remove duplicated function

Signed-off-by: Billy Zha <jinzha1@microsoft.com>

cmd/oras/root/cp.go

@@ -25,6 +25,7 @@ import (
 	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
 	"github.com/spf13/cobra"
 	"oras.land/oras-go/v2"
+	"oras.land/oras-go/v2/content"
 	"oras.land/oras/cmd/oras/internal/display"
 	"oras.land/oras/cmd/oras/internal/option"
 	"oras.land/oras/internal/graph"
@@ -117,7 +118,9 @@ func runCopy(ctx context.Context, opts copyOptions) error {
 	committed := &sync.Map{}
 	extendedCopyOptions := oras.DefaultExtendedCopyOptions
 	extendedCopyOptions.Concurrency = opts.concurrency
-	extendedCopyOptions.FindPredecessors = graph.FindReferrerPredecessors
+	extendedCopyOptions.FindPredecessors = func(ctx context.Context, src content.ReadOnlyGraphStorage, desc ocispec.Descriptor) ([]ocispec.Descriptor, error) {
+		return graph.Referrers(ctx, src, desc, "")
+	}
 	extendedCopyOptions.PreCopy = display.StatusPrinter("Copying", opts.Verbose)
 	extendedCopyOptions.PostCopy = func(ctx context.Context, desc ocispec.Descriptor) error {
 		committed.Store(desc.Digest.String(), desc.Annotations[ocispec.AnnotationTitle])

internal/graph/graph.go

@@ -179,46 +179,6 @@ func Referrers(ctx context.Context, target content.ReadOnlyGraphStorage, desc oc
 	return results, nil
 }
 
-// FindReferrerPredecessors returns referrer nodes of desc in target.
-func FindReferrerPredecessors(ctx context.Context, src content.ReadOnlyGraphStorage, desc ocispec.Descriptor) ([]ocispec.Descriptor, error) {
-	var results []ocispec.Descriptor
-	if repo, ok := src.(registry.ReferrerLister); ok {
-		// get referrers directly
-		err := repo.Referrers(ctx, desc, "", func(referrers []ocispec.Descriptor) error {
-			results = append(results, referrers...)
-			return nil
-		})
-		if err != nil {
-			return nil, err
-		}
-		return results, nil
-	}
-	predecessors, err := src.Predecessors(ctx, desc)
-	if err != nil {
-		return nil, err
-	}
-	for _, node := range predecessors {
-		switch node.MediaType {
-		case MediaTypeArtifactManifest, ocispec.MediaTypeImageManifest:
-			results = append(results, node)
-		case ocispec.MediaTypeImageIndex:
-			fetched, err := fetchBytes(ctx, src, node)
-			if err != nil {
-				return nil, err
-			}
-			// convert to json
-			var index ocispec.Index
-			if err := json.Unmarshal(fetched, &index); err != nil {
-				return nil, err
-			}
-			if index.Subject != nil && content.Equal(*index.Subject, desc) {
-				results = append(results, node)
-			}
-		}
-	}
-	return results, nil
-}
-
 func fetchBytes(ctx context.Context, fetcher content.Fetcher, desc ocispec.Descriptor) ([]byte, error) {
 	rc, err := fetcher.Fetch(ctx, desc)
 	if err != nil {

internal/graph/graph_test.go

@@ -39,14 +39,6 @@ func (e *errLister) Referrers(ctx context.Context, desc ocispec.Descriptor, arti
 	return errors.New("")
 }
 
-type errFinder struct {
-	oras.ReadOnlyGraphTarget
-}
-
-func (e *errFinder) Predecessors(ctx context.Context, node ocispec.Descriptor) ([]ocispec.Descriptor, error) {
-	return nil, errors.New("")
-}
-
 type refLister struct {
 	referrers []ocispec.Descriptor
 	oras.ReadOnlyGraphTarget
@@ -265,92 +257,3 @@ func TestSuccessors(t *testing.T) {
 		})
 	}
 }
-
-func TestFindReferrerPredecessors(t *testing.T) {
-	ctx := context.Background()
-	var blobs [][]byte
-	var descs []ocispec.Descriptor
-	appendBlob := func(mediaType string, blob []byte) {
-		blobs = append(blobs, blob)
-		descs = append(descs, ocispec.Descriptor{
-			MediaType: mediaType,
-			Digest:    digest.FromBytes(blob),
-			Size:      int64(len(blob)),
-		})
-	}
-	generateImage := func(subject *ocispec.Descriptor, annotations map[string]string, config ocispec.Descriptor, layers ...ocispec.Descriptor) {
-		manifest := ocispec.Manifest{
-			Subject:     subject,
-			Config:      config,
-			Layers:      layers,
-			Annotations: annotations,
-		}
-		manifestJSON, err := json.Marshal(manifest)
-		if err != nil {
-			t.Fatal(err)
-		}
-		appendBlob(ocispec.MediaTypeImageManifest, manifestJSON)
-	}
-	generateIndex := func(manifests ...ocispec.Descriptor) {
-		index := ocispec.Index{
-			Manifests: manifests,
-		}
-		manifestJSON, err := json.Marshal(index)
-		if err != nil {
-			t.Fatal(err)
-		}
-		appendBlob(ocispec.MediaTypeImageIndex, manifestJSON)
-	}
-	const (
-		subject = iota
-		imgConfig
-		image
-	)
-	var anno map[string]string
-	appendBlob(ocispec.MediaTypeImageLayer, []byte("blob"))
-	imageType := "test.image"
-	appendBlob(imageType, []byte("config content"))
-	generateImage(&descs[subject], anno, descs[imgConfig])
-	imageDesc := descs[image]
-	imageDesc.Annotations = anno
-	imageDesc.ArtifactType = imageType
-	generateIndex(descs[subject])
-
-	referrers := []ocispec.Descriptor{descs[image], descs[image]}
-	memory := memory.New()
-	for i := range descs {
-		if err := memory.Push(ctx, descs[i], bytes.NewReader(blobs[i])); err != nil {
-			t.Errorf("Error pushing %v\n", err)
-		}
-	}
-	finder := &predecessorFinder{Store: memory}
-	type args struct {
-		ctx  context.Context
-		src  content.ReadOnlyGraphStorage
-		desc ocispec.Descriptor
-	}
-	tests := []struct {
-		name    string
-		args    args
-		want    []ocispec.Descriptor
-		wantErr bool
-	}{
-		{"should failed to get referrers", args{ctx, &errLister{}, ocispec.Descriptor{}}, nil, true},
-		{"should failed to get predecessor", args{ctx, &errFinder{}, ocispec.Descriptor{}}, nil, true},
-		{"should return referrers when target is a referrer lister", args{ctx, &refLister{referrers: referrers}, ocispec.Descriptor{}}, referrers, false},
-		{"should return image for config node", args{ctx, finder, descs[imgConfig]}, []ocispec.Descriptor{descs[image]}, false},
-		{"should return image for subject node", args{ctx, finder, descs[subject]}, []ocispec.Descriptor{descs[image]}, false},
-	}
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			got, err := FindReferrerPredecessors(tt.args.ctx, tt.args.src, tt.args.desc)
-			if (err != nil) != tt.wantErr {
-				t.Errorf("FindReferrerPredecessors() error = %v, wantErr %v", err, tt.wantErr)
-				return
-			}
-			if !reflect.DeepEqual(got, tt.want) {
-				t.Errorf("FindReferrerPredecessors() = %v, want %v", got, tt.want)
-			}
-		})
-	}
-}