Use Sync.Pool pointers to optimise memory usage

Signed-off-by: Paulo Gomes <pjbgf@linux.com>

1 files changed, 13 insertions, 2 deletions

diff --git a/plumbing/format/objfile/writer.go b/plumbing/format/objfile/writer.go
index 2a96a43..248f81b 100644
--- a/plumbing/format/objfile/writer.go
+++ b/plumbing/format/objfile/writer.go
@@ -5,6 +5,7 @@ import (
 	"errors"
 	"io"
 	"strconv"
+	"sync"
 
 	"github.com/go-git/go-git/v5/plumbing"
 )
@@ -18,9 +19,9 @@ var (
 // not close the underlying io.Writer.
 type Writer struct {
 	raw    io.Writer
-	zlib   io.WriteCloser
 	hasher plumbing.Hasher
 	multi  io.Writer
+	zlib   io.WriteCloser
 
 	closed  bool
 	pending int64 // number of unwritten bytes
@@ -31,12 +32,21 @@ type Writer struct {
 // The returned Writer implements io.WriteCloser. Close should be called when
 // finished with the Writer. Close will not close the underlying io.Writer.
 func NewWriter(w io.Writer) *Writer {
+	zlib := zlibPool.Get().(*zlib.Writer)
+	zlib.Reset(w)
+
 	return &Writer{
 		raw:  w,
-		zlib: zlib.NewWriter(w),
+		zlib: zlib,
 	}
 }
 
+var zlibPool = sync.Pool{
+	New: func() interface{} {
+		return zlib.NewWriter(nil)
+	},
+}
+
 // WriteHeader writes the type and the size and prepares to accept the object's
 // contents. If an invalid t is provided, plumbing.ErrInvalidType is returned. If a
 // negative size is provided, ErrNegativeSize is returned.
@@ -100,6 +110,7 @@ func (w *Writer) Hash() plumbing.Hash {
 // Calling Close does not close the wrapped io.Writer originally passed to
 // NewWriter.
 func (w *Writer) Close() error {
+	defer zlibPool.Put(w.zlib)
 	if err := w.zlib.Close(); err != nil {
 		return err
 	}