Use Sync.Pool pointers to optimise memory usage

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

3 files changed, 40 insertions, 7 deletions

diff --git a/plumbing/format/packfile/parser_test.go b/plumbing/format/packfile/parser_test.go
index 09f3f97..651d05f 100644
--- a/plumbing/format/packfile/parser_test.go
+++ b/plumbing/format/packfile/parser_test.go
@@ -10,8 +10,10 @@ import (
 	fixtures "github.com/go-git/go-git-fixtures/v4"
 	"github.com/go-git/go-git/v5"
 	"github.com/go-git/go-git/v5/plumbing"
+	"github.com/go-git/go-git/v5/plumbing/cache"
 	"github.com/go-git/go-git/v5/plumbing/format/packfile"
 	"github.com/go-git/go-git/v5/plumbing/storer"
+	"github.com/go-git/go-git/v5/storage/filesystem"
 	. "gopkg.in/check.v1"
 )
 
@@ -248,3 +250,29 @@ func BenchmarkParseBasic(b *testing.B) {
 		}
 	}
 }
+
+func BenchmarkParser(b *testing.B) {
+	f := fixtures.Basic().One()
+	defer fixtures.Clean()
+
+	b.ResetTimer()
+	for n := 0; n < b.N; n++ {
+		b.StopTimer()
+		scanner := packfile.NewScanner(f.Packfile())
+		fs := osfs.New(os.TempDir())
+		storage := filesystem.NewStorage(fs, cache.NewObjectLRUDefault())
+
+		parser, err := packfile.NewParserWithStorage(scanner, storage)
+		if err != nil {
+			b.Error(err)
+		}
+
+		b.StartTimer()
+		_, err = parser.Parse()
+
+		b.StopTimer()
+		if err != nil {
+			b.Error(err)
+		}
+	}
+}
diff --git a/plumbing/format/packfile/patch_delta.go b/plumbing/format/packfile/patch_delta.go
index 17da11e..053466d 100644
--- a/plumbing/format/packfile/patch_delta.go
+++ b/plumbing/format/packfile/patch_delta.go
@@ -53,9 +53,10 @@ func ApplyDelta(target, base plumbing.EncodedObject, delta []byte) (err error) {
 
 	target.SetSize(int64(dst.Len()))
 
-	b := byteSlicePool.Get().([]byte)
+	bufp := byteSlicePool.Get().(*[]byte)
+	b := *bufp
 	_, err = io.CopyBuffer(w, dst, b)
-	byteSlicePool.Put(b)
+	byteSlicePool.Put(bufp)
 	return err
 }
 
diff --git a/plumbing/format/packfile/scanner.go b/plumbing/format/packfile/scanner.go
index 45d480c..b655594 100644
--- a/plumbing/format/packfile/scanner.go
+++ b/plumbing/format/packfile/scanner.go
@@ -346,15 +346,17 @@ func (s *Scanner) copyObject(w io.Writer) (n int64, err error) {
 	}
 
 	defer ioutil.CheckClose(zr, &err)
-	buf := byteSlicePool.Get().([]byte)
+	bufp := byteSlicePool.Get().(*[]byte)
+	buf := *bufp
 	n, err = io.CopyBuffer(w, zr, buf)
-	byteSlicePool.Put(buf)
+	byteSlicePool.Put(bufp)
 	return
 }
 
 var byteSlicePool = sync.Pool{
 	New: func() interface{} {
-		return make([]byte, 32*1024)
+		b := make([]byte, 32*1024)
+		return &b
 	},
 }
 
@@ -387,9 +389,11 @@ func (s *Scanner) Checksum() (plumbing.Hash, error) {
 
 // Close reads the reader until io.EOF
 func (s *Scanner) Close() error {
-	buf := byteSlicePool.Get().([]byte)
+	bufp := byteSlicePool.Get().(*[]byte)
+	buf := *bufp
 	_, err := io.CopyBuffer(stdioutil.Discard, s.r, buf)
-	byteSlicePool.Put(buf)
+	byteSlicePool.Put(bufp)
+
 	return err
 }