initial commit [ci skip]

engine/compiler/image/image.go

@@ -0,0 +1,71 @@
+// Copyright 2019 Drone.IO Inc. All rights reserved.
+// Use of this source code is governed by the Polyform License
+// that can be found in the LICENSE file.
+
+package image
+
+import "github.com/docker/distribution/reference"
+
+// Trim returns the short image name without tag.
+func Trim(name string) string {
+	ref, err := reference.ParseAnyReference(name)
+	if err != nil {
+		return name
+	}
+	named, err := reference.ParseNamed(ref.String())
+	if err != nil {
+		return name
+	}
+	named = reference.TrimNamed(named)
+	return reference.FamiliarName(named)
+}
+
+// Expand returns the fully qualified image name.
+func Expand(name string) string {
+	ref, err := reference.ParseAnyReference(name)
+	if err != nil {
+		return name
+	}
+	named, err := reference.ParseNamed(ref.String())
+	if err != nil {
+		return name
+	}
+	named = reference.TagNameOnly(named)
+	return named.String()
+}
+
+// Match returns true if the image name matches
+// an image in the list. Note the image tag is not used
+// in the matching logic.
+func Match(from string, to ...string) bool {
+	from = Trim(from)
+	for _, match := range to {
+		if from == Trim(match) {
+			return true
+		}
+	}
+	return false
+}
+
+// MatchTag returns true if the image name matches
+// an image in the list, including the tag.
+func MatchTag(a, b string) bool {
+	return Expand(a) == Expand(b)
+}
+
+// MatchHostname returns true if the image hostname
+// matches the specified hostname.
+func MatchHostname(image, hostname string) bool {
+	ref, err := reference.ParseAnyReference(image)
+	if err != nil {
+		return false
+	}
+	named, err := reference.ParseNamed(ref.String())
+	if err != nil {
+		return false
+	}
+	if hostname == "index.docker.io" {
+		hostname = "docker.io"
+	}
+	return reference.Domain(named) == hostname
+}