mirror of
https://github.com/go-gitea/gitea
synced 2024-10-31 19:28:58 +01:00
156 lines
4.3 KiB
Go
156 lines
4.3 KiB
Go
|
package brotli
|
||
|
|
||
|
import (
|
||
|
"compress/gzip"
|
||
|
"errors"
|
||
|
"io"
|
||
|
"net/http"
|
||
|
|
||
|
"github.com/golang/gddo/httputil"
|
||
|
)
|
||
|
|
||
|
const (
|
||
|
BestSpeed = 0
|
||
|
BestCompression = 11
|
||
|
DefaultCompression = 6
|
||
|
)
|
||
|
|
||
|
// WriterOptions configures Writer.
|
||
|
type WriterOptions struct {
|
||
|
// Quality controls the compression-speed vs compression-density trade-offs.
|
||
|
// The higher the quality, the slower the compression. Range is 0 to 11.
|
||
|
Quality int
|
||
|
// LGWin is the base 2 logarithm of the sliding window size.
|
||
|
// Range is 10 to 24. 0 indicates automatic configuration based on Quality.
|
||
|
LGWin int
|
||
|
}
|
||
|
|
||
|
var (
|
||
|
errEncode = errors.New("brotli: encode error")
|
||
|
errWriterClosed = errors.New("brotli: Writer is closed")
|
||
|
)
|
||
|
|
||
|
// Writes to the returned writer are compressed and written to dst.
|
||
|
// It is the caller's responsibility to call Close on the Writer when done.
|
||
|
// Writes may be buffered and not flushed until Close.
|
||
|
func NewWriter(dst io.Writer) *Writer {
|
||
|
return NewWriterLevel(dst, DefaultCompression)
|
||
|
}
|
||
|
|
||
|
// NewWriterLevel is like NewWriter but specifies the compression level instead
|
||
|
// of assuming DefaultCompression.
|
||
|
// The compression level can be DefaultCompression or any integer value between
|
||
|
// BestSpeed and BestCompression inclusive.
|
||
|
func NewWriterLevel(dst io.Writer, level int) *Writer {
|
||
|
return NewWriterOptions(dst, WriterOptions{
|
||
|
Quality: level,
|
||
|
})
|
||
|
}
|
||
|
|
||
|
// NewWriterOptions is like NewWriter but specifies WriterOptions
|
||
|
func NewWriterOptions(dst io.Writer, options WriterOptions) *Writer {
|
||
|
w := new(Writer)
|
||
|
w.Reset(dst)
|
||
|
w.params.quality = options.Quality
|
||
|
if options.LGWin > 0 {
|
||
|
w.params.lgwin = uint(options.LGWin)
|
||
|
}
|
||
|
return w
|
||
|
}
|
||
|
|
||
|
// Reset discards the Writer's state and makes it equivalent to the result of
|
||
|
// its original state from NewWriter or NewWriterLevel, but writing to dst
|
||
|
// instead. This permits reusing a Writer rather than allocating a new one.
|
||
|
func (w *Writer) Reset(dst io.Writer) {
|
||
|
encoderInitState(w)
|
||
|
w.dst = dst
|
||
|
}
|
||
|
|
||
|
func (w *Writer) writeChunk(p []byte, op int) (n int, err error) {
|
||
|
if w.dst == nil {
|
||
|
return 0, errWriterClosed
|
||
|
}
|
||
|
|
||
|
for {
|
||
|
availableIn := uint(len(p))
|
||
|
nextIn := p
|
||
|
success := encoderCompressStream(w, op, &availableIn, &nextIn)
|
||
|
bytesConsumed := len(p) - int(availableIn)
|
||
|
p = p[bytesConsumed:]
|
||
|
n += bytesConsumed
|
||
|
if !success {
|
||
|
return n, errEncode
|
||
|
}
|
||
|
|
||
|
outputData := encoderTakeOutput(w)
|
||
|
|
||
|
if len(outputData) > 0 {
|
||
|
_, err = w.dst.Write(outputData)
|
||
|
if err != nil {
|
||
|
return n, err
|
||
|
}
|
||
|
}
|
||
|
if len(p) == 0 {
|
||
|
return n, nil
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
// Flush outputs encoded data for all input provided to Write. The resulting
|
||
|
// output can be decoded to match all input before Flush, but the stream is
|
||
|
// not yet complete until after Close.
|
||
|
// Flush has a negative impact on compression.
|
||
|
func (w *Writer) Flush() error {
|
||
|
_, err := w.writeChunk(nil, operationFlush)
|
||
|
return err
|
||
|
}
|
||
|
|
||
|
// Close flushes remaining data to the decorated writer.
|
||
|
func (w *Writer) Close() error {
|
||
|
// If stream is already closed, it is reported by `writeChunk`.
|
||
|
_, err := w.writeChunk(nil, operationFinish)
|
||
|
w.dst = nil
|
||
|
return err
|
||
|
}
|
||
|
|
||
|
// Write implements io.Writer. Flush or Close must be called to ensure that the
|
||
|
// encoded bytes are actually flushed to the underlying Writer.
|
||
|
func (w *Writer) Write(p []byte) (n int, err error) {
|
||
|
return w.writeChunk(p, operationProcess)
|
||
|
}
|
||
|
|
||
|
type nopCloser struct {
|
||
|
io.Writer
|
||
|
}
|
||
|
|
||
|
func (nopCloser) Close() error { return nil }
|
||
|
|
||
|
// HTTPCompressor chooses a compression method (brotli, gzip, or none) based on
|
||
|
// the Accept-Encoding header, sets the Content-Encoding header, and returns a
|
||
|
// WriteCloser that implements that compression. The Close method must be called
|
||
|
// before the current HTTP handler returns.
|
||
|
//
|
||
|
// Due to https://github.com/golang/go/issues/31753, the response will not be
|
||
|
// compressed unless you set a Content-Type header before you call
|
||
|
// HTTPCompressor.
|
||
|
func HTTPCompressor(w http.ResponseWriter, r *http.Request) io.WriteCloser {
|
||
|
if w.Header().Get("Content-Type") == "" {
|
||
|
return nopCloser{w}
|
||
|
}
|
||
|
|
||
|
if w.Header().Get("Vary") == "" {
|
||
|
w.Header().Set("Vary", "Accept-Encoding")
|
||
|
}
|
||
|
|
||
|
encoding := httputil.NegotiateContentEncoding(r, []string{"br", "gzip"})
|
||
|
switch encoding {
|
||
|
case "br":
|
||
|
w.Header().Set("Content-Encoding", "br")
|
||
|
return NewWriter(w)
|
||
|
case "gzip":
|
||
|
w.Header().Set("Content-Encoding", "gzip")
|
||
|
return gzip.NewWriter(w)
|
||
|
}
|
||
|
return nopCloser{w}
|
||
|
}
|