PatchApplier: wrap output's TemporaryBuffer with a CountingOutputStream

The documentation for TemporaryBuffer::length says:
"The length is only accurate after {@link #close()} has been invoked".
However, we need to have the stream open while accessing the length.

This prevents patches on large files to be applied correctly, as the
result get trimmed.

Bug: Google b/309500446
Change-Id: Ic1540f6d0044088f3b46f1fad5f6a28ec254b711

1 files changed, 6 insertions, 2 deletions

diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/patch/PatchApplier.java b/org.eclipse.jgit/src/org/eclipse/jgit/patch/PatchApplier.java
index 1edd85421a..a327095c81 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/patch/PatchApplier.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/patch/PatchApplier.java
@@ -88,6 +88,7 @@ import org.eclipse.jgit.util.TemporaryBuffer;
 import org.eclipse.jgit.util.TemporaryBuffer.LocalFile;
 import org.eclipse.jgit.util.io.BinaryDeltaInputStream;
 import org.eclipse.jgit.util.io.BinaryHunkInputStream;
+import org.eclipse.jgit.util.io.CountingOutputStream;
 import org.eclipse.jgit.util.io.EolStreamTypeUtil;
 import org.eclipse.jgit.util.sha1.SHA1;
 
@@ -1013,7 +1014,10 @@ public class PatchApplier {
 		// We could check if old == new, but the short-circuiting complicates
 		// logic for inCore patching, so just write the new thing regardless.
 		TemporaryBuffer buffer = new TemporaryBuffer.LocalFile(null);
-		try (OutputStream out = buffer) {
+		// TemporaryBuffer::length reports incorrect length until the buffer
+		// is closed. To use it as input for ContentStreamLoader below, we
+		// need a wrapper with a reliable in-progress length.
+		try (CountingOutputStream out = new CountingOutputStream(buffer)) {
 			for (Iterator<ByteBuffer> l = newLines.iterator(); l.hasNext();) {
 				ByteBuffer line = l.next();
 				if (line == null) {
@@ -1026,7 +1030,7 @@ public class PatchApplier {
 				}
 			}
 			return new ContentStreamLoader(buffer::openInputStream,
-					buffer.length());
+				out.getCount());
 		}
 	}