Add skip and limit to git.GetTags (#16897)

* Make GetTags() api similar to GetBranches()
* Use it for Tag/Release page

modules/context/repo.go

@@ -547,7 +547,7 @@ func RepoAssignment(ctx *Context) (cancel context.CancelFunc) {
 		return
 	}
 
-	tags, err := ctx.Repo.GitRepo.GetTags()
+	tags, err := ctx.Repo.GitRepo.GetTags(0, 0)
 	if err != nil {
 		ctx.ServerError("GetTags", err)
 		return

modules/git/repo_tag_gogit.go

@@ -21,7 +21,8 @@ func (repo *Repository) IsTagExist(name string) bool {
 }
 
 // GetTags returns all tags of the repository.
-func (repo *Repository) GetTags() ([]string, error) {
+// returning at most limit tags, or all if limit is 0.
+func (repo *Repository) GetTags(skip, limit int) ([]string, error) {
 	var tagNames []string
 
 	tags, err := repo.gogitRepo.Tags()
@@ -40,5 +41,15 @@ func (repo *Repository) GetTags() ([]string, error) {
 		tagNames[i], tagNames[j] = tagNames[j], tagNames[i]
 	}
 
+	// since we have to reverse order we can paginate only afterwards
+	if len(tagNames) < skip {
+		tagNames = []string{}
+	} else {
+		tagNames = tagNames[skip:]
+	}
+	if limit != 0 && len(tagNames) > limit {
+		tagNames = tagNames[:limit]
+	}
+
 	return tagNames, nil
 }

modules/git/repo_tag_nogogit.go

@@ -18,7 +18,8 @@ func (repo *Repository) IsTagExist(name string) bool {
 }
 
 // GetTags returns all tags of the repository.
-func (repo *Repository) GetTags() (tags []string, err error) {
-	tags, _, err = callShowRef(repo.Path, TagPrefix, "--tags", 0, 0)
+// returning at most limit tags, or all if limit is 0.
+func (repo *Repository) GetTags(skip, limit int) (tags []string, err error) {
+	tags, _, err = callShowRef(repo.Path, TagPrefix, "--tags", skip, limit)
 	return
 }

modules/repository/repo.go

@@ -250,7 +250,7 @@ func SyncReleasesWithTags(repo *models.Repository, gitRepo *git.Repository) erro
 			}
 		}
 	}
-	tags, err := gitRepo.GetTags()
+	tags, err := gitRepo.GetTags(0, 0)
 	if err != nil {
 		return fmt.Errorf("GetTags: %v", err)
 	}