gotosocial/vendor/github.com/yuin/goldmark/parser/code_block.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

100 lines
2.6 KiB
Go

package parser
import (
"github.com/yuin/goldmark/ast"
"github.com/yuin/goldmark/text"
"github.com/yuin/goldmark/util"
)
type codeBlockParser struct {
}
// CodeBlockParser is a BlockParser implementation that parses indented code blocks.
var defaultCodeBlockParser = &codeBlockParser{}
// NewCodeBlockParser returns a new BlockParser that
// parses code blocks.
func NewCodeBlockParser() BlockParser {
return defaultCodeBlockParser
}
func (b *codeBlockParser) Trigger() []byte {
return nil
}
func (b *codeBlockParser) Open(parent ast.Node, reader text.Reader, pc Context) (ast.Node, State) {
line, segment := reader.PeekLine()
pos, padding := util.IndentPosition(line, reader.LineOffset(), 4)
if pos < 0 || util.IsBlank(line) {
return nil, NoChildren
}
node := ast.NewCodeBlock()
reader.AdvanceAndSetPadding(pos, padding)
_, segment = reader.PeekLine()
// if code block line starts with a tab, keep a tab as it is.
if segment.Padding != 0 {
preserveLeadingTabInCodeBlock(&segment, reader, 0)
}
node.Lines().Append(segment)
reader.Advance(segment.Len() - 1)
return node, NoChildren
}
func (b *codeBlockParser) Continue(node ast.Node, reader text.Reader, pc Context) State {
line, segment := reader.PeekLine()
if util.IsBlank(line) {
node.Lines().Append(segment.TrimLeftSpaceWidth(4, reader.Source()))
return Continue | NoChildren
}
pos, padding := util.IndentPosition(line, reader.LineOffset(), 4)
if pos < 0 {
return Close
}
reader.AdvanceAndSetPadding(pos, padding)
_, segment = reader.PeekLine()
// if code block line starts with a tab, keep a tab as it is.
if segment.Padding != 0 {
preserveLeadingTabInCodeBlock(&segment, reader, 0)
}
node.Lines().Append(segment)
reader.Advance(segment.Len() - 1)
return Continue | NoChildren
}
func (b *codeBlockParser) Close(node ast.Node, reader text.Reader, pc Context) {
// trim trailing blank lines
lines := node.Lines()
length := lines.Len() - 1
source := reader.Source()
for length >= 0 {
line := lines.At(length)
if util.IsBlank(line.Value(source)) {
length--
} else {
break
}
}
lines.SetSliced(0, length+1)
}
func (b *codeBlockParser) CanInterruptParagraph() bool {
return false
}
func (b *codeBlockParser) CanAcceptIndentedLine() bool {
return true
}
func preserveLeadingTabInCodeBlock(segment *text.Segment, reader text.Reader, indent int) {
offsetWithPadding := reader.LineOffset() + indent
sl, ss := reader.Position()
reader.SetPosition(sl, text.NewSegment(ss.Start-1, ss.Stop))
if offsetWithPadding == reader.LineOffset() {
segment.Padding = 0
segment.Start--
}
reader.SetPosition(sl, ss)
}