minio/pkg/storage/drivers/memory/blockingwriter.go
2015-05-04 03:55:43 -07:00

66 lines
1.7 KiB
Go

/*
* Minimalist Object Storage, (C) 2015 Minio, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package memory
import (
"io"
"sync"
)
// BlockingWriteCloser is a WriteCloser that blocks until released
type BlockingWriteCloser struct {
w io.WriteCloser
release *sync.WaitGroup
err error
}
// Write to the underlying writer
func (b *BlockingWriteCloser) Write(p []byte) (int, error) {
n, err := b.w.Write(p)
if err != nil {
b.err = err
}
return n, b.err
}
// Close blocks until another goroutine calls Release(error). Returns error code if either
// writer fails or Release is called with an error.
func (b *BlockingWriteCloser) Close() error {
err := b.w.Close()
if err != nil {
b.err = err
}
b.release.Wait()
return b.err
}
// Release the Close, causing it to unblock. Only call this once. Calling it multiple times results in a panic.
func (b *BlockingWriteCloser) Release(err error) {
b.release.Done()
if err != nil {
b.err = err
}
return
}
// NewBlockingWriteCloser Creates a new write closer that must be released by the read consumer.
func NewBlockingWriteCloser(w io.WriteCloser) *BlockingWriteCloser {
wg := &sync.WaitGroup{}
wg.Add(1)
return &BlockingWriteCloser{w: w, release: wg}
}