Remove DefaultChannelHandlerContext.needsLazyBufInit which is used only by the head handler

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

@@ -45,7 +45,6 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
     private final DefaultChannelPipeline pipeline;
     private final String name;
     private final ChannelHandler handler;
-    private boolean needsLazyBufInit;
 
     // Will be set to null if no child executor should be used, otherwise it will be set to the
     // child executor.
@@ -182,7 +181,6 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
         executor = null;
         inByteBuf = null;
         inMsgBuf = null;
-        needsLazyBufInit = true;
     }
 
     DefaultChannelHandlerContext(DefaultChannelPipeline pipeline, String name, TailHandler handler) {
@@ -302,30 +300,19 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
         }
     }
 
-    private void lazyInitHeadHandler() {
+    void initHeadHandler() {
-        if (needsLazyBufInit) {
+        // Must be called for the head handler.
-            EventExecutor exec = executor();
+        HeadHandler h = (HeadHandler) handler;
-            if (exec.inEventLoop()) {
+        if (h.initialized) {
-                if (needsLazyBufInit) {
+            return;
-                    needsLazyBufInit = false;
-                    HeadHandler headHandler = (HeadHandler) handler;
-                    headHandler.init(this);
-                    outByteBuf = headHandler.byteSink;
-                    outMsgBuf = headHandler.msgSink;
-                }
-            } else {
-                try {
-                    getFromFuture(exec.submit(new Runnable() {
-                        @Override
-                        public void run() {
-                            lazyInitHeadHandler();
-                        }
-                    }));
-                } catch (Exception e) {
-                    throw new ChannelPipelineException("failed to initialize an outbound buffer lazily", e);
-                }
-            }
         }
+
+        assert executor().inEventLoop();
+
+        h.init(this);
+        h.initialized = true;
+        outByteBuf = h.byteSink;
+        outMsgBuf = h.msgSink;
     }
 
     private void fillInboundBridge() {
@@ -563,41 +550,6 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
         waitForFuture(executor().submit(r));
     }
 
-    /**
-     * Waits for a future to finish and gets the result.  If the task is interrupted, then the current thread
-     * will be interrupted and this will return {@code null}. It is expected that the task performs any
-     * appropriate locking.
-     * <p>
-     * If the internal call throws a {@link Throwable}, but it is not an instance of {@link Error},
-     * {@link RuntimeException}, or {@link Exception}, then it is wrapped inside an {@link AssertionError}
-     * and that is thrown instead.</p>
-     *
-     * @param future wait for this future
-     * @param <T> the return value type
-     * @return the task's return value, or {@code null} if the task was interrupted.
-     * @see Future#get()
-     * @throws Error if the task threw this.
-     * @throws RuntimeException if the task threw this.
-     * @throws Exception if the task threw this.
-     * @throws ChannelPipelineException with a {@link Throwable} as a cause, if the task threw another type of
-     *         {@link Throwable}.
-     */
-    private static <T> T getFromFuture(Future<T> future) throws Exception {
-        try {
-            return future.get();
-        } catch (ExecutionException ex) {
-            // In the arbitrary case, we can throw Error, RuntimeException, and Exception
-
-            PlatformDependent.throwException(ex.getCause());
-        } catch (InterruptedException ex) {
-            // Interrupt the calling thread (note that this method is not called from the event loop)
-
-            Thread.currentThread().interrupt();
-        }
-
-        return null;
-    }
-
     /**
      * Waits for a future to finish.  If the task is interrupted, then the current thread will be interrupted.
      * It is expected that the task performs any appropriate locking.
@@ -740,7 +692,6 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
 
     @Override
     public ChannelHandlerContext fireChannelRegistered() {
-        lazyInitHeadHandler();
         final DefaultChannelHandlerContext next = findContextInbound();
         EventExecutor executor = next.executor();
         if (executor.inEventLoop()) {
@@ -793,7 +744,6 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
 
     @Override
     public ChannelHandlerContext fireChannelActive() {
-        lazyInitHeadHandler();
         final DefaultChannelHandlerContext next = findContextInbound();
         EventExecutor executor = next.executor();
         if (executor.inEventLoop()) {

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

@@ -908,6 +908,7 @@ final class DefaultChannelPipeline implements ChannelPipeline {
 
     @Override
     public ChannelPipeline fireChannelRegistered() {
+        head.initHeadHandler();
         head.fireChannelRegistered();
         return this;
     }
@@ -926,6 +927,7 @@ final class DefaultChannelPipeline implements ChannelPipeline {
     @Override
     public ChannelPipeline fireChannelActive() {
         firedChannelActive = true;
+        head.initHeadHandler();
         head.fireChannelActive();
 
         if (channel.config().isAutoRead()) {
@@ -1200,12 +1202,14 @@ final class DefaultChannelPipeline implements ChannelPipeline {
         protected final Unsafe unsafe;
         ByteBuf byteSink;
         MessageBuf<Object> msgSink;
+        boolean initialized;
 
         protected HeadHandler(Unsafe unsafe) {
             this.unsafe = unsafe;
         }
 
         void init(ChannelHandlerContext ctx) {
+            assert !initialized;
             switch (ctx.channel().metadata().bufferType()) {
             case BYTE:
                 byteSink = ctx.alloc().ioBuffer();