Simplify the logic for updating OP_WRITE in the NIO transport

- Removed code duplication

transport-udt/src/main/java/io/netty/channel/udt/nio/NioUdtByteConnectorChannel.java

@@ -31,7 +31,6 @@ import io.netty.util.internal.logging.InternalLoggerFactory;
 
 import java.net.InetSocketAddress;
 import java.net.SocketAddress;
-import java.nio.channels.SelectionKey;
 
 import static java.nio.channels.SelectionKey.*;
 
@@ -143,25 +142,10 @@ public class NioUdtByteConnectorChannel extends AbstractNioByteChannel
     }
 
     @Override
-    protected int doWriteBytes(final ByteBuf byteBuf, final boolean lastSpin)
+    protected int doWriteBytes(final ByteBuf byteBuf, final boolean lastSpin) throws Exception {
-            throws Exception {
+        final int expectedWrittenBytes = byteBuf.readableBytes();
-        final int pendingBytes = byteBuf.readableBytes();
+        final int writtenBytes = byteBuf.readBytes(javaChannel(), expectedWrittenBytes);
-        final int writtenBytes = byteBuf.readBytes(javaChannel(), pendingBytes);
+        updateOpWrite(expectedWrittenBytes, writtenBytes, lastSpin);
-        final SelectionKey key = selectionKey();
-        final int interestOps = key.interestOps();
-        if (writtenBytes >= pendingBytes) {
-            // wrote the buffer completely - clear OP_WRITE.
-            if ((interestOps & OP_WRITE) != 0) {
-                key.interestOps(interestOps & ~OP_WRITE);
-            }
-        } else {
-            // wrote partial or nothing - ensure OP_WRITE
-            if (writtenBytes > 0 || lastSpin) {
-                if ((interestOps & OP_WRITE) == 0) {
-                    key.interestOps(interestOps | OP_WRITE);
-                }
-            }
-        }
         return writtenBytes;
     }
 

transport/src/main/java/io/netty/channel/DefaultFileRegion.java

@@ -84,7 +84,7 @@ public class DefaultFileRegion extends AbstractReferenceCounted implements FileR
             return 0L;
         }
 
-        long written =  file.transferTo(this.position + position, count, target);
+        long written = file.transferTo(this.position + position, count, target);
         if (written > 0) {
             transfered += written;
         }

transport/src/main/java/io/netty/channel/nio/AbstractNioByteChannel.java

@@ -24,6 +24,7 @@ import io.netty.channel.FileRegion;
 import io.netty.channel.MessageList;
 import io.netty.channel.RecvByteBufAllocator;
 import io.netty.channel.socket.ChannelInputShutdownEvent;
+import io.netty.util.internal.StringUtil;
 
 import java.io.IOException;
 import java.nio.channels.SelectableChannel;
@@ -124,36 +125,43 @@ public abstract class AbstractNioByteChannel extends AbstractNioChannel {
 
         if (msg instanceof ByteBuf) {
             ByteBuf buf = (ByteBuf) msg;
+            boolean done = false;
             for (int i = config().getWriteSpinCount() - 1; i >= 0; i --) {
                 int localFlushedAmount = doWriteBytes(buf, i == 0);
-                if (localFlushedAmount > 0 || !buf.isReadable()) {
+                if (localFlushedAmount == 0) {
+                    break;
+                }
+                if (!buf.isReadable()) {
+                    done = true;
                     break;
                 }
             }
             // We may could optimize this to write multiple buffers at once (scattering)
-            if (!buf.isReadable()) {
+            if (done) {
                 buf.release();
                 return 1;
             }
         } else if (msg instanceof FileRegion) {
             FileRegion region = (FileRegion) msg;
 
+            boolean done = false;
             for (int i = config().getWriteSpinCount() - 1; i >= 0; i --) {
                 long localFlushedAmount = doWriteFileRegion(region, i == 0);
-                if (localFlushedAmount == -1) {
+                if (localFlushedAmount == 0) {
-                    checkEOF(region);
+                    break;
-                    return 1;
                 }
-                if (localFlushedAmount > 0) {
+                if (region.transfered() >= region.count()) {
+                    done = true;
                     break;
                 }
             }
-            if (region.transfered() >= region.count()) {
+
+            if (done) {
                 region.release();
                 return 1;
             }
         } else {
-            throw new UnsupportedOperationException("Not support writing of message " + msg);
+            throw new UnsupportedOperationException("unsupported message type: " + StringUtil.simpleClassName(msg));
         }
 
         return 0;
@@ -183,4 +191,26 @@ public abstract class AbstractNioByteChannel extends AbstractNioChannel {
      */
     protected abstract int doWriteBytes(ByteBuf buf, boolean lastSpin) throws Exception;
 
+    protected void updateOpWrite(long expectedWrittenBytes, long writtenBytes, boolean lastSpin) {
+        if (writtenBytes >= expectedWrittenBytes) {
+            final SelectionKey key = selectionKey();
+            final int interestOps = key.interestOps();
+            // Wrote the outbound buffer completely - clear OP_WRITE.
+            if ((interestOps & SelectionKey.OP_WRITE) != 0) {
+                key.interestOps(interestOps & ~SelectionKey.OP_WRITE);
+            }
+        } else {
+            // 1) Wrote nothing: buffer is full obviously - set OP_WRITE
+            // 2) Wrote partial data:
+            //    a) lastSpin is false: no need to set OP_WRITE because the caller will try again immediately.
+            //    b) lastSpin is true: set OP_WRITE because the caller will not try again.
+            if (writtenBytes == 0 || lastSpin) {
+                final SelectionKey key = selectionKey();
+                final int interestOps = key.interestOps();
+                if ((interestOps & SelectionKey.OP_WRITE) == 0) {
+                    key.interestOps(interestOps | SelectionKey.OP_WRITE);
+                }
+            }
+        }
+    }
 }

transport/src/main/java/io/netty/channel/socket/nio/NioSocketChannel.java

@@ -35,7 +35,6 @@ import java.net.InetSocketAddress;
 import java.net.SocketAddress;
 import java.nio.channels.SelectionKey;
 import java.nio.channels.SocketChannel;
-import java.nio.channels.WritableByteChannel;
 
 /**
  * {@link io.netty.channel.socket.SocketChannel} which uses NIO selector based implementation.
@@ -231,62 +230,16 @@ public class NioSocketChannel extends AbstractNioByteChannel implements io.netty
     protected int doWriteBytes(ByteBuf buf, boolean lastSpin) throws Exception {
         final int expectedWrittenBytes = buf.readableBytes();
         final int writtenBytes = buf.readBytes(javaChannel(), expectedWrittenBytes);
-
+        updateOpWrite(expectedWrittenBytes, writtenBytes, lastSpin);
-        if (writtenBytes >= expectedWrittenBytes) {
-            final SelectionKey key = selectionKey();
-            final int interestOps = key.interestOps();
-            // Wrote the outbound buffer completely - clear OP_WRITE.
-            if ((interestOps & SelectionKey.OP_WRITE) != 0) {
-                key.interestOps(interestOps & ~SelectionKey.OP_WRITE);
-            }
-        } else {
-            // Wrote something or nothing.
-            // a) If wrote something, the caller will not retry.
-            //    - Set OP_WRITE so that the event loop calls flushForcibly() later.
-            // b) If wrote nothing:
-            //    1) If 'lastSpin' is false, the caller will call this method again real soon.
-            //       - Do not update OP_WRITE.
-            //    2) If 'lastSpin' is true, the caller will not retry.
-            //       - Set OP_WRITE so that the event loop calls flushForcibly() later.
-            if (writtenBytes > 0 || lastSpin) {
-                final SelectionKey key = selectionKey();
-                final int interestOps = key.interestOps();
-                if ((interestOps & SelectionKey.OP_WRITE) == 0) {
-                    key.interestOps(interestOps | SelectionKey.OP_WRITE);
-                }
-            }
-        }
-
         return writtenBytes;
     }
 
     @Override
     protected long doWriteFileRegion(FileRegion region, boolean lastSpin) throws Exception {
-        if (javaChannel() instanceof WritableByteChannel) {
+        final long position = region.transfered();
-            WritableByteChannel wch = javaChannel();
+        final long expectedWrittenBytes = region.count() - position;
-            long localWrittenBytes = region.transferTo(wch, region.transfered());
+        final long writtenBytes = region.transferTo(javaChannel(), position);
-            if (localWrittenBytes > 0 || lastSpin) {
+        updateOpWrite(expectedWrittenBytes, writtenBytes, lastSpin);
-                // check if the region was written complete. If not set OP_WRITE so the eventloop
+        return writtenBytes;
-                // will write the rest once writable again
-                if (region.transfered() < region.count()) {
-                    final SelectionKey key = selectionKey();
-                    final int interestOps = key.interestOps();
-                    if ((interestOps & SelectionKey.OP_WRITE) == 0) {
-                        key.interestOps(interestOps | SelectionKey.OP_WRITE);
-                    }
-                }
-            } else {
-                final SelectionKey key = selectionKey();
-                final int interestOps = key.interestOps();
-                // Wrote the region completely - clear OP_WRITE.
-                if ((interestOps & SelectionKey.OP_WRITE) != 0) {
-                    key.interestOps(interestOps & ~SelectionKey.OP_WRITE);
-                }
-            }
-            return localWrittenBytes;
-        } else {
-            throw new UnsupportedOperationException("Underlying Channel is not of instance "
-                    + WritableByteChannel.class);
-        }
     }
 }