Rft: object pool

bytes/bytes_buffer_pool.go

@@ -23,12 +23,18 @@ import (
 )
 
 var (
-	defaultPool BytesBufferPool
+	defaultPool *ObjectPool
 )
 
+func init() {
+	defaultPool = NewObjectPool(func() PoolObject {
+		return new(bytes.Buffer)
+	})
+}
+
 // GetBytesBuffer returns bytes.Buffer from pool
 func GetBytesBuffer() *bytes.Buffer {
-	return defaultPool.Get()
+	return defaultPool.Get().(*bytes.Buffer)
 }
 
 // PutIoBuffer returns IoBuffer to pool
@@ -36,23 +42,35 @@ func PutBytesBuffer(buf *bytes.Buffer) {
 	defaultPool.Put(buf)
 }
 
-// BytesBufferPool is bytes.Buffer Pool
-type BytesBufferPool struct {
+// Pool object
+type PoolObject interface {
+	Reset()
+}
+
+type New func() PoolObject
+
+// Pool is bytes.Buffer Pool
+type ObjectPool struct {
+	New  New
 	pool sync.Pool
 }
 
+func NewObjectPool(n New) *ObjectPool {
+	return &ObjectPool{New: n}
+}
+
 // take returns *bytes.Buffer from Pool
-func (p *BytesBufferPool) Get() *bytes.Buffer {
+func (p *ObjectPool) Get() PoolObject {
 	v := p.pool.Get()
 	if v == nil {
-		return new(bytes.Buffer)
+		return p.New()
 	}
 
-	return v.(*bytes.Buffer)
+	return v.(PoolObject)
 }
 
 // give returns *byes.Buffer to Pool
-func (p *BytesBufferPool) Put(buf *bytes.Buffer) {
-	buf.Reset()
-	p.pool.Put(buf)
+func (p *ObjectPool) Put(o PoolObject) {
+	o.Reset()
+	p.pool.Put(o)
 }

bytes/bytes_buffer_pool_test.go

@@ -12,4 +12,11 @@ func TestBytesBufferPool(t *testing.T) {
 		t.Error("iobuffer len not match write bytes' size")
 	}
 	PutBytesBuffer(buf)
+	buf2 := GetBytesBuffer()
+	// https://go-review.googlesource.com/c/go/+/162919/
+	// before go 1.13, sync.Pool just reserves some objs before every gc and will be cleanup by gc.
+	// after Go 1.13, maybe there are many reserved objs after gc.
+	if buf != buf2 {
+		t.Errorf("buf pointer %p != buf2 pointer %p", buf, buf2)
+	}
 }

bytes/slice_pool_test.go

@@ -18,6 +18,15 @@ func intN(n int) int {
 	return rand.Intn(n) + 1
 }
 
+func ExampleGetBytes() {
+	// Obtain a buffer from the pool.
+	bufPtr := GetBytes(16)
+	defer PutBytes(bufPtr)
+	buf := *bufPtr
+	copy(buf, []byte("hello, world"))
+	println(string(buf))
+}
+
 func TestSlicePoolSmallBytes(t *testing.T) {
 	pool := NewSlicePool()