Pass the PackOutputStream down the call stack

Rather than storing this in an instance member, pass it down the
calling stack.  Its cleaner, we don't have to poke the stream as
a temporary field, and then unset it.

Change-Id: I0fd323371bc12edb10f0493bf11885d7057aeb13
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

org.eclipse.jgit/src/org/eclipse/jgit/storage/pack/PackWriter.java

@@ -183,8 +183,6 @@ public class PackWriter {
 
 	private final Repository db;
 
-	private PackOutputStream out;
-
 	private final Deflater deflater;
 
 	private ProgressMonitor initMonitor;
@@ -613,14 +611,14 @@ public class PackWriter {
 		if ((reuseDeltas || reuseObjects) && reuseSupport != null)
 			searchForReuse();
 
-		out = new PackOutputStream(packStream, isDeltaBaseAsOffset());
+		final PackOutputStream out = new PackOutputStream(packStream,
+				isDeltaBaseAsOffset());
 
 		writeMonitor.beginTask(WRITING_OBJECTS_PROGRESS, getObjectsNumber());
 		out.writeFileHeader(PACK_VERSION_GENERATED, getObjectsNumber());
-		writeObjects();
-		writeChecksum();
+		writeObjects(out);
+		writeChecksum(out);
 
-		out = null;
 		reader.release();
 		writeMonitor.endTask();
 	}
@@ -644,25 +642,26 @@ public class PackWriter {
 		initMonitor.endTask();
 	}
 
-	private void writeObjects() throws IOException {
+	private void writeObjects(PackOutputStream out) throws IOException {
 		for (List<ObjectToPack> list : objectsLists) {
 			for (ObjectToPack otp : list) {
 				if (writeMonitor.isCancelled())
 					throw new IOException(
 							JGitText.get().packingCancelledDuringObjectsWriting);
 				if (!otp.isWritten())
-					writeObject(otp);
+					writeObject(out, otp);
 			}
 		}
 	}
 
-	private void writeObject(final ObjectToPack otp) throws IOException {
+	private void writeObject(PackOutputStream out, final ObjectToPack otp)
+			throws IOException {
 		if (otp.isWritten())
 			return; // We shouldn't be here.
 
 		otp.markWantWrite();
 		if (otp.isDeltaRepresentation())
-			writeBaseFirst(otp);
+			writeBaseFirst(out, otp);
 
 		out.resetCRC32();
 		otp.setOffset(out.length());
@@ -690,12 +689,13 @@ public class PackWriter {
 
 		// If we reached here, reuse wasn't possible.
 		//
-		writeWholeObjectDeflate(otp);
+		writeWholeObjectDeflate(out, otp);
 		otp.setCRC(out.getCRC32());
 		writeMonitor.update(1);
 	}
 
-	private void writeBaseFirst(final ObjectToPack otp) throws IOException {
+	private void writeBaseFirst(PackOutputStream out, final ObjectToPack otp)
+			throws IOException {
 		ObjectToPack baseInPack = otp.getDeltaBase();
 		if (baseInPack != null) {
 			if (!baseInPack.isWritten()) {
@@ -708,7 +708,7 @@ public class PackWriter {
 					redoSearchForReuse(otp);
 					reuseDeltas = true;
 				} else {
-					writeObject(baseInPack);
+					writeObject(out, baseInPack);
 				}
 			}
 		} else if (!thin) {
@@ -728,8 +728,8 @@ public class PackWriter {
 		reuseSupport.selectObjectRepresentation(this, otp);
 	}
 
-	private void writeWholeObjectDeflate(final ObjectToPack otp)
-			throws IOException {
+	private void writeWholeObjectDeflate(PackOutputStream out,
+			final ObjectToPack otp) throws IOException {
 		final ObjectLoader loader = reader.openObject(otp, otp.getType());
 		final byte[] data = loader.getCachedBytes();
 		out.writeHeader(otp, data.length);
@@ -745,7 +745,7 @@ public class PackWriter {
 		} while (!deflater.finished());
 	}
 
-	private void writeChecksum() throws IOException {
+	private void writeChecksum(PackOutputStream out) throws IOException {
 		packcsum = out.getDigest();
 		out.write(packcsum);
 	}