hugo/markup/goldmark/toc.go
Bjørn Erik Pedersen 90da7664bf Add page fragments support to Related
The main topic of this commit is that you can now index fragments (content heading identifiers) when calling `.Related`.

You can do this by:

* Configure one or more indices with type `fragments`
* The name of those index configurations maps to an (optional) front matter slice with fragment references. This allows you to link
page<->fragment and page<->page.
* This also will index all the fragments (heading identifiers) of the pages.

It's also possible to use type `fragments` indices in shortcode, e.g.:

```
{{ $related := site.RegularPages.Related .Page }}
```

But, and this is important, you need to include the shortcode using the `{{<` delimiter. Not doing so will create infinite loops and timeouts.

This commit also:

* Adds two new methods to Page: Fragments (can also be used to build ToC) and HeadingsFiltered (this is only used in Related Content with
index type `fragments` and `enableFilter` set to true.
* Consolidates all `.Related*` methods into one, which takes either a `Page` or an options map as its only argument.
* Add `context.Context` to all of the content related Page API. Turns out it wasn't strictly needed for this particular feature, but it will
soon become usefil, e.g. in #9339.

Closes #10711
Updates #9339
Updates #10725
2023-02-21 17:56:41 +01:00

128 lines
2.9 KiB
Go

// Copyright 2019 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 goldmark
import (
"bytes"
"github.com/gohugoio/hugo/markup/tableofcontents"
"github.com/yuin/goldmark"
"github.com/yuin/goldmark/ast"
"github.com/yuin/goldmark/parser"
"github.com/yuin/goldmark/renderer"
"github.com/yuin/goldmark/text"
"github.com/yuin/goldmark/util"
)
var (
tocResultKey = parser.NewContextKey()
tocEnableKey = parser.NewContextKey()
)
type tocTransformer struct {
r renderer.Renderer
}
func (t *tocTransformer) Transform(n *ast.Document, reader text.Reader, pc parser.Context) {
if b, ok := pc.Get(tocEnableKey).(bool); !ok || !b {
return
}
var (
toc tableofcontents.Builder
tocHeading = &tableofcontents.Heading{}
level int
row = -1
inHeading bool
headingText bytes.Buffer
)
ast.Walk(n, func(n ast.Node, entering bool) (ast.WalkStatus, error) {
s := ast.WalkStatus(ast.WalkContinue)
if n.Kind() == ast.KindHeading {
if inHeading && !entering {
tocHeading.Title = headingText.String()
headingText.Reset()
toc.AddAt(tocHeading, row, level-1)
tocHeading = &tableofcontents.Heading{}
inHeading = false
return s, nil
}
inHeading = true
}
if !(inHeading && entering) {
return s, nil
}
switch n.Kind() {
case ast.KindHeading:
heading := n.(*ast.Heading)
level = heading.Level
if level == 1 || row == -1 {
row++
}
id, found := heading.AttributeString("id")
if found {
tocHeading.ID = string(id.([]byte))
}
case
ast.KindCodeSpan,
ast.KindLink,
ast.KindImage,
ast.KindEmphasis:
err := t.r.Render(&headingText, reader.Source(), n)
if err != nil {
return s, err
}
return ast.WalkSkipChildren, nil
case
ast.KindAutoLink,
ast.KindRawHTML,
ast.KindText,
ast.KindString:
err := t.r.Render(&headingText, reader.Source(), n)
if err != nil {
return s, err
}
}
return s, nil
})
pc.Set(tocResultKey, toc.Build())
}
type tocExtension struct {
options []renderer.Option
}
func newTocExtension(options []renderer.Option) goldmark.Extender {
return &tocExtension{
options: options,
}
}
func (e *tocExtension) Extend(m goldmark.Markdown) {
r := goldmark.DefaultRenderer()
r.AddOptions(e.options...)
m.Parser().AddOptions(parser.WithASTTransformers(util.Prioritized(&tocTransformer{
r: r,
}, 10)))
}