Fix issue where close can be called in a reentrant fashion by framer writing causing exception to be thrown by transport

core/src/main/java/io/grpc/transport/MessageFramer.java

@@ -219,6 +219,7 @@ public class MessageFramer {
    */
   public void close() {
     if (!isClosed()) {
+      closed = true;
       // With the current code we don't expect readableBytes > 0 to be possible here, added
       // defensively to prevent buffer leak issues if the framer code changes later.
       if (buffer != null && buffer.readableBytes() == 0) {
@@ -226,7 +227,6 @@ public class MessageFramer {
         buffer = null;
       }
       commitToSink(true, true);
-      closed = true;
     }
   }
 

core/src/test/java/io/grpc/transport/MessageFramerTest.java

@@ -34,6 +34,7 @@ package io.grpc.transport;
 import static io.grpc.transport.MessageFramer.Compression;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
 import static org.mockito.Matchers.eq;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.verifyNoMoreInteractions;
@@ -49,6 +50,7 @@ import org.mockito.MockitoAnnotations;
 
 import java.io.ByteArrayInputStream;
 import java.util.Arrays;
+import java.util.concurrent.atomic.AtomicInteger;
 
 /**
  * Tests for {@link MessageFramer}.
@@ -201,6 +203,26 @@ public class MessageFramerTest {
     assertEquals(1, allocator.allocCount);
   }
 
+  @Test
+  public void closeIsRentrantSafe() throws Exception {
+    MessageFramer.Sink reentrant = new MessageFramer.Sink() {
+      int count = 0;
+      @Override
+      public void deliverFrame(WritableBuffer frame, boolean endOfStream, boolean flush) {
+        if (count == 0) {
+          framer.close();
+          count++;
+        } else {
+          fail("received event from reentrant call to close");
+        }
+      }
+    };
+    framer = new MessageFramer(reentrant, allocator, Compression.NONE);
+    writePayload(framer, new byte[]{3, 14});
+    framer.close();
+  }
+
+
   private static WritableBuffer toWriteBuffer(byte[] data) {
     return toWriteBufferWithMinSize(data, 0);
   }