Files in the info directory starting with a `.' are temporary
        files. */
     if (baseNameOf(path).at(0) == '.') return false;
-    return pathExists(infoFileFor(path));
+
+    /* A path is valid if its info file exists and has a non-zero
+       size.  (The non-zero size restriction is to be robust to
+       certain kinds of filesystem corruption, particularly with
+       ext4.) */
+    Path infoFile = infoFileFor(path);
+
+    struct stat st;
+    if (lstat(infoFile.c_str(), &st)) {
+        if (errno == ENOENT) return false;
+        throw SysError(format("getting status of `%1%'") % infoFile);
+    }
+
+    if (st.st_size == 0) return false;
+    
+    return true;
 }
 
 
@@ -419,7 +471,7 @@ PathSet LocalStore::queryValidPaths()
 {
     PathSet paths;
     Strings entries = readDirectory(nixDBPath + "/info");
-    for (Strings::iterator i = entries.begin(); i != entries.end(); ++i)
+    foreach (Strings::iterator, i, entries)
         if (i->at(0) != '.') paths.insert(nixStore + "/" + *i);
     return paths;
 }
@@ -454,7 +506,7 @@ bool LocalStore::queryReferrersInternal(const Path & path, PathSet & referrers)
 
     Paths refs = tokenizeString(readFile(fd), " ");
 
-    for (Paths::iterator i = refs.begin(); i != refs.end(); ++i)
+    foreach (Paths::iterator, i, refs)
         /* Referrers can be invalid (see registerValidPath() for the
            invariant), so we only return one if it is valid. */
         if (isStorePath(*i) && isValidPath(*i)) referrers.insert(*i); else allValid = false;
@@ -495,6 +547,13 @@ void LocalStore::startSubstituter(const Path & substituter, RunningSubstituter &
 
     case 0: /* child */
         try {
+            /* Hack to let "make check" succeed on Darwin.  The
+               libtool wrapper script sets DYLD_LIBRARY_PATH to our
+               libutil (among others), but Perl also depends on a
+               library named libutil.  As a result, substituters
+               written in Perl (i.e. all of them) fail. */
+            unsetenv("DYLD_LIBRARY_PATH");
+            
             fromPipe.readSide.close();
             toPipe.writeSide.close();
             if (dup2(toPipe.readSide, STDIN_FILENO) == -1)
@@ -512,23 +571,16 @@ void LocalStore::startSubstituter(const Path & substituter, RunningSubstituter &
 
     /* Parent. */
     
-    toPipe.readSide.close();
-    fromPipe.writeSide.close();
-
-    run.toBuf = boost::shared_ptr<stdio_filebuf>(new stdio_filebuf(toPipe.writeSide.borrow(), std::ios_base::out));
-    run.to = boost::shared_ptr<std::ostream>(new std::ostream(&*run.toBuf));
-
-    run.fromBuf = boost::shared_ptr<stdio_filebuf>(new stdio_filebuf(fromPipe.readSide.borrow(), std::ios_base::in));
-    run.from = boost::shared_ptr<std::istream>(new std::istream(&*run.fromBuf));
+    run.to = toPipe.writeSide.borrow();
+    run.from = fromPipe.readSide.borrow();
 }
 
 
-template<class T> T getIntLine(std::istream & str)
+template<class T> T getIntLine(int fd)
 {
-    string s;
+    string s = readLine(fd);
     T res;
-    getline(str, s);
-    if (!str || !string2Int(s, res)) throw Error("integer expected from stream");
+    if (!string2Int(s, res)) throw Error("integer expected from stream");
     return res;
 }
 
@@ -538,10 +590,8 @@ bool LocalStore::hasSubstitutes(const Path & path)
     foreach (Paths::iterator, i, substituters) {
         RunningSubstituter & run(runningSubstituters[*i]);
         startSubstituter(*i, run);
-
-        *run.to << "have\n" << path << "\n" << std::flush;
-
-        if (getIntLine<int>(*run.from)) return true;
+        writeLine(run.to, "have\n" + path);
+        if (getIntLine<int>(run.from)) return true;
     }
 
     return false;
@@ -554,19 +604,19 @@ bool LocalStore::querySubstitutablePathInfo(const Path & substituter,
     RunningSubstituter & run(runningSubstituters[substituter]);
     startSubstituter(substituter, run);
 
-    *run.to << "info\n" << path << "\n" << std::flush;
-        
-    if (!getIntLine<int>(*run.from)) return false;
+    writeLine(run.to, "info\n" + path);
+
+    if (!getIntLine<int>(run.from)) return false;
     
-    getline(*run.from, info.deriver);
+    info.deriver = readLine(run.from);
     if (info.deriver != "") assertStorePath(info.deriver);
-    int nrRefs = getIntLine<int>(*run.from);
+    int nrRefs = getIntLine<int>(run.from);
     while (nrRefs--) {
-        Path p; getline(*run.from, p);
+        Path p = readLine(run.from);
         assertStorePath(p);
         info.references.insert(p);
     }
-    info.downloadSize = getIntLine<long long>(*run.from);
+    info.downloadSize = getIntLine<long long>(run.from);
     
     return true;
 }
@@ -595,8 +645,7 @@ static void dfsVisit(std::map<Path, ValidPathInfo> & infos,
 
     ValidPathInfo & info(infos[path]);
     
-    for (PathSet::iterator i = info.references.begin();
-         i != info.references.end(); ++i)
+    foreach (PathSet::iterator, i, info.references)
         if (infos.find(*i) != infos.end())
             dfsVisit(infos, *i, visited, sorted);
 
@@ -611,15 +660,15 @@ void LocalStore::registerValidPaths(const ValidPathInfos & infos)
     /* Sort the paths topologically under the references relation, so
        that if path A is referenced by B, then A is registered before
        B. */
-    for (ValidPathInfos::const_iterator i = infos.begin(); i != infos.end(); ++i)
+    foreach (ValidPathInfos::const_iterator, i, infos)
         infosMap[i->path] = *i;
 
     PathSet visited;
     Paths sorted;
-    for (ValidPathInfos::const_iterator i = infos.begin(); i != infos.end(); ++i)
+    foreach (ValidPathInfos::const_iterator, i, infos)
         dfsVisit(infosMap, i->path, visited, sorted);
 
-    for (Paths::iterator i = sorted.begin(); i != sorted.end(); ++i)
+    foreach (Paths::iterator, i, sorted)
         registerValidPath(infosMap[*i]);
 }
 
@@ -670,16 +719,12 @@ void LocalStore::invalidatePath(const Path & path)
 }
 
 
-Path LocalStore::addToStore(const Path & _srcPath, bool fixed,
-    bool recursive, string hashAlgo, PathFilter & filter)
+Path LocalStore::addToStoreFromDump(const string & dump, const string & name,
+    bool recursive, HashType hashAlgo)
 {
-    Path srcPath(absPath(_srcPath));
-    debug(format("adding `%1%' to the store") % srcPath);
+    Hash h = hashString(hashAlgo, dump);
 
-    std::pair<Path, Hash> pr =
-        computeStorePathForPath(srcPath, fixed, recursive, hashAlgo, filter);
-    Path & dstPath(pr.first);
-    Hash & h(pr.second);
+    Path dstPath = makeFixedOutputPath(recursive, hashAlgo, h, name);
 
     addTempRoot(dstPath);
 
@@ -694,16 +739,22 @@ Path LocalStore::addToStore(const Path & _srcPath, bool fixed,
 
             if (pathExists(dstPath)) deletePathWrapped(dstPath);
 
-            copyPath(srcPath, dstPath, filter);
-
-            Hash h2 = hashPath(htSHA256, dstPath, filter);
-            if (h != h2)
-                throw Error(format("contents of `%1%' changed while copying it to `%2%' (%3% -> %4%)")
-                    % srcPath % dstPath % printHash(h) % printHash(h2));
+            if (recursive) {
+                StringSource source(dump);
+                restorePath(dstPath, source);
+            } else
+                writeFile(dstPath, dump);
 
             canonicalisePathMetaData(dstPath);
-            
-            registerValidPath(dstPath, h, PathSet(), "");
+
+            /* Register the SHA-256 hash of the NAR serialisation of
+               the path in the database.  We may just have computed it
+               above (if called with recursive == true and hashAlgo ==
+               sha256); otherwise, compute it here. */
+            registerValidPath(dstPath,
+                (recursive && hashAlgo == htSHA256) ? h :
+                (recursive ? hashString(htSHA256, dump) : hashPath(htSHA256, dstPath)),
+                PathSet(), "");
         }
 
         outputLock.setDeletion(true);
@@ -713,10 +764,29 @@ Path LocalStore::addToStore(const Path & _srcPath, bool fixed,
 }
 
 
-Path LocalStore::addTextToStore(const string & suffix, const string & s,
+Path LocalStore::addToStore(const Path & _srcPath,
+    bool recursive, HashType hashAlgo, PathFilter & filter)
+{
+    Path srcPath(absPath(_srcPath));
+    debug(format("adding `%1%' to the store") % srcPath);
+
+    /* Read the whole path into memory. This is not a very scalable
+       method for very large paths, but `copyPath' is mainly used for
+       small files. */
+    StringSink sink;
+    if (recursive) 
+        dumpPath(srcPath, sink, filter);
+    else
+        sink.s = readFile(srcPath);
+
+    return addToStoreFromDump(sink.s, baseNameOf(srcPath), recursive, hashAlgo);
+}
+
+
+Path LocalStore::addTextToStore(const string & name, const string & s,
     const PathSet & references)
 {
-    Path dstPath = computeStorePathForText(suffix, s, references);
+    Path dstPath = computeStorePathForText(name, s, references);
     
     addTempRoot(dstPath);
 
@@ -728,7 +798,7 @@ Path LocalStore::addTextToStore(const string & suffix, const string & s,
 
             if (pathExists(dstPath)) deletePathWrapped(dstPath);
 
-            writeStringToFile(dstPath, s);
+            writeFile(dstPath, s);
 
             canonicalisePathMetaData(dstPath);
             
@@ -807,7 +877,7 @@ void LocalStore::exportPath(const Path & path, bool sign,
         Path tmpDir = createTempDir();
         AutoDelete delTmp(tmpDir);
         Path hashFile = tmpDir + "/hash";
-        writeStringToFile(hashFile, printHash(hash));
+        writeFile(hashFile, printHash(hash));
 
         Path secretKey = nixConfDir + "/signing-key.sec";
         checkSecrecy(secretKey);
@@ -854,7 +924,7 @@ Path LocalStore::importPath(bool requireSignature, Source & source)
        store path follows the archive data proper), and besides, we
        don't know yet whether the signature is valid. */
     Path tmpDir = createTempDir(nixStore);
-    AutoDelete delTmp(tmpDir);
+    AutoDelete delTmp(tmpDir); /* !!! could be GC'ed! */
     Path unpacked = tmpDir + "/unpacked";
 
     restorePath(unpacked, hashAndReadSource);
@@ -883,7 +953,7 @@ Path LocalStore::importPath(bool requireSignature, Source & source)
 
         if (requireSignature) {
             Path sigFile = tmpDir + "/sig";
-            writeStringToFile(sigFile, signature);
+            writeFile(sigFile, signature);
 
             Strings args;
             args.push_back("rsautl");
@@ -913,7 +983,14 @@ Path LocalStore::importPath(bool requireSignature, Source & source)
 
     if (!isValidPath(dstPath)) {
 
-        PathLocks outputLock(singleton<PathSet, Path>(dstPath));
+        PathLocks outputLock;
+
+        /* Lock the output path.  But don't lock if we're being called
+           from a build hook (whose parent process already acquired a
+           lock on this path). */
+        Strings locksHeld = tokenizeString(getEnv("NIX_HELD_LOCKS"));
+        if (find(locksHeld.begin(), locksHeld.end(), dstPath) == locksHeld.end())
+            outputLock.lockPaths(singleton<PathSet, Path>(dstPath));
 
         if (!isValidPath(dstPath)) {
 
@@ -971,7 +1048,7 @@ void LocalStore::verifyStore(bool checkContents)
 
     PathSet validPaths2 = queryValidPaths(), validPaths;
     
-    for (PathSet::iterator i = validPaths2.begin(); i != validPaths2.end(); ++i) {
+    foreach (PathSet::iterator, i, validPaths2) {
         checkInterrupt();
         if (!isStorePath(*i)) {
             printMsg(lvlError, format("path `%1%' is not in the Nix store") % *i);
@@ -979,8 +1056,18 @@ void LocalStore::verifyStore(bool checkContents)
         } else if (!pathExists(*i)) {
             printMsg(lvlError, format("path `%1%' disappeared") % *i);
             invalidatePath(*i);
-        } else
-            validPaths.insert(*i);
+        } else {
+            Path infoFile = infoFileFor(*i);
+            struct stat st;
+            if (lstat(infoFile.c_str(), &st))
+                throw SysError(format("getting status of `%1%'") % infoFile);
+            if (st.st_size == 0) {
+                printMsg(lvlError, format("removing corrupt info file `%1%'") % infoFile);
+                if (unlink(infoFile.c_str()) == -1)
+                    throw SysError(format("unlinking `%1%'") % infoFile);
+            }
+            else validPaths.insert(*i);
+        }
     }
 
 
@@ -989,26 +1076,25 @@ void LocalStore::verifyStore(bool checkContents)
 
     std::map<Path, PathSet> referrersCache;
     
-    for (PathSet::iterator i = validPaths.begin(); i != validPaths.end(); ++i) {
+    foreach (PathSet::iterator, i, validPaths) {
         bool update = false;
-        ValidPathInfo info = queryPathInfo(*i);
+        ValidPathInfo info = queryPathInfo(*i, true);
 
         /* Check the references: each reference should be valid, and
            it should have a matching referrer. */
-        for (PathSet::iterator j = info.references.begin();
-             j != info.references.end(); ++j)
-        {
-            if (referrersCache.find(*j) == referrersCache.end())
-                queryReferrers(*j, referrersCache[*j]);
-            if (referrersCache[*j].find(*i) == referrersCache[*j].end()) {
-                printMsg(lvlError, format("adding missing referrer mapping from `%1%' to `%2%'")
-                    % *j % *i);
-                appendReferrer(*j, *i, true);
-            }
+        foreach (PathSet::iterator, j, info.references) {
             if (validPaths.find(*j) == validPaths.end()) {
                 printMsg(lvlError, format("incomplete closure: `%1%' needs missing `%2%'")
                     % *i % *j);
                 /* nothing we can do about it... */
+            } else {
+                if (referrersCache.find(*j) == referrersCache.end())
+                    queryReferrers(*j, referrersCache[*j]);
+                if (referrersCache[*j].find(*i) == referrersCache[*j].end()) {
+                    printMsg(lvlError, format("adding missing referrer mapping from `%1%' to `%2%'")
+                        % *j % *i);
+                    appendReferrer(*j, *i, true);
+                }
             }
         }
 
@@ -1020,7 +1106,11 @@ void LocalStore::verifyStore(bool checkContents)
         }
 
         /* Check the content hash (optionally - slow). */
-        if (checkContents) {
+        if (info.hash.hashSize == 0) {
+            printMsg(lvlError, format("re-hashing `%1%'") % *i);
+            info.hash = hashPath(htSHA256, *i);
+            update = true;
+        } else if (checkContents) {
             debug(format("checking contents of `%1%'") % *i);
             Hash current = hashPath(info.hash.type, *i);
             if (current != info.hash) {
@@ -1042,10 +1132,12 @@ void LocalStore::verifyStore(bool checkContents)
     std::map<Path, PathSet> referencesCache;
     
     Strings entries = readDirectory(nixDBPath + "/referrer");
-    for (Strings::iterator i = entries.begin(); i != entries.end(); ++i) {
+    foreach (Strings::iterator, i, entries) {
         Path from = nixStore + "/" + *i;
         
         if (validPaths.find(from) == validPaths.end()) {
+            /* !!! This removes lock files as well.  Need to check
+               whether that's okay. */
             printMsg(lvlError, format("removing referrers file for invalid `%1%'") % from);
             Path p = referrersFileFor(from);
             if (unlink(p.c_str()) == -1)
@@ -1064,7 +1156,7 @@ void LocalStore::verifyStore(bool checkContents)
 
         /* Each referrer should have a matching reference. */
         PathSet referrersNew;
-        for (PathSet::iterator j = referrers.begin(); j != referrers.end(); ++j) {
+        foreach (PathSet::iterator, j, referrers) {
             if (referencesCache.find(*j) == referencesCache.end())
                 queryReferences(*j, referencesCache[*j]);
             if (referencesCache[*j].find(from) == referencesCache[*j].end()) {
@@ -1079,4 +1171,16 @@ void LocalStore::verifyStore(bool checkContents)
 }
 
 
+/* Upgrade from schema 4 (Nix 0.11) to schema 5 (Nix >= 0.12).  The
+   old schema uses Berkeley DB, the new one stores store path
+   meta-information in files. */
+void LocalStore::upgradeStore12()
+{
+    throw Error(
+        "Your Nix store has a database in Berkeley DB format,\n"
+        "which is no longer supported. To convert to the new format,\n"
+        "please upgrade Nix to version 0.12 first.");
+}
+
+
 }

src/libstore/local-store.hh

@@ -3,8 +3,6 @@
 
 #include <string>
 
-#include <ext/stdio_filebuf.h>
-
 #include "store-api.hh"
 #include "util.hh"
 
@@ -36,15 +34,10 @@ struct OptimiseStats
 };
 
 
-typedef __gnu_cxx::stdio_filebuf<char> stdio_filebuf;
-
-
 struct RunningSubstituter
 {
     Pid pid;
-    boost::shared_ptr<stdio_filebuf> toBuf, fromBuf;
-    boost::shared_ptr<std::ostream> to;
-    boost::shared_ptr<std::istream> from;
+    AutoCloseFD to, from;
 };
 
 
@@ -89,11 +82,18 @@ public:
     bool querySubstitutablePathInfo(const Path & substituter,
         const Path & path, SubstitutablePathInfo & info);
     
-    Path addToStore(const Path & srcPath, bool fixed = false,
-        bool recursive = false, string hashAlgo = "",
+    Path addToStore(const Path & srcPath,
+        bool recursive = true, HashType hashAlgo = htSHA256,
         PathFilter & filter = defaultPathFilter);
 
-    Path addTextToStore(const string & suffix, const string & s,
+    /* Like addToStore(), but the contents of the path are contained
+       in `dump', which is either a NAR serialisation (if recursive ==
+       true) or simply the contents of a regular file (if recursive ==
+       false). */
+    Path addToStoreFromDump(const string & dump, const string & name,
+        bool recursive = true, HashType hashAlgo = htSHA256);
+
+    Path addTextToStore(const string & name, const string & s,
         const PathSet & references);
 
     void exportPath(const Path & path, bool sign,
@@ -137,6 +137,13 @@ public:
 
     void registerValidPaths(const ValidPathInfos & infos);
 
+    /* Register that the build of a derivation with output `path' has
+       failed. */
+    void registerFailedPath(const Path & path);
+
+    /* Query whether `path' previously failed to build. */
+    bool hasPathFailed(const Path & path);
+
 private:
 
     Path schemaPath;
@@ -151,12 +158,17 @@ private:
     /* Store paths for which the referrers file must be purged. */
     PathSet delayedUpdates;
 
+    /* Whether to do an fsync() after writing Nix metadata. */
+    bool doFsync;
+
     int getSchema();
 
     void registerValidPath(const ValidPathInfo & info, bool ignoreValidity = false);
 
-    ValidPathInfo queryPathInfo(const Path & path);
+    ValidPathInfo queryPathInfo(const Path & path, bool ignoreErrors = false);
 
+    void appendReferrer(const Path & from, const Path & to, bool lock);
+    
     void rewriteReferrers(const Path & path, bool purge, PathSet referrers);
 
     void flushDelayedUpdates();
@@ -167,24 +179,24 @@ private:
     
     void upgradeStore12();
 
-    void gcPath(const GCOptions & options, GCResults & results,
-        const Path & path);
-
-    void gcPathRecursive(const GCOptions & options,
-        GCResults & results, PathSet & done, const Path & path);
+    struct GCState;
 
+    bool tryToDelete(GCState & state, const Path & path);
+    
+    PathSet findDerivers(GCState & state, const Path & path);
+    
+    bool isActiveTempFile(const GCState & state,
+        const Path & path, const string & suffix);
+        
     void startSubstituter(const Path & substituter,
         RunningSubstituter & runningSubstituter);
 };
 
 
-/* Copy a path recursively. */
-void copyPath(const Path & src, const Path & dst);
-
 /* "Fix", or canonicalise, the meta-data of the files in a store path
    after it has been built.  In particular:
-   - the last modification date on each file is set to 0 (i.e.,
-     00:00:00 1/1/1970 UTC)
+   - the last modification date on each file is set to 1 (i.e.,
+     00:00:01 1/1/1970 UTC)
    - the permissions are set of 444 or 555 (i.e., read-only with or
      without execute permission; setuid bits etc. are cleared)
    - the owner and group are set to the Nix user and group, if we're

src/libstore/misc.cc

@@ -19,7 +19,7 @@ Derivation derivationFromPath(const Path & drvPath)
 
 
 void computeFSClosure(const Path & storePath,
-    PathSet & paths, bool flipDirection)
+    PathSet & paths, bool flipDirection, bool includeOutputs)
 {
     if (paths.find(storePath) != paths.end()) return;
     paths.insert(storePath);
@@ -30,16 +30,21 @@ void computeFSClosure(const Path & storePath,
     else
         store->queryReferences(storePath, references);
 
-    for (PathSet::iterator i = references.begin();
-         i != references.end(); ++i)
-        computeFSClosure(*i, paths, flipDirection);
+    if (includeOutputs && isDerivation(storePath)) {
+        Derivation drv = derivationFromPath(storePath);
+        foreach (DerivationOutputs::iterator, i, drv.outputs)
+            if (store->isValidPath(i->second.path))
+                computeFSClosure(i->second.path, paths, flipDirection, true);
+    }
+
+    foreach (PathSet::iterator, i, references)
+        computeFSClosure(*i, paths, flipDirection, includeOutputs);
 }
 
 
 Path findOutput(const Derivation & drv, string id)
 {
-    for (DerivationOutputs::const_iterator i = drv.outputs.begin();
-         i != drv.outputs.end(); ++i)
+    foreach (DerivationOutputs::const_iterator, i, drv.outputs)
         if (i->first == id) return i->second.path;
     throw Error(format("derivation has no output `%1%'") % id);
 }
@@ -67,20 +72,17 @@ void queryMissing(const PathSet & targets,
             Derivation drv = derivationFromPath(p);
 
             bool mustBuild = false;
-            for (DerivationOutputs::iterator i = drv.outputs.begin();
-                 i != drv.outputs.end(); ++i)
+            foreach (DerivationOutputs::iterator, i, drv.outputs)
                 if (!store->isValidPath(i->second.path) && !store->hasSubstitutes(i->second.path))
                     mustBuild = true;
 
             if (mustBuild) {
                 willBuild.insert(p);
                 todo.insert(drv.inputSrcs.begin(), drv.inputSrcs.end());
-                for (DerivationInputs::iterator i = drv.inputDrvs.begin();
-                     i != drv.inputDrvs.end(); ++i)
+                foreach (DerivationInputs::iterator, i, drv.inputDrvs)
                     todo.insert(i->first);
             } else 
-                for (DerivationOutputs::iterator i = drv.outputs.begin();
-                     i != drv.outputs.end(); ++i)
+                foreach (DerivationOutputs::iterator, i, drv.outputs)
                     todo.insert(i->second.path);
         }
 

src/libstore/misc.hh

@@ -19,7 +19,8 @@ Derivation derivationFromPath(const Path & drvPath);
    `referrers' relation instead of the `references' relation is
    returned. */
 void computeFSClosure(const Path & storePath,
-    PathSet & paths, bool flipDirection = false);
+    PathSet & paths, bool flipDirection = false,
+    bool includeOutputs = false);
 
 /* Return the path corresponding to the output identifier `id' in the
    given derivation. */

src/libstore/optimise-store.cc

@@ -5,6 +5,7 @@
 #include <sys/stat.h>
 #include <unistd.h>
 #include <errno.h>
+#include <stdio.h>
 
 
 namespace nix {
@@ -131,7 +132,7 @@ static void hashAndLink(bool dryRun, HashToPath & hashToPath,
 
     if (S_ISDIR(st.st_mode)) {
         Strings names = readDirectory(path);
-	for (Strings::iterator i = names.begin(); i != names.end(); ++i)
+	foreach (Strings::iterator, i, names)
 	    hashAndLink(dryRun, hashToPath, stats, path + "/" + *i);
     }
 }
@@ -143,7 +144,7 @@ void LocalStore::optimiseStore(bool dryRun, OptimiseStats & stats)
 
     PathSet paths = queryValidPaths();
 
-    for (PathSet::iterator i = paths.begin(); i != paths.end(); ++i) {
+    foreach (PathSet::iterator, i, paths) {
         addTempRoot(*i);
         if (!isValidPath(*i)) continue; /* path was GC'ed, probably */
         startNest(nest, lvlChatty, format("hashing files in `%1%'") % *i);

src/libstore/pathlocks.cc

@@ -141,9 +141,9 @@ PathLocks::PathLocks(const PathSet & paths, const string & waitMsg)
 }
 
 
-void PathLocks::lockPaths(const PathSet & _paths, const string & waitMsg)
+bool PathLocks::lockPaths(const PathSet & _paths,
+    const string & waitMsg, bool wait)
 {
-    /* May be called only once! */
     assert(fds.empty());
     
     /* Note that `fds' is built incrementally so that the destructor
@@ -155,7 +155,7 @@ void PathLocks::lockPaths(const PathSet & _paths, const string & waitMsg)
     paths.sort();
     
     /* Acquire the lock for each path. */
-    for (Paths::iterator i = paths.begin(); i != paths.end(); i++) {
+    foreach (Paths::iterator, i, paths) {
         checkInterrupt();
         Path path = *i;
         Path lockPath = path + ".lock";
@@ -174,8 +174,15 @@ void PathLocks::lockPaths(const PathSet & _paths, const string & waitMsg)
 
             /* Acquire an exclusive lock. */
             if (!lockFile(fd, ltWrite, false)) {
-                if (waitMsg != "") printMsg(lvlError, waitMsg);
-                lockFile(fd, ltWrite, true);
+                if (wait) {
+                    if (waitMsg != "") printMsg(lvlError, waitMsg);
+                    lockFile(fd, ltWrite, true);
+                } else {
+                    /* Failed to lock this path; release all other
+                       locks. */
+                    unlock();
+                    return false;
+                }
             }
 
             debug(format("lock acquired on `%1%'") % lockPath);
@@ -199,12 +206,20 @@ void PathLocks::lockPaths(const PathSet & _paths, const string & waitMsg)
         fds.push_back(FDPair(fd.borrow(), lockPath));
         lockedPaths.insert(lockPath);
     }
+
+    return true;
 }
 
 
 PathLocks::~PathLocks()
 {
-    for (list<FDPair>::iterator i = fds.begin(); i != fds.end(); i++) {
+    unlock();
+}
+
+
+void PathLocks::unlock()
+{
+    foreach (list<FDPair>::iterator, i, fds) {
         if (deletePaths) deleteLockFilePreClose(i->second, i->first);
 
         lockedPaths.erase(i->second);
@@ -216,6 +231,8 @@ PathLocks::~PathLocks()
 
         debug(format("lock released on `%1%'") % i->second);
     }
+
+    fds.clear();
 }
 
 

src/libstore/pathlocks.hh

@@ -33,9 +33,11 @@ public:
     PathLocks();
     PathLocks(const PathSet & paths,
         const string & waitMsg = "");
-    void lockPaths(const PathSet & _paths,
-        const string & waitMsg = "");
+    bool lockPaths(const PathSet & _paths,
+        const string & waitMsg = "",
+        bool wait = true);
     ~PathLocks();
+    void unlock();
     void setDeletion(bool deletePaths);
 };
 

src/libstore/references.cc

@@ -1,17 +1,10 @@
 #include "references.hh"
 #include "hash.hh"
 #include "util.hh"
+#include "archive.hh"
 
-#include <cerrno>
-#include <cstring>
-#include <cstdlib>
 #include <map>
-
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <unistd.h>
-#include <dirent.h>
-#include <fcntl.h>
+#include <cstdlib>
 
 
 namespace nix {
@@ -20,8 +13,8 @@ namespace nix {
 static unsigned int refLength = 32; /* characters */
 
 
-static void search(size_t len, const unsigned char * s,
-    StringSet & ids, StringSet & seen)
+static void search(const unsigned char * s, unsigned int len, 
+    StringSet & hashes, StringSet & seen)
 {
     static bool initialised = false;
     static bool isBase32[256];
@@ -43,93 +36,60 @@ static void search(size_t len, const unsigned char * s,
             }
         if (!match) continue;
         string ref((const char *) s + i, refLength);
-        if (ids.find(ref) != ids.end()) {
+        if (hashes.find(ref) != hashes.end()) {
             debug(format("found reference to `%1%' at offset `%2%'")
                   % ref % i);
             seen.insert(ref);
-            ids.erase(ref);
+            hashes.erase(ref);
         }
         ++i;
     }
 }
 
 
-void checkPath(const string & path,
-    StringSet & ids, StringSet & seen)
+struct RefScanSink : Sink
 {
-    checkInterrupt();
+    HashSink hashSink;
+    StringSet hashes;
+    StringSet seen;
+
+    string tail;
+
+    RefScanSink() : hashSink(htSHA256) { }
     
-    debug(format("checking `%1%'") % path);
+    void operator () (const unsigned char * data, unsigned int len);
+};
 
-    struct stat st;
-    if (lstat(path.c_str(), &st))
-        throw SysError(format("getting attributes of path `%1%'") % path);
 
-    if (S_ISDIR(st.st_mode)) {
-        Strings names = readDirectory(path);
-	for (Strings::iterator i = names.begin(); i != names.end(); i++) {
-            search(i->size(), (const unsigned char *) i->c_str(), ids, seen);
-            checkPath(path + "/" + *i, ids, seen);
-        }
-    }
+void RefScanSink::operator () (const unsigned char * data, unsigned int len)
+{
+    hashSink(data, len);
 
-    else if (S_ISREG(st.st_mode)) {
-        
-        AutoCloseFD fd = open(path.c_str(), O_RDONLY);
-        if (fd == -1) throw SysError(format("opening file `%1%'") % path);
+    /* It's possible that a reference spans the previous and current
+       fragment, so search in the concatenation of the tail of the
+       previous fragment and the start of the current fragment. */
+    string s = tail + string((const char *) data, len > refLength ? refLength : len);
+    search((const unsigned char *) s.c_str(), s.size(), hashes, seen);
 
-        size_t bufSize = 1024 * 1024;
-        assert(refLength <= bufSize);
-        unsigned char * buf = new unsigned char[bufSize];
+    search(data, len, hashes, seen);
 
-        size_t left = st.st_size;
-        bool firstBlock = true;
-        
-        while (left > 0) {
-            checkInterrupt();
-            
-            size_t read = left > bufSize ? bufSize : left;
-            size_t copiedBytes = 0;
-
-            if (!firstBlock) {
-                /* Move the last (refLength - 1) bytes from the last
-                   block to the start of the buffer to deal with
-                   references that cross block boundaries. */
-                copiedBytes = refLength - 1;
-                if (read + copiedBytes > bufSize)
-                    read -= copiedBytes;
-                memcpy(buf, buf + (bufSize - copiedBytes), copiedBytes);
-            }
-            firstBlock = false;
-
-            readFull(fd, buf + copiedBytes, read);
-            left -= read;
-
-            search(copiedBytes + read, buf, ids, seen);
-        }
-        
-        delete[] buf; /* !!! autodelete */
-    }
-    
-    else if (S_ISLNK(st.st_mode)) {
-        string target = readLink(path);
-        search(target.size(), (const unsigned char *) target.c_str(), ids, seen);
-    }
-    
-    else throw Error(format("unknown file type: %1%") % path);
+    unsigned int tailLen = len <= refLength ? len : refLength;
+    tail =
+        string(tail, tail.size() < refLength - tailLen ? 0 : tail.size() - (refLength - tailLen)) +
+        string((const char *) data + len - tailLen, tailLen);
 }
 
 
-PathSet scanForReferences(const string & path, const PathSet & paths)
+PathSet scanForReferences(const string & path,
+    const PathSet & refs, Hash & hash)
 {
+    RefScanSink sink;
     std::map<string, Path> backMap;
-    StringSet ids;
-    StringSet seen;
 
     /* For efficiency (and a higher hit rate), just search for the
        hash part of the file name.  (This assumes that all references
        have the form `HASH-bla'). */
-    for (PathSet::const_iterator i = paths.begin(); i != paths.end(); i++) {
+    foreach (PathSet::const_iterator, i, refs) {
         string baseName = baseNameOf(*i);
         string::size_type pos = baseName.find('-');
         if (pos == string::npos)
@@ -138,21 +98,25 @@ PathSet scanForReferences(const string & path, const PathSet & paths)
         assert(s.size() == refLength);
         assert(backMap.find(s) == backMap.end());
         // parseHash(htSHA256, s);
-        ids.insert(s);
+        sink.hashes.insert(s);
         backMap[s] = *i;
     }
 
-    checkPath(path, ids, seen);
+    /* Look for the hashes in the NAR dump of the path. */
+    dumpPath(path, sink);
 
+    /* Map the hashes found back to their store paths. */
     PathSet found;
-    for (StringSet::iterator i = seen.begin(); i != seen.end(); i++) {
+    foreach (StringSet::iterator, i, sink.seen) {
         std::map<string, Path>::iterator j;
         if ((j = backMap.find(*i)) == backMap.end()) abort();
         found.insert(j->second);
     }
 
+    hash = sink.hashSink.finish();
+        
     return found;
 }
 
- 
+
 }

src/libstore/references.hh

@@ -2,10 +2,12 @@
 #define __REFERENCES_H
 
 #include "types.hh"
+#include "hash.hh"
 
 namespace nix {
 
-PathSet scanForReferences(const Path & path, const PathSet & refs);
+PathSet scanForReferences(const Path & path, const PathSet & refs,
+    Hash & hash);
     
 }
 

src/libstore/remote-store.cc

@@ -29,14 +29,22 @@ Path readStorePath(Source & from)
 PathSet readStorePaths(Source & from)
 {
     PathSet paths = readStringSet(from);
-    for (PathSet::iterator i = paths.begin(); i != paths.end(); ++i)
-        assertStorePath(*i);
+    foreach (PathSet::iterator, i, paths) assertStorePath(*i);
     return paths;
 }
 
 
 RemoteStore::RemoteStore()
 {
+    initialised = false;
+}
+
+
+void RemoteStore::openConnection()
+{
+    if (initialised) return;
+    initialised = true;
+
     string remoteMode = getEnv("NIX_REMOTE");
 
     if (remoteMode == "slave")
@@ -64,8 +72,8 @@ RemoteStore::RemoteStore()
             throw Error("Nix daemon protocol version not supported");
         writeInt(PROTOCOL_VERSION, to);
         processStderr();
-
-    } catch (Error & e) {
+    }
+    catch (Error & e) {
         throw Error(format("cannot start worker (%1%)")
             % e.msg());
     }
@@ -194,6 +202,7 @@ void RemoteStore::setOptions()
 
 bool RemoteStore::isValidPath(const Path & path)
 {
+    openConnection();
     writeInt(wopIsValidPath, to);
     writeString(path, to);
     processStderr();
@@ -204,12 +213,14 @@ bool RemoteStore::isValidPath(const Path & path)
 
 PathSet RemoteStore::queryValidPaths()
 {
+    openConnection();
     throw Error("not implemented");
 }
 
 
 bool RemoteStore::hasSubstitutes(const Path & path)
 {
+    openConnection();
     writeInt(wopHasSubstitutes, to);
     writeString(path, to);
     processStderr();
@@ -221,6 +232,7 @@ bool RemoteStore::hasSubstitutes(const Path & path)
 bool RemoteStore::querySubstitutablePathInfo(const Path & path,
     SubstitutablePathInfo & info)
 {
+    openConnection();
     if (GET_PROTOCOL_MINOR(daemonVersion) < 3) return false;
     writeInt(wopQuerySubstitutablePathInfo, to);
     writeString(path, to);
@@ -237,6 +249,7 @@ bool RemoteStore::querySubstitutablePathInfo(const Path & path,
 
 Hash RemoteStore::queryPathHash(const Path & path)
 {
+    openConnection();
     writeInt(wopQueryPathHash, to);
     writeString(path, to);
     processStderr();
@@ -248,6 +261,7 @@ Hash RemoteStore::queryPathHash(const Path & path)
 void RemoteStore::queryReferences(const Path & path,
     PathSet & references)
 {
+    openConnection();
     writeInt(wopQueryReferences, to);
     writeString(path, to);
     processStderr();
@@ -259,6 +273,7 @@ void RemoteStore::queryReferences(const Path & path,
 void RemoteStore::queryReferrers(const Path & path,
     PathSet & referrers)
 {
+    openConnection();
     writeInt(wopQueryReferrers, to);
     writeString(path, to);
     processStderr();
@@ -269,6 +284,7 @@ void RemoteStore::queryReferrers(const Path & path,
 
 Path RemoteStore::queryDeriver(const Path & path)
 {
+    openConnection();
     writeInt(wopQueryDeriver, to);
     writeString(path, to);
     processStderr();
@@ -278,27 +294,31 @@ Path RemoteStore::queryDeriver(const Path & path)
 }
 
 
-Path RemoteStore::addToStore(const Path & _srcPath, bool fixed,
-    bool recursive, string hashAlgo, PathFilter & filter)
+Path RemoteStore::addToStore(const Path & _srcPath,
+    bool recursive, HashType hashAlgo, PathFilter & filter)
 {
+    openConnection();
+    
     Path srcPath(absPath(_srcPath));
     
     writeInt(wopAddToStore, to);
     writeString(baseNameOf(srcPath), to);
-    writeInt(fixed ? 1 : 0, to);
+    /* backwards compatibility hack */
+    writeInt((hashAlgo == htSHA256 && recursive) ? 0 : 1, to);
     writeInt(recursive ? 1 : 0, to);
-    writeString(hashAlgo, to);
+    writeString(printHashType(hashAlgo), to);
     dumpPath(srcPath, to, filter);
     processStderr();
     return readStorePath(from);
 }
 
 
-Path RemoteStore::addTextToStore(const string & suffix, const string & s,
+Path RemoteStore::addTextToStore(const string & name, const string & s,
     const PathSet & references)
 {
+    openConnection();
     writeInt(wopAddTextToStore, to);
-    writeString(suffix, to);
+    writeString(name, to);
     writeString(s, to);
     writeStringSet(references, to);
     
@@ -310,6 +330,7 @@ Path RemoteStore::addTextToStore(const string & suffix, const string & s,
 void RemoteStore::exportPath(const Path & path, bool sign,
     Sink & sink)
 {
+    openConnection();
     writeInt(wopExportPath, to);
     writeString(path, to);
     writeInt(sign ? 1 : 0, to);
@@ -320,10 +341,10 @@ void RemoteStore::exportPath(const Path & path, bool sign,
 
 Path RemoteStore::importPath(bool requireSignature, Source & source)
 {
+    openConnection();
     writeInt(wopImportPath, to);
     /* We ignore requireSignature, since the worker forces it to true
-       anyway. */
-    
+       anyway. */    
     processStderr(0, &source);
     return readStorePath(from);
 }
@@ -331,6 +352,7 @@ Path RemoteStore::importPath(bool requireSignature, Source & source)
 
 void RemoteStore::buildDerivations(const PathSet & drvPaths)
 {
+    openConnection();
     writeInt(wopBuildDerivations, to);
     writeStringSet(drvPaths, to);
     processStderr();
@@ -340,6 +362,7 @@ void RemoteStore::buildDerivations(const PathSet & drvPaths)
 
 void RemoteStore::ensurePath(const Path & path)
 {
+    openConnection();
     writeInt(wopEnsurePath, to);
     writeString(path, to);
     processStderr();
@@ -349,6 +372,7 @@ void RemoteStore::ensurePath(const Path & path)
 
 void RemoteStore::addTempRoot(const Path & path)
 {
+    openConnection();
     writeInt(wopAddTempRoot, to);
     writeString(path, to);
     processStderr();
@@ -358,6 +382,7 @@ void RemoteStore::addTempRoot(const Path & path)
 
 void RemoteStore::addIndirectRoot(const Path & path)
 {
+    openConnection();
     writeInt(wopAddIndirectRoot, to);
     writeString(path, to);
     processStderr();
@@ -367,6 +392,7 @@ void RemoteStore::addIndirectRoot(const Path & path)
 
 void RemoteStore::syncWithGC()
 {
+    openConnection();
     writeInt(wopSyncWithGC, to);
     processStderr();
     readInt(from);
@@ -375,6 +401,7 @@ void RemoteStore::syncWithGC()
 
 Roots RemoteStore::findRoots()
 {
+    openConnection();
     writeInt(wopFindRoots, to);
     processStderr();
     unsigned int count = readInt(from);
@@ -390,12 +417,19 @@ Roots RemoteStore::findRoots()
 
 void RemoteStore::collectGarbage(const GCOptions & options, GCResults & results)
 {
+    openConnection();
+    
     writeInt(wopCollectGarbage, to);
     writeInt(options.action, to);
     writeStringSet(options.pathsToDelete, to);
     writeInt(options.ignoreLiveness, to);
     writeLongLong(options.maxFreed, to);
     writeInt(options.maxLinks, to);
+    if (GET_PROTOCOL_MINOR(daemonVersion) >= 5) {
+        /* removed options */
+        writeInt(0, to);
+        writeInt(0, to);
+    }
     
     processStderr();
     

src/libstore/remote-store.hh

@@ -42,11 +42,11 @@ public:
     bool querySubstitutablePathInfo(const Path & path,
         SubstitutablePathInfo & info);
     
-    Path addToStore(const Path & srcPath, bool fixed = false,
-        bool recursive = false, string hashAlgo = "",
+    Path addToStore(const Path & srcPath,
+        bool recursive = true, HashType hashAlgo = htSHA256,
         PathFilter & filter = defaultPathFilter);
 
-    Path addTextToStore(const string & suffix, const string & s,
+    Path addTextToStore(const string & name, const string & s,
         const PathSet & references);
 
     void exportPath(const Path & path, bool sign,
@@ -74,6 +74,9 @@ private:
     FdSource from;
     Pid child;
     unsigned int daemonVersion;
+    bool initialised;
+
+    void openConnection();
 
     void processStderr(Sink * sink = 0, Source * source = 0);
 

src/libstore/store-api.cc

@@ -1,16 +1,11 @@
 #include "store-api.hh"
 #include "globals.hh"
 #include "util.hh"
+#include "derivations.hh"
 
 #include <limits.h>
 
 
-/* Needed for some ancient environments. */
-#ifndef ULLONG_MAX
-#define ULLONG_MAX 18446744073709551615
-#endif
-
-
 namespace nix {
 
 
@@ -18,10 +13,8 @@ GCOptions::GCOptions()
 {
     action = gcDeleteDead;
     ignoreLiveness = false;
-    maxFreed = ULLONG_MAX;
+    maxFreed = 0;
     maxLinks = 0;
-    useAtime = false;
-    maxAtime = (time_t) -1;
 }
 
 
@@ -60,6 +53,18 @@ Path toStorePath(const Path & path)
 }
 
 
+string getNameOfStorePath(const Path & path)
+{
+    Path::size_type slash = path.rfind('/');
+    string p = slash == Path::npos ? path : string(path, slash + 1);
+    Path::size_type dash = p.find('-');
+    assert(dash != Path::npos);
+    string p2 = string(p, dash + 1);
+    if (isDerivation(p2)) p2 = string(p2, 0, p2.size() - 4);
+    return p2;
+}
+
+
 Path followLinksToStore(const Path & _path)
 {
     Path path = absPath(_path);
@@ -87,7 +92,7 @@ void checkStoreName(const string & name)
        reasons (e.g., "." and ".."). */
     if (string(name, 0, 1) == ".")
         throw Error(format("illegal name: `%1%'") % name);
-    for (string::const_iterator i = name.begin(); i != name.end(); ++i)
+    foreach (string::const_iterator, i, name)
         if (!((*i >= 'A' && *i <= 'Z') ||
               (*i >= 'a' && *i <= 'z') ||
               (*i >= '0' && *i <= '9') ||
@@ -99,55 +104,113 @@ void checkStoreName(const string & name)
 }
 
 
+/* Store paths have the following form:
+
+   <store>/<h>-<name>
+
+   where
+
+   <store> = the location of the Nix store, usually /nix/store
+   
+   <name> = a human readable name for the path, typically obtained
+     from the name attribute of the derivation, or the name of the
+     source file from which the store path is created
+     
+   <h> = base-32 representation of the first 160 bits of a SHA-256
+     hash of <s>; the hash part of the store name
+     
+   <s> = the string "<type>:sha256:<h2>:<store>:<name>";
+     note that it includes the location of the store as well as the
+     name to make sure that changes to either of those are reflected
+     in the hash (e.g. you won't get /nix/store/<h>-name1 and
+     /nix/store/<h>-name2 with equal hash parts).
+     
+   <type> = one of:
+     "text:<r1>:<r2>:...<rN>"
+       for plain text files written to the store using
+       addTextToStore(); <r1> ... <rN> are the references of the
+       path.
+     "source"
+       for paths copied to the store using addToStore() when recursive
+       = true and hashAlgo = "sha256"
+     "output:out"
+       for either the outputs created by derivations, OR paths copied
+       to the store using addToStore() with recursive != true or
+       hashAlgo != "sha256" (in that case "source" is used; it's
+       silly, but it's done that way for compatibility).
+
+   <h2> = base-16 representation of a SHA-256 hash of:
+     if <type> = "text:...":
+       the string written to the resulting store path
+     if <type> = "source":
+       the serialisation of the path from which this store path is
+       copied, as returned by hashPath()
+     if <type> = "output:out":
+       for non-fixed derivation outputs:
+         the derivation (see hashDerivationModulo() in
+         primops.cc)
+       for paths copied by addToStore() or produced by fixed-output
+       derivations:
+         the string "fixed:out:<rec><algo>:<hash>:", where
+           <rec> = "r:" for recursive (path) hashes, or "" or flat
+             (file) hashes
+           <algo> = "md5", "sha1" or "sha256"
+           <hash> = base-16 representation of the path or flat hash of
+             the contents of the path (or expected contents of the
+             path for fixed-output derivations)
+
+   It would have been nicer to handle fixed-output derivations under
+   "source", e.g. have something like "source:<rec><algo>", but we're
+   stuck with this for now...
+
+   The main reason for this way of computing names is to prevent name
+   collisions (for security).  For instance, it shouldn't be feasible
+   to come up with a derivation whose output path collides with the
+   path for a copied source.  The former would have a <s> starting with
+   "output:out:", while the latter would have a <2> starting with
+   "source:".
+*/
+
+
 Path makeStorePath(const string & type,
-    const Hash & hash, const string & suffix)
+    const Hash & hash, const string & name)
 {
     /* e.g., "source:sha256:1abc...:/nix/store:foo.tar.gz" */
     string s = type + ":sha256:" + printHash(hash) + ":"
-        + nixStore + ":" + suffix;
+        + nixStore + ":" + name;
 
-    checkStoreName(suffix);
+    checkStoreName(name);
 
     return nixStore + "/"
         + printHash32(compressHash(hashString(htSHA256, s), 20))
-        + "-" + suffix;
+        + "-" + name;
 }
 
 
 Path makeFixedOutputPath(bool recursive,
-    string hashAlgo, Hash hash, string name)
+    HashType hashAlgo, Hash hash, string name)
 {
-    /* !!! copy/paste from primops.cc */
-    Hash h = hashString(htSHA256, "fixed:out:"
-        + (recursive ? (string) "r:" : "") + hashAlgo + ":"
-        + printHash(hash) + ":"
-        + "");
-    return makeStorePath("output:out", h, name);
+    return hashAlgo == htSHA256 && recursive
+        ? makeStorePath("source", hash, name)
+        : makeStorePath("output:out", hashString(htSHA256,
+                "fixed:out:" + (recursive ? (string) "r:" : "") +
+                printHashType(hashAlgo) + ":" + printHash(hash) + ":"),
+            name);
 }
 
 
 std::pair<Path, Hash> computeStorePathForPath(const Path & srcPath,
-    bool fixed, bool recursive, string hashAlgo, PathFilter & filter)
+    bool recursive, HashType hashAlgo, PathFilter & filter)
 {
-    Hash h = hashPath(htSHA256, srcPath, filter);
-
-    string baseName = baseNameOf(srcPath);
-
-    Path dstPath;
-    
-    if (fixed) {
-        HashType ht(parseHashType(hashAlgo));
-        Hash h2 = recursive ? hashPath(ht, srcPath, filter) : hashFile(ht, srcPath);
-        dstPath = makeFixedOutputPath(recursive, hashAlgo, h2, baseName);
-    }
-        
-    else dstPath = makeStorePath("source", h, baseName);
-
+    HashType ht(hashAlgo);
+    Hash h = recursive ? hashPath(ht, srcPath, filter) : hashFile(ht, srcPath);
+    string name = baseNameOf(srcPath);
+    Path dstPath = makeFixedOutputPath(recursive, hashAlgo, h, name);
     return std::pair<Path, Hash>(dstPath, h);
 }
 
 
-Path computeStorePathForText(const string & suffix, const string & s,
+Path computeStorePathForText(const string & name, const string & s,
     const PathSet & references)
 {
     Hash hash = hashString(htSHA256, s);
@@ -155,11 +218,11 @@ Path computeStorePathForText(const string & suffix, const string & s,
        hacky, but we can't put them in `s' since that would be
        ambiguous. */
     string type = "text";
-    for (PathSet::const_iterator i = references.begin(); i != references.end(); ++i) {
+    foreach (PathSet::const_iterator, i, references) {
         type += ":";
         type += *i;
     }
-    return makeStorePath(type, hash, suffix);
+    return makeStorePath(type, hash, name);
 }
 
 
@@ -171,7 +234,7 @@ string makeValidityRegistration(const PathSet & paths,
 {
     string s = "";
     
-    for (PathSet::iterator i = paths.begin(); i != paths.end(); ++i) {
+    foreach (PathSet::iterator, i, paths) {
         s += *i + "\n";
 
         if (showHash)
@@ -185,8 +248,7 @@ string makeValidityRegistration(const PathSet & paths,
 
         s += (format("%1%\n") % references.size()).str();
             
-        for (PathSet::iterator j = references.begin();
-             j != references.end(); ++j)
+        foreach (PathSet::iterator, j, references)
             s += *j + "\n";
     }
 
@@ -220,9 +282,7 @@ ValidPathInfo decodeValidPathInfo(std::istream & str, bool hashGiven)
 string showPaths(const PathSet & paths)
 {
     string s;
-    for (PathSet::const_iterator i = paths.begin();
-         i != paths.end(); ++i)
-    {
+    foreach (PathSet::const_iterator, i, paths) {
         if (s.size() != 0) s += ", ";
         s += "`" + *i + "'";
     }

src/libstore/store-api.hh

@@ -22,10 +22,6 @@ struct GCOptions
 {
     /* Garbage collector operation:
 
-       - `gcReturnRoots': find and return the set of roots for the
-         garbage collector.  These are the store paths symlinked to in
-         the `gcroots' directory.
-
        - `gcReturnLive': return the set of paths reachable from
          (i.e. in the closure of) the roots.
 
@@ -38,7 +34,6 @@ struct GCOptions
           `pathsToDelete', insofar as they are not reachable.
     */
     typedef enum {
-        gcReturnRoots,
         gcReturnLive,
         gcReturnDead,
         gcDeleteDead,
@@ -56,29 +51,14 @@ struct GCOptions
     /* For `gcDeleteSpecific', the paths to delete. */
     PathSet pathsToDelete;
 
-    /* Stop after at least `maxFreed' bytes have been freed. */
+    /* Stop after at least `maxFreed' bytes have been freed.  0 means
+       no limit. */
     unsigned long long maxFreed;
 
     /* Stop after the number of hard links to the Nix store directory
        has dropped below `maxLinks'. */
     unsigned int maxLinks;
 
-    /* Delete paths in order of ascending last access time.  I.e.,
-       prefer deleting unrecently used paths.  Useful in conjunction
-       with `maxFreed' and `maxLinks' (or manual interruption).  The
-       access time of a path is defined as the highest atime of any
-       non-directory, non-symlink file under that path.  Directories
-       and symlinks are ignored because their atimes are frequently
-       mass-updated, e.g. by `locate'.  Note that optimiseStore()
-       somewhat reduces the usefulness of this option: it hard-links
-       regular files and symlink together, giving them a "shared"
-       atime. */
-    bool useAtime;
-
-    /* Do not delete paths newer than `maxAtime'.  -1 means no age
-       limit. */
-    time_t maxAtime;
-
     GCOptions();
 };
 
@@ -173,13 +153,13 @@ public:
        derivation is pre-loaded into the Nix store.  The function
        object `filter' can be used to exclude files (see
        libutil/archive.hh). */
-    virtual Path addToStore(const Path & srcPath, bool fixed = false,
-        bool recursive = false, string hashAlgo = "",
+    virtual Path addToStore(const Path & srcPath,
+        bool recursive = true, HashType hashAlgo = htSHA256,
         PathFilter & filter = defaultPathFilter) = 0;
 
     /* Like addToStore, but the contents written to the output path is
        a regular file containing the given string. */
-    virtual Path addTextToStore(const string & suffix, const string & s,
+    virtual Path addTextToStore(const string & name, const string & s,
         const PathSet & references) = 0;
 
     /* Export a store path, that is, create a NAR dump of the store
@@ -263,6 +243,12 @@ void checkStoreName(const string & name);
 Path toStorePath(const Path & path);
 
 
+/* Get the "name" part of a store path, that is, the part after the
+   hash and the dash, and with any ".drv" suffix removed
+   (e.g. /nix/store/<hash>-foo-1.2.3.drv => foo-1.2.3). */
+string getNameOfStorePath(const Path & path);
+
+
 /* Follow symlinks until we end up with a path in the Nix store. */
 Path followLinksToStore(const Path & path);
 
@@ -274,10 +260,10 @@ Path followLinksToStorePath(const Path & path);
 
 /* Constructs a unique store path name. */
 Path makeStorePath(const string & type,
-    const Hash & hash, const string & suffix);
+    const Hash & hash, const string & name);
     
 Path makeFixedOutputPath(bool recursive,
-    string hashAlgo, Hash hash, string name);
+    HashType hashAlgo, Hash hash, string name);
 
 
 /* This is the preparatory part of addToStore() and addToStoreFixed();
@@ -285,7 +271,7 @@ Path makeFixedOutputPath(bool recursive,
    Returns the store path and the cryptographic hash of the
    contents of srcPath. */
 std::pair<Path, Hash> computeStorePathForPath(const Path & srcPath,
-    bool fixed = false, bool recursive = false, string hashAlgo = "",
+    bool recursive = true, HashType hashAlgo = htSHA256,
     PathFilter & filter = defaultPathFilter);
 
 /* Preparatory part of addTextToStore().
@@ -302,7 +288,7 @@ std::pair<Path, Hash> computeStorePathForPath(const Path & srcPath,
    simply yield a different store path, so other users wouldn't be
    affected), but it has some backwards compatibility issues (the
    hashing scheme changes), so I'm not doing that for now. */
-Path computeStorePathForText(const string & suffix, const string & s,
+Path computeStorePathForText(const string & name, const string & s,
     const PathSet & references);
 
 

src/libstore/upgrade-schema.cc

@@ -1,108 +0,0 @@
-#include "db.hh"
-#include "hash.hh"
-#include "util.hh"
-#include "local-store.hh"
-#include "globals.hh"
-#include "pathlocks.hh"
-#include "config.h"
-
-#include <iostream>
-
-
-namespace nix {
-
-
-Hash parseHashField(const Path & path, const string & s);
-
-
-/* Upgrade from schema 4 (Nix 0.11) to schema 5 (Nix >= 0.12).  The
-   old schema uses Berkeley DB, the new one stores store path
-   meta-information in files. */
-void LocalStore::upgradeStore12()
-{
-#if OLD_DB_COMPAT
-    
-#ifdef __CYGWIN__
-    /* Cygwin can't upgrade a read lock to a write lock... */
-    lockFile(globalLock, ltNone, true);
-#endif
-
-    if (!lockFile(globalLock, ltWrite, false)) {
-        printMsg(lvlError, "waiting for exclusive access to the Nix store...");
-        lockFile(globalLock, ltWrite, true);
-    }
-
-    printMsg(lvlError, "upgrading Nix store to new schema (this may take a while)...");
-
-    if (getSchema() >= nixSchemaVersion) return; /* somebody else beat us to it */
-
-    /* Open the old Nix database and tables. */
-    Database nixDB;
-    nixDB.open(nixDBPath);
-    
-    /* dbValidPaths :: Path -> ()
-
-       The existence of a key $p$ indicates that path $p$ is valid
-       (that is, produced by a succesful build). */
-    TableId dbValidPaths = nixDB.openTable("validpaths");
-
-    /* dbReferences :: Path -> [Path]
-
-       This table lists the outgoing file system references for each
-       output path that has been built by a Nix derivation.  These are
-       found by scanning the path for the hash components of input
-       paths. */
-    TableId dbReferences = nixDB.openTable("references");
-
-    /* dbReferrers :: Path -> Path
-
-       This table is just the reverse mapping of dbReferences.  This
-       table can have duplicate keys, each corresponding value
-       denoting a single referrer. */
-    // Not needed for conversion: it's just the inverse of
-    // references.
-    // TableId dbReferrers = nixDB.openTable("referrers");
-
-    /* dbDerivers :: Path -> [Path]
-
-       This table lists the derivation used to build a path.  There
-       can only be multiple such paths for fixed-output derivations
-       (i.e., derivations specifying an expected hash). */
-    TableId dbDerivers = nixDB.openTable("derivers");
-
-    Paths paths;
-    nixDB.enumTable(noTxn, dbValidPaths, paths);
-    
-    for (Paths::iterator i = paths.begin(); i != paths.end(); ++i) {
-        ValidPathInfo info;
-        info.path = *i;
-        
-        Paths references;
-        nixDB.queryStrings(noTxn, dbReferences, *i, references);
-        info.references.insert(references.begin(), references.end());
-        
-        string s;
-        nixDB.queryString(noTxn, dbValidPaths, *i, s);
-        info.hash = parseHashField(*i, s);
-        
-        nixDB.queryString(noTxn, dbDerivers, *i, info.deriver);
-        
-        registerValidPath(info, true);
-        std::cerr << ".";
-    }
-
-    std::cerr << std::endl;
-
-    writeFile(schemaPath, (format("%1%") % nixSchemaVersion).str());
-
-    lockFile(globalLock, ltRead, true);
-
-#else
-    throw Error(
-        "Your Nix store has a database in Berkeley DB format. To convert\n"
-        "to the new format, please compile Nix with Berkeley DB support.");
-#endif
-}
-
-
-}

src/libstore/worker-protocol.hh

@@ -8,7 +8,7 @@ namespace nix {
 #define WORKER_MAGIC_1 0x6e697863
 #define WORKER_MAGIC_2 0x6478696f
 
-#define PROTOCOL_VERSION 0x104
+#define PROTOCOL_VERSION 0x105
 #define GET_PROTOCOL_MAJOR(x) ((x) & 0xff00)
 #define GET_PROTOCOL_MINOR(x) ((x) & 0x00ff)
 

src/libutil/archive.cc

@@ -1,7 +1,10 @@
+#include "config.h"
+
 #include <cerrno>
 #include <algorithm>
 #include <vector>
 
+#define _XOPEN_SOURCE 600
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <unistd.h>
@@ -47,17 +50,17 @@ static void dumpEntries(const Path & path, Sink & sink, PathFilter & filter)
 }
 
 
-static void dumpContents(const Path & path, unsigned int size, 
+static void dumpContents(const Path & path, size_t size, 
     Sink & sink)
 {
     writeString("contents", sink);
-    writeInt(size, sink);
+    writeLongLong(size, sink);
 
     AutoCloseFD fd = open(path.c_str(), O_RDONLY);
     if (fd == -1) throw SysError(format("opening file `%1%'") % path);
     
     unsigned char buf[65536];
-    unsigned int left = size;
+    size_t left = size;
 
     while (left > 0) {
         size_t n = left > sizeof(buf) ? sizeof(buf) : left;
@@ -85,7 +88,7 @@ static void dump(const Path & path, Sink & sink, PathFilter & filter)
             writeString("executable", sink);
             writeString("", sink);
         }
-        dumpContents(path, st.st_size, sink);
+        dumpContents(path, (size_t) st.st_size, sink);
     } 
 
     else if (S_ISDIR(st.st_mode)) {
@@ -101,7 +104,7 @@ static void dump(const Path & path, Sink & sink, PathFilter & filter)
         writeString(readLink(path), sink);
     }
 
-    else throw Error("unknown file type: " + path);
+    else throw Error(format("file `%1%' has an unknown type") % path);
 
     writeString(")", sink);
 }
@@ -114,9 +117,9 @@ void dumpPath(const Path & path, Sink & sink, PathFilter & filter)
 }
 
 
-static Error badArchive(string s)
+static SerialisationError badArchive(string s)
 {
-    return Error("bad archive: " + s);
+    return SerialisationError("bad archive: " + s);
 }
 
 
@@ -129,10 +132,11 @@ static void skipGeneric(Source & source)
 }
 
 
-static void restore(const Path & path, Source & source);
+static void parse(ParseSink & sink, Source & source, const Path & path);
 
 
-static void restoreEntry(const Path & path, Source & source)
+
+static void parseEntry(ParseSink & sink, Source & source, const Path & path)
 {
     string s, name;
 
@@ -150,7 +154,7 @@ static void restoreEntry(const Path & path, Source & source)
             name = readString(source);
         } else if (s == "node") {
             if (s == "") throw badArchive("entry name missing");
-            restore(path + "/" + name, source);
+            parse(sink, source, path + "/" + name);
         } else {
             throw badArchive("unknown field " + s);
             skipGeneric(source);
@@ -159,26 +163,31 @@ static void restoreEntry(const Path & path, Source & source)
 }
 
 
-static void restoreContents(int fd, const Path & path, Source & source)
+static void parseContents(ParseSink & sink, Source & source, const Path & path)
 {
-    unsigned int size = readInt(source);
-    unsigned int left = size;
+    unsigned long long size = readLongLong(source);
+    
+    sink.preallocateContents(size);
+
+    unsigned long long left = size;
     unsigned char buf[65536];
 
     while (left) {
         checkInterrupt();
         unsigned int n = sizeof(buf);
-        if (n > left) n = left;
+        if ((unsigned long long) n > left) n = left;
         source(buf, n);
-        writeFull(fd, buf, n);
+        sink.receiveContents(buf, n);
         left -= n;
     }
 
+    sink.finalizeContents(size);
+
     readPadding(size, source);
 }
 
 
-static void restore(const Path & path, Source & source)
+static void parse(ParseSink & sink, Source & source, const Path & path)
 {
     string s;
 
@@ -186,7 +195,6 @@ static void restore(const Path & path, Source & source)
     if (s != "(") throw badArchive("expected open tag");
 
     enum { tpUnknown, tpRegular, tpDirectory, tpSymlink } type = tpUnknown;
-    AutoCloseFD fd;
 
     while (1) {
         checkInterrupt();
@@ -204,15 +212,12 @@ static void restore(const Path & path, Source & source)
 
             if (t == "regular") {
                 type = tpRegular;
-                fd = open(path.c_str(), O_CREAT | O_EXCL | O_WRONLY, 0666);
-                if (fd == -1)
-                    throw SysError("creating file " + path);
+                sink.createRegularFile(path);
             }
 
             else if (t == "directory") {
+                sink.createDirectory(path);
                 type = tpDirectory;
-                if (mkdir(path.c_str(), 0777) == -1)
-                    throw SysError("creating directory " + path);
             }
 
             else if (t == "symlink") {
@@ -224,42 +229,114 @@ static void restore(const Path & path, Source & source)
         }
 
         else if (s == "contents" && type == tpRegular) {
-            restoreContents(fd, path, source);
+            parseContents(sink, source, path);
         }
 
         else if (s == "executable" && type == tpRegular) {
             readString(source);
-            struct stat st;
-            if (fstat(fd, &st) == -1)
-                throw SysError("fstat");
-            if (fchmod(fd, st.st_mode | (S_IXUSR | S_IXGRP | S_IXOTH)) == -1)
-                throw SysError("fchmod");
+            sink.isExecutable();
         }
 
         else if (s == "entry" && type == tpDirectory) {
-            restoreEntry(path, source);
+            parseEntry(sink, source, path);
         }
 
         else if (s == "target" && type == tpSymlink) {
             string target = readString(source);
-            if (symlink(target.c_str(), path.c_str()) == -1)
-                throw SysError("creating symlink " + path);
+            sink.createSymlink(path, target);
         }
 
         else {
             throw badArchive("unknown field " + s);
             skipGeneric(source);
         }
-        
     }
 }
 
 
+void parseDump(ParseSink & sink, Source & source)
+{
+    string version;    
+    try {
+        version = readString(source);
+    } catch (SerialisationError & e) {
+        /* This generally means the integer at the start couldn't be
+           decoded.  Ignore and throw the exception below. */
+    }
+    if (version != archiveVersion1)
+        throw badArchive("input doesn't look like a Nix archive");
+    parse(sink, source, "");
+}
+
+
+struct RestoreSink : ParseSink
+{
+    Path dstPath;
+    AutoCloseFD fd;
+
+    void createDirectory(const Path & path)
+    {
+        Path p = dstPath + path;
+        if (mkdir(p.c_str(), 0777) == -1)
+            throw SysError(format("creating directory `%1%'") % p);
+    };
+
+    void createRegularFile(const Path & path)
+    {
+        Path p = dstPath + path;
+        fd = open(p.c_str(), O_CREAT | O_EXCL | O_WRONLY, 0666);
+        if (fd == -1) throw SysError(format("creating file `%1%'") % p);
+    }
+
+    void isExecutable()
+    {
+        struct stat st;
+        if (fstat(fd, &st) == -1)
+            throw SysError("fstat");
+        if (fchmod(fd, st.st_mode | (S_IXUSR | S_IXGRP | S_IXOTH)) == -1)
+            throw SysError("fchmod");
+    }
+
+    void preallocateContents(unsigned long long len)
+    {
+#if HAVE_POSIX_FALLOCATE
+        if (len) {
+            errno = posix_fallocate(fd, 0, len);
+            /* Note that EINVAL may indicate that the underlying
+               filesystem doesn't support preallocation (e.g. on
+               OpenSolaris).  Since preallocation is just an
+               optimisation, ignore it. */
+            if (errno && errno != EINVAL)
+                throw SysError(format("preallocating file of %1% bytes") % len);
+        }
+#endif
+    }
+
+    void receiveContents(unsigned char * data, unsigned int len)
+    {
+        writeFull(fd, data, len);
+    }
+
+    void finalizeContents(unsigned long long size)
+    {
+        errno = ftruncate(fd, size);
+        if (errno) throw SysError(format("truncating file to its allocated length of %1% bytes") % size);
+    }
+
+    void createSymlink(const Path & path, const string & target)
+    {
+        Path p = dstPath + path;
+        if (symlink(target.c_str(), p.c_str()) == -1)
+            throw SysError(format("creating symlink `%1%'") % p);
+    }
+};
+
+ 
 void restorePath(const Path & path, Source & source)
 {
-    if (readString(source) != archiveVersion1)
-        throw badArchive("expected Nix archive");
-    restore(path, source);
+    RestoreSink sink;
+    sink.dstPath = path;
+    parseDump(sink, source);
 }
 
  

src/libutil/archive.hh

@@ -56,6 +56,21 @@ extern PathFilter defaultPathFilter;
 void dumpPath(const Path & path, Sink & sink,
     PathFilter & filter = defaultPathFilter);
 
+struct ParseSink
+{
+    virtual void createDirectory(const Path & path) { };
+    
+    virtual void createRegularFile(const Path & path) { };
+    virtual void isExecutable() { };
+    virtual void preallocateContents(unsigned long long size) { };
+    virtual void receiveContents(unsigned char * data, unsigned int len) { };
+    virtual void finalizeContents(unsigned long long size) { };
+
+    virtual void createSymlink(const Path & path, const string & target) { };
+};
+    
+void parseDump(ParseSink & sink, Source & source);
+
 void restorePath(const Path & path, Source & source);
 
  

src/libutil/aterm-map.hh

@@ -1,8 +1,8 @@
 #ifndef __ATERM_MAP_H
 #define __ATERM_MAP_H
 
-typedef struct _ATerm * ATerm;
-
+#include <aterm1.h>
+#include <aterm2.h>
 #include <assert.h>
 
 

src/libutil/hash.cc

@@ -335,4 +335,13 @@ HashType parseHashType(const string & s)
 }
 
  
+string printHashType(HashType ht)
+{
+    if (ht == htMD5) return "md5";
+    else if (ht == htSHA1) return "sha1";
+    else if (ht == htSHA256) return "sha256";
+    else throw Error("cannot print unknown hash type");
+}
+
+ 
 }

src/libutil/hash.hh

@@ -82,6 +82,9 @@ Hash compressHash(const Hash & hash, unsigned int newSize);
 /* Parse a string representing a hash type. */
 HashType parseHashType(const string & s);
 
+/* And the reverse. */
+string printHashType(HashType ht);
+
 
 union Ctx;
 

src/libutil/serialise.cc

@@ -80,7 +80,7 @@ void readPadding(unsigned int len, Source & source)
         unsigned int n = 8 - (len % 8);
         source(zero, n);
         for (unsigned int i = 0; i < n; i++)
-            if (zero[i]) throw Error("non-zero padding");
+            if (zero[i]) throw SerialisationError("non-zero padding");
     }
 }
 
@@ -90,7 +90,7 @@ unsigned int readInt(Source & source)
     unsigned char buf[8];
     source(buf, sizeof(buf));
     if (buf[4] || buf[5] || buf[6] || buf[7])
-        throw Error("implementation cannot deal with > 32-bit integers");
+        throw SerialisationError("implementation cannot deal with > 32-bit integers");
     return
         buf[0] |
         (buf[1] << 8) |

src/libutil/serialise.hh

@@ -35,7 +35,7 @@ struct FdSink : Sink
 
     FdSink()
     {
-        fd = 0;
+        fd = -1;
     }
     
     FdSink(int fd) 
@@ -54,7 +54,7 @@ struct FdSource : Source
 
     FdSource()
     {
-        fd = 0;
+        fd = -1;
     }
     
     FdSource(int fd) 
@@ -80,9 +80,9 @@ struct StringSink : Sink
 /* A source that reads data from a string. */
 struct StringSource : Source
 {
-    string & s;
+    const string & s;
     unsigned int pos;
-    StringSource(string & _s) : s(_s), pos(0) { }
+    StringSource(const string & _s) : s(_s), pos(0) { }
     virtual void operator () (unsigned char * data, unsigned int len)
     {
         s.copy((char *) data, len, pos);
@@ -106,6 +106,9 @@ string readString(Source & source);
 StringSet readStringSet(Source & source);
 
 
+MakeError(SerialisationError, Error)
+
+
 }
 
 

src/libutil/types.hh

@@ -24,12 +24,14 @@ using boost::format;
 class BaseError : public std::exception 
 {
 protected:
+    string prefix_; // used for location traces etc.
     string err;
 public:
     BaseError(const format & f);
     ~BaseError() throw () { };
     const char * what() const throw () { return err.c_str(); }
     const string & msg() const throw () { return err; }
+    const string & prefix() const throw () { return prefix_; }
     BaseError & addPrefix(const format & f);
 };
 

src/libutil/util.cc

@@ -15,6 +15,7 @@
 #include <sys/wait.h>
 #include <sys/types.h>
 #include <fcntl.h>
+#include <unistd.h>
 
 #include "util.hh"
 
@@ -33,7 +34,7 @@ BaseError::BaseError(const format & f)
 
 BaseError & BaseError::addPrefix(const format & f)
 {
-    err = f.str() + err;
+    prefix_ = f.str() + prefix_;
     return *this;
 }
 
@@ -220,12 +221,40 @@ string readFile(const Path & path)
 }
 
 
-void writeFile(const Path & path, const string & s)
+void writeFile(const Path & path, const string & s, bool doFsync)
 {
     AutoCloseFD fd = open(path.c_str(), O_WRONLY | O_TRUNC | O_CREAT, 0666);
     if (fd == -1)
         throw SysError(format("opening file `%1%'") % path);
     writeFull(fd, (unsigned char *) s.c_str(), s.size());
+    if (doFsync) fdatasync(fd);
+}
+
+
+string readLine(int fd)
+{
+    string s;
+    while (1) {
+        checkInterrupt();
+        char ch;
+        ssize_t rd = read(fd, &ch, 1);
+        if (rd == -1) {
+            if (errno != EINTR)
+                throw SysError("reading a line");
+        } else if (rd == 0)
+            throw Error("unexpected EOF reading a line");
+        else {
+            if (ch == '\n') return s;
+            s += ch;
+        }
+    }
+}
+
+
+void writeLine(int fd, string s)
+{
+    s += '\n';
+    writeFull(fd, (const unsigned char *) s.c_str(), s.size());
 }
 
 
@@ -270,8 +299,10 @@ static void _deletePath(const Path & path, unsigned long long & bytesFreed,
     if (lstat(path.c_str(), &st))
 	throw SysError(format("getting attributes of path `%1%'") % path);
 
-    bytesFreed += st.st_size;
-    blocksFreed += st.st_blocks;
+    if (!S_ISDIR(st.st_mode) && st.st_nlink == 1) {
+        bytesFreed += st.st_size;
+        blocksFreed += st.st_blocks;
+    }
 
     if (S_ISDIR(st.st_mode)) {
 	Strings names = readDirectory(path);
@@ -384,16 +415,6 @@ Paths createDirs(const Path & path)
 }
 
 
-void writeStringToFile(const Path & path, const string & s)
-{
-    AutoCloseFD fd(open(path.c_str(),
-        O_CREAT | O_EXCL | O_WRONLY, 0666));
-    if (fd == -1)
-        throw SysError(format("creating file `%1%'") % path);
-    writeFull(fd, (unsigned char *) s.c_str(), s.size());
-}
-
-
 LogType logType = ltPretty;
 Verbosity verbosity = lvlInfo;
 
@@ -469,11 +490,7 @@ void warnOnce(bool & haveWarned, const format & f)
 
 static void defaultWriteToStderr(const unsigned char * buf, size_t count)
 {
-    try {
-        writeFull(STDERR_FILENO, buf, count);
-    } catch (SysError & e) {
-        /* ignore EPIPE etc. */
-    }
+    writeFull(STDERR_FILENO, buf, count);
 }
 
 
@@ -1030,22 +1047,6 @@ string int2String(int n)
 }
 
 
-bool string2Int(const string & s, int & n)
-{
-    std::istringstream str(s);
-    str >> n;
-    return str && str.get() == EOF;
-}
-
-
-bool string2Int(const string & s, long long & n)
-{
-    std::istringstream str(s);
-    str >> n;
-    return str && str.get() == EOF;
-}
-
-
 bool hasSuffix(const string & s, const string & suffix)
 {
     return s.size() >= suffix.size() && string(s, s.size() - suffix.size()) == suffix;

src/libutil/util.hh

@@ -1,6 +1,8 @@
 #ifndef __UTIL_H
 #define __UTIL_H
 
+#include "config.h"
+
 #include "types.hh"
 
 #include <sys/types.h>
@@ -8,6 +10,8 @@
 #include <unistd.h>
 #include <signal.h>
 
+#include <cstdio>
+
 
 namespace nix {
 
@@ -58,7 +62,13 @@ string readFile(int fd);
 string readFile(const Path & path);
 
 /* Write a string to a file. */
-void writeFile(const Path & path, const string & s);
+void writeFile(const Path & path, const string & s, bool doFsync = false);
+
+/* Read a line from a file descriptor. */
+string readLine(int fd);
+
+/* Write a line to a file descriptor. */
+void writeLine(int fd, string s);
 
 /* Compute the sum of the sizes of all files in `path'. */
 void computePathSize(const Path & path,
@@ -83,10 +93,6 @@ Path createTempDir(const Path & tmpRoot = "", const Path & prefix = "nix",
    list of created directories, in order of creation. */
 Paths createDirs(const Path & path);
 
-/* Create a file and write the given text to it.  The file is written
-   in binary mode (i.e., no end-of-line conversions).  The path should
-   not already exist. */
-void writeStringToFile(const Path & path, const string & s);
 
 template<class T, class A>
 T singleton(const A & a)
@@ -289,9 +295,14 @@ bool statusOk(int status);
 
 
 /* Parse a string into an integer. */
+template<class N> bool string2Int(const string & s, N & n)
+{
+    std::istringstream str(s);
+    str >> n;
+    return str && str.get() == EOF;
+}
+
 string int2String(int n);
-bool string2Int(const string & s, int & n);
-bool string2Int(const string & s, long long & n);
 
 
 /* Return true iff `s' ends in `suffix'. */

src/nix-env/Makefile.am

@@ -3,7 +3,7 @@ bin_PROGRAMS = nix-env
 nix_env_SOURCES = nix-env.cc profiles.cc profiles.hh help.txt
 nix_env_LDADD = ../libmain/libmain.la ../libexpr/libexpr.la \
  ../libstore/libstore.la ../libutil/libutil.la \
- ../boost/format/libformat.la ${bdb_lib} ${aterm_lib}
+ ../boost/format/libformat.la ${aterm_lib} @ADDITIONAL_NETWORK_LIBS@
 
 nix-env.o: help.txt.hh
 
@@ -11,6 +11,6 @@ nix-env.o: help.txt.hh
 	../bin2c/bin2c helpText < $< > $@ || (rm $@ && exit 1)
 
 AM_CXXFLAGS = \
- -I$(srcdir)/.. ${bdb_include} ${aterm_include} \
+ -I$(srcdir)/.. ${aterm_include} \
  -I$(srcdir)/../libutil -I$(srcdir)/../libstore \
  -I$(srcdir)/../libexpr -I$(srcdir)/../libmain -I../libexpr

src/nix-env/nix-env.cc

@@ -251,15 +251,14 @@ static string optimisticLockProfile(const Path & profile)
 }
 
 
-static bool createUserEnv(EvalState & state, const DrvInfos & elems,
+static bool createUserEnv(EvalState & state, DrvInfos & elems,
     const Path & profile, bool keepDerivations,
     const string & lockToken)
 {
     /* Build the components in the user environment, if they don't
        exist already. */
     PathSet drvsToBuild;
-    for (DrvInfos::const_iterator i = elems.begin(); 
-         i != elems.end(); ++i)
+    foreach (DrvInfos::const_iterator, i, elems)
         /* Call to `isDerivation' is for compatibility with Nix <= 0.7
            user environments. */
         if (i->queryDrvPath(state) != "" &&
@@ -277,19 +276,16 @@ static bool createUserEnv(EvalState & state, const DrvInfos & elems,
     PathSet references;
     ATermList manifest = ATempty;
     ATermList inputs = ATempty;
-    for (DrvInfos::const_iterator i = elems.begin(); 
-         i != elems.end(); ++i)
-    {
+    foreach (DrvInfos::iterator, i, elems) {
         /* Create a pseudo-derivation containing the name, system,
            output path, and optionally the derivation path, as well as
            the meta attributes. */
         Path drvPath = keepDerivations ? i->queryDrvPath(state) : "";
 
+        /* Round trip to get rid of "bad" meta values (like
+           functions). */
         MetaInfo meta = i->queryMetaInfo(state);
-        ATermList metaList = ATempty;
-        foreach (MetaInfo::iterator, j, meta)
-            metaList = ATinsert(metaList,
-                makeBind(toATerm(j->first), makeStr(j->second), makeNoPos()));
+        i->setMetaInfo(meta);
         
         ATermList as = ATmakeList5(
             makeBind(toATerm("type"),
@@ -300,7 +296,8 @@ static bool createUserEnv(EvalState & state, const DrvInfos & elems,
                 makeStr(i->system), makeNoPos()),
             makeBind(toATerm("outPath"),
                 makeStr(i->queryOutPath(state)), makeNoPos()), 
-            makeBind(toATerm("meta"), makeAttrs(metaList), makeNoPos()));
+            makeBind(toATerm("meta"),
+                i->attrs->get(toATerm("meta")), makeNoPos()));
         
         if (drvPath != "") as = ATinsert(as, 
             makeBind(toATerm("drvPath"),
@@ -330,7 +327,7 @@ static bool createUserEnv(EvalState & state, const DrvInfos & elems,
         makeBind(toATerm("derivations"),
             makeList(ATreverse(manifest)), makeNoPos()),
         makeBind(toATerm("manifest"),
-            makeStr(manifestFile, singleton<PathSet>(manifestFile)), makeNoPos())
+            makeStr(manifestFile, ATmakeList1(makeContextElem(toATerm(manifestFile), makeNull()))), makeNoPos())
         )));
 
     /* Instantiate it. */
@@ -361,13 +358,23 @@ static bool createUserEnv(EvalState & state, const DrvInfos & elems,
 }
 
 
+static int getPriority(EvalState & state, const DrvInfo & drv)
+{
+    MetaValue value = drv.queryMetaInfo(state, "priority");
+    int prio = 0;
+    if (value.type == MetaValue::tpInt) prio = value.intValue;
+    else if (value.type == MetaValue::tpString)
+        /* Backwards compatibility.  Priorities used to be strings
+           before we had support for integer meta field. */
+        string2Int(value.stringValue, prio);
+    return prio;
+}
+
+
 static int comparePriorities(EvalState & state,
     const DrvInfo & drv1, const DrvInfo & drv2)
 {
-    int prio1, prio2;
-    if (!string2Int(drv1.queryMetaInfo(state, "priority"), prio1)) prio1 = 0;
-    if (!string2Int(drv2.queryMetaInfo(state, "priority"), prio2)) prio2 = 0;
-    return prio2 - prio1; /* higher number = lower priority, so negate */
+    return getPriority(state, drv2) - getPriority(state, drv1);
 }
 
 
@@ -594,6 +601,13 @@ static void printMissing(EvalState & state, const DrvInfos & elems)
 }
 
 
+static bool keep(MetaInfo & meta)
+{
+    MetaValue value = meta["keep"];
+    return value.type == MetaValue::tpString && value.stringValue == "true";
+}
+
+
 static void installDerivations(Globals & globals,
     const Strings & args, const Path & profile)
 {
@@ -628,7 +642,7 @@ static void installDerivations(Globals & globals,
             MetaInfo meta = i->queryMetaInfo(globals.state);
             if (!globals.preserveInstalled &&
                 newNames.find(drvName.name) != newNames.end() &&
-                meta["keep"] != "true")
+                !keep(meta))
                 printMsg(lvlInfo,
                     format("replacing old `%1%'") % i->name);
             else
@@ -690,52 +704,59 @@ static void upgradeDerivations(Globals & globals,
         foreach (DrvInfos::iterator, i, installedElems) {
             DrvName drvName(i->name);
 
-            MetaInfo meta = i->queryMetaInfo(globals.state);
-            if (meta["keep"] == "true") {
-                newElems.push_back(*i);
-                continue;
-            }
+            try {
 
-            /* Find the derivation in the input Nix expression with
-               the same name that satisfies the version constraints
-               specified by upgradeType.  If there are multiple
-               matches, take the one with the highest priority.  If
-               there are still multiple matches, take the one with the
-               highest version. */
-            DrvInfos::iterator bestElem = availElems.end();
-            DrvName bestName;
-            foreach (DrvInfos::iterator, j, availElems) {
-                DrvName newName(j->name);
-                if (newName.name == drvName.name) {
-                    int d = comparePriorities(globals.state, *i, *j);
-                    if (d == 0) d = compareVersions(drvName.version, newName.version);
-                    if (upgradeType == utLt && d < 0 ||
-                        upgradeType == utLeq && d <= 0 ||
-                        upgradeType == utEq && d == 0 ||
-                        upgradeType == utAlways)
-                    {
-                        int d2 = -1;
-                        if (bestElem != availElems.end()) {
-                            d2 = comparePriorities(globals.state, *bestElem, *j);
-                            if (d2 == 0) d2 = compareVersions(bestName.version, newName.version);
-                        }
-                        if (d2 < 0) {
-                            bestElem = j;
-                            bestName = newName;
+                MetaInfo meta = i->queryMetaInfo(globals.state);
+                if (keep(meta)) {
+                    newElems.push_back(*i);
+                    continue;
+                }
+
+                /* Find the derivation in the input Nix expression
+                   with the same name that satisfies the version
+                   constraints specified by upgradeType.  If there are
+                   multiple matches, take the one with the highest
+                   priority.  If there are still multiple matches,
+                   take the one with the highest version. */
+                DrvInfos::iterator bestElem = availElems.end();
+                DrvName bestName;
+                foreach (DrvInfos::iterator, j, availElems) {
+                    DrvName newName(j->name);
+                    if (newName.name == drvName.name) {
+                        int d = comparePriorities(globals.state, *i, *j);
+                        if (d == 0) d = compareVersions(drvName.version, newName.version);
+                        if ((upgradeType == utLt && d < 0) ||
+                            (upgradeType == utLeq && d <= 0) ||
+                            (upgradeType == utEq && d == 0) ||
+                            upgradeType == utAlways)
+                        {
+                            int d2 = -1;
+                            if (bestElem != availElems.end()) {
+                                d2 = comparePriorities(globals.state, *bestElem, *j);
+                                if (d2 == 0) d2 = compareVersions(bestName.version, newName.version);
+                            }
+                            if (d2 < 0) {
+                                bestElem = j;
+                                bestName = newName;
+                            }
                         }
                     }
                 }
-            }
+                
+                if (bestElem != availElems.end() &&
+                    i->queryOutPath(globals.state) !=
+                    bestElem->queryOutPath(globals.state))
+                {
+                    printMsg(lvlInfo,
+                        format("upgrading `%1%' to `%2%'")
+                        % i->name % bestElem->name);
+                    newElems.push_back(*bestElem);
+                } else newElems.push_back(*i);
 
-            if (bestElem != availElems.end() &&
-                i->queryOutPath(globals.state) !=
-                bestElem->queryOutPath(globals.state))
-            {
-                printMsg(lvlInfo,
-                    format("upgrading `%1%' to `%2%'")
-                    % i->name % bestElem->name);
-                newElems.push_back(*bestElem);
-            } else newElems.push_back(*i);
+            } catch (Error & e) {
+                e.addPrefix(format("while trying to find an upgrade for `%1%':\n") % i->name);
+                throw;
+            }
         }
     
         printMissing(globals.state, newElems);
@@ -770,7 +791,10 @@ static void setMetaFlag(EvalState & state, DrvInfo & drv,
     const string & name, const string & value)
 {
     MetaInfo meta = drv.queryMetaInfo(state);
-    meta[name] = value;
+    MetaValue v;
+    v.type = MetaValue::tpString;
+    v.stringValue = value;
+    meta[name] = v;
     drv.setMetaInfo(meta);
 }
 
@@ -913,7 +937,7 @@ void printTable(Table & table)
     vector<unsigned int> widths;
     widths.resize(nrColumns);
     
-    for (Table::iterator i = table.begin(); i != table.end(); ++i) {
+    foreach (Table::iterator, i, table) {
         assert(i->size() == nrColumns);
         Strings::iterator j;
         unsigned int column;
@@ -921,14 +945,15 @@ void printTable(Table & table)
             if (j->size() > widths[column]) widths[column] = j->size();
     }
 
-    for (Table::iterator i = table.begin(); i != table.end(); ++i) { 
+    foreach (Table::iterator, i, table) { 
         Strings::iterator j;
         unsigned int column;
-        for (j = i->begin(), column = 0; j != i->end(); ++j, ++column)
-        {
-            cout << *j;
+        for (j = i->begin(), column = 0; j != i->end(); ++j, ++column) {
+            string s = *j;
+            replace(s.begin(), s.end(), '\n', ' ');
+            cout << s;
             if (column < nrColumns - 1)
-                cout << string(widths[column] - j->size() + 2, ' ');
+                cout << string(widths[column] - s.size() + 2, ' ');
         }
         cout << std::endl;
     }
@@ -1075,9 +1100,7 @@ static void opQuery(Globals & globals,
     XMLWriter xml(true, *(xmlOutput ? &cout : &dummy));
     XMLOpenElement xmlRoot(xml, "items");
     
-    for (vector<DrvInfo>::iterator i = elems2.begin();
-         i != elems2.end(); ++i)
-    {
+    foreach (vector<DrvInfo>::iterator, i, elems2) {
         try {
 
             /* For table output. */
@@ -1164,7 +1187,8 @@ static void opQuery(Globals & globals,
 
             if (printDescription) {
                 MetaInfo meta = i->queryMetaInfo(globals.state);
-                string descr = meta["description"];
+                MetaValue value = meta["description"];
+                string descr = value.type == MetaValue::tpString ? value.stringValue : "";
                 if (xmlOutput) {
                     if (descr != "") attrs["description"] = descr;
                 } else
@@ -1178,8 +1202,23 @@ static void opQuery(Globals & globals,
                     for (MetaInfo::iterator j = meta.begin(); j != meta.end(); ++j) {
                         XMLAttrs attrs2;
                         attrs2["name"] = j->first;
-                        attrs2["value"] = j->second;
-                        xml.writeEmptyElement("meta", attrs2);
+                        if (j->second.type == MetaValue::tpString) {
+                            attrs2["type"] = "string";
+                            attrs2["value"] = j->second.stringValue;
+                            xml.writeEmptyElement("meta", attrs2);
+                        } else if (j->second.type == MetaValue::tpInt) {
+                            attrs2["type"] = "int";
+                            attrs2["value"] = (format("%1%") % j->second.intValue).str();
+                            xml.writeEmptyElement("meta", attrs2);
+                        } else if (j->second.type == MetaValue::tpStrings) {
+                            attrs2["type"] = "strings";
+                            XMLOpenElement m(xml, "meta", attrs2);
+                            foreach (Strings::iterator, k, j->second.stringValues) { 
+                                XMLAttrs attrs3;
+                                attrs3["value"] = *k;
+                                xml.writeEmptyElement("string", attrs3);
+                           }
+                        }
                     }
                 }
                 else
@@ -1230,12 +1269,13 @@ static void switchGeneration(Globals & globals, int dstGen)
             (dstGen >= 0 && i->number == dstGen))
             dst = *i;
 
-    if (!dst)
+    if (!dst) {
         if (dstGen == prevGen)
             throw Error(format("no generation older than the current (%1%) exists")
                 % curGen);
         else
             throw Error(format("generation %1% does not exist") % dstGen);
+    }
 
     printMsg(lvlInfo, format("switching from generation %1% to %2%")
         % curGen % dst.number);

src/nix-hash/Makefile.am

@@ -2,7 +2,7 @@ bin_PROGRAMS = nix-hash
 
 nix_hash_SOURCES = nix-hash.cc help.txt
 nix_hash_LDADD = ../libmain/libmain.la ../libstore/libstore.la ../libutil/libutil.la \
- ../boost/format/libformat.la ${bdb_lib} ${aterm_lib}
+ ../boost/format/libformat.la ${aterm_lib} @ADDITIONAL_NETWORK_LIBS@
 
 nix-hash.o: help.txt.hh