forgejo/vendor/github.com/yuin/goldmark/parser/atx_heading.go
zeripath 27757714d0 Change markdown rendering from blackfriday to goldmark (#9533)
* Move to goldmark

Markdown rendering moved from blackfriday to the goldmark.

Multiple subtle changes required to the goldmark extensions to keep
current rendering and defaults.

Can go further with goldmark linkify and have this work within markdown
rendering making the link processor unnecessary.

Need to think about how to go about allowing extensions - at present it
seems that these would be hard to do without recompilation.

* linter fixes

Co-authored-by: Lauris BH <lauris@nix.lv>
2019-12-31 03:53:28 +02:00

243 lines
5.6 KiB
Go

package parser
import (
"github.com/yuin/goldmark/ast"
"github.com/yuin/goldmark/text"
"github.com/yuin/goldmark/util"
)
// A HeadingConfig struct is a data structure that holds configuration of the renderers related to headings.
type HeadingConfig struct {
AutoHeadingID bool
Attribute bool
}
// SetOption implements SetOptioner.
func (b *HeadingConfig) SetOption(name OptionName, value interface{}) {
switch name {
case optAutoHeadingID:
b.AutoHeadingID = true
case optAttribute:
b.Attribute = true
}
}
// A HeadingOption interface sets options for heading parsers.
type HeadingOption interface {
Option
SetHeadingOption(*HeadingConfig)
}
// AutoHeadingID is an option name that enables auto IDs for headings.
const optAutoHeadingID OptionName = "AutoHeadingID"
type withAutoHeadingID struct {
}
func (o *withAutoHeadingID) SetParserOption(c *Config) {
c.Options[optAutoHeadingID] = true
}
func (o *withAutoHeadingID) SetHeadingOption(p *HeadingConfig) {
p.AutoHeadingID = true
}
// WithAutoHeadingID is a functional option that enables custom heading ids and
// auto generated heading ids.
func WithAutoHeadingID() HeadingOption {
return &withAutoHeadingID{}
}
type withHeadingAttribute struct {
Option
}
func (o *withHeadingAttribute) SetHeadingOption(p *HeadingConfig) {
p.Attribute = true
}
// WithHeadingAttribute is a functional option that enables custom heading attributes.
func WithHeadingAttribute() HeadingOption {
return &withHeadingAttribute{WithAttribute()}
}
type atxHeadingParser struct {
HeadingConfig
}
// NewATXHeadingParser return a new BlockParser that can parse ATX headings.
func NewATXHeadingParser(opts ...HeadingOption) BlockParser {
p := &atxHeadingParser{}
for _, o := range opts {
o.SetHeadingOption(&p.HeadingConfig)
}
return p
}
func (b *atxHeadingParser) Trigger() []byte {
return []byte{'#'}
}
func (b *atxHeadingParser) Open(parent ast.Node, reader text.Reader, pc Context) (ast.Node, State) {
line, segment := reader.PeekLine()
pos := pc.BlockOffset()
if pos < 0 {
return nil, NoChildren
}
i := pos
for ; i < len(line) && line[i] == '#'; i++ {
}
level := i - pos
if i == pos || level > 6 {
return nil, NoChildren
}
l := util.TrimLeftSpaceLength(line[i:])
if l == 0 {
return nil, NoChildren
}
start := i + l
if start >= len(line) {
start = len(line) - 1
}
origstart := start
stop := len(line) - util.TrimRightSpaceLength(line)
node := ast.NewHeading(level)
parsed := false
if b.Attribute { // handles special case like ### heading ### {#id}
start--
closureClose := -1
closureOpen := -1
for j := start; j < stop; {
c := line[j]
if util.IsEscapedPunctuation(line, j) {
j += 2
} else if util.IsSpace(c) && j < stop-1 && line[j+1] == '#' {
closureOpen = j + 1
k := j + 1
for ; k < stop && line[k] == '#'; k++ {
}
closureClose = k
break
} else {
j++
}
}
if closureClose > 0 {
reader.Advance(closureClose)
attrs, ok := ParseAttributes(reader)
parsed = ok
if parsed {
for _, attr := range attrs {
node.SetAttribute(attr.Name, attr.Value)
}
node.Lines().Append(text.NewSegment(segment.Start+start+1-segment.Padding, segment.Start+closureOpen-segment.Padding))
}
}
}
if !parsed {
start = origstart
stop := len(line) - util.TrimRightSpaceLength(line)
if stop <= start { // empty headings like '##[space]'
stop = start
} else {
i = stop - 1
for ; line[i] == '#' && i >= start; i-- {
}
if i != stop-1 && !util.IsSpace(line[i]) {
i = stop - 1
}
i++
stop = i
}
if len(util.TrimRight(line[start:stop], []byte{'#'})) != 0 { // empty heading like '### ###'
node.Lines().Append(text.NewSegment(segment.Start+start-segment.Padding, segment.Start+stop-segment.Padding))
}
}
return node, NoChildren
}
func (b *atxHeadingParser) Continue(node ast.Node, reader text.Reader, pc Context) State {
return Close
}
func (b *atxHeadingParser) Close(node ast.Node, reader text.Reader, pc Context) {
if b.Attribute {
_, ok := node.AttributeString("id")
if !ok {
parseLastLineAttributes(node, reader, pc)
}
}
if b.AutoHeadingID {
id, ok := node.AttributeString("id")
if !ok {
generateAutoHeadingID(node.(*ast.Heading), reader, pc)
} else {
pc.IDs().Put(id.([]byte))
}
}
}
func (b *atxHeadingParser) CanInterruptParagraph() bool {
return true
}
func (b *atxHeadingParser) CanAcceptIndentedLine() bool {
return false
}
func generateAutoHeadingID(node *ast.Heading, reader text.Reader, pc Context) {
var line []byte
lastIndex := node.Lines().Len() - 1
if lastIndex > -1 {
lastLine := node.Lines().At(lastIndex)
line = lastLine.Value(reader.Source())
}
headingID := pc.IDs().Generate(line, ast.KindHeading)
node.SetAttribute(attrNameID, headingID)
}
func parseLastLineAttributes(node ast.Node, reader text.Reader, pc Context) {
lastIndex := node.Lines().Len() - 1
if lastIndex < 0 { // empty headings
return
}
lastLine := node.Lines().At(lastIndex)
line := lastLine.Value(reader.Source())
lr := text.NewReader(line)
var attrs Attributes
var ok bool
var start text.Segment
var sl int
var end text.Segment
for {
c := lr.Peek()
if c == text.EOF {
break
}
if c == '\\' {
lr.Advance(1)
if lr.Peek() == '{' {
lr.Advance(1)
}
continue
}
if c == '{' {
sl, start = lr.Position()
attrs, ok = ParseAttributes(lr)
_, end = lr.Position()
lr.SetPosition(sl, start)
}
lr.Advance(1)
}
if ok && util.IsBlank(line[end.Stop:]) {
for _, attr := range attrs {
node.SetAttribute(attr.Name, attr.Value)
}
lastLine.Stop = lastLine.Start + start.Start
node.Lines().Set(lastIndex, lastLine)
}
}