XMPPTCPConnection: Move openStream() call from writer into reader thread

and also call notifyConnectionError() on exception thrown by
openStream().

In hindsight I wonder why openStream() was ever called in the writer
thread, as it only caused unnecessary synchronization overhead, as can
be seen by the initialOpenStreamSend synchronization point.

smack-tcp/src/main/java/org/jivesoftware/smack/tcp/XMPPTCPConnection.java

@@ -160,9 +160,6 @@ public class XMPPTCPConnection extends AbstractXMPPConnection {
      */
     protected final PacketReader packetReader = new PacketReader();
 
-    private final SynchronizationPoint<Exception> initialOpenStreamSend = new SynchronizationPoint<>(
-                    this, "initial open stream element send to server");
-
     /**
      *
      */
@@ -536,7 +533,6 @@ public class XMPPTCPConnection extends AbstractXMPPConnection {
         compressSyncPoint.init();
         smResumedSyncPoint.init();
         smEnabledSyncPoint.init();
-        initialOpenStreamSend.init();
     }
 
     @Override
@@ -898,8 +894,10 @@ public class XMPPTCPConnection extends AbstractXMPPConnection {
          * Parse top-level packets in order to process them further.
          */
         private void parsePackets() {
+            boolean initialStreamOpenSend = false;
             try {
-                initialOpenStreamSend.checkIfSuccessOrWait();
+                openStream();
+                initialStreamOpenSend = true;
                 int eventType = parser.getEventType();
                 while (!done) {
                     switch (eventType) {
@@ -1119,8 +1117,9 @@ public class XMPPTCPConnection extends AbstractXMPPConnection {
             catch (Exception e) {
                 closingStreamReceived.reportFailure(e);
                 // The exception can be ignored if the the connection is 'done'
-                // or if the it was caused because the socket got closed
-                if (!(done || packetWriter.queue.isShutdown())) {
+                // or if the it was caused because the socket got closed. It can not be ignored if it
+                // happened before (or while) the initial stream opened was send.
+                if (!(done || packetWriter.queue.isShutdown()) || !initialStreamOpenSend) {
                     // Close the connection and notify connection listeners of the
                     // error.
                     notifyConnectionError(e);
@@ -1275,8 +1274,6 @@ public class XMPPTCPConnection extends AbstractXMPPConnection {
         private void writePackets() {
             Exception writerException = null;
             try {
-                openStream();
-                initialOpenStreamSend.reportSuccess();
                 // Write out packets from the queue.
                 while (!done()) {
                     Element element = nextStreamElement();

smack-tcp/src/test/java/org/jivesoftware/smack/tcp/PacketWriterTest.java

@@ -16,13 +16,16 @@
  */
 package org.jivesoftware.smack.tcp;
 
+import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.fail;
 
 import java.io.IOException;
 import java.io.Writer;
 import java.util.concurrent.BrokenBarrierException;
 import java.util.concurrent.CyclicBarrier;
+import java.util.concurrent.atomic.AtomicReference;
 
+import org.jivesoftware.smack.SmackException;
 import org.jivesoftware.smack.SmackException.NotConnectedException;
 import org.jivesoftware.smack.packet.Message;
 import org.jivesoftware.smack.tcp.XMPPTCPConnection.PacketWriter;
@@ -45,19 +48,24 @@ public class PacketWriterTest {
      * @throws NotConnectedException
      * @throws XmppStringprepException
      */
-    @SuppressWarnings("javadoc")
     @Test
     public void shouldBlockAndUnblockTest() throws InterruptedException, BrokenBarrierException, NotConnectedException, XmppStringprepException {
         XMPPTCPConnection connection = new XMPPTCPConnection("user", "pass", "example.org");
         final PacketWriter pw = connection.packetWriter;
-        connection.setWriter(new BlockingStringWriter());
+        BlockingStringWriter blockingStringWriter = new BlockingStringWriter();
+        connection.setWriter(blockingStringWriter);
         connection.packetWriter.init();
 
-        for (int i = 0; i < XMPPTCPConnection.PacketWriter.QUEUE_SIZE; i++) {
+        // Now insert QUEUE_SIZE + 1 stanzas into the outgoing queue to make sure that the queue is filled until its
+        // full capacity. The +1 is because the writer thread will dequeue one stanza and try to write it into the
+        // blocking writer.
+        for (int i = 0; i < XMPPTCPConnection.PacketWriter.QUEUE_SIZE + 1; i++) {
             pw.sendStreamElement(new Message());
         }
 
         final CyclicBarrier barrier = new CyclicBarrier(2);
+        final AtomicReference<Exception> unexpectedThreadExceptionReference = new AtomicReference<>();
+        final AtomicReference<Exception> expectedThreadExceptionReference = new AtomicReference<>();
         shutdown = false;
         prematureUnblocked = false;
         Thread t = new Thread(new Runnable() {
@@ -71,12 +79,19 @@ public class PacketWriterTest {
                         prematureUnblocked = true;
                     }
                 }
-                catch (Exception e) {
+                catch (SmackException.NotConnectedException e) {
+                    // This is the exception we expect.
+                    expectedThreadExceptionReference.set(e);
                 }
+                catch (BrokenBarrierException | InterruptedException e) {
+                    unexpectedThreadExceptionReference.set(e);
+                }
+
                 try {
                     barrier.await();
                 }
                 catch (InterruptedException | BrokenBarrierException e) {
+                    unexpectedThreadExceptionReference.set(e);
                 }
             }
         });
@@ -90,28 +105,55 @@ public class PacketWriterTest {
 
         // Set to true for testing purposes, so that shutdown() won't wait packet writer
         pw.shutdownDone.reportSuccess();
-        // Shutdown the packetwriter
+        // Shutdown the packetwriter, this will also interrupt the writer thread, which is what we hope to happen in the
+        // thread created above.
         pw.shutdown(false);
         shutdown = true;
         barrier.await();
+
+        t.join(60000);
+
+        Exception unexpectedThreadException = unexpectedThreadExceptionReference.get();
+        try {
             if (prematureUnblocked) {
-            fail("Should not unblock before the thread got shutdown");
+                String failureMessage = "Should not unblock before the thread got shutdown.";
+                if (unexpectedThreadException != null) {
+                    failureMessage += " Unexpected thread exception thrown: " + unexpectedThreadException;
                 }
-        synchronized (t) {
-            t.notify();
+                fail(failureMessage);
+            }
+            else if (unexpectedThreadException != null) {
+                fail("Unexpected thread exception: " + unexpectedThreadException);
+            }
+
+            assertNotNull("Did not encounter expected exception on sendStreamElement()", expectedThreadExceptionReference.get());
+        }
+        finally {
+            blockingStringWriter.unblock();
         }
     }
 
     public static class BlockingStringWriter extends Writer {
+        private boolean blocked = true;
+
         @Override
-        @SuppressWarnings("WaitNotInLoop")
         public void write(char[] cbuf, int off, int len) throws IOException {
+            synchronized (this) {
+                while (blocked) {
                     try {
                         wait();
                     }
                     catch (InterruptedException e) {
+                        throw new AssertionError(e);
                     }
                 }
+            }
+        }
+
+        public synchronized void unblock() {
+            blocked = false;
+            notify();
+        }
 
         @Override
         public void flush() throws IOException {