package buf import ( "io" "net" "sync" "v2ray.com/core/common" "v2ray.com/core/common/errors" ) // BufferToBytesWriter is a Writer that writes alloc.Buffer into underlying writer. type BufferToBytesWriter struct { io.Writer cache [][]byte } // WriteMultiBuffer implements Writer. This method takes ownership of the given buffer. func (w *BufferToBytesWriter) WriteMultiBuffer(mb MultiBuffer) error { defer mb.Release() size := mb.Len() if size == 0 { return nil } if len(mb) == 1 { return WriteAllBytes(w.Writer, mb[0].Bytes()) } bs := w.cache for _, b := range mb { bs = append(bs, b.Bytes()) } w.cache = bs defer func() { for idx := range w.cache { w.cache[idx] = nil } w.cache = w.cache[:0] }() nb := net.Buffers(bs) for size > 0 { n, err := nb.WriteTo(w.Writer) if err != nil { return err } size -= int32(n) } return nil } // ReadFrom implements io.ReaderFrom. func (w *BufferToBytesWriter) ReadFrom(reader io.Reader) (int64, error) { var sc SizeCounter err := Copy(NewReader(reader), w, CountSize(&sc)) return sc.Size, err } // BufferedWriter is a Writer with internal buffer. type BufferedWriter struct { sync.Mutex writer Writer buffer *Buffer buffered bool } // NewBufferedWriter creates a new BufferedWriter. func NewBufferedWriter(writer Writer) *BufferedWriter { return &BufferedWriter{ writer: writer, buffer: New(), buffered: true, } } // WriteByte implements io.ByteWriter. func (w *BufferedWriter) WriteByte(c byte) error { return common.Error2(w.Write([]byte{c})) } // Write implements io.Writer. func (w *BufferedWriter) Write(b []byte) (int, error) { if len(b) == 0 { return 0, nil } w.Lock() defer w.Unlock() if !w.buffered { if writer, ok := w.writer.(io.Writer); ok { return writer.Write(b) } } totalBytes := 0 for len(b) > 0 { if w.buffer == nil { w.buffer = New() } nBytes, err := w.buffer.Write(b) totalBytes += nBytes if err != nil { return totalBytes, err } if !w.buffered || w.buffer.IsFull() { if err := w.flushInternal(); err != nil { return totalBytes, err } } b = b[nBytes:] } return totalBytes, nil } // WriteMultiBuffer implements Writer. It takes ownership of the given MultiBuffer. func (w *BufferedWriter) WriteMultiBuffer(b MultiBuffer) error { if b.IsEmpty() { return nil } w.Lock() defer w.Unlock() if !w.buffered { return w.writer.WriteMultiBuffer(b) } defer b.Release() for !b.IsEmpty() { if w.buffer == nil { w.buffer = New() } if _, err := w.buffer.ReadFrom(&b); err != nil { return err } if w.buffer.IsFull() { if err := w.flushInternal(); err != nil { return err } } } return nil } // Flush flushes buffered content into underlying writer. func (w *BufferedWriter) Flush() error { w.Lock() defer w.Unlock() return w.flushInternal() } func (w *BufferedWriter) flushInternal() error { if w.buffer.IsEmpty() { return nil } b := w.buffer w.buffer = nil if writer, ok := w.writer.(io.Writer); ok { err := WriteAllBytes(writer, b.Bytes()) b.Release() return err } return w.writer.WriteMultiBuffer(NewMultiBufferValue(b)) } // SetBuffered sets whether the internal buffer is used. If set to false, Flush() will be called to clear the buffer. func (w *BufferedWriter) SetBuffered(f bool) error { w.Lock() defer w.Unlock() w.buffered = f if !f { return w.flushInternal() } return nil } // ReadFrom implements io.ReaderFrom. func (w *BufferedWriter) ReadFrom(reader io.Reader) (int64, error) { if err := w.SetBuffered(false); err != nil { return 0, err } var sc SizeCounter err := Copy(NewReader(reader), w, CountSize(&sc)) return sc.Size, err } // Close implements io.Closable. func (w *BufferedWriter) Close() error { if err := w.Flush(); err != nil { return err } return common.Close(w.writer) } // SequentialWriter is a Writer that writes MultiBuffer sequentially into the underlying io.Writer. type SequentialWriter struct { io.Writer } // WriteMultiBuffer implements Writer. func (w *SequentialWriter) WriteMultiBuffer(mb MultiBuffer) error { defer mb.Release() for _, b := range mb { if b.IsEmpty() { continue } if err := WriteAllBytes(w.Writer, b.Bytes()); err != nil { return err } } return nil } type noOpWriter byte func (noOpWriter) WriteMultiBuffer(b MultiBuffer) error { b.Release() return nil } func (noOpWriter) Write(b []byte) (int, error) { return len(b), nil } func (noOpWriter) ReadFrom(reader io.Reader) (int64, error) { b := New() defer b.Release() totalBytes := int64(0) for { b.Clear() _, err := b.ReadFrom(reader) totalBytes += int64(b.Len()) if err != nil { if errors.Cause(err) == io.EOF { return totalBytes, nil } return totalBytes, err } } } var ( // Discard is a Writer that swallows all contents written in. Discard Writer = noOpWriter(0) // DiscardBytes is an io.Writer that swallows all contents written in. DiscardBytes io.Writer = noOpWriter(0) )