webdav: improve webdav upload speed

weed/util/buffered_writer/buffered_writer.go

@@ -0,0 +1,52 @@
+package buffered_writer
+
+import (
+	"bytes"
+	"io"
+)
+
+var _ = io.WriteCloser(&BufferedWriteCloser{})
+
+type BufferedWriteCloser struct {
+	buffer          bytes.Buffer
+	bufferLimit     int
+	position        int64
+	nextFlushOffset int64
+	FlushFunc       func([]byte, int64) error
+	CloseFunc       func() error
+}
+
+func NewBufferedWriteCloser(bufferLimit int) *BufferedWriteCloser {
+	return &BufferedWriteCloser{
+		bufferLimit: bufferLimit,
+	}
+}
+
+func (b *BufferedWriteCloser) Write(p []byte) (n int, err error) {
+
+	if b.buffer.Len()+len(p) >= b.bufferLimit {
+		if err := b.FlushFunc(b.buffer.Bytes(), b.nextFlushOffset); err != nil {
+			return 0, err
+		}
+		b.nextFlushOffset += int64(b.buffer.Len())
+		b.buffer.Reset()
+	}
+
+	return b.buffer.Write(p)
+
+}
+
+func (b *BufferedWriteCloser) Close() error {
+	if b.buffer.Len() > 0 {
+		if err := b.FlushFunc(b.buffer.Bytes(), b.nextFlushOffset); err != nil {
+			return err
+		}
+	}
+	if b.CloseFunc != nil {
+		if err := b.CloseFunc(); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}