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gitea/modules/markup/markdown/math/block_parser.go
wxiaoguang 3c4a06273f
Refactor markdown render (#32736)
and add some tests
2024-12-06 20:00:24 +08:00

128 lines
3.7 KiB
Go

// Copyright 2022 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package math
import (
"bytes"
giteaUtil "code.gitea.io/gitea/modules/util"
"github.com/yuin/goldmark/ast"
"github.com/yuin/goldmark/parser"
"github.com/yuin/goldmark/text"
"github.com/yuin/goldmark/util"
)
type blockParser struct {
parseDollars bool
endBytesDollars []byte
endBytesBracket []byte
}
// NewBlockParser creates a new math BlockParser
func NewBlockParser(parseDollarBlocks bool) parser.BlockParser {
return &blockParser{
parseDollars: parseDollarBlocks,
endBytesDollars: []byte{'$', '$'},
endBytesBracket: []byte{'\\', ']'},
}
}
// Open parses the current line and returns a result of parsing.
func (b *blockParser) Open(parent ast.Node, reader text.Reader, pc parser.Context) (ast.Node, parser.State) {
line, segment := reader.PeekLine()
pos := pc.BlockOffset()
if pos == -1 || len(line[pos:]) < 2 {
return nil, parser.NoChildren
}
var dollars bool
if b.parseDollars && line[pos] == '$' && line[pos+1] == '$' {
dollars = true
} else if line[pos] == '\\' && line[pos+1] == '[' {
if len(line[pos:]) >= 3 && line[pos+2] == '!' && bytes.Contains(line[pos:], []byte(`\]`)) {
// do not process escaped attention block: "> \[!NOTE\]"
return nil, parser.NoChildren
}
dollars = false
} else {
return nil, parser.NoChildren
}
node := NewBlock(dollars, pos)
// Now we need to check if the ending block is on the segment...
endBytes := giteaUtil.Iif(dollars, b.endBytesDollars, b.endBytesBracket)
idx := bytes.Index(line[pos+2:], endBytes)
if idx >= 0 {
// for case $$ ... $$ any other text
for i := pos + 2 + idx + 2; i < len(line); i++ {
if line[i] != ' ' && line[i] != '\n' {
return nil, parser.NoChildren
}
}
segment.Start += pos + 2
segment.Stop = segment.Start + idx
node.Lines().Append(segment)
node.Closed = true
node.Inline = true
return node, parser.Close | parser.NoChildren
}
segment.Start += pos + 2
node.Lines().Append(segment)
return node, parser.NoChildren
}
// Continue parses the current line and returns a result of parsing.
func (b *blockParser) Continue(node ast.Node, reader text.Reader, pc parser.Context) parser.State {
block := node.(*Block)
if block.Closed {
return parser.Close
}
line, segment := reader.PeekLine()
w, pos := util.IndentWidth(line, reader.LineOffset())
if w < 4 {
endBytes := giteaUtil.Iif(block.Dollars, b.endBytesDollars, b.endBytesBracket)
if bytes.HasPrefix(line[pos:], endBytes) && util.IsBlank(line[pos+len(endBytes):]) {
if util.IsBlank(line[pos+len(endBytes):]) {
newline := giteaUtil.Iif(line[len(line)-1] != '\n', 0, 1)
reader.Advance(segment.Stop - segment.Start - newline + segment.Padding)
return parser.Close
}
}
}
start := segment.Start + giteaUtil.Iif(pos > block.Indent, block.Indent, pos)
seg := text.NewSegmentPadding(start, segment.Stop, segment.Padding)
node.Lines().Append(seg)
return parser.Continue | parser.NoChildren
}
// Close will be called when the parser returns Close.
func (b *blockParser) Close(node ast.Node, reader text.Reader, pc parser.Context) {
// noop
}
// CanInterruptParagraph returns true if the parser can interrupt paragraphs,
// otherwise false.
func (b *blockParser) CanInterruptParagraph() bool {
return true
}
// CanAcceptIndentedLine returns true if the parser can open new node when
// the given line is being indented more than 3 spaces.
func (b *blockParser) CanAcceptIndentedLine() bool {
return false
}
// Trigger returns a list of characters that triggers Parse method of
// this parser.
// If Trigger returns a nil, Open will be called with any lines.
//
// We leave this as nil as our parse method is quick enough
func (b *blockParser) Trigger() []byte {
return nil
}