v2ray-core/common/buf/buffered_writer.go

73 lines
1.7 KiB
Go

package buf
import "io"
// BufferedWriter is an io.Writer with internal buffer. It writes to underlying writer when buffer is full or on demand.
// This type is not thread safe.
type BufferedWriter struct {
writer io.Writer
buffer *Buffer
buffered bool
}
// NewBufferedWriter creates a new BufferedWriter.
func NewBufferedWriter(writer io.Writer) *BufferedWriter {
return NewBufferedWriterSize(writer, 1024)
}
func NewBufferedWriterSize(writer io.Writer, size uint32) *BufferedWriter {
return &BufferedWriter{
writer: writer,
buffer: NewLocal(int(size)),
buffered: true,
}
}
// Write implements io.Writer.
func (w *BufferedWriter) Write(b []byte) (int, error) {
if !w.buffered || w.buffer == nil {
return w.writer.Write(b)
}
bytesWritten := 0
for bytesWritten < len(b) {
nBytes, err := w.buffer.Write(b[bytesWritten:])
if err != nil {
return bytesWritten, err
}
bytesWritten += nBytes
if w.buffer.IsFull() {
if err := w.Flush(); err != nil {
return bytesWritten, err
}
}
}
return bytesWritten, nil
}
// Flush writes all buffered content into underlying writer, if any.
func (w *BufferedWriter) Flush() error {
defer w.buffer.Clear()
for !w.buffer.IsEmpty() {
nBytes, err := w.writer.Write(w.buffer.Bytes())
if err != nil {
return err
}
w.buffer.SliceFrom(nBytes)
}
return nil
}
// IsBuffered returns true if this BufferedWriter holds a buffer.
func (w *BufferedWriter) IsBuffered() bool {
return w.buffered
}
// SetBuffered controls whether the BufferedWriter holds a buffer for writing. If not buffered, any write() calls into underlying writer directly.
func (w *BufferedWriter) SetBuffered(cached bool) error {
w.buffered = cached
if !cached && !w.buffer.IsEmpty() {
return w.Flush()
}
return nil
}