From dce7157be99043fd285ba7242425520287bd2bf5 Mon Sep 17 00:00:00 2001
From: Norman Maurer <norman_maurer@apple.com>
Date: Tue, 21 Jan 2020 07:44:04 -0800
Subject: [PATCH] Remove extra field from ChunkedWriteHandler to make it less
 error-prone (#9958)

Motivation:

At the moment we use an extra field in ChunedWriteHandler to hold the current write. This is not needed and makes sense even more error-prone. We can just peek in the queue.

Modifications:

Use Queue.peek() to keep track of current write

Result:

Less error-prone code
---
 .../handler/stream/ChunkedWriteHandler.java   | 22 +++++--------------
 1 file changed, 6 insertions(+), 16 deletions(-)

diff --git a/handler/src/main/java/io/netty/handler/stream/ChunkedWriteHandler.java b/handler/src/main/java/io/netty/handler/stream/ChunkedWriteHandler.java
index 675b316911..bf8da55c20 100644
--- a/handler/src/main/java/io/netty/handler/stream/ChunkedWriteHandler.java
+++ b/handler/src/main/java/io/netty/handler/stream/ChunkedWriteHandler.java
@@ -70,7 +70,6 @@ public class ChunkedWriteHandler implements ChannelHandler {
 
     private final Queue<PendingWrite> queue = new ArrayDeque<>();
     private volatile ChannelHandlerContext ctx;
-    private PendingWrite currentWrite;
 
     public ChunkedWriteHandler() {
     }
@@ -142,13 +141,7 @@ public class ChunkedWriteHandler implements ChannelHandler {
 
     private void discard(Throwable cause) {
         for (;;) {
-            PendingWrite currentWrite = this.currentWrite;
-
-            if (this.currentWrite == null) {
-                currentWrite = queue.poll();
-            } else {
-                this.currentWrite = null;
-            }
+            PendingWrite currentWrite = queue.poll();
 
             if (currentWrite == null) {
                 break;
@@ -198,9 +191,7 @@ public class ChunkedWriteHandler implements ChannelHandler {
         boolean requiresFlush = true;
         ByteBufAllocator allocator = ctx.alloc();
         while (channel.isWritable()) {
-            if (currentWrite == null) {
-                currentWrite = queue.poll();
-            }
+            final PendingWrite currentWrite = queue.peek();
 
             if (currentWrite == null) {
                 break;
@@ -216,11 +207,10 @@ public class ChunkedWriteHandler implements ChannelHandler {
                 // as this had to be done already by someone who resolved the
                 // promise (using ChunkedInput.close method).
                 // See https://github.com/netty/netty/issues/8700.
-                this.currentWrite = null;
+                queue.remove();
                 continue;
             }
 
-            final PendingWrite currentWrite = this.currentWrite;
             final Object pendingMessage = currentWrite.msg;
 
             if (pendingMessage instanceof ChunkedInput) {
@@ -239,7 +229,7 @@ public class ChunkedWriteHandler implements ChannelHandler {
                         suspend = false;
                     }
                 } catch (final Throwable t) {
-                    this.currentWrite = null;
+                    queue.remove();
 
                     if (message != null) {
                         ReferenceCountUtil.release(message);
@@ -265,7 +255,7 @@ public class ChunkedWriteHandler implements ChannelHandler {
 
                 ChannelFuture f = ctx.write(message);
                 if (endOfInput) {
-                    this.currentWrite = null;
+                    queue.remove();
 
                     // Register a listener which will close the input once the write is complete.
                     // This is needed because the Chunk may have some resource bound that can not
@@ -312,7 +302,7 @@ public class ChunkedWriteHandler implements ChannelHandler {
                 ctx.flush();
                 requiresFlush = false;
             } else {
-                this.currentWrite = null;
+                queue.remove();
                 ctx.write(pendingMessage, currentWrite.promise);
                 requiresFlush = true;
             }