Merge pull request #4414 from dmcgowan/discard-content

Set content labels based on content type

images/mediatypes.go

@@ -125,3 +125,31 @@ func IsKnownConfig(mt string) bool {
 	}
 	return false
 }
+
+// ChildGCLabels returns the label for a given descriptor to reference it
+func ChildGCLabels(desc ocispec.Descriptor) []string {
+	mt := desc.MediaType
+	if IsKnownConfig(mt) {
+		return []string{"containerd.io/gc.ref.content.config"}
+	}
+
+	switch mt {
+	case MediaTypeDockerSchema2Manifest, ocispec.MediaTypeImageManifest:
+		return []string{"containerd.io/gc.ref.content.m."}
+	}
+
+	if IsLayerType(mt) {
+		return []string{"containerd.io/gc.ref.content.l."}
+	}
+
+	return []string{"containerd.io/gc.ref.content."}
+}
+
+// ChildGCLabelsFilterLayers returns the labels for a given descriptor to
+// reference it, skipping layer media types
+func ChildGCLabelsFilterLayers(desc ocispec.Descriptor) []string {
+	if IsLayerType(desc.MediaType) {
+		return nil
+	}
+	return ChildGCLabels(desc)
+}