refactor: Create tag handlers (oras-project#1437)

Signed-off-by: Terry Howe <[email protected]>
Co-authored-by: Billy Zha <[email protected]>

cmd/oras/internal/display/metadata/interface.go

@@ -22,7 +22,7 @@ import (
 
 // PushHandler handles metadata output for push events.
 type PushHandler interface {
-	TagHandler
+	TaggedHandler
 
 	OnCopied(opts *option.Target) error
 	OnCompleted(root ocispec.Descriptor) error
@@ -60,8 +60,15 @@ type PullHandler interface {
 	OnCompleted(opts *option.Target, desc ocispec.Descriptor) error
 }
 
-// TagHandler handles status output for tag command.
-type TagHandler interface {
+// TaggedHandler handles status output for tag command.
+type TaggedHandler interface {
 	// OnTagged is called when each tagging operation is done.
 	OnTagged(desc ocispec.Descriptor, tag string) error
 }
+
+// TagHandler handles status output for tag command.
+type TagHandler interface {
+	// OnTagging is called when tagging starts.
+	OnTagging(desc ocispec.Descriptor, tag string) error
+	TaggedHandler
+}

cmd/oras/internal/display/metadata/json/push.go

@@ -40,7 +40,7 @@ func NewPushHandler(out io.Writer) metadata.PushHandler {
 	}
 }
 
-// OnTagged implements metadata.TagHandler.
+// OnTagged implements metadata.TaggedHandler.
 func (ph *PushHandler) OnTagged(desc ocispec.Descriptor, tag string) error {
 	ph.tagged.AddTag(tag)
 	return nil

cmd/oras/internal/display/metadata/template/push.go

@@ -42,7 +42,7 @@ func NewPushHandler(out io.Writer, template string) metadata.PushHandler {
 	}
 }
 
-// OnTagged implements metadata.TagHandler.
+// OnTagged implements metadata.TaggedHandler.
 func (ph *PushHandler) OnTagged(desc ocispec.Descriptor, tag string) error {
 	ph.tagged.AddTag(tag)
 	return nil

cmd/oras/internal/display/metadata/text/tag.go

@@ -0,0 +1,52 @@
+/*
+Copyright The ORAS Authors.
+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 text
+
+import (
+	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
+	"oras.land/oras/cmd/oras/internal/display/metadata"
+	"oras.land/oras/cmd/oras/internal/output"
+	"sync"
+)
+
+// TagHandler handles text metadata output for tag events.
+type TagHandler struct {
+	printer   *output.Printer
+	printOnce sync.Once
+	refPrefix string
+}
+
+// NewTagHandler returns a new handler for tag events.
+func NewTagHandler(printer *output.Printer, refPrefix string) metadata.TagHandler {
+	return &TagHandler{
+		printer:   printer,
+		refPrefix: refPrefix,
+	}
+}
+
+// OnTagging is called when the tagging is complete.
+func (ah *TagHandler) OnTagging(desc ocispec.Descriptor, _ string) (err error) {
+	ah.printOnce.Do(func() {
+		ref := ah.refPrefix + "@" + desc.Digest.String()
+		err = ah.printer.Println("Tagging", ref)
+	})
+	return err
+}
+
+// OnTagged is called when the tagging is complete.
+func (ah *TagHandler) OnTagged(_ ocispec.Descriptor, tag string) error {
+	return ah.printer.Println("Tagged", tag)
+}

cmd/oras/internal/display/status/deprecated.go

@@ -16,35 +16,15 @@ limitations under the License.
 package status
 
 import (
-	"oras.land/oras/cmd/oras/internal/output"
-	"sync"
-
 	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
 	"oras.land/oras-go/v2"
+	"oras.land/oras/cmd/oras/internal/output"
 	"oras.land/oras/internal/listener"
 )
 
 // Types and functions in this file are deprecated and should be removed when
 // no-longer referenced.
 
-// NewTagStatusHintPrinter creates a wrapper type for printing
-// tag status and hint.
-func NewTagStatusHintPrinter(printer *output.Printer, target oras.Target, refPrefix string) oras.Target {
-	var printHint sync.Once
-	var printHintErr error
-	onTagging := func(desc ocispec.Descriptor, tag string) error {
-		printHint.Do(func() {
-			ref := refPrefix + "@" + desc.Digest.String()
-			printHintErr = printer.Println("Tagging", ref)
-		})
-		return printHintErr
-	}
-	onTagged := func(desc ocispec.Descriptor, tag string) error {
-		return printer.Println("Tagged", tag)
-	}
-	return listener.NewTagListener(target, onTagging, onTagged)
-}
-
 // NewTagStatusPrinter creates a wrapper type for printing tag status.
 func NewTagStatusPrinter(printer *output.Printer, target oras.Target) oras.Target {
 	return listener.NewTagListener(target, nil, func(desc ocispec.Descriptor, tag string) error {

cmd/oras/root/tag.go

@@ -18,14 +18,15 @@ package root
 import (
 	"errors"
 	"fmt"
+	"oras.land/oras/cmd/oras/internal/display/metadata/text"
+	"oras.land/oras/internal/listener"
 
 	"github.com/spf13/cobra"
 	"oras.land/oras-go/v2"
 	"oras.land/oras-go/v2/errdef"
 	"oras.land/oras-go/v2/registry/remote"
 	"oras.land/oras/cmd/oras/internal/argument"
 	"oras.land/oras/cmd/oras/internal/command"
-	"oras.land/oras/cmd/oras/internal/display/status"
 	oerrors "oras.land/oras/cmd/oras/internal/errors"
 	"oras.land/oras/cmd/oras/internal/option"
 )
@@ -114,9 +115,11 @@ func tagManifest(cmd *cobra.Command, opts *tagOptions) error {
 
 	tagNOpts := oras.DefaultTagNOptions
 	tagNOpts.Concurrency = opts.concurrency
+	tagHandler := text.NewTagHandler(opts.Printer, fmt.Sprintf("[%s] %s", opts.Type, opts.Path))
+	tagListener := listener.NewTagListener(target, tagHandler.OnTagging, tagHandler.OnTagged)
 	_, err = oras.TagN(
 		ctx,
-		status.NewTagStatusHintPrinter(opts.Printer, target, fmt.Sprintf("[%s] %s", opts.Type, opts.Path)),
+		tagListener,
 		opts.Reference,
 		opts.targetRefs,
 		tagNOpts,