diff options
Diffstat (limited to 'vendor/github.com/gorilla/websocket/compression.go')
-rw-r--r-- | vendor/github.com/gorilla/websocket/compression.go | 85 |
1 files changed, 85 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 000000000..e2ac7617b --- /dev/null +++ b/vendor/github.com/gorilla/websocket/compression.go @@ -0,0 +1,85 @@ +// Copyright 2016 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" +) + +func decompressNoContextTakeover(r io.Reader) io.Reader { + 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" + + return flate.NewReader(io.MultiReader(r, strings.NewReader(tail))) +} + +func compressNoContextTakeover(w io.WriteCloser) (io.WriteCloser, error) { + tw := &truncWriter{w: w} + fw, err := flate.NewWriter(tw, 3) + return &flateWrapper{fw: fw, tw: tw}, err +} + +// 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 flateWrapper struct { + fw *flate.Writer + tw *truncWriter +} + +func (w *flateWrapper) Write(p []byte) (int, error) { + return w.fw.Write(p) +} + +func (w *flateWrapper) Close() error { + err1 := w.fw.Flush() + 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 +} |