diff --git a/mozilla/xpcom/ds/nsBuffer.cpp b/mozilla/xpcom/ds/nsBuffer.cpp
index 23e6e5d89c8..67aa32b3108 100644
--- a/mozilla/xpcom/ds/nsBuffer.cpp
+++ b/mozilla/xpcom/ds/nsBuffer.cpp
@@ -155,7 +155,7 @@ nsBuffer::Read(char* toBuf, PRUint32 bufLen, PRUint32 *readCount)
 
     *readCount = 0;
     while (bufLen > 0) {
-        rv = GetReadBuffer(&readBufferLen, &readBuffer);
+        rv = GetReadBuffer(0, &readBuffer, &readBufferLen);
         if (rv == NS_BASE_STREAM_EOF)      // all we're going to get
             return *readCount > 0 ? NS_OK : NS_BASE_STREAM_EOF;
         if (NS_FAILED(rv)) return rv;
@@ -181,7 +181,9 @@ nsBuffer::Read(char* toBuf, PRUint32 bufLen, PRUint32 *readCount)
 }
 
 NS_IMETHODIMP
-nsBuffer::GetReadBuffer(PRUint32 *readBufferLength, char* *result)
+nsBuffer::GetReadBuffer(PRUint32 startPosition, 
+                        char* *result,
+                        PRUint32 *readBufferLength)
 {
     if (mReadSegment == nsnull) {
         if (PR_CLIST_IS_EMPTY(&mSegments)) {
@@ -229,7 +231,7 @@ nsBuffer::Write(const char* fromBuf, PRUint32 bufLen, PRUint32 *writeCount)
     while (bufLen > 0) {
         PRUint32 writeBufLen;
         char* writeBuf;
-        rv = GetWriteBuffer(&writeBufLen, &writeBuf);
+        rv = GetWriteBuffer(0, &writeBuf, &writeBufLen);
         if (NS_FAILED(rv)) {
             // if we failed to allocate a new segment, we're probably out
             // of memory, but we don't care -- just report what we were
@@ -254,7 +256,7 @@ nsBuffer::Write(const char* fromBuf, PRUint32 bufLen, PRUint32 *writeCount)
 }
 
 NS_IMETHODIMP
-nsBuffer::Write(nsIInputStream* fromStream, PRUint32 *writeCount)
+nsBuffer::WriteFrom(nsIInputStream* fromStream, PRUint32 count, PRUint32 *writeCount)
 {
     nsresult rv;
 
@@ -262,10 +264,10 @@ nsBuffer::Write(nsIInputStream* fromStream, PRUint32 *writeCount)
         return NS_BASE_STREAM_EOF;
 
     *writeCount = 0;
-    while (PR_TRUE) {
+    while (count > 0) {
         PRUint32 writeBufLen;
         char* writeBuf;
-        rv = GetWriteBuffer(&writeBufLen, &writeBuf);
+        rv = GetWriteBuffer(0, &writeBuf, &writeBufLen);
         if (NS_FAILED(rv)) {
             // if we failed to allocate a new segment, we're probably out
             // of memory, but we don't care -- just report what we were
@@ -274,13 +276,14 @@ nsBuffer::Write(nsIInputStream* fromStream, PRUint32 *writeCount)
         }
 
         PRUint32 readCount;
-        rv = fromStream->Read(writeBuf, writeBufLen, &readCount);
+        rv = fromStream->Read(writeBuf, PR_MIN(writeBufLen, count), &readCount);
         if (NS_FAILED(rv)) {
             // if we failed to read just report what we were
             // able to write so far
             return NS_OK;
         }
         *writeCount += readCount;
+        count -= readCount;
         // set the write cursor after the data is valid
         if (mWriteCursor + readCount == mWriteSegmentEnd) {
             mWriteSegment = nsnull;      // allocate a new segment next time around
@@ -294,7 +297,9 @@ nsBuffer::Write(nsIInputStream* fromStream, PRUint32 *writeCount)
 }
 
 NS_IMETHODIMP
-nsBuffer::GetWriteBuffer(PRUint32 *writeBufferLength, char* *result)
+nsBuffer::GetWriteBuffer(PRUint32 startPosition,
+                         char* *result,
+                         PRUint32 *writeBufferLength)
 {
     if (mEOF)
         return NS_BASE_STREAM_EOF;
diff --git a/mozilla/xpcom/ds/nsBuffer.h b/mozilla/xpcom/ds/nsBuffer.h
index 094e6ef88a1..30002e54993 100644
--- a/mozilla/xpcom/ds/nsBuffer.h
+++ b/mozilla/xpcom/ds/nsBuffer.h
@@ -35,11 +35,15 @@ public:
     NS_IMETHOD Init(PRUint32 growBySize, PRUint32 maxSize,
                     nsIAllocator* allocator);
     NS_IMETHOD Read(char* toBuf, PRUint32 bufLen, PRUint32 *readCount);
-    NS_IMETHOD GetReadBuffer(PRUint32 *readBufferLength, char* *result);
+    NS_IMETHOD GetReadBuffer(PRUint32 startPosition, 
+                             char* *result,
+                             PRUint32 *readBufferLength);
 
     NS_IMETHOD Write(const char* fromBuf, PRUint32 bufLen, PRUint32 *writeCount);
-    NS_IMETHOD Write(nsIInputStream* fromStream, PRUint32 *writeCount);
-    NS_IMETHOD GetWriteBuffer(PRUint32 *writeBufferLength, char* *result);
+    NS_IMETHOD WriteFrom(nsIInputStream* fromStream, PRUint32 count, PRUint32 *writeCount);
+    NS_IMETHOD GetWriteBuffer(PRUint32 startPosition,
+                              char* *result,
+                              PRUint32 *writeBufferLength);
     NS_IMETHOD SetEOF();
 
     // nsBuffer methods:
diff --git a/mozilla/xpcom/ds/nsIBuffer.h b/mozilla/xpcom/ds/nsIBuffer.h
index ef05cdff3ea..4c9a42466d5 100644
--- a/mozilla/xpcom/ds/nsIBuffer.h
+++ b/mozilla/xpcom/ds/nsIBuffer.h
@@ -54,11 +54,15 @@ public:
                     nsIAllocator* allocator) = 0;
 
     NS_IMETHOD Read(char* toBuf, PRUint32 bufLen, PRUint32 *readCount) = 0;
-    NS_IMETHOD GetReadBuffer(PRUint32 *readBufferLength, char* *result) = 0;
+    NS_IMETHOD GetReadBuffer(PRUint32 startPosition, 
+                             char* *result,
+                             PRUint32 *readBufferLength) = 0;
 
     NS_IMETHOD Write(const char* fromBuf, PRUint32 bufLen, PRUint32 *writeCount) = 0;
-    NS_IMETHOD Write(nsIInputStream* fromStream, PRUint32 *writeCount) = 0;
-    NS_IMETHOD GetWriteBuffer(PRUint32 *writeBufferLength, char* *result) = 0;
+    NS_IMETHOD WriteFrom(nsIInputStream* fromStream, PRUint32 count, PRUint32 *writeCount) = 0;
+    NS_IMETHOD GetWriteBuffer(PRUint32 startPosition,
+                              char* *result,
+                              PRUint32 *writeBufferLength) = 0;
     NS_IMETHOD SetEOF() = 0;
 };
 
diff --git a/mozilla/xpcom/io/nsIByteBufferInputStream.h b/mozilla/xpcom/io/nsIByteBufferInputStream.h
index b55ab0bd234..f253bd24b39 100644
--- a/mozilla/xpcom/io/nsIByteBufferInputStream.h
+++ b/mozilla/xpcom/io/nsIByteBufferInputStream.h
@@ -42,7 +42,7 @@ class nsIByteBufferInputStream : public nsIInputStream {
 public:
     NS_DEFINE_STATIC_IID_ACCESSOR(NS_IBYTEBUFFERINPUTSTREAM_IID);
 
-    NS_IMETHOD Fill(nsIInputStream* stream, PRUint32 *aWriteCount) = 0;
+    NS_IMETHOD Fill(nsIInputStream* stream, PRUint32 aCount, PRUint32 *aWriteCount) = 0;
 
     NS_IMETHOD Fill(const char* aBuf, PRUint32 aCount, PRUint32 *aWriteCount) = 0;
 
diff --git a/mozilla/xpcom/io/nsPipe.cpp b/mozilla/xpcom/io/nsPipe.cpp
index 0c31ddf9216..8c9f17810a8 100644
--- a/mozilla/xpcom/io/nsPipe.cpp
+++ b/mozilla/xpcom/io/nsPipe.cpp
@@ -17,7 +17,7 @@
  */
 
 #include "nsIBuffer.h"
-#include "nsIInputStream.h"
+#include "nsIBufferInputStream.h"
 #include "nsIOutputStream.h"
 #include "nsAutoLock.h"
 
@@ -25,7 +25,7 @@ class nsBufferInputStream;
 
 ////////////////////////////////////////////////////////////////////////////////
 
-class nsBufferInputStream : public nsIInputStream
+class nsBufferInputStream : public nsIBufferInputStream
 {
 public:
     NS_DECL_ISUPPORTS
@@ -37,6 +37,11 @@ public:
     NS_IMETHOD GetLength(PRUint32 *aLength);
     NS_IMETHOD Read(char* aBuf, PRUint32 aCount, PRUint32 *aReadCount); 
 
+    // nsIBufferInputStream methods:
+    NS_IMETHOD GetBuffer(PRUint32 startPosition, char * *bufferSegment,
+                         PRUint32 *bufferSegmentSize);
+    NS_IMETHOD Find(char * aString, PRInt32 *_retval);
+
     // nsBufferInputStream methods:
     nsBufferInputStream(nsIBuffer* buf, PRBool blocking);
     virtual ~nsBufferInputStream();
@@ -45,7 +50,7 @@ public:
         nsresult rv;
         PRUint32 amt;
         char* buf;
-        rv = mBuffer->GetReadBuffer(&amt, &buf); // should never fail
+        rv = mBuffer->GetReadBuffer(0, &buf, &amt); // should never fail
         NS_ASSERTION(NS_SUCCEEDED(rv), "GetInputBuffer failed");
         return amt;
     }
@@ -70,7 +75,8 @@ public:
 
     // nsIOutputStream methods:
     NS_IMETHOD Write(const char* aBuf, PRUint32 aCount, PRUint32 *aWriteCount); 
-    NS_IMETHOD Write(nsIInputStream* fromStream, PRUint32 *aWriteCount);
+    NS_IMETHOD WriteFrom(nsIInputStream* fromStream, PRUint32 aCount,
+                         PRUint32 *aWriteCount);
     NS_IMETHOD Flush(void);
 
     // nsBufferOutputStream methods:
@@ -143,7 +149,7 @@ nsBufferInputStream::GetLength(PRUint32 *aLength)
         return NS_BASE_STREAM_CLOSED;
 
     char* buf;
-    return mBuffer->GetReadBuffer(aLength, &buf);
+    return mBuffer->GetReadBuffer(0, &buf, aLength);
 }
 
 NS_IMETHODIMP
@@ -174,6 +180,19 @@ nsBufferInputStream::Read(char* aBuf, PRUint32 aCount, PRUint32 *aReadCount)
     return rv;
 }
 
+NS_IMETHODIMP
+nsBufferInputStream::GetBuffer(PRUint32 startPosition, char * *bufferSegment,
+                               PRUint32 *bufferSegmentSize)
+{
+    return NS_ERROR_NOT_IMPLEMENTED;
+}
+ 
+NS_IMETHODIMP
+nsBufferInputStream::Find(char * aString, PRInt32 *_retval)
+{
+    return NS_ERROR_NOT_IMPLEMENTED;
+}
+
 nsresult
 nsBufferInputStream::SetEOF()
 {
@@ -206,7 +225,7 @@ nsBufferInputStream::Fill()
             // check read buffer again while in the monitor
             PRUint32 amt;
             char* buf;
-            rv = mBuffer->GetReadBuffer(&amt, &buf);
+            rv = mBuffer->GetReadBuffer(0, &buf, &amt);
             if (rv == NS_BASE_STREAM_EOF) return rv;
             if (NS_SUCCEEDED(rv) && amt > 0) return NS_OK;
 
@@ -320,7 +339,8 @@ nsBufferOutputStream::Write(const char* aBuf, PRUint32 aCount, PRUint32 *aWriteC
 }
 
 NS_IMETHODIMP
-nsBufferOutputStream::Write(nsIInputStream* fromStream, PRUint32 *aWriteCount)
+nsBufferOutputStream::WriteFrom(nsIInputStream* fromStream, PRUint32 aCount,
+                                PRUint32 *aWriteCount)
 {
     if (mBuffer == nsnull)
         return NS_BASE_STREAM_CLOSED;
@@ -328,9 +348,9 @@ nsBufferOutputStream::Write(nsIInputStream* fromStream, PRUint32 *aWriteCount)
     nsresult rv = NS_OK;
     *aWriteCount = 0;
 
-    while (PR_TRUE) {   // write until fromStream gets EOF
+    while (aCount > 0) {
         PRUint32 amt;
-        rv = mBuffer->Write(fromStream, &amt);
+        rv = mBuffer->WriteFrom(fromStream, aCount, &amt);
         if (rv == NS_BASE_STREAM_EOF)
             return *aWriteCount > 0 ? NS_OK : rv;
         if (NS_FAILED(rv)) return rv;
@@ -339,6 +359,7 @@ nsBufferOutputStream::Write(nsIInputStream* fromStream, PRUint32 *aWriteCount)
             if (NS_FAILED(rv)) return rv;
         }
         else {
+            aCount -= amt;
             *aWriteCount += amt;
         }
     }
@@ -358,7 +379,7 @@ nsBufferOutputStream::Flush(void)
         // check write buffer again while in the monitor
         PRUint32 amt;
         char* buf;
-        rv = mBuffer->GetWriteBuffer(&amt, &buf);
+        rv = mBuffer->GetWriteBuffer(0, &buf, &amt);
         if (rv == NS_BASE_STREAM_EOF) return rv;
         if (NS_SUCCEEDED(rv) && amt > 0) return NS_OK;
 
diff --git a/mozilla/xpcom/tests/TestBuffers.cpp b/mozilla/xpcom/tests/TestBuffers.cpp
index 673777055c3..4eb324d2306 100644
--- a/mozilla/xpcom/tests/TestBuffers.cpp
+++ b/mozilla/xpcom/tests/TestBuffers.cpp
@@ -39,7 +39,7 @@ public:
         char buf[100];
         PRUint32 readCnt;
         char* readBuf;
-        rv = mReadBuffer->GetReadBuffer(&readCnt, &readBuf);
+        rv = mReadBuffer->GetReadBuffer(0, &readBuf, &readCnt);
         if (NS_FAILED(rv)) return rv;
         while (!(mDone && readCnt == 0)) {
             rv = mReadBuffer->Read(buf, 99, &readCnt);
@@ -52,7 +52,7 @@ public:
                     break;
                 mon.Notify(); // wake up writer
                 mon.Wait();   // wait for more
-                rv = mReadBuffer->GetReadBuffer(&readCnt, &readBuf);
+                rv = mReadBuffer->GetReadBuffer(0, &readBuf, &readCnt);
                 if (NS_FAILED(rv)) return rv;
             }
             else {