[API] generalize list header (#16551)

* Add info about list endpoints to CONTRIBUTING.md

* Let all list endpoints return X-Total-Count header 

* Add TODOs for GetCombinedCommitStatusByRef

* Fix models/issue_stopwatch.go

* Rrefactor models.ListDeployKeys

* Introduce helper func and use them for SetLinkHeader related func

2 files changed, 9 insertions, 13 deletions

diff --git a/modules/git/repo_tag.go b/modules/git/repo_tag.go
index d91c3ca979..44d7a048bc 100644
--- a/modules/git/repo_tag.go
+++ b/modules/git/repo_tag.go
@@ -10,6 +10,7 @@ import (
 	"strings"
 
 	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/util"
 )
 
 // TagPrefix tags prefix path on the repository
@@ -160,24 +161,18 @@ func (repo *Repository) GetTag(name string) (*Tag, error) {
 }
 
 // GetTagInfos returns all tag infos of the repository.
-func (repo *Repository) GetTagInfos(page, pageSize int) ([]*Tag, error) {
+func (repo *Repository) GetTagInfos(page, pageSize int) ([]*Tag, int, error) {
 	// TODO this a slow implementation, makes one git command per tag
 	stdout, err := NewCommand("tag").RunInDir(repo.Path)
 	if err != nil {
-		return nil, err
+		return nil, 0, err
 	}
 
 	tagNames := strings.Split(strings.TrimRight(stdout, "\n"), "\n")
+	tagsTotal := len(tagNames)
 
 	if page != 0 {
-		skip := (page - 1) * pageSize
-		if skip >= len(tagNames) {
-			return nil, nil
-		}
-		if (len(tagNames) - skip) < pageSize {
-			pageSize = len(tagNames) - skip
-		}
-		tagNames = tagNames[skip : skip+pageSize]
+		tagNames = util.PaginateSlice(tagNames, page, pageSize).([]string)
 	}
 
 	var tags = make([]*Tag, 0, len(tagNames))
@@ -189,13 +184,13 @@ func (repo *Repository) GetTagInfos(page, pageSize int) ([]*Tag, error) {
 
 		tag, err := repo.GetTag(tagName)
 		if err != nil {
-			return nil, err
+			return nil, tagsTotal, err
 		}
 		tag.Name = tagName
 		tags = append(tags, tag)
 	}
 	sortTagsByTime(tags)
-	return tags, nil
+	return tags, tagsTotal, nil
 }
 
 // GetTagType gets the type of the tag, either commit (simple) or tag (annotated)
diff --git a/modules/git/repo_tag_test.go b/modules/git/repo_tag_test.go
index 6feae8d913..cfab9edd8f 100644
--- a/modules/git/repo_tag_test.go
+++ b/modules/git/repo_tag_test.go
@@ -18,9 +18,10 @@ func TestRepository_GetTags(t *testing.T) {
 	assert.NoError(t, err)
 	defer bareRepo1.Close()
 
-	tags, err := bareRepo1.GetTagInfos(0, 0)
+	tags, total, err := bareRepo1.GetTagInfos(0, 0)
 	assert.NoError(t, err)
 	assert.Len(t, tags, 1)
+	assert.Equal(t, len(tags), total)
 	assert.EqualValues(t, "test", tags[0].Name)
 	assert.EqualValues(t, "3ad28a9149a2864384548f3d17ed7f38014c9e8a", tags[0].ID.String())
 	assert.EqualValues(t, "tag", tags[0].Type)