mirror of https://github.com/docker/docs.git
120 lines
3.5 KiB
Go
120 lines
3.5 KiB
Go
// Package pools provides a collection of pools which provide various
|
|
// data types with buffers. These can be used to lower the number of
|
|
// memory allocations and reuse buffers.
|
|
//
|
|
// New pools should be added to this package to allow them to be
|
|
// shared across packages.
|
|
//
|
|
// Utility functions which operate on pools should be added to this
|
|
// package to allow them to be reused.
|
|
package pools
|
|
|
|
import (
|
|
"bufio"
|
|
"io"
|
|
"sync"
|
|
|
|
"github.com/docker/docker/pkg/ioutils"
|
|
)
|
|
|
|
var (
|
|
// BufioReader32KPool is a pool which returns bufio.Reader with a 32K buffer.
|
|
BufioReader32KPool *BufioReaderPool
|
|
// BufioWriter32KPool is a pool which returns bufio.Writer with a 32K buffer.
|
|
BufioWriter32KPool *BufioWriterPool
|
|
)
|
|
|
|
const buffer32K = 32 * 1024
|
|
|
|
// BufioReaderPool is a bufio reader that uses sync.Pool.
|
|
type BufioReaderPool struct {
|
|
pool sync.Pool
|
|
}
|
|
|
|
func init() {
|
|
BufioReader32KPool = newBufioReaderPoolWithSize(buffer32K)
|
|
BufioWriter32KPool = newBufioWriterPoolWithSize(buffer32K)
|
|
}
|
|
|
|
// newBufioReaderPoolWithSize is unexported because new pools should be
|
|
// added here to be shared where required.
|
|
func newBufioReaderPoolWithSize(size int) *BufioReaderPool {
|
|
pool := sync.Pool{
|
|
New: func() interface{} { return bufio.NewReaderSize(nil, size) },
|
|
}
|
|
return &BufioReaderPool{pool: pool}
|
|
}
|
|
|
|
// Get returns a bufio.Reader which reads from r. The buffer size is that of the pool.
|
|
func (bufPool *BufioReaderPool) Get(r io.Reader) *bufio.Reader {
|
|
buf := bufPool.pool.Get().(*bufio.Reader)
|
|
buf.Reset(r)
|
|
return buf
|
|
}
|
|
|
|
// Put puts the bufio.Reader back into the pool.
|
|
func (bufPool *BufioReaderPool) Put(b *bufio.Reader) {
|
|
b.Reset(nil)
|
|
bufPool.pool.Put(b)
|
|
}
|
|
|
|
// Copy is a convenience wrapper which uses a buffer to avoid allocation in io.Copy.
|
|
func Copy(dst io.Writer, src io.Reader) (written int64, err error) {
|
|
buf := BufioReader32KPool.Get(src)
|
|
written, err = io.Copy(dst, buf)
|
|
BufioReader32KPool.Put(buf)
|
|
return
|
|
}
|
|
|
|
// NewReadCloserWrapper returns a wrapper which puts the bufio.Reader back
|
|
// into the pool and closes the reader if it's an io.ReadCloser.
|
|
func (bufPool *BufioReaderPool) NewReadCloserWrapper(buf *bufio.Reader, r io.Reader) io.ReadCloser {
|
|
return ioutils.NewReadCloserWrapper(r, func() error {
|
|
if readCloser, ok := r.(io.ReadCloser); ok {
|
|
readCloser.Close()
|
|
}
|
|
bufPool.Put(buf)
|
|
return nil
|
|
})
|
|
}
|
|
|
|
// BufioWriterPool is a bufio writer that uses sync.Pool.
|
|
type BufioWriterPool struct {
|
|
pool sync.Pool
|
|
}
|
|
|
|
// newBufioWriterPoolWithSize is unexported because new pools should be
|
|
// added here to be shared where required.
|
|
func newBufioWriterPoolWithSize(size int) *BufioWriterPool {
|
|
pool := sync.Pool{
|
|
New: func() interface{} { return bufio.NewWriterSize(nil, size) },
|
|
}
|
|
return &BufioWriterPool{pool: pool}
|
|
}
|
|
|
|
// Get returns a bufio.Writer which writes to w. The buffer size is that of the pool.
|
|
func (bufPool *BufioWriterPool) Get(w io.Writer) *bufio.Writer {
|
|
buf := bufPool.pool.Get().(*bufio.Writer)
|
|
buf.Reset(w)
|
|
return buf
|
|
}
|
|
|
|
// Put puts the bufio.Writer back into the pool.
|
|
func (bufPool *BufioWriterPool) Put(b *bufio.Writer) {
|
|
b.Reset(nil)
|
|
bufPool.pool.Put(b)
|
|
}
|
|
|
|
// NewWriteCloserWrapper returns a wrapper which puts the bufio.Writer back
|
|
// into the pool and closes the writer if it's an io.Writecloser.
|
|
func (bufPool *BufioWriterPool) NewWriteCloserWrapper(buf *bufio.Writer, w io.Writer) io.WriteCloser {
|
|
return ioutils.NewWriteCloserWrapper(w, func() error {
|
|
buf.Flush()
|
|
if writeCloser, ok := w.(io.WriteCloser); ok {
|
|
writeCloser.Close()
|
|
}
|
|
bufPool.Put(buf)
|
|
return nil
|
|
})
|
|
}
|