1c208f2b7e
If a root is a regular file, then its name must denote a store path. For instance, the existence of the file /nix/var/nix/gcroots/per-user/eelco/hydra-roots/wzc3cy1wwwd6d0dgxpa77ijr1yp50s6v-libxml2-2.7.7 would cause /nix/store/wzc3cy1wwwd6d0dgxpa77ijr1yp50s6v-libxml2-2.7.7 to be a root. This is useful because it involves less I/O (no need for a readlink() call) and takes up less disk space (the symlink target typically takes up a full disk block, while directory entries are packed more efficiently). This is particularly important for hydra.nixos.org, which has hundreds of thousands of roots, and where reading the roots can take 25 minutes.
Nix is a purely functional package manager. For installation and usage instructions, please read the manual, which can be found in `docs/manual/manual.html', and additionally at the Nix website at <http://nixos.org/>. Acknowledgments This product includes software developed by the OpenSSL Project for use in the OpenSSL Toolkit (http://www.OpenSSL.org/).