Add resources.Copy

Implemented by most Resource objects, but not Page (for now).

Fixes #9313

helpers/general.go

@@ -33,8 +33,6 @@ import (
 
 	"github.com/mitchellh/hashstructure"
 
-	"github.com/gohugoio/hugo/hugofs"
-
 	"github.com/gohugoio/hugo/common/hugo"
 
 	"github.com/spf13/afero"
@@ -521,13 +519,7 @@ func PrintFs(fs afero.Fs, path string, w io.Writer) {
 	}
 
 	afero.Walk(fs, path, func(path string, info os.FileInfo, err error) error {
-		var filename string
-		var meta any
-		if fim, ok := info.(hugofs.FileMetaInfo); ok {
-			filename = fim.Meta().Filename
-			meta = fim.Meta()
-		}
-		fmt.Fprintf(w, "    %q %q\t\t%v\n", path, filename, meta)
+		fmt.Println(path)
 		return nil
 	})
 }

resources/image.go

@@ -144,6 +144,15 @@ func (i *imageResource) Clone() resource.Resource {
 	}
 }
 
+func (i *imageResource) cloneTo(targetPath string) resource.Resource {
+	gr := i.baseResource.cloneTo(targetPath).(baseResource)
+	return &imageResource{
+		root:         i.root,
+		Image:        i.WithSpec(gr),
+		baseResource: gr,
+	}
+}
+
 func (i *imageResource) cloneWithUpdates(u *transformationUpdate) (baseResource, error) {
 	base, err := i.baseResource.cloneWithUpdates(u)
 	if err != nil {

resources/resource.go

@@ -1,4 +1,4 @@
-// Copyright 2019 The Hugo Authors. All rights reserved.
+// Copyright 2022 The Hugo Authors. 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.
@@ -120,8 +120,19 @@ func (t transformerNotAvailable) Key() internal.ResourceTransformationKey {
 	return t.key
 }
 
+// resourceCopier is for internal use.
+type resourceCopier interface {
+	cloneTo(targetPath string) resource.Resource
+}
+
+// Copy copies r to the targetPath given.
+func Copy(r resource.Resource, targetPath string) resource.Resource {
+	return r.(resourceCopier).cloneTo(targetPath)
+}
+
 type baseResourceResource interface {
 	resource.Cloner
+	resourceCopier
 	resource.ContentProvider
 	resource.Resource
 	resource.Identifier
@@ -225,6 +236,20 @@ func (l *genericResource) Clone() resource.Resource {
 	return l.clone()
 }
 
+func (l *genericResource) cloneTo(targetPath string) resource.Resource {
+	c := l.clone()
+
+	targetPath = helpers.ToSlashTrimLeading(targetPath)
+	dir, file := path.Split(targetPath)
+
+	c.resourcePathDescriptor = &resourcePathDescriptor{
+		relTargetDirFile: dirFile{dir: dir, file: file},
+	}
+
+	return c
+
+}
+
 func (l *genericResource) Content() (any, error) {
 	if err := l.initContent(); err != nil {
 		return nil, err

resources/resource/resourcetypes.go

@@ -26,8 +26,7 @@ var (
 	_ ResourceError        = (*resourceError)(nil)
 )
 
-// Cloner is an internal template and not meant for use in the templates. It
-// may change without notice.
+// Cloner is for internal use.
 type Cloner interface {
 	Clone() Resource
 }

resources/resource_factories/create/create.go

@@ -51,6 +51,13 @@ func New(rs *resources.Spec) *Client {
 	}
 }
 
+// Copy copies r to the new targetPath.
+func (c *Client) Copy(r resource.Resource, targetPath string) (resource.Resource, error) {
+	return c.rs.ResourceCache.GetOrCreate(resources.ResourceCacheKey(targetPath), func() (resource.Resource, error) {
+		return resources.Copy(r, targetPath), nil
+	})
+}
+
 // Get creates a new Resource by opening the given filename in the assets filesystem.
 func (c *Client) Get(filename string) (resource.Resource, error) {
 	filename = filepath.Clean(filename)

resources/transform.go

@@ -42,6 +42,7 @@ import (
 
 var (
 	_ resource.ContentResource        = (*resourceAdapter)(nil)
+	_ resourceCopier                  = (*resourceAdapter)(nil)
 	_ resource.ReadSeekCloserResource = (*resourceAdapter)(nil)
 	_ resource.Resource               = (*resourceAdapter)(nil)
 	_ resource.Source                 = (*resourceAdapter)(nil)
@@ -175,6 +176,19 @@ func (r *resourceAdapter) Data() any {
 	return r.target.Data()
 }
 
+func (r resourceAdapter) cloneTo(targetPath string) resource.Resource {
+	newtTarget := r.target.cloneTo(targetPath)
+	newInner := &resourceAdapterInner{
+		spec:   r.spec,
+		target: newtTarget.(transformableResource),
+	}
+	if r.resourceAdapterInner.publishOnce != nil {
+		newInner.publishOnce = &publishOnce{}
+	}
+	r.resourceAdapterInner = newInner
+	return &r
+}
+
 func (r *resourceAdapter) Crop(spec string) (images.ImageResource, error) {
 	return r.getImageOps().Crop(spec)
 }
@@ -596,6 +610,7 @@ type transformableResource interface {
 	resource.ContentProvider
 	resource.Resource
 	resource.Identifier
+	resourceCopier
 }
 
 type transformationUpdate struct {

tpl/resources/integration_test.go

@@ -0,0 +1,100 @@
+// Copyright 2022s The Hugo Authors. 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 resources_test
+
+import (
+	"testing"
+
+	qt "github.com/frankban/quicktest"
+	"github.com/gohugoio/hugo/hugolib"
+)
+
+func TestCopy(t *testing.T) {
+	t.Parallel()
+
+	files := `
+-- config.toml --
+baseURL = "http://example.com/blog"
+-- assets/images/pixel.png --
+iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mNkYPhfDwAChwGA60e6kgAAAABJRU5ErkJggg==
+-- layouts/index.html --
+{{/* Image resources */}}
+{{ $img := resources.Get "images/pixel.png" }}
+{{ $imgCopy1 := $img | resources.Copy "images/copy.png"  }}
+{{ $imgCopy1 = $imgCopy1.Resize "3x4"}}
+{{ $imgCopy2 := $imgCopy1 | resources.Copy "images/copy2.png" }}
+{{ $imgCopy3 := $imgCopy1 | resources.Copy "images/copy3.png" }}
+Image Orig:  {{ $img.RelPermalink}}|{{ $img.MediaType }}|{{ $img.Width }}|{{ $img.Height }}|
+Image Copy1:  {{ $imgCopy1.RelPermalink}}|{{ $imgCopy1.MediaType }}|{{ $imgCopy1.Width }}|{{ $imgCopy1.Height }}|
+Image Copy2:  {{ $imgCopy2.RelPermalink}}|{{ $imgCopy2.MediaType }}|{{ $imgCopy2.Width }}|{{ $imgCopy2.Height }}|
+Image Copy3:  {{ $imgCopy3.MediaType }}|{{ $imgCopy3.Width }}|{{ $imgCopy3.Height }}|
+
+{{/* Generic resources */}}
+{{ $targetPath := "js/vars.js" }}
+{{ $orig := "let foo;" | resources.FromString "js/foo.js" }}
+{{ $copy1 := $orig | resources.Copy "js/copies/bar.js" }}
+{{ $copy2 := $orig | resources.Copy "js/copies/baz.js" | fingerprint "md5" }}
+{{ $copy3 := $copy2 | resources.Copy "js/copies/moo.js" | minify }}
+
+Orig: {{ $orig.RelPermalink}}|{{ $orig.MediaType }}|{{ $orig.Content | safeJS }}|
+Copy1: {{ $copy1.RelPermalink}}|{{ $copy1.MediaType }}|{{ $copy1.Content | safeJS }}|
+Copy2: {{ $copy2.RelPermalink}}|{{ $copy2.MediaType }}|{{ $copy2.Content | safeJS }}|
+Copy3: {{ $copy3.RelPermalink}}|{{ $copy3.MediaType }}|{{ $copy3.Content | safeJS }}|
+
+	`
+
+	b := hugolib.NewIntegrationTestBuilder(
+		hugolib.IntegrationTestConfig{
+			T:           t,
+			TxtarString: files,
+		}).Build()
+
+	b.AssertFileContent("public/index.html", `
+Image Orig:  /blog/images/pixel.png|image/png|1|1|
+Image Copy1:  /blog/images/copy_hu8aa3346827e49d756ff4e630147c42b5_70_3x4_resize_box_3.png|image/png|3|4|
+Image Copy2:  /blog/images/copy2.png|image/png|3|4
+Image Copy3:  image/png|3|4|
+Orig: /blog/js/foo.js|application/javascript|let foo;|
+Copy1: /blog/js/copies/bar.js|application/javascript|let foo;|
+Copy2: /blog/js/copies/baz.a677329fc6c4ad947e0c7116d91f37a2.js|application/javascript|let foo;|
+Copy3: /blog/js/copies/moo.a677329fc6c4ad947e0c7116d91f37a2.min.js|application/javascript|let foo|
+
+		`)
+
+	b.AssertDestinationExists("images/copy2.png", true)
+	// No permalink used.
+	b.AssertDestinationExists("images/copy3.png", false)
+
+}
+
+func TestCopyPageShouldFail(t *testing.T) {
+	t.Parallel()
+
+	files := `
+-- config.toml --
+-- layouts/index.html --
+{{/* This is currently not supported. */}}
+{{ $copy := .Copy "copy.md" }}
+
+	`
+
+	b, err := hugolib.NewIntegrationTestBuilder(
+		hugolib.IntegrationTestConfig{
+			T:           t,
+			TxtarString: files,
+		}).BuildE()
+
+	b.Assert(err, qt.IsNotNil)
+
+}

tpl/resources/resources.go

@@ -111,6 +111,15 @@ func (ns *Namespace) getscssClientDartSass() (*dartsass.Client, error) {
 	return ns.scssClientDartSass, err
 }
 
+// Copy copies r to the new targetPath in s.
+func (ns *Namespace) Copy(s any, r resource.Resource) (resource.Resource, error) {
+	targetPath, err := cast.ToStringE(s)
+	if err != nil {
+		panic(err)
+	}
+	return ns.createClient.Copy(r, targetPath)
+}
+
 // Get locates the filename given in Hugo's assets filesystem
 // and creates a Resource object that can be used for further transformations.
 func (ns *Namespace) Get(filename any) resource.Resource {