Move ParseImageReferences to cri util

Avoids importing image service for utility function.

Signed-off-by: Derek McGowan <derek@mcg.dev>

pkg/cri/util/references.go

@@ -0,0 +1,37 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package util
+
+import reference "github.com/distribution/reference"
+
+// ParseImageReferences parses a list of arbitrary image references and returns
+// the repotags and repodigests
+func ParseImageReferences(refs []string) ([]string, []string) {
+	var tags, digests []string
+	for _, ref := range refs {
+		parsed, err := reference.ParseAnyReference(ref)
+		if err != nil {
+			continue
+		}
+		if _, ok := parsed.(reference.Canonical); ok {
+			digests = append(digests, parsed.String())
+		} else if _, ok := parsed.(reference.Tagged); ok {
+			tags = append(tags, parsed.String())
+		}
+	}
+	return tags, digests
+}