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hugo/markup/goldmark/internal/extensions/attributes/attributes.go

126 lines
3.2 KiB
Go

package attributes
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"
)
// This extension is based on/inspired by https://github.com/mdigger/goldmark-attributes
// MIT License
// Copyright (c) 2019 Dmitry Sedykh
var (
kindAttributesBlock = ast.NewNodeKind("AttributesBlock")
defaultParser = new(attrParser)
defaultTransformer = new(transformer)
attributes goldmark.Extender = new(attrExtension)
)
func New() goldmark.Extender {
return attributes
}
type attrExtension struct{}
func (a *attrExtension) Extend(m goldmark.Markdown) {
m.Parser().AddOptions(
parser.WithBlockParsers(
util.Prioritized(defaultParser, 100)),
parser.WithASTTransformers(
util.Prioritized(defaultTransformer, 100),
),
)
}
type attrParser struct{}
func (a *attrParser) CanAcceptIndentedLine() bool {
return false
}
func (a *attrParser) CanInterruptParagraph() bool {
return true
}
func (a *attrParser) Close(node ast.Node, reader text.Reader, pc parser.Context) {
}
func (a *attrParser) Continue(node ast.Node, reader text.Reader, pc parser.Context) parser.State {
return parser.Close
}
func (a *attrParser) Open(parent ast.Node, reader text.Reader, pc parser.Context) (ast.Node, parser.State) {
if attrs, ok := parser.ParseAttributes(reader); ok {
// add attributes
node := &attributesBlock{
BaseBlock: ast.BaseBlock{},
}
for _, attr := range attrs {
node.SetAttribute(attr.Name, attr.Value)
}
return node, parser.NoChildren
}
return nil, parser.RequireParagraph
}
func (a *attrParser) Trigger() []byte {
return []byte{'{'}
}
type attributesBlock struct {
ast.BaseBlock
}
func (a *attributesBlock) Dump(source []byte, level int) {
attrs := a.Attributes()
list := make(map[string]string, len(attrs))
for _, attr := range attrs {
var (
name = util.BytesToReadOnlyString(attr.Name)
value = util.BytesToReadOnlyString(util.EscapeHTML(attr.Value.([]byte)))
)
list[name] = value
}
ast.DumpHelper(a, source, level, list, nil)
}
func (a *attributesBlock) Kind() ast.NodeKind {
return kindAttributesBlock
}
type transformer struct{}
func (a *transformer) Transform(node *ast.Document, reader text.Reader, pc parser.Context) {
attributes := make([]ast.Node, 0, 500)
ast.Walk(node, func(node ast.Node, entering bool) (ast.WalkStatus, error) {
if entering && node.Kind() == kindAttributesBlock {
// Attributes for fenced code blocks are handled in their own extension,
// but note that we currently only support code block attributes when
// CodeFences=true.
if node.PreviousSibling() != nil && node.PreviousSibling().Kind() != ast.KindFencedCodeBlock && !node.HasBlankPreviousLines() {
attributes = append(attributes, node)
return ast.WalkSkipChildren, nil
}
}
return ast.WalkContinue, nil
})
for _, attr := range attributes {
if prev := attr.PreviousSibling(); prev != nil &&
prev.Type() == ast.TypeBlock {
for _, attr := range attr.Attributes() {
if _, found := prev.Attribute(attr.Name); !found {
prev.SetAttribute(attr.Name, attr.Value)
}
}
}
// remove attributes node
attr.Parent().RemoveChild(attr.Parent(), attr)
}
}