gotosocial/vendor/github.com/yuin/goldmark/parser/link_ref.go
Autumn! eb08529f35
[chore/bugfix] Switch markdown from blackfriday to goldmark (#1267)
Co-authored-by: Autumn! <autumnull@posteo.net>
2022-12-16 12:20:22 +01:00

152 lines
3.3 KiB
Go

package parser
import (
"github.com/yuin/goldmark/ast"
"github.com/yuin/goldmark/text"
"github.com/yuin/goldmark/util"
)
type linkReferenceParagraphTransformer struct {
}
// LinkReferenceParagraphTransformer is a ParagraphTransformer implementation
// that parses and extracts link reference from paragraphs.
var LinkReferenceParagraphTransformer = &linkReferenceParagraphTransformer{}
func (p *linkReferenceParagraphTransformer) Transform(node *ast.Paragraph, reader text.Reader, pc Context) {
lines := node.Lines()
block := text.NewBlockReader(reader.Source(), lines)
removes := [][2]int{}
for {
start, end := parseLinkReferenceDefinition(block, pc)
if start > -1 {
if start == end {
end++
}
removes = append(removes, [2]int{start, end})
continue
}
break
}
offset := 0
for _, remove := range removes {
if lines.Len() == 0 {
break
}
s := lines.Sliced(remove[1]-offset, lines.Len())
lines.SetSliced(0, remove[0]-offset)
lines.AppendAll(s)
offset = remove[1]
}
if lines.Len() == 0 {
t := ast.NewTextBlock()
t.SetBlankPreviousLines(node.HasBlankPreviousLines())
node.Parent().ReplaceChild(node.Parent(), node, t)
return
}
node.SetLines(lines)
}
func parseLinkReferenceDefinition(block text.Reader, pc Context) (int, int) {
block.SkipSpaces()
line, _ := block.PeekLine()
if line == nil {
return -1, -1
}
startLine, _ := block.Position()
width, pos := util.IndentWidth(line, 0)
if width > 3 {
return -1, -1
}
if width != 0 {
pos++
}
if line[pos] != '[' {
return -1, -1
}
block.Advance(pos + 1)
segments, found := block.FindClosure('[', ']', linkFindClosureOptions)
if !found {
return -1, -1
}
var label []byte
if segments.Len() == 1 {
label = block.Value(segments.At(0))
} else {
for i := 0; i < segments.Len(); i++ {
s := segments.At(i)
label = append(label, block.Value(s)...)
}
}
if util.IsBlank(label) {
return -1, -1
}
if block.Peek() != ':' {
return -1, -1
}
block.Advance(1)
block.SkipSpaces()
destination, ok := parseLinkDestination(block)
if !ok {
return -1, -1
}
line, _ = block.PeekLine()
isNewLine := line == nil || util.IsBlank(line)
endLine, _ := block.Position()
_, spaces, _ := block.SkipSpaces()
opener := block.Peek()
if opener != '"' && opener != '\'' && opener != '(' {
if !isNewLine {
return -1, -1
}
ref := NewReference(label, destination, nil)
pc.AddReference(ref)
return startLine, endLine + 1
}
if spaces == 0 {
return -1, -1
}
block.Advance(1)
closer := opener
if opener == '(' {
closer = ')'
}
segments, found = block.FindClosure(opener, closer, linkFindClosureOptions)
if !found {
if !isNewLine {
return -1, -1
}
ref := NewReference(label, destination, nil)
pc.AddReference(ref)
block.AdvanceLine()
return startLine, endLine + 1
}
var title []byte
if segments.Len() == 1 {
title = block.Value(segments.At(0))
} else {
for i := 0; i < segments.Len(); i++ {
s := segments.At(i)
title = append(title, block.Value(s)...)
}
}
line, _ = block.PeekLine()
if line != nil && !util.IsBlank(line) {
if !isNewLine {
return -1, -1
}
ref := NewReference(label, destination, title)
pc.AddReference(ref)
return startLine, endLine
}
endLine, _ = block.Position()
ref := NewReference(label, destination, title)
pc.AddReference(ref)
return startLine, endLine + 1
}