bufpool: Return *Buffer

3 files changed, 26 insertions, 32 deletions

diff --git a/internal/bufpool/buffers.go b/internal/bufpool/buffers.go
index 24b29fb5..27c017bd 100644
--- a/internal/bufpool/buffers.go
+++ b/internal/bufpool/buffers.go
@@ -23,11 +23,10 @@ const (
 // pooled buffer, the caller should invoke Release() to return it to the pool.
 //
 // Buffers must not be copied after first use; doing so can cause double-returns
-// to the pool and data races. A zero-value Buffer is not valid for use.
-//
-//go:nocopy
+// to the pool and data races. A zero-value Buffer is not valid for use. Use
+// the pointer type (*Buffer) returned by Borrow/FromOwned to avoid accidental
+// copies.
 type Buffer struct {
-	_    noCopy
 	buf  []byte
 	pool poolIndex
 }
@@ -70,28 +69,28 @@ var bufferPools = func() []sync.Pool {
 // unpooled buffer is allocated.
 //
 // The caller must call Release() when finished using the returned Buffer.
-func Borrow(capHint int) Buffer {
+func Borrow(capHint int) *Buffer {
 	if capHint < DefaultBufferCap {
 		capHint = DefaultBufferCap
 	}
 	classIdx, classCap, pooled := classFor(capHint)
 	if !pooled {
 		newBuf := make([]byte, 0, capHint)
-		return Buffer{buf: newBuf, pool: unpooled}
+		return &Buffer{buf: newBuf, pool: unpooled}
 	}
 	buf := bufferPools[classIdx].Get().(*[]byte)
 	if cap(*buf) < classCap {
 		*buf = make([]byte, 0, classCap)
 	}
 	slice := (*buf)[:0]
-	return Buffer{buf: slice, pool: poolIndex(classIdx)}
+	return &Buffer{buf: slice, pool: poolIndex(classIdx)}
 }
 
 // FromOwned constructs a Buffer from a caller-owned byte slice. The resulting
 // Buffer does not participate in pooling and will never be returned to the
 // internal pool when released.
-func FromOwned(buf []byte) Buffer {
-	return Buffer{buf: buf, pool: unpooled}
+func FromOwned(buf []byte) *Buffer {
+	return &Buffer{buf: buf, pool: unpooled}
 }
 
 // Resize adjusts the length of the buffer to n bytes. If n exceeds the current
@@ -187,8 +186,3 @@ func (buf *Buffer) returnToPool() {
 	tmp := buf.buf[:0]
 	bufferPools[int(buf.pool)].Put(&tmp)
 }
-
-type noCopy struct{}
-
-func (*noCopy) Lock()   {}
-func (*noCopy) Unlock() {}
diff --git a/internal/flatex/decompress_bytes.go b/internal/flatex/decompress_bytes.go
index 5e29f82d..ce6d0558 100644
--- a/internal/flatex/decompress_bytes.go
+++ b/internal/flatex/decompress_bytes.go
@@ -25,26 +25,26 @@ var bufferDecompressorPool = sync.Pool{
 
 // Decompress inflates the provided DEFLATE stream and returns the full output
 // in a pooled bufpool.Buffer along with the number of consumed bytes from src.
-func Decompress(src []byte) (bufpool.Buffer, int, error) {
+func Decompress(src []byte) (*bufpool.Buffer, int, error) {
 	return DecompressDictSized(src, nil, 0)
 }
 
 // DecompressDict inflates the provided DEFLATE stream using dict as the preset
 // dictionary and returns the full output in a pooled bufpool.Buffer. The second
 // returned value reports how many bytes of src were consumed.
-func DecompressDict(src []byte, dict []byte) (bufpool.Buffer, int, error) {
+func DecompressDict(src []byte, dict []byte) (*bufpool.Buffer, int, error) {
 	return DecompressDictSized(src, dict, 0)
 }
 
 // DecompressDictSized is like DecompressDict but allows providing an expected
 // output size to pre-size the destination buffer and avoid repeated growth.
 // A non-positive sizeHint falls back to the default buffer capacity.
-func DecompressDictSized(src []byte, dict []byte, sizeHint int) (bufpool.Buffer, int, error) {
+func DecompressDictSized(src []byte, dict []byte, sizeHint int) (*bufpool.Buffer, int, error) {
 	d := bufferDecompressorPool.Get().(*bufferDecompressor)
 	defer bufferDecompressorPool.Put(d)
 
 	if err := d.inflater.reset(src, dict); err != nil {
-		return bufpool.Buffer{}, 0, err
+		return nil, 0, err
 	}
 
 	out := bufpool.Borrow(sizeHint)
@@ -61,7 +61,7 @@ func DecompressDictSized(src []byte, dict []byte, sizeHint int) (bufpool.Buffer,
 				return out, d.inflater.pos, nil
 			}
 			out.Release()
-			return bufpool.Buffer{}, 0, d.inflater.err
+			return nil, 0, d.inflater.err
 		}
 		d.inflater.step(&d.inflater)
 		if d.inflater.err != nil && len(d.inflater.toRead) == 0 {
diff --git a/internal/zlibx/decompress.go b/internal/zlibx/decompress.go
index c6eb65e5..68a92587 100644
--- a/internal/zlibx/decompress.go
+++ b/internal/zlibx/decompress.go
@@ -11,71 +11,71 @@ import (
 
 // Decompress inflates the provided zlib wrapped stream and returns the
 // uncompressed data inside a pooled bufpool.Buffer.
-func Decompress(src []byte) (bufpool.Buffer, error) {
+func Decompress(src []byte) (*bufpool.Buffer, error) {
 	return DecompressSized(src, 0)
 }
 
 // DecompressSized inflates the provided zlib stream, using sizeHint to
 // preallocate the output buffer when known (e.g. packfile entries).
-func DecompressSized(src []byte, sizeHint int) (bufpool.Buffer, error) {
+func DecompressSized(src []byte, sizeHint int) (*bufpool.Buffer, error) {
 	return DecompressDictSized(src, nil, sizeHint)
 }
 
 // DecompressDict is like Decompress but accepts a preset dictionary. The
 // dictionary must match the checksum embedded in the stream if the dictionary
 // flag is present.
-func DecompressDict(src []byte, dict []byte) (bufpool.Buffer, error) {
+func DecompressDict(src []byte, dict []byte) (*bufpool.Buffer, error) {
 	return DecompressDictSized(src, dict, 0)
 }
 
 // DecompressDictSized is like DecompressDict but allows providing an expected
 // uncompressed size to avoid buffer growth copies.
-func DecompressDictSized(src []byte, dict []byte, sizeHint int) (bufpool.Buffer, error) {
+func DecompressDictSized(src []byte, dict []byte, sizeHint int) (*bufpool.Buffer, error) {
 	if len(src) < 6 {
-		return bufpool.Buffer{}, io.ErrUnexpectedEOF
+		return nil, io.ErrUnexpectedEOF
 	}
 
 	cmf := src[0]
 	flg := src[1]
 	if (cmf&0x0f != zlibDeflate) || (cmf>>4 > zlibMaxWindow) || (binary.BigEndian.Uint16(src[:2])%31 != 0) {
-		return bufpool.Buffer{}, ErrHeader
+		return nil, ErrHeader
 	}
 
 	offset := 2
 	haveDict := flg&0x20 != 0
 	if haveDict {
 		if len(src) < offset+4 {
-			return bufpool.Buffer{}, io.ErrUnexpectedEOF
+			return nil, io.ErrUnexpectedEOF
 		}
 		if dict == nil {
-			return bufpool.Buffer{}, ErrDictionary
+			return nil, ErrDictionary
 		}
 		checksum := binary.BigEndian.Uint32(src[offset : offset+4])
 		if checksum != adler32.Checksum(dict) {
-			return bufpool.Buffer{}, ErrDictionary
+			return nil, ErrDictionary
 		}
 		offset += 4
 	}
 
 	if len(src[offset:]) < 4 {
-		return bufpool.Buffer{}, io.ErrUnexpectedEOF
+		return nil, io.ErrUnexpectedEOF
 	}
 
 	deflateData := src[offset:]
 	out, consumed, err := flatex.DecompressDictSized(deflateData, dict, sizeHint)
 	if err != nil {
-		return bufpool.Buffer{}, err
+		return nil, err
 	}
 
 	checksumPos := offset + consumed
 	if checksumPos+4 > len(src) {
 		out.Release()
-		return bufpool.Buffer{}, io.ErrUnexpectedEOF
+		return nil, io.ErrUnexpectedEOF
 	}
 	expected := binary.BigEndian.Uint32(src[checksumPos : checksumPos+4])
 	if expected != adler32.Checksum(out.Bytes()) {
 		out.Release()
-		return bufpool.Buffer{}, ErrChecksum
+		return nil, ErrChecksum
 	}
 	return out, nil
 }