rpc_util: add default recv buffer pool with nop functionality

This change eliminates the need for nil checks on the shared recv buffer pool, resulting in a more simplified codebase.

dialoptions.go

@@ -619,6 +619,7 @@ func defaultDialOptions() dialOptions {
 			ReadBufferSize:  defaultReadBufSize,
 			UseProxy:        true,
 		},
+		sharedRecvBufferPool: nopBufferPool{},
 	}
 }
 

rpc_util.go

@@ -613,11 +613,7 @@ func (p *parser) recvMsg(maxReceiveMessageSize int) (pf payloadFormat, msg []byt
 	if int(length) > maxReceiveMessageSize {
 		return 0, nil, status.Errorf(codes.ResourceExhausted, "grpc: received message larger than max (%d vs. %d)", length, maxReceiveMessageSize)
 	}
-	if p.sharedRecvBufferPool != nil {
-		msg = p.sharedRecvBufferPool.Get(int(length))
-	} else {
-		msg = make([]byte, int(length))
-	}
+	msg = p.sharedRecvBufferPool.Get(int(length))
 	if _, err := p.r.Read(msg); err != nil {
 		if err == io.EOF {
 			err = io.ErrUnexpectedEOF
@@ -805,16 +801,8 @@ func recv(p *parser, c baseCodec, s *transport.Stream, dc Decompressor, m interf
 		return status.Errorf(codes.Internal, "grpc: failed to unmarshal the received message: %v", err)
 	}
 	if payInfo != nil {
-		if p.sharedRecvBufferPool != nil {
-			if len(buf) != 0 {
-				payInfo.uncompressedBytes = make([]byte, len(buf))
-				copy(payInfo.uncompressedBytes, buf)
-			}
-		} else {
-			payInfo.uncompressedBytes = buf
-		}
-	}
-	if p.sharedRecvBufferPool != nil {
+		payInfo.uncompressedBytes = buf
+	} else {
 		p.sharedRecvBufferPool.Put(&buf)
 	}
 	return nil

rpc_util_test.go

@@ -65,7 +65,7 @@ func (s) TestSimpleParsing(t *testing.T) {
 		{append([]byte{0, 1, 0, 0, 0}, bigMsg...), nil, bigMsg, compressionNone},
 	} {
 		buf := fullReader{bytes.NewReader(test.p)}
-		parser := &parser{r: buf}
+		parser := &parser{r: buf, sharedRecvBufferPool: nopBufferPool{}}
 		pt, b, err := parser.recvMsg(math.MaxInt32)
 		if err != test.err || !bytes.Equal(b, test.b) || pt != test.pt {
 			t.Fatalf("parser{%v}.recvMsg(_) = %v, %v, %v\nwant %v, %v, %v", test.p, pt, b, err, test.pt, test.b, test.err)
@@ -77,7 +77,7 @@ func (s) TestMultipleParsing(t *testing.T) {
 	// Set a byte stream consists of 3 messages with their headers.
 	p := []byte{0, 0, 0, 0, 1, 'a', 0, 0, 0, 0, 2, 'b', 'c', 0, 0, 0, 0, 1, 'd'}
 	b := fullReader{bytes.NewReader(p)}
-	parser := &parser{r: b}
+	parser := &parser{r: b, sharedRecvBufferPool: nopBufferPool{}}
 
 	wantRecvs := []struct {
 		pt   payloadFormat

server.go

@@ -184,6 +184,7 @@ var defaultServerOptions = serverOptions{
 	connectionTimeout:     120 * time.Second,
 	writeBufferSize:       defaultWriteBufSize,
 	readBufferSize:        defaultReadBufSize,
+	sharedRecvBufferPool:  nopBufferPool{},
 }
 var globalServerOptions []ServerOption
 

shared_buffer_pool.go

@@ -151,3 +151,15 @@ func makeFallbackBytesPool() bufferPool {
 		},
 	}
 }
+
+// nopBufferPool is a buffer pool just makes new buffer without pooling.
+type nopBufferPool struct {
+}
+
+func (nopBufferPool) Get(length int) []byte {
+	return make([]byte, length)
+}
+
+func (nopBufferPool) Put(*[]byte) {
+
+}