packfile/decoder: speed up packfile iterator when specific type (#200)

1 files changed, 46 insertions, 0 deletions

diff --git a/plumbing/format/packfile/decoder_test.go b/plumbing/format/packfile/decoder_test.go
index 10d3bc2..0ab5bc8 100644
--- a/plumbing/format/packfile/decoder_test.go
+++ b/plumbing/format/packfile/decoder_test.go
@@ -47,6 +47,52 @@ func (s *ReaderSuite) TestDecode(c *C) {
 	})
 }
 
+func (s *ReaderSuite) TestDecodeByType(c *C) {
+	ts := []plumbing.ObjectType{
+		plumbing.CommitObject,
+		plumbing.TagObject,
+		plumbing.TreeObject,
+		plumbing.BlobObject,
+	}
+
+	fixtures.Basic().ByTag("packfile").Test(c, func(f *fixtures.Fixture) {
+		for _, t := range ts {
+			storage := memory.NewStorage()
+			scanner := packfile.NewScanner(f.Packfile())
+			d, err := packfile.NewDecoderForType(scanner, storage, t)
+			c.Assert(err, IsNil)
+			defer d.Close()
+
+			_, count, err := scanner.Header()
+			c.Assert(err, IsNil)
+
+			var i uint32
+			for i = 0; i < count; i++ {
+				obj, err := d.DecodeObject()
+				c.Assert(err, IsNil)
+
+				if obj != nil {
+					c.Assert(obj.Type(), Equals, t)
+				}
+			}
+		}
+	})
+}
+func (s *ReaderSuite) TestDecodeByTypeConstructor(c *C) {
+	f := fixtures.Basic().ByTag("packfile").One()
+	storage := memory.NewStorage()
+	scanner := packfile.NewScanner(f.Packfile())
+
+	_, err := packfile.NewDecoderForType(scanner, storage, plumbing.OFSDeltaObject)
+	c.Assert(err, Equals, plumbing.ErrInvalidType)
+
+	_, err = packfile.NewDecoderForType(scanner, storage, plumbing.REFDeltaObject)
+	c.Assert(err, Equals, plumbing.ErrInvalidType)
+
+	_, err = packfile.NewDecoderForType(scanner, storage, plumbing.InvalidObject)
+	c.Assert(err, Equals, plumbing.ErrInvalidType)
+}
+
 func (s *ReaderSuite) TestDecodeMultipleTimes(c *C) {
 	f := fixtures.Basic().ByTag("packfile").One()
 	scanner := packfile.NewScanner(f.Packfile())