resources: Move resource interfaces into its own package

resources/resource_transformers/tocss/scss/client.go

@@ -0,0 +1,111 @@
+// Copyright 2018 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 scss
+
+import (
+	"github.com/bep/go-tocss/scss"
+	"github.com/gohugoio/hugo/helpers"
+	"github.com/gohugoio/hugo/hugolib/filesystems"
+	"github.com/gohugoio/hugo/resources"
+	"github.com/gohugoio/hugo/resources/resource"
+
+	"github.com/mitchellh/mapstructure"
+)
+
+type Client struct {
+	rs     *resources.Spec
+	sfs    *filesystems.SourceFilesystem
+	workFs *filesystems.SourceFilesystem
+}
+
+func New(fs *filesystems.SourceFilesystem, rs *resources.Spec) (*Client, error) {
+	return &Client{sfs: fs, workFs: rs.BaseFs.Work, rs: rs}, nil
+}
+
+type Options struct {
+
+	// Hugo, will by default, just replace the extension of the source
+	// to .css, e.g. "scss/main.scss" becomes "scss/main.css". You can
+	// control this by setting this, e.g. "styles/main.css" will create
+	// a Resource with that as a base for RelPermalink etc.
+	TargetPath string
+
+	// Hugo automatically adds the entry directories (where the main.scss lives)
+	// for project and themes to the list of include paths sent to LibSASS.
+	// Any paths set in this setting will be appended. Note that these will be
+	// treated as relative to the working dir, i.e. no include paths outside the
+	// project/themes.
+	IncludePaths []string
+
+	// Default is nested.
+	// One of nested, expanded, compact, compressed.
+	OutputStyle string
+
+	// Precision of floating point math.
+	Precision int
+
+	// When enabled, Hugo will generate a source map.
+	EnableSourceMap bool
+}
+
+type options struct {
+	// The options we receive from the end user.
+	from Options
+
+	// The options we send to the SCSS library.
+	to scss.Options
+}
+
+func (c *Client) ToCSS(res resource.Resource, opts Options) (resource.Resource, error) {
+	internalOptions := options{
+		from: opts,
+	}
+
+	// Transfer values from client.
+	internalOptions.to.Precision = opts.Precision
+	internalOptions.to.OutputStyle = scss.OutputStyleFromString(opts.OutputStyle)
+
+	if internalOptions.to.Precision == 0 {
+		// bootstrap-sass requires 8 digits precision. The libsass default is 5.
+		// https://github.com/twbs/bootstrap-sass/blob/master/README.md#sass-number-precision
+		internalOptions.to.Precision = 8
+	}
+
+	return c.rs.Transform(
+		res,
+		&toCSSTransformation{c: c, options: internalOptions},
+	)
+}
+
+type toCSSTransformation struct {
+	c       *Client
+	options options
+}
+
+func (t *toCSSTransformation) Key() resources.ResourceTransformationKey {
+	return resources.NewResourceTransformationKey("tocss", t.options.from)
+}
+
+func DecodeOptions(m map[string]interface{}) (opts Options, err error) {
+	if m == nil {
+		return
+	}
+	err = mapstructure.WeakDecode(m, &opts)
+
+	if opts.TargetPath != "" {
+		opts.TargetPath = helpers.ToSlashTrimLeading(opts.TargetPath)
+	}
+
+	return
+}