app/imageoper: index only for OCI manifests

app/imageoper/ociaux.go

@@ -21,11 +21,6 @@ import (
 	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
 )
 
-const (
-	oiiMediaType = "application/vnd.oci.image.index.v1+json"
-	oimMediaType = "application/vnd.oci.image.manifest.v1+json"
-)
-
 func indexFromManigestDescrs(mandescrs []descr.Manifest) (ocispec.Index, []byte, error) {
 	var err error
 	var indexdata []byte
@@ -37,6 +32,10 @@ func indexFromManigestDescrs(mandescrs []descr.Manifest) (ocispec.Index, []byte,
 	for _, mandescr := range mandescrs {
 		var man ocispec.Manifest
 
+		if mandescr.ContentType != oimMediaType && mandescr.ContentType != ddmMediaType {
+			continue
+		}
+
 		man.Subject = &ocispec.Descriptor{}
 		man.Subject.Platform = &ocispec.Platform{}
 		man.Config = ocispec.Descriptor{}