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hugo/markup/goldmark/images/transform.go

76 lines
2.0 KiB
Go

package images
import (
"github.com/yuin/goldmark"
"github.com/yuin/goldmark/ast"
"github.com/yuin/goldmark/parser"
"github.com/yuin/goldmark/text"
"github.com/yuin/goldmark/util"
)
type (
imagesExtension struct {
wrapStandAloneImageWithinParagraph bool
}
)
const (
// Used to signal to the rendering step that an image is used in a block context.
// Dont's change this; the prefix must match the internalAttrPrefix in the root goldmark package.
AttrIsBlock = "_h__isBlock"
AttrOrdinal = "_h__ordinal"
)
func New(wrapStandAloneImageWithinParagraph bool) goldmark.Extender {
return &imagesExtension{wrapStandAloneImageWithinParagraph: wrapStandAloneImageWithinParagraph}
}
func (e *imagesExtension) Extend(m goldmark.Markdown) {
m.Parser().AddOptions(
parser.WithASTTransformers(
util.Prioritized(&Transformer{wrapStandAloneImageWithinParagraph: e.wrapStandAloneImageWithinParagraph}, 300),
),
)
}
type Transformer struct {
wrapStandAloneImageWithinParagraph bool
}
// Transform transforms the provided Markdown AST.
func (t *Transformer) Transform(doc *ast.Document, reader text.Reader, pctx parser.Context) {
var ordinal int
ast.Walk(doc, func(node ast.Node, enter bool) (ast.WalkStatus, error) {
if !enter {
return ast.WalkContinue, nil
}
if n, ok := node.(*ast.Image); ok {
parent := n.Parent()
n.SetAttributeString(AttrOrdinal, ordinal)
ordinal++
if !t.wrapStandAloneImageWithinParagraph {
isBlock := parent.ChildCount() == 1
if isBlock {
n.SetAttributeString(AttrIsBlock, true)
}
if isBlock && parent.Kind() == ast.KindParagraph {
for _, attr := range parent.Attributes() {
// Transfer any attribute set down to the image.
// Image elements does not support attributes on its own,
// so it's safe to just set without checking first.
n.SetAttribute(attr.Name, attr.Value)
}
grandParent := parent.Parent()
grandParent.ReplaceChild(grandParent, parent, n)
}
}
}
return ast.WalkContinue, nil
})
}