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-rw-r--r--modules/markup/markdown/math/block_parser.go125
1 files changed, 125 insertions, 0 deletions
diff --git a/modules/markup/markdown/math/block_parser.go b/modules/markup/markdown/math/block_parser.go
new file mode 100644
index 0000000..527df84
--- /dev/null
+++ b/modules/markup/markdown/math/block_parser.go
@@ -0,0 +1,125 @@
+// 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 {
+ // for case $$ ... $$ any other text
+ for i := pos + idx + 4; i < len(line); i++ {
+ if line[i] != ' ' && line[i] != '\n' {
+ return nil, parser.NoChildren
+ }
+ }
+ 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
+}