1 files changed, 148 insertions, 0 deletions
diff --git a/vendor/github.com/gorilla/websocket/compression.go b/vendor/github.com/gorilla/websocket/compression.go
new file mode 100644
index 00000000..813ffb1e
--- /dev/null
+++ b/vendor/github.com/gorilla/websocket/compression.go
@@ -0,0 +1,148 @@
+// Copyright 2017 The Gorilla WebSocket 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 websocket
+
+import (
+	"compress/flate"
+	"errors"
+	"io"
+	"strings"
+	"sync"
+)
+
+const (
+	minCompressionLevel     = -2 // flate.HuffmanOnly not defined in Go < 1.6
+	maxCompressionLevel     = flate.BestCompression
+	defaultCompressionLevel = 1
+)
+
+var (
+	flateWriterPools [maxCompressionLevel - minCompressionLevel + 1]sync.Pool
+	flateReaderPool  = sync.Pool{New: func() interface{} {
+		return flate.NewReader(nil)
+	}}
+)
+
+func decompressNoContextTakeover(r io.Reader) io.ReadCloser {
+	const tail =
+	// Add four bytes as specified in RFC
+	"\x00\x00\xff\xff" +
+		// Add final block to squelch unexpected EOF error from flate reader.
+		"\x01\x00\x00\xff\xff"
+
+	fr, _ := flateReaderPool.Get().(io.ReadCloser)
+	fr.(flate.Resetter).Reset(io.MultiReader(r, strings.NewReader(tail)), nil)
+	return &flateReadWrapper{fr}
+}
+
+func isValidCompressionLevel(level int) bool {
+	return minCompressionLevel <= level && level <= maxCompressionLevel
+}
+
+func compressNoContextTakeover(w io.WriteCloser, level int) io.WriteCloser {
+	p := &flateWriterPools[level-minCompressionLevel]
+	tw := &truncWriter{w: w}
+	fw, _ := p.Get().(*flate.Writer)
+	if fw == nil {
+		fw, _ = flate.NewWriter(tw, level)
+	} else {
+		fw.Reset(tw)
+	}
+	return &flateWriteWrapper{fw: fw, tw: tw, p: p}
+}
+
+// truncWriter is an io.Writer that writes all but the last four bytes of the
+// stream to another io.Writer.
+type truncWriter struct {
+	w io.WriteCloser
+	n int
+	p [4]byte
+}
+
+func (w *truncWriter) Write(p []byte) (int, error) {
+	n := 0
+
+	// fill buffer first for simplicity.
+	if w.n < len(w.p) {
+		n = copy(w.p[w.n:], p)
+		p = p[n:]
+		w.n += n
+		if len(p) == 0 {
+			return n, nil
+		}
+	}
+
+	m := len(p)
+	if m > len(w.p) {
+		m = len(w.p)
+	}
+
+	if nn, err := w.w.Write(w.p[:m]); err != nil {
+		return n + nn, err
+	}
+
+	copy(w.p[:], w.p[m:])
+	copy(w.p[len(w.p)-m:], p[len(p)-m:])
+	nn, err := w.w.Write(p[:len(p)-m])
+	return n + nn, err
+}
+
+type flateWriteWrapper struct {
+	fw *flate.Writer
+	tw *truncWriter
+	p  *sync.Pool
+}
+
+func (w *flateWriteWrapper) Write(p []byte) (int, error) {
+	if w.fw == nil {
+		return 0, errWriteClosed
+	}
+	return w.fw.Write(p)
+}
+
+func (w *flateWriteWrapper) Close() error {
+	if w.fw == nil {
+		return errWriteClosed
+	}
+	err1 := w.fw.Flush()
+	w.p.Put(w.fw)
+	w.fw = nil
+	if w.tw.p != [4]byte{0, 0, 0xff, 0xff} {
+		return errors.New("websocket: internal error, unexpected bytes at end of flate stream")
+	}
+	err2 := w.tw.w.Close()
+	if err1 != nil {
+		return err1
+	}
+	return err2
+}
+
+type flateReadWrapper struct {
+	fr io.ReadCloser
+}
+
+func (r *flateReadWrapper) Read(p []byte) (int, error) {
+	if r.fr == nil {
+		return 0, io.ErrClosedPipe
+	}
+	n, err := r.fr.Read(p)
+	if err == io.EOF {
+		// Preemptively place the reader back in the pool. This helps with
+		// scenarios where the application does not call NextReader() soon after
+		// this final read.
+		r.Close()
+	}
+	return n, err
+}
+
+func (r *flateReadWrapper) Close() error {
+	if r.fr == nil {
+		return io.ErrClosedPipe
+	}
+	err := r.fr.Close()
+	flateReaderPool.Put(r.fr)
+	r.fr = nil
+	return err
+}