remove Buffer method totally

Signed-off-by: Ben Ye <[email protected]>

pkg/block/indexheader/binary_reader.go

@@ -76,15 +76,19 @@ func WriteBinary(ctx context.Context, bkt objstore.BucketReader, id ulid.ULID, f
 	if err != nil {
 		return nil, errors.Wrap(err, "new index reader")
 	}
+	var memWriterBuf []byte
 	tmpFilename := ""
 	if filename != "" {
 		tmpFilename = filename + ".tmp"
+	} else {
+		// Initialize the buffer for memWriter only.
+		memWriterBuf = make([]byte, 32*1024)
 	}
 
 	// Buffer for copying and encbuffers.
 	// This also will control the size of file writer buffer.
 	buf := make([]byte, 32*1024)
-	bw, err := newBinaryWriter(id, tmpFilename, buf)
+	bw, err := newBinaryWriter(id, tmpFilename, buf, memWriterBuf)
 	if err != nil {
 		return nil, errors.Wrap(err, "new binary index header writer")
 	}
@@ -127,7 +131,7 @@ func WriteBinary(ctx context.Context, bkt objstore.BucketReader, id ulid.ULID, f
 		return nil, os.Rename(tmpFilename, filename)
 	}
 
-	return bw.Buffer(), nil
+	return memWriterBuf, nil
 }
 
 type chunkedIndexReader struct {
@@ -249,7 +253,7 @@ type binaryWriter struct {
 	crc32 hash.Hash
 }
 
-func newBinaryWriter(id ulid.ULID, cacheFilename string, buf []byte) (w *binaryWriter, err error) {
+func newBinaryWriter(id ulid.ULID, cacheFilename string, buf []byte, memWriterBuf []byte) (w *binaryWriter, err error) {
 	var binWriter PosWriter
 	if cacheFilename != "" {
 		dir := filepath.Dir(cacheFilename)
@@ -282,7 +286,7 @@ func newBinaryWriter(id ulid.ULID, cacheFilename string, buf []byte) (w *binaryW
 		}
 		binWriter = fileWriter
 	} else {
-		binWriter = NewMemoryWriter(id, len(buf))
+		binWriter = NewMemoryWriter(id, memWriterBuf)
 	}
 
 	w = &binaryWriter{
@@ -303,7 +307,6 @@ func newBinaryWriter(id ulid.ULID, cacheFilename string, buf []byte) (w *binaryW
 type PosWriter interface {
 	Pos() uint64
 	Write(bufs ...[]byte) error
-	Buffer() []byte
 	Flush() error
 	Sync() error
 	Close() error
@@ -315,10 +318,10 @@ type MemoryWriter struct {
 	pos uint64
 }
 
-func NewMemoryWriter(id ulid.ULID, size int) *MemoryWriter {
+func NewMemoryWriter(id ulid.ULID, buf []byte) *MemoryWriter {
 	return &MemoryWriter{
 		id:  id,
-		buf: bytes.NewBuffer(make([]byte, size)),
+		buf: bytes.NewBuffer(buf),
 		pos: 0,
 	}
 }
@@ -345,10 +348,6 @@ func (mw *MemoryWriter) Write(bufs ...[]byte) error {
 	return nil
 }
 
-func (mw *MemoryWriter) Buffer() []byte {
-	return mw.buf.Bytes()
-}
-
 func (mw *MemoryWriter) Flush() error {
 	return nil
 }
@@ -404,11 +403,6 @@ func (fw *FileWriter) Write(bufs ...[]byte) error {
 	return nil
 }
 
-// Buffer is not used at all for FileWriter.
-func (fw *FileWriter) Buffer() []byte {
-	return nil
-}
-
 func (fw *FileWriter) Flush() error {
 	return fw.fileWriter.Flush()
 }
@@ -465,10 +459,6 @@ func (w *binaryWriter) Write(p []byte) (int, error) {
 	return int(w.writer.Pos() - n), err
 }
 
-func (w *binaryWriter) Buffer() []byte {
-	return w.writer.Buffer()
-}
-
 func (w *binaryWriter) Close() error {
 	return w.writer.Close()
 }