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forgejo/modules/markup/markdown/math/block_parser.go
Gusted e1a82a15d3
[GITEA] Require Latex code to have a end sequence
- Currently the parser will look for `\[` and `$$` to detect when Latex
code starts, it will look for `\]` and `$$` respectively in order to
determine the end of the code. However if no end is found the parser
assumes the rest of the input is part of the Latex code.
- Adjust the parser's behavior to not allow the case to assume the rest
of the input is part of the Latex code and requires in order to
determine if some input is Latex code that the end sequence is also
specified.
- Example: `\[hello]` would no longer be detected as Latex code with
this patch.
- Added unit tests.
- Resolves https://codeberg.org/forgejo/forgejo/issues/1817

(cherry picked from commit 452aef1bb1)
(cherry picked from commit 8a857c24b0)
(cherry picked from commit acd1456db9)
(cherry picked from commit 6523b45073)
(cherry picked from commit e2e1a8afe7)
(cherry picked from commit a46ef652eb)
(cherry picked from commit 54d5a8c073)
(cherry picked from commit 4a88dc6416)
(cherry picked from commit f88b58be3f)
(cherry picked from commit 316ff9767f)
2024-02-05 16:09:41 +01:00

119 lines
3.3 KiB
Go

// Copyright 2022 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package math
import (
"bytes"
"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
}
// NewBlockParser creates a new math BlockParser
func NewBlockParser(parseDollarBlocks bool) parser.BlockParser {
return &blockParser{
parseDollars: parseDollarBlocks,
}
}
// 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
}
dollars := false
if b.parseDollars && line[pos] == '$' && line[pos+1] == '$' {
dollars = true
} else if line[pos] != '\\' || line[pos+1] != '[' {
return nil, parser.NoChildren
}
node := NewBlock(dollars, pos)
// Now we need to check if the ending block is on the segment...
endBytes := []byte{'\\', ']'}
if dollars {
endBytes = []byte{'$', '$'}
}
idx := bytes.Index(line[pos+2:], endBytes)
if idx >= 0 {
segment.Stop = segment.Start + idx + 2
reader.Advance(segment.Len() - 1)
segment.Start += 2
node.Lines().Append(segment)
node.Closed = true
return node, parser.Close | parser.NoChildren
}
return nil, 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, 0)
if w < 4 {
if block.Dollars {
i := pos
for ; i < len(line) && line[i] == '$'; i++ {
}
length := i - pos
if length >= 2 && util.IsBlank(line[i:]) {
reader.Advance(segment.Stop - segment.Start - segment.Padding)
block.Closed = true
return parser.Close
}
} else if len(line[pos:]) > 1 && line[pos] == '\\' && line[pos+1] == ']' && util.IsBlank(line[pos+2:]) {
reader.Advance(segment.Stop - segment.Start - segment.Padding)
block.Closed = true
return parser.Close
}
}
pos, padding := util.IndentPosition(line, 0, block.Indent)
seg := text.NewSegmentPadding(segment.Start+pos, segment.Stop, padding)
node.Lines().Append(seg)
reader.AdvanceAndSetPadding(segment.Stop-segment.Start-pos-1, padding)
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
}