From cfaed1219f883cc23974342a51444d8fbe84cc45 Mon Sep 17 00:00:00 2001
From: old driver <laosijikaichele@gmail.com>
Date: Tue, 25 May 2021 14:19:02 +0800
Subject: [PATCH] Add fast path in ByteBufUtil.compare and ByteBufUtil.equals
 methods (#11296)

Motivation:

When object-references are both same, the method should return 0 directly with no necessary go loop&compare the content of the ByteBuf.

Modification:

Added short circuit when both object-references are the same for equals and compare methods.

Result:

Added short circuit code.
---
 buffer/src/main/java/io/netty/buffer/AbstractByteBuf.java | 2 +-
 buffer/src/main/java/io/netty/buffer/ByteBufUtil.java     | 6 ++++++
 buffer/src/main/java/io/netty/buffer/SwappedByteBuf.java  | 3 ---
 3 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/buffer/src/main/java/io/netty/buffer/AbstractByteBuf.java b/buffer/src/main/java/io/netty/buffer/AbstractByteBuf.java
index fb15250271..d16753e257 100644
--- a/buffer/src/main/java/io/netty/buffer/AbstractByteBuf.java
+++ b/buffer/src/main/java/io/netty/buffer/AbstractByteBuf.java
@@ -1344,7 +1344,7 @@ public abstract class AbstractByteBuf extends ByteBuf {
 
     @Override
     public boolean equals(Object o) {
-        return this == o || (o instanceof ByteBuf && ByteBufUtil.equals(this, (ByteBuf) o));
+        return o instanceof ByteBuf && ByteBufUtil.equals(this, (ByteBuf) o);
     }
 
     @Override
diff --git a/buffer/src/main/java/io/netty/buffer/ByteBufUtil.java b/buffer/src/main/java/io/netty/buffer/ByteBufUtil.java
index 675510be51..73d297a815 100644
--- a/buffer/src/main/java/io/netty/buffer/ByteBufUtil.java
+++ b/buffer/src/main/java/io/netty/buffer/ByteBufUtil.java
@@ -299,6 +299,9 @@ public final class ByteBufUtil {
      * This method is useful when implementing a new buffer type.
      */
     public static boolean equals(ByteBuf bufferA, ByteBuf bufferB) {
+        if (bufferA == bufferB) {
+            return true;
+        }
         final int aLen = bufferA.readableBytes();
         if (aLen != bufferB.readableBytes()) {
             return false;
@@ -311,6 +314,9 @@ public final class ByteBufUtil {
      * This method is useful when implementing a new buffer type.
      */
     public static int compare(ByteBuf bufferA, ByteBuf bufferB) {
+        if (bufferA == bufferB) {
+            return 0;
+        }
         final int aLen = bufferA.readableBytes();
         final int bLen = bufferB.readableBytes();
         final int minLength = Math.min(aLen, bLen);
diff --git a/buffer/src/main/java/io/netty/buffer/SwappedByteBuf.java b/buffer/src/main/java/io/netty/buffer/SwappedByteBuf.java
index 87783c5c95..7e038a6e87 100644
--- a/buffer/src/main/java/io/netty/buffer/SwappedByteBuf.java
+++ b/buffer/src/main/java/io/netty/buffer/SwappedByteBuf.java
@@ -1048,9 +1048,6 @@ public class SwappedByteBuf extends ByteBuf {
 
     @Override
     public boolean equals(Object obj) {
-        if (this == obj) {
-            return true;
-        }
         if (obj instanceof ByteBuf) {
             return ByteBufUtil.equals(this, (ByteBuf) obj);
         }