mirror of https://github.com/docker/cli.git
142 lines
3.4 KiB
Go
142 lines
3.4 KiB
Go
// Copyright 2019+ Klaus Post. All rights reserved.
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// License information can be found in the LICENSE file.
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package zstd
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import (
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"errors"
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"io"
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"sync"
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)
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// ZipMethodWinZip is the method for Zstandard compressed data inside Zip files for WinZip.
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// See https://www.winzip.com/win/en/comp_info.html
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const ZipMethodWinZip = 93
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// ZipMethodPKWare is the original method number used by PKWARE to indicate Zstandard compression.
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// Deprecated: This has been deprecated by PKWARE, use ZipMethodWinZip instead for compression.
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// See https://pkware.cachefly.net/webdocs/APPNOTE/APPNOTE-6.3.9.TXT
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const ZipMethodPKWare = 20
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// zipReaderPool is the default reader pool.
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var zipReaderPool = sync.Pool{New: func() interface{} {
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z, err := NewReader(nil, WithDecoderLowmem(true), WithDecoderMaxWindow(128<<20), WithDecoderConcurrency(1))
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if err != nil {
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panic(err)
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}
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return z
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}}
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// newZipReader creates a pooled zip decompressor.
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func newZipReader(opts ...DOption) func(r io.Reader) io.ReadCloser {
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pool := &zipReaderPool
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if len(opts) > 0 {
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opts = append([]DOption{WithDecoderLowmem(true), WithDecoderMaxWindow(128 << 20)}, opts...)
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// Force concurrency 1
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opts = append(opts, WithDecoderConcurrency(1))
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// Create our own pool
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pool = &sync.Pool{}
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}
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return func(r io.Reader) io.ReadCloser {
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dec, ok := pool.Get().(*Decoder)
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if ok {
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dec.Reset(r)
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} else {
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d, err := NewReader(r, opts...)
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if err != nil {
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panic(err)
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}
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dec = d
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}
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return &pooledZipReader{dec: dec, pool: pool}
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}
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}
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type pooledZipReader struct {
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mu sync.Mutex // guards Close and Read
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pool *sync.Pool
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dec *Decoder
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}
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func (r *pooledZipReader) Read(p []byte) (n int, err error) {
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r.mu.Lock()
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defer r.mu.Unlock()
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if r.dec == nil {
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return 0, errors.New("read after close or EOF")
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}
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dec, err := r.dec.Read(p)
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if err == io.EOF {
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r.dec.Reset(nil)
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r.pool.Put(r.dec)
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r.dec = nil
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}
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return dec, err
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}
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func (r *pooledZipReader) Close() error {
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r.mu.Lock()
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defer r.mu.Unlock()
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var err error
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if r.dec != nil {
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err = r.dec.Reset(nil)
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r.pool.Put(r.dec)
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r.dec = nil
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}
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return err
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}
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type pooledZipWriter struct {
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mu sync.Mutex // guards Close and Read
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enc *Encoder
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pool *sync.Pool
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}
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func (w *pooledZipWriter) 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.enc == nil {
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return 0, errors.New("Write after Close")
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}
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return w.enc.Write(p)
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}
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func (w *pooledZipWriter) 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.enc != nil {
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err = w.enc.Close()
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w.pool.Put(w.enc)
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w.enc = nil
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}
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return err
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}
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// ZipCompressor returns a compressor that can be registered with zip libraries.
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// The provided encoder options will be used on all encodes.
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func ZipCompressor(opts ...EOption) func(w io.Writer) (io.WriteCloser, error) {
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var pool sync.Pool
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return func(w io.Writer) (io.WriteCloser, error) {
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enc, ok := pool.Get().(*Encoder)
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if ok {
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enc.Reset(w)
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} else {
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var err error
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enc, err = NewWriter(w, opts...)
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if err != nil {
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return nil, err
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}
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}
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return &pooledZipWriter{enc: enc, pool: &pool}, nil
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}
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}
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// ZipDecompressor returns a decompressor that can be registered with zip libraries.
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// See ZipCompressor for example.
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// Options can be specified. WithDecoderConcurrency(1) is forced,
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// and by default a 128MB maximum decompression window is specified.
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// The window size can be overridden if required.
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func ZipDecompressor(opts ...DOption) func(r io.Reader) io.ReadCloser {
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return newZipReader(opts...)
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}
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