/
writer_async.go
84 lines (71 loc) · 1.13 KB
/
writer_async.go
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package log
import (
"bytes"
"errors"
"sync"
)
type AsyncWriter struct {
writer Writer
c chan []byte
close chan *sync.WaitGroup
}
var ErrAsyncWriterFull = errors.New("async writer full")
func (p *AsyncWriter) Write(b []byte) (n int, err error) {
select {
case p.c <- b:
return len(b), nil
default:
return 0, ErrAsyncWriterFull
}
}
func (p *AsyncWriter) Close() error {
var w sync.WaitGroup
w.Add(1)
select {
case p.close <- &w:
w.Wait()
default:
}
return nil
}
func NewAsyncWriter(writer Writer) *AsyncWriter {
p := &AsyncWriter{
writer: writer,
c: make(chan []byte, 1024),
close: make(chan *sync.WaitGroup, 1),
}
go func() {
var cache bytes.Buffer
for {
cache.Reset()
select {
case c := <-p.c:
cache.Write(c)
for {
select {
case c := <-p.c:
cache.Write(c)
default:
goto OUT
}
}
OUT:
p.writer.Write(cache.Bytes())
case w := <-p.close:
for {
select {
case c := <-p.c:
cache.Write(c)
default:
goto END
}
}
END:
p.writer.Write(cache.Bytes())
w.Done()
return
}
}
}()
return p
}