chore: use readRetainedSlice to avoid copy in SpdyFrameDecoder (#14573)

He-Pin · web-flow · commit fdc10c42dc59 · 2024-12-13T21:56:34.000+01:00
Motivation:

We can use readRetainedSlice to reduce the copy of bytes in
`SpdyFrameDecoder`.

Modification:

Make use of `readRetainedSlice` instead of new a byteBuf and copy data
to it.

Result:
Less copy
diff --git a/codec-http/src/main/java/io/netty/handler/codec/spdy/SpdyFrameDecoder.java b/codec-http/src/main/java/io/netty/handler/codec/spdy/SpdyFrameDecoder.java
@@ -161,8 +161,7 @@ public void decode(ByteBuf buffer) {
                         return;
                     }
 
-                    ByteBuf data = buffer.alloc().buffer(dataLength);
-                    data.writeBytes(buffer, dataLength);
+                    ByteBuf data = buffer.readRetainedSlice(dataLength);
                     length -= dataLength;
 
                     if (length == 0) {
@@ -361,8 +360,7 @@ public void decode(ByteBuf buffer) {
                     }
 
                     int compressedBytes = Math.min(buffer.readableBytes(), length);
-                    ByteBuf headerBlock = buffer.alloc().buffer(compressedBytes);
-                    headerBlock.writeBytes(buffer, compressedBytes);
+                    ByteBuf headerBlock = buffer.readRetainedSlice(compressedBytes);
                     length -= compressedBytes;
 
                     delegate.readHeaderBlock(headerBlock);
@@ -445,8 +443,7 @@ protected boolean decodeUnknownFrame(int frameType, byte flags, int length, Byte
             return false;
         }
         if (delegate instanceof SpdyFrameDecoderExtendedDelegate) {
-            ByteBuf data = buffer.alloc().buffer(length);
-            data.writeBytes(buffer, length);
+            ByteBuf data = buffer.readRetainedSlice(length);
             ((SpdyFrameDecoderExtendedDelegate) delegate).readUnknownFrame(frameType, flags, data);
         } else {
             buffer.skipBytes(length);
