1 files changed, 82 insertions, 0 deletions
diff --git a/pkg/v1/types/types.go b/pkg/v1/types/types.go
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+// Copyright 2018 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 types holds common OCI media types.
+package types
+
+// MediaType is an enumeration of the supported mime types that an element of an image might have.
+type MediaType string
+
+// The collection of known MediaType values.
+const (
+	OCIContentDescriptor           MediaType = "application/vnd.oci.descriptor.v1+json"
+	OCIImageIndex                  MediaType = "application/vnd.oci.image.index.v1+json"
+	OCIManifestSchema1             MediaType = "application/vnd.oci.image.manifest.v1+json"
+	OCIConfigJSON                  MediaType = "application/vnd.oci.image.config.v1+json"
+	OCILayer                       MediaType = "application/vnd.oci.image.layer.v1.tar+gzip"
+	OCILayerZStd                   MediaType = "application/vnd.oci.image.layer.v1.tar+zstd"
+	OCIRestrictedLayer             MediaType = "application/vnd.oci.image.layer.nondistributable.v1.tar+gzip"
+	OCIUncompressedLayer           MediaType = "application/vnd.oci.image.layer.v1.tar"
+	OCIUncompressedRestrictedLayer MediaType = "application/vnd.oci.image.layer.nondistributable.v1.tar"
+
+	DockerManifestSchema1       MediaType = "application/vnd.docker.distribution.manifest.v1+json"
+	DockerManifestSchema1Signed MediaType = "application/vnd.docker.distribution.manifest.v1+prettyjws"
+	DockerManifestSchema2       MediaType = "application/vnd.docker.distribution.manifest.v2+json"
+	DockerManifestList          MediaType = "application/vnd.docker.distribution.manifest.list.v2+json"
+	DockerLayer                 MediaType = "application/vnd.docker.image.rootfs.diff.tar.gzip"
+	DockerConfigJSON            MediaType = "application/vnd.docker.container.image.v1+json"
+	DockerPluginConfig          MediaType = "application/vnd.docker.plugin.v1+json"
+	DockerForeignLayer          MediaType = "application/vnd.docker.image.rootfs.foreign.diff.tar.gzip"
+	DockerUncompressedLayer     MediaType = "application/vnd.docker.image.rootfs.diff.tar"
+
+	OCIVendorPrefix    = "vnd.oci"
+	DockerVendorPrefix = "vnd.docker"
+)
+
+// IsDistributable returns true if a layer is distributable, see:
+// https://github.com/opencontainers/image-spec/blob/master/layer.md#non-distributable-layers
+func (m MediaType) IsDistributable() bool {
+	switch m {
+	case DockerForeignLayer, OCIRestrictedLayer, OCIUncompressedRestrictedLayer:
+		return false
+	}
+	return true
+}
+
+// IsImage returns true if the mediaType represents an image manifest, as opposed to something else, like an index.
+func (m MediaType) IsImage() bool {
+	switch m {
+	case OCIManifestSchema1, DockerManifestSchema2:
+		return true
+	}
+	return false
+}
+
+// IsIndex returns true if the mediaType represents an index, as opposed to something else, like an image.
+func (m MediaType) IsIndex() bool {
+	switch m {
+	case OCIImageIndex, DockerManifestList:
+		return true
+	}
+	return false
+}
+
+// IsConfig returns true if the mediaType represents a config, as opposed to something else, like an image.
+func (m MediaType) IsConfig() bool {
+	switch m {
+	case OCIConfigJSON, DockerConfigJSON:
+		return true
+	}
+	return false
+}