UploadPack: Consolidate the sideband handling code to one place

This consolidates the sideband stream creation code and the error
handling code for the sideband-allowed part in the Git protocol to one
place.

Change-Id: I0e3e94564f50d1be32006f9d8bcd1ef1ce6bf07e
Signed-off-by: Masaya Suzuki <masayasuzuki@google.com>

org.eclipse.jgit/src/org/eclipse/jgit/transport/UploadPack.java

@@ -809,11 +809,6 @@ public class UploadPack {
 			} else {
 				service(pckOut);
 			}
-		} catch (UploadPackInternalServerErrorException err) {
-			// UploadPackInternalServerErrorException is a special exception
-			// that indicates an error is already written to the client. Do
-			// nothing.
-			throw err;
 		} catch (ServiceMayNotContinueException err) {
 			if (!err.isOutput() && err.getMessage() != null) {
 				try {
@@ -2117,45 +2112,42 @@ public class UploadPack {
 		Set<String> caps = req.getClientCapabilities();
 		boolean sideband = caps.contains(OPTION_SIDE_BAND)
 				|| caps.contains(OPTION_SIDE_BAND_64K);
+
 		if (sideband) {
 			errOut = new SideBandErrorWriter();
 
-			try {
-				sendPack(true, req, accumulator, allTags, unshallowCommits,
-						deepenNots, pckOut);
-			} catch (ServiceMayNotContinueException err) {
-				String message = err.getMessage();
-				if (message == null) {
-					message = JGitText.get().internalServerError;
-				}
-				try {
-					errOut.writeError(message);
-				} catch (IOException e) {
-					err.addSuppressed(e);
-					throw err;
-				}
-				throw new UploadPackInternalServerErrorException(err);
-			} catch (IOException | RuntimeException | Error err) {
-				try {
-					errOut.writeError(JGitText.get().internalServerError);
-				} catch (IOException e) {
-					err.addSuppressed(e);
-					throw err;
-				}
-				throw new UploadPackInternalServerErrorException(err);
+			int bufsz = SideBandOutputStream.SMALL_BUF;
+			if (req.getClientCapabilities().contains(OPTION_SIDE_BAND_64K)) {
+				bufsz = SideBandOutputStream.MAX_BUF;
+			}
+			OutputStream packOut = new SideBandOutputStream(
+					SideBandOutputStream.CH_DATA, bufsz, rawOut);
+
+			ProgressMonitor pm = NullProgressMonitor.INSTANCE;
+			if (!req.getClientCapabilities().contains(OPTION_NO_PROGRESS)) {
+				msgOut = new SideBandOutputStream(
+						SideBandOutputStream.CH_PROGRESS, bufsz, rawOut);
+				pm = new SideBandProgressMonitor(msgOut);
 			}
+
+			sendPack(pm, pckOut, packOut, req, accumulator, allTags,
+					unshallowCommits, deepenNots);
+			pckOut.end();
 		} else {
-			sendPack(false, req, accumulator, allTags, unshallowCommits, deepenNots,
-					pckOut);
+			sendPack(NullProgressMonitor.INSTANCE, pckOut, rawOut, req,
+					accumulator, allTags, unshallowCommits, deepenNots);
 		}
 	}
 
 	/**
 	 * Send the requested objects to the client.
 	 *
-	 * @param sideband
-	 *            whether to wrap the pack in side-band pkt-lines, interleaved
-	 *            with progress messages and errors.
+	 * @param pm
+	 *            progress monitor
+	 * @param pckOut
+	 *            PacketLineOut that shares the output with packOut
+	 * @param packOut
+	 *            packfile output
 	 * @param req
 	 *            request being processed
 	 * @param accumulator
@@ -2167,35 +2159,14 @@ public class UploadPack {
 	 *            shallow commits on the client that are now becoming unshallow
 	 * @param deepenNots
 	 *            objects that the client specified using --shallow-exclude
-	 * @param pckOut
-	 *            output writer
 	 * @throws IOException
 	 *             if an error occurred while generating or writing the pack.
 	 */
-	private void sendPack(final boolean sideband,
-			FetchRequest req,
+	private void sendPack(ProgressMonitor pm, PacketLineOut pckOut,
+			OutputStream packOut, FetchRequest req,
 			PackStatistics.Accumulator accumulator,
-			@Nullable Collection<Ref> allTags,
-			List<ObjectId> unshallowCommits,
-			List<ObjectId> deepenNots,
-			PacketLineOut pckOut) throws IOException {
-		ProgressMonitor pm = NullProgressMonitor.INSTANCE;
-		OutputStream packOut = rawOut;
-
-		if (sideband) {
-			int bufsz = SideBandOutputStream.SMALL_BUF;
-			if (req.getClientCapabilities().contains(OPTION_SIDE_BAND_64K))
-				bufsz = SideBandOutputStream.MAX_BUF;
-
-			packOut = new SideBandOutputStream(SideBandOutputStream.CH_DATA,
-					bufsz, rawOut);
-			if (!req.getClientCapabilities().contains(OPTION_NO_PROGRESS)) {
-				msgOut = new SideBandOutputStream(
-						SideBandOutputStream.CH_PROGRESS, bufsz, rawOut);
-				pm = new SideBandProgressMonitor(msgOut);
-			}
-		}
-
+			@Nullable Collection<Ref> allTags, List<ObjectId> unshallowCommits,
+			List<ObjectId> deepenNots) throws IOException {
 		if (wantAll.isEmpty()) {
 			preUploadHook.onSendPack(this, wantIds, commonBase);
 		} else {
@@ -2338,9 +2309,6 @@ public class UploadPack {
 			}
 			pw.close();
 		}
-
-		if (sideband)
-			pckOut.end();
 	}
 
 	private static void findSymrefs(