聊聊gost的ObjectPool

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本文主要研究一下gost的ObjectPool

ObjectPool

gost/bytes/bytes_buffer_pool.go

// 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 *ObjectPool) Get() PoolObject {
	v := p.pool.Get()
	if v == nil {
		return p.New()
	}

	return v.(PoolObject)
}

// give returns *byes.Buffer to Pool
func (p *ObjectPool) Put(o PoolObject) {
	o.Reset()
	p.pool.Put(o)
}

// Pool object
type PoolObject interface {
	Reset()
}

type New func() PoolObject

ObjectPool定义了New及sync.Pool属性,它提供了Get、Put方法,同时还有NewObjectPool工程方法;New是一个func,返回PoolObject;PoolObject接口定义了Reset方法

defaultPool

gost/bytes/bytes_buffer_pool.go

var (
	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().(*bytes.Buffer)
}

// PutIoBuffer returns IoBuffer to pool
func PutBytesBuffer(buf *bytes.Buffer) {
	defaultPool.Put(buf)
}

defaultPool创建的ObjectPool,其Reset方法为new(bytes.Buffer),其GetBytesBuffer将defaultPool.Get()转换为*bytes.Buffer类型

实例

gost/bytes/bytes_buffer_pool_test.go

func TestBytesBufferPool(t *testing.T) {
	buf := GetBytesBuffer()
	bytes := []byte{0x00, 0x01, 0x02, 0x03, 0x04}
	buf.Write(bytes)
	if buf.Len() != len(bytes) {
		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)
	//}
}

这里展示用GetBytesBuffer获取buf,再通过PutBytesBuffer归还buf

小结

gost的ObjectPool定义了New及sync.Pool属性,它提供了Get、Put方法,同时还有NewObjectPool工程方法;New是一个func,返回PoolObject;PoolObject接口定义了Reset方法。

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