Add support for sha256 repositories (#23894)

Currently only SHA1 repositories are supported by Gitea. This adds
support for alternate SHA256 with the additional aim of easier support
for additional hash types in the future.

Fixes: #13794
Limited by: https://github.com/go-git/go-git/issues/899
Depend on: #28138

<img width="776" alt="图片" src="https://github.com/go-gitea/gitea/assets/81045/5448c9a7-608e-4341-a149-5dd0069c9447">

---------

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: 6543 <6543@obermui.de>

1 files changed, 16 insertions, 0 deletions

diff --git a/modules/git/object_id.go b/modules/git/object_id.go
index 01c23ed3da..4f8c39ee1d 100644
--- a/modules/git/object_id.go
+++ b/modules/git/object_id.go
@@ -16,6 +16,7 @@ type ObjectID interface {
 	Type() ObjectFormat
 }
 
+/* SHA1 */
 type Sha1Hash [20]byte
 
 func (h *Sha1Hash) String() string {
@@ -39,6 +40,21 @@ func MustIDFromString(hexHash string) ObjectID {
 	return id
 }
 
+/* SHA256 */
+type Sha256Hash [32]byte
+
+func (h *Sha256Hash) String() string {
+	return hex.EncodeToString(h[:])
+}
+
+func (h *Sha256Hash) IsZero() bool {
+	empty := Sha256Hash{}
+	return bytes.Equal(empty[:], h[:])
+}
+func (h *Sha256Hash) RawValue() []byte { return h[:] }
+func (*Sha256Hash) Type() ObjectFormat { return Sha256ObjectFormat }
+
+/* utility */
 func NewIDFromString(hexHash string) (ObjectID, error) {
 	var theObjectFormat ObjectFormat
 	for _, objectFormat := range SupportedObjectFormats {