Allow PreUploadHook.onSendPack to send messages to the client

Before transmitting to the client a hook may want to send along
a text message ahead of the pack, such as a "message of the day".
Enable this usage by mirroring the message sending API from
ReceivePack on the UploadPack instance, using the side band.

Change-Id: I31cd254a4ddb816641397a3e9c2c20212471c37f

diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/transport/UploadPack.java b/org.eclipse.jgit/src/org/eclipse/jgit/transport/UploadPack.java
index 5347eb713cf94ab978acbcc292a2f65aa8e098e4..6ae08acaa2164e562769fc42a6de4d16ee012c64 100644 (file)
--- a/org.eclipse.jgit/src/org/eclipse/jgit/transport/UploadPack.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/transport/UploadPack.java
@@ -80,6 +80,7 @@ import org.eclipse.jgit.revwalk.filter.CommitTimeRevFilter;
 import org.eclipse.jgit.storage.pack.PackConfig;
 import org.eclipse.jgit.transport.BasePackFetchConnection.MultiAck;
 import org.eclipse.jgit.transport.RefAdvertiser.PacketLineOutRefAdvertiser;
+import org.eclipse.jgit.util.io.DisabledOutputStream;
 import org.eclipse.jgit.util.io.InterruptTimer;
 import org.eclipse.jgit.util.io.TimeoutInputStream;
 import org.eclipse.jgit.util.io.TimeoutOutputStream;
@@ -192,6 +193,8 @@ public class UploadPack {
 
        private PacketLineOut pckOut;
 
+       private OutputStream msgOut = DisabledOutputStream.INSTANCE;
+
        /** The refs we advertised as existing at the start of the connection. */
        private Map<String, Ref> refs;
 
@@ -504,6 +507,8 @@ public class UploadPack {
                try {
                        rawIn = input;
                        rawOut = output;
+                       if (messages != null)
+                               msgOut = messages;
 
                        if (timeout > 0) {
                                final Thread caller = Thread.currentThread();
@@ -520,6 +525,7 @@ public class UploadPack {
                        pckOut = new PacketLineOut(rawOut);
                        service();
                } finally {
+                       msgOut = DisabledOutputStream.INSTANCE;
                        walk.release();
                        if (timer != null) {
                                try {
@@ -692,6 +698,29 @@ public class UploadPack {
                adv.end();
        }
 
+       /**
+        * Send a message to the client, if it supports receiving them.
+        * <p>
+        * If the client doesn't support receiving messages, the message will be
+        * discarded, with no other indication to the caller or to the client.
+        *
+        * @param what
+        *            string describing the problem identified by the hook. The
+        *            string must not end with an LF, and must not contain an LF.
+        */
+       public void sendMessage(String what) {
+               try {
+                       msgOut.write(Constants.encode(what + "\n")); //$NON-NLS-1$
+               } catch (IOException e) {
+                       // Ignore write failures.
+               }
+       }
+
+       /** @return an underlying stream for sending messages to the client, or null. */
+       public OutputStream getMessageOutputStream() {
+               return msgOut;
+       }
+
        private void recvWants() throws IOException {
                boolean isFirst = true;
                for (;;) {
@@ -1076,7 +1105,6 @@ public class UploadPack {
        private void sendPack(final boolean sideband) throws IOException {
                ProgressMonitor pm = NullProgressMonitor.INSTANCE;
                OutputStream packOut = rawOut;
-               SideBandOutputStream msgOut = null;
 
                if (sideband) {
                        int bufsz = SideBandOutputStream.SMALL_BUF;
@@ -1181,7 +1209,7 @@ public class UploadPack {
                        pw.writePack(pm, NullProgressMonitor.INSTANCE, packOut);
                        statistics = pw.getStatistics();
 
-                       if (msgOut != null) {
+                       if (msgOut != DisabledOutputStream.INSTANCE) {
                                String msg = pw.getStatistics().getMessage() + '\n';
                                msgOut.write(Constants.encode(msg));
                                msgOut.flush();