Clean up the css related template funcs package structure

Deprecate and move:

* resources.ToCSS => css.SASS
* resources.PostProcess => css.PostProcess
* resources.Babel => js.Babel

Updates #12618

1 files changed, 143 insertions, 2 deletions

diff --git a/tpl/css/css.go b/tpl/css/css.go
index 51fa1d518..145cb3aad 100644
--- a/tpl/css/css.go
+++ b/tpl/css/css.go
@@ -2,17 +2,40 @@ package css
 
 import (
 	"context"
+	"errors"
+	"fmt"
+	"sync"
 
+	"github.com/gohugoio/hugo/common/maps"
+	"github.com/gohugoio/hugo/common/paths"
 	"github.com/gohugoio/hugo/common/types/css"
 	"github.com/gohugoio/hugo/deps"
+	"github.com/gohugoio/hugo/resources"
+	"github.com/gohugoio/hugo/resources/resource"
+	"github.com/gohugoio/hugo/resources/resource_transformers/babel"
+	"github.com/gohugoio/hugo/resources/resource_transformers/postcss"
+	"github.com/gohugoio/hugo/resources/resource_transformers/tocss/dartsass"
+	"github.com/gohugoio/hugo/resources/resource_transformers/tocss/scss"
 	"github.com/gohugoio/hugo/tpl/internal"
+	"github.com/gohugoio/hugo/tpl/internal/resourcehelpers"
 	"github.com/spf13/cast"
 )
 
 const name = "css"
 
 // Namespace provides template functions for the "css" namespace.
-type Namespace struct{}
+type Namespace struct {
+	d                 *deps.Deps
+	scssClientLibSass *scss.Client
+	postcssClient     *postcss.Client
+	babelClient       *babel.Client
+
+	// The Dart Client requires a os/exec process, so  only
+	// create it if we really need it.
+	// This is mostly to avoid creating one per site build test.
+	scssClientDartSassInit sync.Once
+	scssClientDartSass     *dartsass.Client
+}
 
 // Quoted returns a string that needs to be quoted in CSS.
 func (ns *Namespace) Quoted(v any) css.QuotedString {
@@ -26,17 +49,135 @@ func (ns *Namespace) Unquoted(v any) css.UnquotedString {
 	return css.UnquotedString(s)
 }
 
+// PostCSS processes the given Resource with PostCSS.
+func (ns *Namespace) PostCSS(args ...any) (resource.Resource, error) {
+	if len(args) > 2 {
+		return nil, errors.New("must not provide more arguments than resource object and options")
+	}
+
+	r, m, err := resourcehelpers.ResolveArgs(args)
+	if err != nil {
+		return nil, err
+	}
+
+	return ns.postcssClient.Process(r, m)
+}
+
+// Sass processes the given Resource with Sass.
+func (ns *Namespace) Sass(args ...any) (resource.Resource, error) {
+	if len(args) > 2 {
+		return nil, errors.New("must not provide more arguments than resource object and options")
+	}
+
+	const (
+		// Transpiler implementation can be controlled from the client by
+		// setting the 'transpiler' option.
+		// Default is currently 'libsass', but that may change.
+		transpilerDart    = "dartsass"
+		transpilerLibSass = "libsass"
+	)
+
+	var (
+		r          resources.ResourceTransformer
+		m          map[string]any
+		targetPath string
+		err        error
+		ok         bool
+		transpiler = transpilerLibSass
+	)
+
+	r, targetPath, ok = resourcehelpers.ResolveIfFirstArgIsString(args)
+
+	if !ok {
+		r, m, err = resourcehelpers.ResolveArgs(args)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	if m != nil {
+		if t, _, found := maps.LookupEqualFold(m, "transpiler"); found {
+			switch t {
+			case transpilerDart, transpilerLibSass:
+				transpiler = cast.ToString(t)
+			default:
+				return nil, fmt.Errorf("unsupported transpiler %q; valid values are %q or %q", t, transpilerLibSass, transpilerDart)
+			}
+		}
+	}
+
+	if transpiler == transpilerLibSass {
+		var options scss.Options
+		if targetPath != "" {
+			options.TargetPath = paths.ToSlashTrimLeading(targetPath)
+		} else if m != nil {
+			options, err = scss.DecodeOptions(m)
+			if err != nil {
+				return nil, err
+			}
+		}
+
+		return ns.scssClientLibSass.ToCSS(r, options)
+	}
+
+	if m == nil {
+		m = make(map[string]any)
+	}
+	if targetPath != "" {
+		m["targetPath"] = targetPath
+	}
+
+	client, err := ns.getscssClientDartSass()
+	if err != nil {
+		return nil, err
+	}
+
+	return client.ToCSS(r, m)
+}
+
 func init() {
 	f := func(d *deps.Deps) *internal.TemplateFuncsNamespace {
-		ctx := &Namespace{}
+		scssClient, err := scss.New(d.BaseFs.Assets, d.ResourceSpec)
+		if err != nil {
+			panic(err)
+		}
+		ctx := &Namespace{
+			d:                 d,
+			scssClientLibSass: scssClient,
+			postcssClient:     postcss.New(d.ResourceSpec),
+			babelClient:       babel.New(d.ResourceSpec),
+		}
 
 		ns := &internal.TemplateFuncsNamespace{
 			Name:    name,
 			Context: func(cctx context.Context, args ...any) (any, error) { return ctx, nil },
 		}
 
+		ns.AddMethodMapping(ctx.Sass,
+			[]string{"toCSS"},
+			[][2]string{},
+		)
+
+		ns.AddMethodMapping(ctx.PostCSS,
+			[]string{"postCSS"},
+			[][2]string{},
+		)
+
 		return ns
 	}
 
 	internal.AddTemplateFuncsNamespace(f)
 }
+
+func (ns *Namespace) getscssClientDartSass() (*dartsass.Client, error) {
+	var err error
+	ns.scssClientDartSassInit.Do(func() {
+		ns.scssClientDartSass, err = dartsass.New(ns.d.BaseFs.Assets, ns.d.ResourceSpec)
+		if err != nil {
+			return
+		}
+		ns.d.BuildClosers.Add(ns.scssClientDartSass)
+	})
+
+	return ns.scssClientDartSass, err
+}