380 lines
8.2 KiB
Go
380 lines
8.2 KiB
Go
package parser
|
|
|
|
import (
|
|
"fmt"
|
|
"strings"
|
|
|
|
"github.com/yuin/goldmark/ast"
|
|
"github.com/yuin/goldmark/text"
|
|
"github.com/yuin/goldmark/util"
|
|
)
|
|
|
|
var linkLabelStateKey = NewContextKey()
|
|
|
|
type linkLabelState struct {
|
|
ast.BaseInline
|
|
|
|
Segment text.Segment
|
|
|
|
IsImage bool
|
|
|
|
Prev *linkLabelState
|
|
|
|
Next *linkLabelState
|
|
|
|
First *linkLabelState
|
|
|
|
Last *linkLabelState
|
|
}
|
|
|
|
func newLinkLabelState(segment text.Segment, isImage bool) *linkLabelState {
|
|
return &linkLabelState{
|
|
Segment: segment,
|
|
IsImage: isImage,
|
|
}
|
|
}
|
|
|
|
func (s *linkLabelState) Text(source []byte) []byte {
|
|
return s.Segment.Value(source)
|
|
}
|
|
|
|
func (s *linkLabelState) Dump(source []byte, level int) {
|
|
fmt.Printf("%slinkLabelState: \"%s\"\n", strings.Repeat(" ", level), s.Text(source))
|
|
}
|
|
|
|
var kindLinkLabelState = ast.NewNodeKind("LinkLabelState")
|
|
|
|
func (s *linkLabelState) Kind() ast.NodeKind {
|
|
return kindLinkLabelState
|
|
}
|
|
|
|
func pushLinkLabelState(pc Context, v *linkLabelState) {
|
|
tlist := pc.Get(linkLabelStateKey)
|
|
var list *linkLabelState
|
|
if tlist == nil {
|
|
list = v
|
|
v.First = v
|
|
v.Last = v
|
|
pc.Set(linkLabelStateKey, list)
|
|
} else {
|
|
list = tlist.(*linkLabelState)
|
|
l := list.Last
|
|
list.Last = v
|
|
l.Next = v
|
|
v.Prev = l
|
|
}
|
|
}
|
|
|
|
func removeLinkLabelState(pc Context, d *linkLabelState) {
|
|
tlist := pc.Get(linkLabelStateKey)
|
|
var list *linkLabelState
|
|
if tlist == nil {
|
|
return
|
|
}
|
|
list = tlist.(*linkLabelState)
|
|
|
|
if d.Prev == nil {
|
|
list = d.Next
|
|
if list != nil {
|
|
list.First = d
|
|
list.Last = d.Last
|
|
list.Prev = nil
|
|
pc.Set(linkLabelStateKey, list)
|
|
} else {
|
|
pc.Set(linkLabelStateKey, nil)
|
|
}
|
|
} else {
|
|
d.Prev.Next = d.Next
|
|
if d.Next != nil {
|
|
d.Next.Prev = d.Prev
|
|
}
|
|
}
|
|
if list != nil && d.Next == nil {
|
|
list.Last = d.Prev
|
|
}
|
|
d.Next = nil
|
|
d.Prev = nil
|
|
d.First = nil
|
|
d.Last = nil
|
|
}
|
|
|
|
type linkParser struct {
|
|
}
|
|
|
|
var defaultLinkParser = &linkParser{}
|
|
|
|
// NewLinkParser return a new InlineParser that parses links.
|
|
func NewLinkParser() InlineParser {
|
|
return defaultLinkParser
|
|
}
|
|
|
|
func (s *linkParser) Trigger() []byte {
|
|
return []byte{'!', '[', ']'}
|
|
}
|
|
|
|
var linkBottom = NewContextKey()
|
|
|
|
func (s *linkParser) Parse(parent ast.Node, block text.Reader, pc Context) ast.Node {
|
|
line, segment := block.PeekLine()
|
|
if line[0] == '!' {
|
|
if len(line) > 1 && line[1] == '[' {
|
|
block.Advance(1)
|
|
pc.Set(linkBottom, pc.LastDelimiter())
|
|
return processLinkLabelOpen(block, segment.Start+1, true, pc)
|
|
}
|
|
return nil
|
|
}
|
|
if line[0] == '[' {
|
|
pc.Set(linkBottom, pc.LastDelimiter())
|
|
return processLinkLabelOpen(block, segment.Start, false, pc)
|
|
}
|
|
|
|
// line[0] == ']'
|
|
tlist := pc.Get(linkLabelStateKey)
|
|
if tlist == nil {
|
|
return nil
|
|
}
|
|
last := tlist.(*linkLabelState).Last
|
|
if last == nil {
|
|
return nil
|
|
}
|
|
block.Advance(1)
|
|
removeLinkLabelState(pc, last)
|
|
if s.containsLink(last) { // a link in a link text is not allowed
|
|
ast.MergeOrReplaceTextSegment(last.Parent(), last, last.Segment)
|
|
return nil
|
|
}
|
|
|
|
c := block.Peek()
|
|
l, pos := block.Position()
|
|
var link *ast.Link
|
|
var hasValue bool
|
|
if c == '(' { // normal link
|
|
link = s.parseLink(parent, last, block, pc)
|
|
} else if c == '[' { // reference link
|
|
link, hasValue = s.parseReferenceLink(parent, last, block, pc)
|
|
if link == nil && hasValue {
|
|
ast.MergeOrReplaceTextSegment(last.Parent(), last, last.Segment)
|
|
return nil
|
|
}
|
|
}
|
|
|
|
if link == nil {
|
|
// maybe shortcut reference link
|
|
block.SetPosition(l, pos)
|
|
ssegment := text.NewSegment(last.Segment.Stop, segment.Start)
|
|
maybeReference := block.Value(ssegment)
|
|
ref, ok := pc.Reference(util.ToLinkReference(maybeReference))
|
|
if !ok {
|
|
ast.MergeOrReplaceTextSegment(last.Parent(), last, last.Segment)
|
|
return nil
|
|
}
|
|
link = ast.NewLink()
|
|
s.processLinkLabel(parent, link, last, pc)
|
|
link.Title = ref.Title()
|
|
link.Destination = ref.Destination()
|
|
}
|
|
if last.IsImage {
|
|
last.Parent().RemoveChild(last.Parent(), last)
|
|
return ast.NewImage(link)
|
|
}
|
|
last.Parent().RemoveChild(last.Parent(), last)
|
|
return link
|
|
}
|
|
|
|
func (s *linkParser) containsLink(last *linkLabelState) bool {
|
|
if last.IsImage {
|
|
return false
|
|
}
|
|
var c ast.Node
|
|
for c = last; c != nil; c = c.NextSibling() {
|
|
if _, ok := c.(*ast.Link); ok {
|
|
return true
|
|
}
|
|
}
|
|
return false
|
|
}
|
|
|
|
func processLinkLabelOpen(block text.Reader, pos int, isImage bool, pc Context) *linkLabelState {
|
|
start := pos
|
|
if isImage {
|
|
start--
|
|
}
|
|
state := newLinkLabelState(text.NewSegment(start, pos+1), isImage)
|
|
pushLinkLabelState(pc, state)
|
|
block.Advance(1)
|
|
return state
|
|
}
|
|
|
|
func (s *linkParser) processLinkLabel(parent ast.Node, link *ast.Link, last *linkLabelState, pc Context) {
|
|
var bottom ast.Node
|
|
if v := pc.Get(linkBottom); v != nil {
|
|
bottom = v.(ast.Node)
|
|
}
|
|
pc.Set(linkBottom, nil)
|
|
ProcessDelimiters(bottom, pc)
|
|
for c := last.NextSibling(); c != nil; {
|
|
next := c.NextSibling()
|
|
parent.RemoveChild(parent, c)
|
|
link.AppendChild(link, c)
|
|
c = next
|
|
}
|
|
}
|
|
|
|
func (s *linkParser) parseReferenceLink(parent ast.Node, last *linkLabelState, block text.Reader, pc Context) (*ast.Link, bool) {
|
|
_, orgpos := block.Position()
|
|
block.Advance(1) // skip '['
|
|
line, segment := block.PeekLine()
|
|
endIndex := util.FindClosure(line, '[', ']', false, true)
|
|
if endIndex < 0 {
|
|
return nil, false
|
|
}
|
|
|
|
block.Advance(endIndex + 1)
|
|
ssegment := segment.WithStop(segment.Start + endIndex)
|
|
maybeReference := block.Value(ssegment)
|
|
if util.IsBlank(maybeReference) { // collapsed reference link
|
|
ssegment = text.NewSegment(last.Segment.Stop, orgpos.Start-1)
|
|
maybeReference = block.Value(ssegment)
|
|
}
|
|
|
|
ref, ok := pc.Reference(util.ToLinkReference(maybeReference))
|
|
if !ok {
|
|
return nil, true
|
|
}
|
|
|
|
link := ast.NewLink()
|
|
s.processLinkLabel(parent, link, last, pc)
|
|
link.Title = ref.Title()
|
|
link.Destination = ref.Destination()
|
|
return link, true
|
|
}
|
|
|
|
func (s *linkParser) parseLink(parent ast.Node, last *linkLabelState, block text.Reader, pc Context) *ast.Link {
|
|
block.Advance(1) // skip '('
|
|
block.SkipSpaces()
|
|
var title []byte
|
|
var destination []byte
|
|
var ok bool
|
|
if block.Peek() == ')' { // empty link like '[link]()'
|
|
block.Advance(1)
|
|
} else {
|
|
destination, ok = parseLinkDestination(block)
|
|
if !ok {
|
|
return nil
|
|
}
|
|
block.SkipSpaces()
|
|
if block.Peek() == ')' {
|
|
block.Advance(1)
|
|
} else {
|
|
title, ok = parseLinkTitle(block)
|
|
if !ok {
|
|
return nil
|
|
}
|
|
block.SkipSpaces()
|
|
if block.Peek() == ')' {
|
|
block.Advance(1)
|
|
} else {
|
|
return nil
|
|
}
|
|
}
|
|
}
|
|
|
|
link := ast.NewLink()
|
|
s.processLinkLabel(parent, link, last, pc)
|
|
link.Destination = destination
|
|
link.Title = title
|
|
return link
|
|
}
|
|
|
|
func parseLinkDestination(block text.Reader) ([]byte, bool) {
|
|
block.SkipSpaces()
|
|
line, _ := block.PeekLine()
|
|
if block.Peek() == '<' {
|
|
i := 1
|
|
for i < len(line) {
|
|
c := line[i]
|
|
if c == '\\' && i < len(line)-1 && util.IsPunct(line[i+1]) {
|
|
i += 2
|
|
continue
|
|
} else if c == '>' {
|
|
block.Advance(i + 1)
|
|
return line[1:i], true
|
|
}
|
|
i++
|
|
}
|
|
return nil, false
|
|
}
|
|
opened := 0
|
|
i := 0
|
|
for i < len(line) {
|
|
c := line[i]
|
|
if c == '\\' && i < len(line)-1 && util.IsPunct(line[i+1]) {
|
|
i += 2
|
|
continue
|
|
} else if c == '(' {
|
|
opened++
|
|
} else if c == ')' {
|
|
opened--
|
|
if opened < 0 {
|
|
break
|
|
}
|
|
} else if util.IsSpace(c) {
|
|
break
|
|
}
|
|
i++
|
|
}
|
|
block.Advance(i)
|
|
return line[:i], len(line[:i]) != 0
|
|
}
|
|
|
|
func parseLinkTitle(block text.Reader) ([]byte, bool) {
|
|
block.SkipSpaces()
|
|
opener := block.Peek()
|
|
if opener != '"' && opener != '\'' && opener != '(' {
|
|
return nil, false
|
|
}
|
|
closer := opener
|
|
if opener == '(' {
|
|
closer = ')'
|
|
}
|
|
savedLine, savedPosition := block.Position()
|
|
var title []byte
|
|
for i := 0; ; i++ {
|
|
line, _ := block.PeekLine()
|
|
if line == nil {
|
|
block.SetPosition(savedLine, savedPosition)
|
|
return nil, false
|
|
}
|
|
offset := 0
|
|
if i == 0 {
|
|
offset = 1
|
|
}
|
|
pos := util.FindClosure(line[offset:], opener, closer, false, true)
|
|
if pos < 0 {
|
|
title = append(title, line[offset:]...)
|
|
block.AdvanceLine()
|
|
continue
|
|
}
|
|
pos += offset + 1 // 1: closer
|
|
block.Advance(pos)
|
|
if i == 0 { // avoid allocating new slice
|
|
return line[offset : pos-1], true
|
|
}
|
|
return append(title, line[offset:pos-1]...), true
|
|
}
|
|
}
|
|
|
|
func (s *linkParser) CloseBlock(parent ast.Node, block text.Reader, pc Context) {
|
|
tlist := pc.Get(linkLabelStateKey)
|
|
if tlist == nil {
|
|
return
|
|
}
|
|
for s := tlist.(*linkLabelState); s != nil; {
|
|
next := s.Next
|
|
removeLinkLabelState(pc, s)
|
|
s.Parent().ReplaceChild(s.Parent(), s, ast.NewTextSegment(s.Segment))
|
|
s = next
|
|
}
|
|
}
|