Add archive/zip from go1.7rc5 tag

In preparation to patch in some custom functionality (parallel
compression and zero-decompress zip to zip copying)

Change-Id: I96a36efc09c715f6b55290af40ebfdde9ae72e33

1 files changed, 153 insertions, 0 deletions

diff --git a/third_party/zip/register.go b/third_party/zip/register.go
new file mode 100644
index 00000000..2e76386b
--- /dev/null
+++ b/third_party/zip/register.go
@@ -0,0 +1,153 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package zip
+
+import (
+	"compress/flate"
+	"errors"
+	"io"
+	"io/ioutil"
+	"sync"
+)
+
+// A Compressor returns a new compressing writer, writing to w.
+// The WriteCloser's Close method must be used to flush pending data to w.
+// The Compressor itself must be safe to invoke from multiple goroutines
+// simultaneously, but each returned writer will be used only by
+// one goroutine at a time.
+type Compressor func(w io.Writer) (io.WriteCloser, error)
+
+// A Decompressor returns a new decompressing reader, reading from r.
+// The ReadCloser's Close method must be used to release associated resources.
+// The Decompressor itself must be safe to invoke from multiple goroutines
+// simultaneously, but each returned reader will be used only by
+// one goroutine at a time.
+type Decompressor func(r io.Reader) io.ReadCloser
+
+var flateWriterPool sync.Pool
+
+func newFlateWriter(w io.Writer) io.WriteCloser {
+	fw, ok := flateWriterPool.Get().(*flate.Writer)
+	if ok {
+		fw.Reset(w)
+	} else {
+		fw, _ = flate.NewWriter(w, 5)
+	}
+	return &pooledFlateWriter{fw: fw}
+}
+
+type pooledFlateWriter struct {
+	mu sync.Mutex // guards Close and Write
+	fw *flate.Writer
+}
+
+func (w *pooledFlateWriter) Write(p []byte) (n int, err error) {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+	if w.fw == nil {
+		return 0, errors.New("Write after Close")
+	}
+	return w.fw.Write(p)
+}
+
+func (w *pooledFlateWriter) Close() error {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+	var err error
+	if w.fw != nil {
+		err = w.fw.Close()
+		flateWriterPool.Put(w.fw)
+		w.fw = nil
+	}
+	return err
+}
+
+var flateReaderPool sync.Pool
+
+func newFlateReader(r io.Reader) io.ReadCloser {
+	fr, ok := flateReaderPool.Get().(io.ReadCloser)
+	if ok {
+		fr.(flate.Resetter).Reset(r, nil)
+	} else {
+		fr = flate.NewReader(r)
+	}
+	return &pooledFlateReader{fr: fr}
+}
+
+type pooledFlateReader struct {
+	mu sync.Mutex // guards Close and Read
+	fr io.ReadCloser
+}
+
+func (r *pooledFlateReader) Read(p []byte) (n int, err error) {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	if r.fr == nil {
+		return 0, errors.New("Read after Close")
+	}
+	return r.fr.Read(p)
+}
+
+func (r *pooledFlateReader) Close() error {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	var err error
+	if r.fr != nil {
+		err = r.fr.Close()
+		flateReaderPool.Put(r.fr)
+		r.fr = nil
+	}
+	return err
+}
+
+var (
+	mu sync.RWMutex // guards compressor and decompressor maps
+
+	compressors = map[uint16]Compressor{
+		Store:   func(w io.Writer) (io.WriteCloser, error) { return &nopCloser{w}, nil },
+		Deflate: func(w io.Writer) (io.WriteCloser, error) { return newFlateWriter(w), nil },
+	}
+
+	decompressors = map[uint16]Decompressor{
+		Store:   ioutil.NopCloser,
+		Deflate: newFlateReader,
+	}
+)
+
+// RegisterDecompressor allows custom decompressors for a specified method ID.
+// The common methods Store and Deflate are built in.
+func RegisterDecompressor(method uint16, dcomp Decompressor) {
+	mu.Lock()
+	defer mu.Unlock()
+
+	if _, ok := decompressors[method]; ok {
+		panic("decompressor already registered")
+	}
+	decompressors[method] = dcomp
+}
+
+// RegisterCompressor registers custom compressors for a specified method ID.
+// The common methods Store and Deflate are built in.
+func RegisterCompressor(method uint16, comp Compressor) {
+	mu.Lock()
+	defer mu.Unlock()
+
+	if _, ok := compressors[method]; ok {
+		panic("compressor already registered")
+	}
+	compressors[method] = comp
+}
+
+func compressor(method uint16) Compressor {
+	mu.RLock()
+	defer mu.RUnlock()
+	return compressors[method]
+}
+
+func decompressor(method uint16) Decompressor {
+	mu.RLock()
+	defer mu.RUnlock()
+	return decompressors[method]
+}