112 lines
2.6 KiB
Go
112 lines
2.6 KiB
Go
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// Copyright 2010 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package zip
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import (
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"errors"
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"io"
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"io/ioutil"
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"sync"
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"github.com/klauspost/compress/flate"
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)
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// A Compressor returns a compressing writer, writing to the
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// provided writer. On Close, any pending data should be flushed.
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type Compressor func(io.Writer) (io.WriteCloser, error)
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// Decompressor is a function that wraps a Reader with a decompressing Reader.
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// The decompressed ReadCloser is returned to callers who open files from
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// within the archive. These callers are responsible for closing this reader
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// when they're finished reading.
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type Decompressor func(io.Reader) io.ReadCloser
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var flateWriterPool sync.Pool
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func newFlateWriter(w io.Writer) io.WriteCloser {
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fw, ok := flateWriterPool.Get().(*flate.Writer)
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if ok {
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fw.Reset(w)
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} else {
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fw, _ = flate.NewWriter(w, 5)
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}
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return &pooledFlateWriter{fw: fw}
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}
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type pooledFlateWriter struct {
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mu sync.Mutex // guards Close and Write
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fw *flate.Writer
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}
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func (w *pooledFlateWriter) Write(p []byte) (n int, err error) {
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w.mu.Lock()
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defer w.mu.Unlock()
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if w.fw == nil {
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return 0, errors.New("Write after Close")
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}
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return w.fw.Write(p)
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}
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func (w *pooledFlateWriter) Close() error {
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w.mu.Lock()
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defer w.mu.Unlock()
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var err error
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if w.fw != nil {
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err = w.fw.Close()
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flateWriterPool.Put(w.fw)
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w.fw = nil
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}
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return err
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}
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var (
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mu sync.RWMutex // guards compressor and decompressor maps
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compressors = map[uint16]Compressor{
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Store: func(w io.Writer) (io.WriteCloser, error) { return &nopCloser{w}, nil },
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Deflate: func(w io.Writer) (io.WriteCloser, error) { return newFlateWriter(w), nil },
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}
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decompressors = map[uint16]Decompressor{
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Store: ioutil.NopCloser,
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Deflate: flate.NewReader,
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}
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)
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// RegisterDecompressor allows custom decompressors for a specified method ID.
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func RegisterDecompressor(method uint16, d Decompressor) {
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mu.Lock()
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defer mu.Unlock()
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if _, ok := decompressors[method]; ok {
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panic("decompressor already registered")
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}
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decompressors[method] = d
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}
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// RegisterCompressor registers custom compressors for a specified method ID.
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// The common methods Store and Deflate are built in.
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func RegisterCompressor(method uint16, comp Compressor) {
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mu.Lock()
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defer mu.Unlock()
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if _, ok := compressors[method]; ok {
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panic("compressor already registered")
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}
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compressors[method] = comp
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}
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func compressor(method uint16) Compressor {
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mu.RLock()
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defer mu.RUnlock()
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return compressors[method]
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}
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func decompressor(method uint16) Decompressor {
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mu.RLock()
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defer mu.RUnlock()
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return decompressors[method]
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}
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