io: WithCompression resuse snappy.Reader and snappy.Writer

utils/io/io.go

@@ -18,8 +18,6 @@ import (
 	"io"
 	"sync"
 
-	"github.com/golang/snappy"
-
 	"github.com/fatedier/frp/utils/crypto"
 	"github.com/fatedier/frp/utils/pool"
 )
@@ -55,8 +53,13 @@ func WithEncryption(rwc io.ReadWriteCloser, key []byte) (io.ReadWriteCloser, err
 }
 
 func WithCompression(rwc io.ReadWriteCloser) io.ReadWriteCloser {
-	return WrapReadWriteCloser(snappy.NewReader(rwc), snappy.NewWriter(rwc), func() error {
-		return rwc.Close()
+	sr := pool.GetSnappyReader(rwc)
+	sw := pool.GetSnappyWriter(rwc)
+	return WrapReadWriteCloser(sr, sw, func() error {
+		err := rwc.Close()
+		pool.PutSnappyReader(sr)
+		pool.PutSnappyWriter(sw)
+		return err
 	})
 }
 
@@ -64,13 +67,18 @@ type ReadWriteCloser struct {
 	r       io.Reader
 	w       io.Writer
 	closeFn func() error
+
+	closed bool
+	mu     sync.Mutex
 }
 
+// closeFn will be called only once
 func WrapReadWriteCloser(r io.Reader, w io.Writer, closeFn func() error) io.ReadWriteCloser {
 	return &ReadWriteCloser{
 		r:       r,
 		w:       w,
 		closeFn: closeFn,
+		closed:  false,
 	}
 }
 
@@ -83,6 +91,14 @@ func (rwc *ReadWriteCloser) Write(p []byte) (n int, err error) {
 }
 
 func (rwc *ReadWriteCloser) Close() (errRet error) {
+	rwc.mu.Lock()
+	if rwc.closed {
+		rwc.mu.Unlock()
+		return
+	}
+	rwc.closed = true
+	rwc.mu.Unlock()
+
 	var err error
 	if rc, ok := rwc.r.(io.Closer); ok {
 		err = rc.Close()

utils/pool/snappy.go

@@ -0,0 +1,57 @@
+// Copyright 2017 fatedier, fatedier@gmail.com
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package pool
+
+import (
+	"io"
+	"sync"
+
+	"github.com/golang/snappy"
+)
+
+var (
+	snappyReaderPool sync.Pool
+	snappyWriterPool sync.Pool
+)
+
+func GetSnappyReader(r io.Reader) *snappy.Reader {
+	var x interface{}
+	x = snappyReaderPool.Get()
+	if x == nil {
+		return snappy.NewReader(r)
+	}
+	sr := x.(*snappy.Reader)
+	sr.Reset(r)
+	return sr
+}
+
+func PutSnappyReader(sr *snappy.Reader) {
+	snappyReaderPool.Put(sr)
+}
+
+func GetSnappyWriter(w io.Writer) *snappy.Writer {
+	var x interface{}
+	x = snappyWriterPool.Get()
+	if x == nil {
+		return snappy.NewWriter(w)
+	}
+	sw := x.(*snappy.Writer)
+	sw.Reset(w)
+	return sw
+}
+
+func PutSnappyWriter(sw *snappy.Writer) {
+	snappyWriterPool.Put(sw)
+}