/
async.go
64 lines (53 loc) · 1.12 KB
/
async.go
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package klog
import (
"io"
"os"
"github.com/valyala/bytebufferpool"
"go.uber.org/atomic"
)
var _ io.Writer = (*AsyncWriter)(nil)
type AsyncWriter struct {
w io.Writer
c chan *bytebufferpool.ByteBuffer
size int
closed *atomic.Bool
bufferPool bytebufferpool.Pool
}
func NewAsyncWriter(writer io.Writer, size int) *AsyncWriter {
w := &AsyncWriter{
w: writer,
c: make(chan *bytebufferpool.ByteBuffer, size),
size: size,
closed: atomic.NewBool(false),
}
go w.loop()
return w
}
func (w *AsyncWriter) Write(p []byte) (n int, err error) {
if w.closed.Load() {
return 0, os.ErrClosed
}
// 缓冲池已满,主动丢弃
if len(w.c) >= w.size {
return 0, nil
}
// 异步情况下,不能直接使用传入的切片,需要拷贝,防止被篡改
buf := w.bufferPool.Get()
n, err = buf.Write(p)
if err != nil {
return 0, err
}
w.c <- buf
return n, nil
}
func (w *AsyncWriter) loop() {
for buf := range w.c {
_, _ = w.w.Write(buf.Bytes())
w.bufferPool.Put(buf)
}
}
func (w *AsyncWriter) Close() {
if w.closed.CompareAndSwap(false, true) {
close(w.c)
}
}