oci: Split refhandler to support history

Author: jonjohnsonjr

internal/explore/explore.go

@@ -1530,22 +1530,26 @@ func headerData(ref name.Reference, desc v1.Descriptor) *HeaderData {
 		sep = "&"
 	}
 
-	if _, ok := ref.(name.Tag); ok {
-		if ref.Context().RegistryStr() == "cgr.dev" {
-			handler = "?history="
-		}
-	}
-	return &HeaderData{
+	hdr := &HeaderData{
 		Repo:             ref.Context().String(),
 		Reference:        ref.String(),
 		CosignTags:       []CosignTag{},
 		Descriptor:       &desc,
+		RefHandler:       handler,
 		Handler:          handler,
 		QuerySep:         sep,
 		EscapedMediaType: url.QueryEscape(string(desc.MediaType)),
 		MediaTypeLink:    getLink(string(desc.MediaType)),
 		HumanSize:        humanizeSize(desc.Size),
 	}
+
+	if _, ok := ref.(name.Tag); ok {
+		if ref.Context().RegistryStr() == "cgr.dev" {
+			hdr.RefHandler = "?history="
+		}
+	}
+
+	return hdr
 }
 
 func humanizeSize(size int64) string {

internal/explore/templates.go

@@ -293,7 +293,7 @@ input ~ .tab {          /* grey line between tab and contents */
 <div>
 <h1><a class="top" href="/"><img class="crane" src="/favicon.svg"/> <span class="link">Registry Explorer</span></a></h1>
 {{ if .Up }}
-<h2>{{ if and (ne .Up.Parent "docker.io") (ne .Up.Parent "index.docker.io") }}<a class="mt" href="/?repo={{.Up.Parent}}">{{.Up.Parent}}</a>{{else}}{{.Up.Parent}}{{end}}{{.Up.Separator}}{{if .Handler }}<a class="mt" href="/{{.Handler}}{{.Reference}}{{if .EscapedMediaType}}{{.QuerySep}}mt={{.EscapedMediaType}}{{end}}">{{.Up.Child}}</a>{{else}}{{.Up.Child}}{{end}}{{ range .CosignTags }} (<a href="/?image={{$.Repo}}:{{.Tag}}">{{.Short}}</a>){{end}}{{if .Referrers}} <a href="/?referrers={{$.Repo}}@{{$.Descriptor.Digest}}">(referrers)</a>{{end}}</h2>
+<h2>{{ if and (ne .Up.Parent "docker.io") (ne .Up.Parent "index.docker.io") }}<a class="mt" href="/?repo={{.Up.Parent}}">{{.Up.Parent}}</a>{{else}}{{.Up.Parent}}{{end}}{{.Up.Separator}}{{if .RefHandler }}<a class="mt" href="/{{.RefHandler}}{{.Reference}}{{if .EscapedMediaType}}{{.QuerySep}}mt={{.EscapedMediaType}}{{end}}">{{.Up.Child}}</a>{{else}}{{.Up.Child}}{{end}}{{ range .CosignTags }} (<a href="/?image={{$.Repo}}:{{.Tag}}">{{.Short}}</a>){{end}}{{if .Referrers}} <a href="/?referrers={{$.Repo}}@{{$.Descriptor.Digest}}">(referrers)</a>{{end}}</h2>
 {{ else }}
 	<h2>{{.Reference}}{{ range .CosignTags }} (<a href="/?image={{$.Repo}}:{{.Tag}}">{{.Short}}</a>){{end}}{{if .Referrers}} <a href="/?referrers={{$.Repo}}@{{$.Descriptor.Digest}}">(referrers)</a>{{end}}</h2>
 {{ end }}
@@ -356,6 +356,7 @@ type HeaderData struct {
 	Reference        string
 	Up               *RepoParent
 	Descriptor       *v1.Descriptor
+	RefHandler       string
 	Handler          string
 	EscapedMediaType string
 	QuerySep         string