关于golang:聊聊gost的ObjectPool

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本文次要钻研一下 gost 的 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 办法，同时还有 NewObjectPool 工程办法；New 是一个 func，返回 PoolObject；PoolObject 接口定义了 Reset 办法

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 创立的 ObjectPool，其 Reset 办法为 new(bytes.Buffer)，其 GetBytesBuffer 将 defaultPool.Get()转换为 *bytes.Buffer 类型

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)
    //}
}