CRI: Move reference sorting to reference package

Signed-off-by: Maksym Pavlenko <pavlenko.maksym@gmail.com>

pkg/cri/store/image/image.go

@@ -24,6 +24,7 @@ import (
 	"github.com/containerd/containerd"
 	"github.com/containerd/containerd/errdefs"
 	"github.com/containerd/containerd/pkg/cri/util"
+	"github.com/containerd/containerd/reference"
 
 	imagedigest "github.com/opencontainers/go-digest"
 	"github.com/opencontainers/go-digest/digestset"
@@ -205,7 +206,7 @@ func (s *store) add(img Image) error {
 		return nil
 	}
 	// Or else, merge and sort the references.
-	i.References = sortReferences(util.MergeStringSlices(i.References, img.References))
+	i.References = reference.Sort(util.MergeStringSlices(i.References, img.References))
 	s.images[img.ID] = i
 	return nil
 }

reference/sort.go

@@ -14,7 +14,7 @@
    limitations under the License.
 */
 
-package image
+package reference
 
 import (
 	"sort"
@@ -22,8 +22,8 @@ import (
 	"github.com/containerd/containerd/reference/docker"
 )
 
-// sortReferences sorts references by refRank then string comparison
-func sortReferences(references []string) []string {
+// Sort sorts references by refRank then string comparison
+func Sort(references []string) []string {
 	var prefs []docker.Reference
 	var bad []string
 

reference/sort_test.go

@@ -14,7 +14,7 @@
    limitations under the License.
 */
 
-package image
+package reference
 
 import (
 	"io"
@@ -68,7 +68,7 @@ func TestReferenceSorting(t *testing.T) {
 			expected: []string{r2("name-1", "tag"), r2("name-2", "tag"), r2("name-3", "tag")},
 		},
 	} {
-		sorted := sortReferences(tc.unsorted)
+		sorted := Sort(tc.unsorted)
 		if len(sorted) != len(tc.expected) {
 			t.Errorf("[%d]: Mismatched sized, got %d, expected %d", i, len(sorted), len(tc.expected))
 			continue