1 files changed, 92 insertions, 0 deletions
diff --git a/pkg/v1/match/match.go b/pkg/v1/match/match.go
new file mode 100644
index 0000000..98b1ff9
--- /dev/null
+++ b/pkg/v1/match/match.go
@@ -0,0 +1,92 @@
+// Copyright 2020 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 match provides functionality for conveniently matching a v1.Descriptor.
+package match
+
+import (
+	v1 "github.com/google/go-containerregistry/pkg/v1"
+	imagespec "github.com/opencontainers/image-spec/specs-go/v1"
+)
+
+// Matcher function that is given a v1.Descriptor, and returns whether or
+// not it matches a given rule. Can match on anything it wants in the Descriptor.
+type Matcher func(desc v1.Descriptor) bool
+
+// Name returns a match.Matcher that matches based on the value of the
+//
+//	"org.opencontainers.image.ref.name" annotation:
+//
+// github.com/opencontainers/image-spec/blob/v1.0.1/annotations.md#pre-defined-annotation-keys
+func Name(name string) Matcher {
+	return Annotation(imagespec.AnnotationRefName, name)
+}
+
+// Annotation returns a match.Matcher that matches based on the provided annotation.
+func Annotation(key, value string) Matcher {
+	return func(desc v1.Descriptor) bool {
+		if desc.Annotations == nil {
+			return false
+		}
+		if aValue, ok := desc.Annotations[key]; ok && aValue == value {
+			return true
+		}
+		return false
+	}
+}
+
+// Platforms returns a match.Matcher that matches on any one of the provided platforms.
+// Ignores any descriptors that do not have a platform.
+func Platforms(platforms ...v1.Platform) Matcher {
+	return func(desc v1.Descriptor) bool {
+		if desc.Platform == nil {
+			return false
+		}
+		for _, platform := range platforms {
+			if desc.Platform.Equals(platform) {
+				return true
+			}
+		}
+		return false
+	}
+}
+
+// MediaTypes returns a match.Matcher that matches at least one of the provided media types.
+func MediaTypes(mediaTypes ...string) Matcher {
+	mts := map[string]bool{}
+	for _, media := range mediaTypes {
+		mts[media] = true
+	}
+	return func(desc v1.Descriptor) bool {
+		if desc.MediaType == "" {
+			return false
+		}
+		if _, ok := mts[string(desc.MediaType)]; ok {
+			return true
+		}
+		return false
+	}
+}
+
+// Digests returns a match.Matcher that matches at least one of the provided Digests
+func Digests(digests ...v1.Hash) Matcher {
+	digs := map[v1.Hash]bool{}
+	for _, digest := range digests {
+		digs[digest] = true
+	}
+	return func(desc v1.Descriptor) bool {
+		_, ok := digs[desc.Digest]
+		return ok
+	}
+}