mirror of
https://github.com/cwinfo/matterbridge.git
synced 2024-11-10 12:10:26 +00:00
665 lines
16 KiB
Go
665 lines
16 KiB
Go
// Copyright (c) 2017-present Mattermost, Inc. All Rights Reserved.
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// See License.txt for license information.
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package markdown
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import (
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"container/list"
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"strings"
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"unicode"
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"unicode/utf8"
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)
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type Inline interface {
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IsInline() bool
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}
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type inlineBase struct{}
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func (inlineBase) IsInline() bool { return true }
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type Text struct {
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inlineBase
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Text string
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Range Range
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}
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type CodeSpan struct {
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inlineBase
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Code string
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}
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type HardLineBreak struct {
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inlineBase
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}
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type SoftLineBreak struct {
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inlineBase
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}
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type InlineLinkOrImage struct {
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inlineBase
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Children []Inline
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RawDestination Range
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markdown string
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rawTitle string
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}
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func (i *InlineLinkOrImage) Destination() string {
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return Unescape(i.markdown[i.RawDestination.Position:i.RawDestination.End])
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}
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func (i *InlineLinkOrImage) Title() string {
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return Unescape(i.rawTitle)
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}
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type InlineLink struct {
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InlineLinkOrImage
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}
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type InlineImage struct {
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InlineLinkOrImage
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}
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type ReferenceLinkOrImage struct {
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inlineBase
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*ReferenceDefinition
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Children []Inline
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}
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type ReferenceLink struct {
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ReferenceLinkOrImage
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}
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type ReferenceImage struct {
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ReferenceLinkOrImage
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}
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type Autolink struct {
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inlineBase
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Children []Inline
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RawDestination Range
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markdown string
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}
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func (i *Autolink) Destination() string {
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destination := Unescape(i.markdown[i.RawDestination.Position:i.RawDestination.End])
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if strings.HasPrefix(destination, "www") {
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destination = "http://" + destination
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}
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return destination
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}
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type delimiterType int
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const (
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linkOpeningDelimiter delimiterType = iota
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imageOpeningDelimiter
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)
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type delimiter struct {
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Type delimiterType
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IsInactive bool
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TextNode int
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Range Range
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}
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type inlineParser struct {
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markdown string
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ranges []Range
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referenceDefinitions []*ReferenceDefinition
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raw string
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position int
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inlines []Inline
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delimiterStack *list.List
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}
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func newInlineParser(markdown string, ranges []Range, referenceDefinitions []*ReferenceDefinition) *inlineParser {
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return &inlineParser{
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markdown: markdown,
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ranges: ranges,
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referenceDefinitions: referenceDefinitions,
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delimiterStack: list.New(),
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}
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}
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func (p *inlineParser) parseBackticks() {
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count := 1
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for i := p.position + 1; i < len(p.raw) && p.raw[i] == '`'; i++ {
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count++
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}
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opening := p.raw[p.position : p.position+count]
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search := p.position + count
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for search < len(p.raw) {
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end := strings.Index(p.raw[search:], opening)
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if end == -1 {
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break
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}
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if search+end+count < len(p.raw) && p.raw[search+end+count] == '`' {
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search += end + count
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for search < len(p.raw) && p.raw[search] == '`' {
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search++
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}
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continue
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}
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code := strings.Join(strings.Fields(p.raw[p.position+count:search+end]), " ")
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p.position = search + end + count
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p.inlines = append(p.inlines, &CodeSpan{
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Code: code,
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})
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return
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}
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p.position += len(opening)
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absPos := relativeToAbsolutePosition(p.ranges, p.position-len(opening))
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p.inlines = append(p.inlines, &Text{
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Text: opening,
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Range: Range{absPos, absPos + len(opening)},
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})
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}
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func (p *inlineParser) parseLineEnding() {
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if p.position >= 1 && p.raw[p.position-1] == '\t' {
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p.inlines = append(p.inlines, &HardLineBreak{})
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} else if p.position >= 2 && p.raw[p.position-1] == ' ' && (p.raw[p.position-2] == '\t' || p.raw[p.position-1] == ' ') {
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p.inlines = append(p.inlines, &HardLineBreak{})
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} else {
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p.inlines = append(p.inlines, &SoftLineBreak{})
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}
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p.position++
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if p.position < len(p.raw) && p.raw[p.position] == '\n' {
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p.position++
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}
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}
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func (p *inlineParser) parseEscapeCharacter() {
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if p.position+1 < len(p.raw) && isEscapableByte(p.raw[p.position+1]) {
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absPos := relativeToAbsolutePosition(p.ranges, p.position+1)
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p.inlines = append(p.inlines, &Text{
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Text: string(p.raw[p.position+1]),
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Range: Range{absPos, absPos + len(string(p.raw[p.position+1]))},
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})
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p.position += 2
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} else {
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absPos := relativeToAbsolutePosition(p.ranges, p.position)
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p.inlines = append(p.inlines, &Text{
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Text: `\`,
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Range: Range{absPos, absPos + 1},
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})
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p.position++
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}
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}
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func (p *inlineParser) parseText() {
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if next := strings.IndexAny(p.raw[p.position:], "\r\n\\`&![]wW:"); next == -1 {
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absPos := relativeToAbsolutePosition(p.ranges, p.position)
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p.inlines = append(p.inlines, &Text{
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Text: strings.TrimRightFunc(p.raw[p.position:], isWhitespace),
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Range: Range{absPos, absPos + len(p.raw[p.position:])},
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})
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p.position = len(p.raw)
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} else {
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absPos := relativeToAbsolutePosition(p.ranges, p.position)
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if p.raw[p.position+next] == '\r' || p.raw[p.position+next] == '\n' {
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s := strings.TrimRightFunc(p.raw[p.position:p.position+next], isWhitespace)
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p.inlines = append(p.inlines, &Text{
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Text: s,
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Range: Range{absPos, absPos + len(s)},
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})
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} else {
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if next == 0 {
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// Always read at least one character since 'w', 'W', and ':' may not actually match another
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// type of node
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next = 1
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}
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p.inlines = append(p.inlines, &Text{
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Text: p.raw[p.position : p.position+next],
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Range: Range{absPos, absPos + next},
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})
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}
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p.position += next
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}
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}
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func (p *inlineParser) parseLinkOrImageDelimiter() {
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absPos := relativeToAbsolutePosition(p.ranges, p.position)
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if p.raw[p.position] == '[' {
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p.inlines = append(p.inlines, &Text{
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Text: "[",
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Range: Range{absPos, absPos + 1},
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})
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p.delimiterStack.PushBack(&delimiter{
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Type: linkOpeningDelimiter,
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TextNode: len(p.inlines) - 1,
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Range: Range{p.position, p.position + 1},
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})
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p.position++
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} else if p.raw[p.position] == '!' && p.position+1 < len(p.raw) && p.raw[p.position+1] == '[' {
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p.inlines = append(p.inlines, &Text{
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Text: "![",
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Range: Range{absPos, absPos + 2},
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})
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p.delimiterStack.PushBack(&delimiter{
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Type: imageOpeningDelimiter,
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TextNode: len(p.inlines) - 1,
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Range: Range{p.position, p.position + 2},
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})
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p.position += 2
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} else {
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p.inlines = append(p.inlines, &Text{
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Text: "!",
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Range: Range{absPos, absPos + 1},
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})
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p.position++
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}
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}
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func (p *inlineParser) peekAtInlineLinkDestinationAndTitle(position int, isImage bool) (destination, title Range, end int, ok bool) {
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if position >= len(p.raw) || p.raw[position] != '(' {
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return
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}
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position++
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destinationStart := nextNonWhitespace(p.raw, position)
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if destinationStart >= len(p.raw) {
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return
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} else if p.raw[destinationStart] == ')' {
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return Range{destinationStart, destinationStart}, Range{destinationStart, destinationStart}, destinationStart + 1, true
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}
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destination, end, ok = parseLinkDestination(p.raw, destinationStart)
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if !ok {
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return
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}
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position = end
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if isImage && position < len(p.raw) && isWhitespaceByte(p.raw[position]) {
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dimensionsStart := nextNonWhitespace(p.raw, position)
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if dimensionsStart >= len(p.raw) {
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return
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}
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if p.raw[dimensionsStart] == '=' {
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// Read optional image dimensions even if we don't use them
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_, end, ok = parseImageDimensions(p.raw, dimensionsStart)
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if !ok {
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return
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}
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position = end
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}
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}
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if position < len(p.raw) && isWhitespaceByte(p.raw[position]) {
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titleStart := nextNonWhitespace(p.raw, position)
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if titleStart >= len(p.raw) {
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return
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} else if p.raw[titleStart] == ')' {
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return destination, Range{titleStart, titleStart}, titleStart + 1, true
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}
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if p.raw[titleStart] == '"' || p.raw[titleStart] == '\'' || p.raw[titleStart] == '(' {
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title, end, ok = parseLinkTitle(p.raw, titleStart)
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if !ok {
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return
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}
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position = end
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}
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}
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closingPosition := nextNonWhitespace(p.raw, position)
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if closingPosition >= len(p.raw) || p.raw[closingPosition] != ')' {
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return Range{}, Range{}, 0, false
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}
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return destination, title, closingPosition + 1, true
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}
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func (p *inlineParser) referenceDefinition(label string) *ReferenceDefinition {
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clean := strings.Join(strings.Fields(label), " ")
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for _, d := range p.referenceDefinitions {
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if strings.EqualFold(clean, strings.Join(strings.Fields(d.Label()), " ")) {
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return d
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}
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}
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return nil
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}
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func (p *inlineParser) lookForLinkOrImage() {
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for element := p.delimiterStack.Back(); element != nil; element = element.Prev() {
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d := element.Value.(*delimiter)
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if d.Type != imageOpeningDelimiter && d.Type != linkOpeningDelimiter {
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continue
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}
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if d.IsInactive {
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p.delimiterStack.Remove(element)
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break
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}
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isImage := d.Type == imageOpeningDelimiter
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var inline Inline
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if destination, title, next, ok := p.peekAtInlineLinkDestinationAndTitle(p.position+1, isImage); ok {
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destinationMarkdownPosition := relativeToAbsolutePosition(p.ranges, destination.Position)
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linkOrImage := InlineLinkOrImage{
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Children: append([]Inline(nil), p.inlines[d.TextNode+1:]...),
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RawDestination: Range{destinationMarkdownPosition, destinationMarkdownPosition + destination.End - destination.Position},
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markdown: p.markdown,
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rawTitle: p.raw[title.Position:title.End],
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}
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if d.Type == imageOpeningDelimiter {
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inline = &InlineImage{linkOrImage}
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} else {
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inline = &InlineLink{linkOrImage}
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}
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p.position = next
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} else {
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referenceLabel := ""
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label, next, hasLinkLabel := parseLinkLabel(p.raw, p.position+1)
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if hasLinkLabel && label.End > label.Position {
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referenceLabel = p.raw[label.Position:label.End]
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} else {
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referenceLabel = p.raw[d.Range.End:p.position]
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if !hasLinkLabel {
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next = p.position + 1
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}
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}
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if referenceLabel != "" {
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if reference := p.referenceDefinition(referenceLabel); reference != nil {
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linkOrImage := ReferenceLinkOrImage{
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ReferenceDefinition: reference,
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Children: append([]Inline(nil), p.inlines[d.TextNode+1:]...),
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}
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if d.Type == imageOpeningDelimiter {
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inline = &ReferenceImage{linkOrImage}
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} else {
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inline = &ReferenceLink{linkOrImage}
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}
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p.position = next
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}
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}
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}
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if inline != nil {
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if d.Type == imageOpeningDelimiter {
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p.inlines = append(p.inlines[:d.TextNode], inline)
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} else {
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p.inlines = append(p.inlines[:d.TextNode], inline)
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for element := element.Prev(); element != nil; element = element.Prev() {
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if d := element.Value.(*delimiter); d.Type == linkOpeningDelimiter {
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d.IsInactive = true
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}
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}
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}
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p.delimiterStack.Remove(element)
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return
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} else {
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p.delimiterStack.Remove(element)
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break
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}
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}
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absPos := relativeToAbsolutePosition(p.ranges, p.position)
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p.inlines = append(p.inlines, &Text{
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Text: "]",
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Range: Range{absPos, absPos + 1},
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})
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p.position++
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}
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func CharacterReference(ref string) string {
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if ref == "" {
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return ""
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}
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if ref[0] == '#' {
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if len(ref) < 2 {
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return ""
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}
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n := 0
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if ref[1] == 'X' || ref[1] == 'x' {
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if len(ref) < 3 {
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return ""
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}
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for i := 2; i < len(ref); i++ {
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if i > 9 {
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return ""
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}
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d := ref[i]
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switch {
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case d >= '0' && d <= '9':
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n = n*16 + int(d-'0')
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case d >= 'a' && d <= 'f':
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n = n*16 + 10 + int(d-'a')
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case d >= 'A' && d <= 'F':
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n = n*16 + 10 + int(d-'A')
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default:
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return ""
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}
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}
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} else {
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for i := 1; i < len(ref); i++ {
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if i > 8 || ref[i] < '0' || ref[i] > '9' {
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return ""
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}
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n = n*10 + int(ref[i]-'0')
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}
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}
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c := rune(n)
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if c == '\u0000' || !utf8.ValidRune(c) {
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return string(unicode.ReplacementChar)
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}
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return string(c)
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}
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if entity, ok := htmlEntities[ref]; ok {
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return entity
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}
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return ""
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}
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func (p *inlineParser) parseCharacterReference() {
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absPos := relativeToAbsolutePosition(p.ranges, p.position)
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p.position++
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if semicolon := strings.IndexByte(p.raw[p.position:], ';'); semicolon == -1 {
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p.inlines = append(p.inlines, &Text{
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Text: "&",
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Range: Range{absPos, absPos + 1},
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})
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} else if s := CharacterReference(p.raw[p.position : p.position+semicolon]); s != "" {
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p.position += semicolon + 1
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p.inlines = append(p.inlines, &Text{
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Text: s,
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Range: Range{absPos, absPos + len(s)},
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})
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} else {
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p.inlines = append(p.inlines, &Text{
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Text: "&",
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Range: Range{absPos, absPos + 1},
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})
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}
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}
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func (p *inlineParser) parseAutolink(c rune) bool {
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for element := p.delimiterStack.Back(); element != nil; element = element.Prev() {
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d := element.Value.(*delimiter)
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if !d.IsInactive {
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return false
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}
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}
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var link Range
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if c == ':' {
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var ok bool
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link, ok = parseURLAutolink(p.raw, p.position)
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if !ok {
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return false
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}
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// Since the current position is at the colon, we have to rewind the parsing slightly so that
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// we don't duplicate the URL scheme
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rewind := strings.Index(p.raw[link.Position:link.End], ":")
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if rewind != -1 {
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lastInline := p.inlines[len(p.inlines)-1]
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lastText, ok := lastInline.(*Text)
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if !ok {
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// This should never occur since parseURLAutolink will only return a non-empty value
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// when the previous text ends in a valid URL protocol which would mean that the previous
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// node is a Text node
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return false
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}
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p.inlines = p.inlines[0 : len(p.inlines)-1]
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p.inlines = append(p.inlines, &Text{
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Text: lastText.Text[:len(lastText.Text)-rewind],
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Range: Range{lastText.Range.Position, lastText.Range.End - rewind},
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})
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p.position -= rewind
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}
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} else if c == 'w' || c == 'W' {
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var ok bool
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link, ok = parseWWWAutolink(p.raw, p.position)
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if !ok {
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return false
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}
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}
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linkMarkdownPosition := relativeToAbsolutePosition(p.ranges, link.Position)
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linkRange := Range{linkMarkdownPosition, linkMarkdownPosition + link.End - link.Position}
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p.inlines = append(p.inlines, &Autolink{
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Children: []Inline{
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&Text{
|
|
Text: p.raw[link.Position:link.End],
|
|
Range: linkRange,
|
|
},
|
|
},
|
|
RawDestination: linkRange,
|
|
markdown: p.markdown,
|
|
})
|
|
p.position += (link.End - link.Position)
|
|
|
|
return true
|
|
}
|
|
|
|
func (p *inlineParser) Parse() []Inline {
|
|
for _, r := range p.ranges {
|
|
p.raw += p.markdown[r.Position:r.End]
|
|
}
|
|
|
|
for p.position < len(p.raw) {
|
|
c, _ := utf8.DecodeRuneInString(p.raw[p.position:])
|
|
|
|
switch c {
|
|
case '\r', '\n':
|
|
p.parseLineEnding()
|
|
case '\\':
|
|
p.parseEscapeCharacter()
|
|
case '`':
|
|
p.parseBackticks()
|
|
case '&':
|
|
p.parseCharacterReference()
|
|
case '!', '[':
|
|
p.parseLinkOrImageDelimiter()
|
|
case ']':
|
|
p.lookForLinkOrImage()
|
|
case 'w', 'W', ':':
|
|
matched := p.parseAutolink(c)
|
|
|
|
if !matched {
|
|
p.parseText()
|
|
}
|
|
default:
|
|
p.parseText()
|
|
}
|
|
}
|
|
|
|
return p.inlines
|
|
}
|
|
|
|
func ParseInlines(markdown string, ranges []Range, referenceDefinitions []*ReferenceDefinition) (inlines []Inline) {
|
|
return newInlineParser(markdown, ranges, referenceDefinitions).Parse()
|
|
}
|
|
|
|
func MergeInlineText(inlines []Inline) []Inline {
|
|
var ret []Inline
|
|
for i, v := range inlines {
|
|
// always add first node
|
|
if i == 0 {
|
|
ret = append(ret, v)
|
|
continue
|
|
}
|
|
// not a text node? nothing to merge
|
|
text, ok := v.(*Text)
|
|
if !ok {
|
|
ret = append(ret, v)
|
|
continue
|
|
}
|
|
// previous node is not a text node? nothing to merge
|
|
prevText, ok := ret[len(ret)-1].(*Text)
|
|
if !ok {
|
|
ret = append(ret, v)
|
|
continue
|
|
}
|
|
// previous node is not right before this one
|
|
if prevText.Range.End != text.Range.Position {
|
|
ret = append(ret, v)
|
|
continue
|
|
}
|
|
// we have two consecutive text nodes
|
|
ret[len(ret)-1] = &Text{
|
|
Text: prevText.Text + text.Text,
|
|
Range: Range{prevText.Range.Position, text.Range.End},
|
|
}
|
|
}
|
|
return ret
|
|
}
|
|
|
|
func Unescape(markdown string) string {
|
|
ret := ""
|
|
|
|
position := 0
|
|
for position < len(markdown) {
|
|
c, cSize := utf8.DecodeRuneInString(markdown[position:])
|
|
|
|
switch c {
|
|
case '\\':
|
|
if position+1 < len(markdown) && isEscapableByte(markdown[position+1]) {
|
|
ret += string(markdown[position+1])
|
|
position += 2
|
|
} else {
|
|
ret += `\`
|
|
position++
|
|
}
|
|
case '&':
|
|
position++
|
|
if semicolon := strings.IndexByte(markdown[position:], ';'); semicolon == -1 {
|
|
ret += "&"
|
|
} else if s := CharacterReference(markdown[position : position+semicolon]); s != "" {
|
|
position += semicolon + 1
|
|
ret += s
|
|
} else {
|
|
ret += "&"
|
|
}
|
|
default:
|
|
ret += string(c)
|
|
position += cSize
|
|
}
|
|
}
|
|
|
|
return ret
|
|
}
|