tree: tweak reference checking

We're already fetching the references and using them in the map, so
might as well check those when we come to print them out.

Use the SBOM suffix from ociremote rather than redefining it.

Signed-off-by: Rob Best <robertbest89@gmail.com>

cmd/cosign/cli/tree.go

@@ -19,7 +19,6 @@ import (
 	"context"
 	"fmt"
 	"os"
-	"strings"
 
 	v1 "github.com/google/go-containerregistry/pkg/v1"
 
@@ -47,12 +46,6 @@ func Tree() *cobra.Command {
 	return cmd
 }
 
-const (
-	SignatureTagSuffix   = ".sig"
-	SBOMTagSuffix        = ".sbom"
-	AttestationTagSuffix = ".att"
-)
-
 func TreeCmd(ctx context.Context, regOpts options.RegistryOptions, imageRef string) error {
 	scsaMap := map[name.Tag][]v1.Layer{}
 	ref, err := name.ParseReference(imageRef)
@@ -110,7 +103,7 @@ func TreeCmd(ctx context.Context, regOpts options.RegistryOptions, imageRef stri
 		return err
 	}
 
-	sbombs, err := simg.Attachment("sbom")
+	sbombs, err := simg.Attachment(ociremote.SBOMTagSuffix)
 	if err == nil {
 		layers, err := sbombs.Layers()
 		if err != nil {
@@ -128,12 +121,12 @@ func TreeCmd(ctx context.Context, regOpts options.RegistryOptions, imageRef stri
 	}
 
 	for t, k := range scsaMap {
-		switch {
-		case strings.HasSuffix(t.TagStr(), SignatureTagSuffix):
+		switch t {
+		case sigRef:
 			fmt.Fprintf(os.Stdout, "└── 🔐 Signatures for an image tag: %s\n", t.String())
-		case strings.HasSuffix(t.TagStr(), SBOMTagSuffix):
+		case sbomRef:
 			fmt.Fprintf(os.Stdout, "└── 📦 SBOMs for an image tag: %s\n", t.String())
-		case strings.HasSuffix(t.TagStr(), AttestationTagSuffix):
+		case attRef:
 			fmt.Fprintf(os.Stdout, "└── 💾 Attestations for an image tag: %s\n", t.String())
 		}