1 files changed, 204 insertions, 0 deletions
diff --git a/pkg/v1/mutate/index.go b/pkg/v1/mutate/index.go
new file mode 100644
index 0000000..ba062f9
--- /dev/null
+++ b/pkg/v1/mutate/index.go
@@ -0,0 +1,204 @@
+// Copyright 2019 Google LLC All Rights Reserved.
+//
+// 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 mutate
+
+import (
+	"encoding/json"
+	"fmt"
+
+	"github.com/google/go-containerregistry/pkg/logs"
+	v1 "github.com/google/go-containerregistry/pkg/v1"
+	"github.com/google/go-containerregistry/pkg/v1/match"
+	"github.com/google/go-containerregistry/pkg/v1/partial"
+	"github.com/google/go-containerregistry/pkg/v1/types"
+)
+
+func computeDescriptor(ia IndexAddendum) (*v1.Descriptor, error) {
+	desc, err := partial.Descriptor(ia.Add)
+	if err != nil {
+		return nil, err
+	}
+
+	// The IndexAddendum allows overriding Descriptor values.
+	if ia.Descriptor.Size != 0 {
+		desc.Size = ia.Descriptor.Size
+	}
+	if string(ia.Descriptor.MediaType) != "" {
+		desc.MediaType = ia.Descriptor.MediaType
+	}
+	if ia.Descriptor.Digest != (v1.Hash{}) {
+		desc.Digest = ia.Descriptor.Digest
+	}
+	if ia.Descriptor.Platform != nil {
+		desc.Platform = ia.Descriptor.Platform
+	}
+	if len(ia.Descriptor.URLs) != 0 {
+		desc.URLs = ia.Descriptor.URLs
+	}
+	if len(ia.Descriptor.Annotations) != 0 {
+		desc.Annotations = ia.Descriptor.Annotations
+	}
+	if ia.Descriptor.Data != nil {
+		desc.Data = ia.Descriptor.Data
+	}
+
+	return desc, nil
+}
+
+type index struct {
+	base v1.ImageIndex
+	adds []IndexAddendum
+	// remove is removed before adds
+	remove match.Matcher
+
+	computed    bool
+	manifest    *v1.IndexManifest
+	annotations map[string]string
+	mediaType   *types.MediaType
+	imageMap    map[v1.Hash]v1.Image
+	indexMap    map[v1.Hash]v1.ImageIndex
+	layerMap    map[v1.Hash]v1.Layer
+	subject     *v1.Descriptor
+}
+
+var _ v1.ImageIndex = (*index)(nil)
+
+func (i *index) MediaType() (types.MediaType, error) {
+	if i.mediaType != nil {
+		return *i.mediaType, nil
+	}
+	return i.base.MediaType()
+}
+
+func (i *index) Size() (int64, error) { return partial.Size(i) }
+
+func (i *index) compute() error {
+	// Don't re-compute if already computed.
+	if i.computed {
+		return nil
+	}
+
+	i.imageMap = make(map[v1.Hash]v1.Image)
+	i.indexMap = make(map[v1.Hash]v1.ImageIndex)
+	i.layerMap = make(map[v1.Hash]v1.Layer)
+
+	m, err := i.base.IndexManifest()
+	if err != nil {
+		return err
+	}
+	manifest := m.DeepCopy()
+	manifests := manifest.Manifests
+
+	if i.remove != nil {
+		var cleanedManifests []v1.Descriptor
+		for _, m := range manifests {
+			if !i.remove(m) {
+				cleanedManifests = append(cleanedManifests, m)
+			}
+		}
+		manifests = cleanedManifests
+	}
+
+	for _, add := range i.adds {
+		desc, err := computeDescriptor(add)
+		if err != nil {
+			return err
+		}
+
+		manifests = append(manifests, *desc)
+		if idx, ok := add.Add.(v1.ImageIndex); ok {
+			i.indexMap[desc.Digest] = idx
+		} else if img, ok := add.Add.(v1.Image); ok {
+			i.imageMap[desc.Digest] = img
+		} else if l, ok := add.Add.(v1.Layer); ok {
+			i.layerMap[desc.Digest] = l
+		} else {
+			logs.Warn.Printf("Unexpected index addendum: %T", add.Add)
+		}
+	}
+
+	manifest.Manifests = manifests
+
+	if i.mediaType != nil {
+		manifest.MediaType = *i.mediaType
+	}
+
+	if i.annotations != nil {
+		if manifest.Annotations == nil {
+			manifest.Annotations = map[string]string{}
+		}
+		for k, v := range i.annotations {
+			manifest.Annotations[k] = v
+		}
+	}
+	manifest.Subject = i.subject
+
+	i.manifest = manifest
+	i.computed = true
+	return nil
+}
+
+func (i *index) Image(h v1.Hash) (v1.Image, error) {
+	if img, ok := i.imageMap[h]; ok {
+		return img, nil
+	}
+	return i.base.Image(h)
+}
+
+func (i *index) ImageIndex(h v1.Hash) (v1.ImageIndex, error) {
+	if idx, ok := i.indexMap[h]; ok {
+		return idx, nil
+	}
+	return i.base.ImageIndex(h)
+}
+
+type withLayer interface {
+	Layer(v1.Hash) (v1.Layer, error)
+}
+
+// Workaround for #819.
+func (i *index) Layer(h v1.Hash) (v1.Layer, error) {
+	if layer, ok := i.layerMap[h]; ok {
+		return layer, nil
+	}
+	if wl, ok := i.base.(withLayer); ok {
+		return wl.Layer(h)
+	}
+	return nil, fmt.Errorf("layer not found: %s", h)
+}
+
+// Digest returns the sha256 of this image's manifest.
+func (i *index) Digest() (v1.Hash, error) {
+	if err := i.compute(); err != nil {
+		return v1.Hash{}, err
+	}
+	return partial.Digest(i)
+}
+
+// Manifest returns this image's Manifest object.
+func (i *index) IndexManifest() (*v1.IndexManifest, error) {
+	if err := i.compute(); err != nil {
+		return nil, err
+	}
+	return i.manifest.DeepCopy(), nil
+}
+
+// RawManifest returns the serialized bytes of Manifest()
+func (i *index) RawManifest() ([]byte, error) {
+	if err := i.compute(); err != nil {
+		return nil, err
+	}
+	return json.Marshal(i.manifest)
+}