first-commit

modules/markup/markdown/math/block_node.go

@@ -0,0 +1,42 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package math
+
+import "github.com/yuin/goldmark/ast"
+
+// Block represents a display math block e.g. $$...$$ or \[...\]
+type Block struct {
+	ast.BaseBlock
+	Dollars bool
+	Indent  int
+	Closed  bool
+	Inline  bool
+}
+
+// KindBlock is the node kind for math blocks
+var KindBlock = ast.NewNodeKind("MathBlock")
+
+// NewBlock creates a new math Block
+func NewBlock(dollars bool, indent int) *Block {
+	return &Block{
+		Dollars: dollars,
+		Indent:  indent,
+	}
+}
+
+// Dump dumps the block to a string
+func (n *Block) Dump(source []byte, level int) {
+	m := map[string]string{}
+	ast.DumpHelper(n, source, level, m, nil)
+}
+
+// Kind returns KindBlock for math Blocks
+func (n *Block) Kind() ast.NodeKind {
+	return KindBlock
+}
+
+// IsRaw returns true as this block should not be processed further
+func (n *Block) IsRaw() bool {
+	return true
+}

modules/markup/markdown/math/block_parser.go

@@ -0,0 +1,136 @@
+// 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
+	parseSquare     bool
+	endBytesDollars []byte
+	endBytesSquare  []byte
+}
+
+// NewBlockParser creates a new math BlockParser
+func NewBlockParser(parseDollars, parseSquare bool) parser.BlockParser {
+	return &blockParser{
+		parseDollars:    parseDollars,
+		parseSquare:     parseSquare,
+		endBytesDollars: []byte{'$', '$'},
+		endBytesSquare:  []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 b.parseSquare && 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.endBytesSquare)
+	idx := bytes.Index(line[pos+2:], endBytes)
+	if idx >= 0 {
+		// for case: "$$ ... $$ any other text" (this case will be handled by the inline parser)
+		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
+	}
+
+	// for case "\[ ... ]" (no close marker on the same line)
+	for i := pos + 2 + idx + 2; i < len(line); i++ {
+		if line[i] != ' ' && line[i] != '\n' {
+			return nil, 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.endBytesSquare)
+		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
+}

modules/markup/markdown/math/block_renderer.go

@@ -0,0 +1,61 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package math
+
+import (
+	"html/template"
+
+	"code.gitea.io/gitea/modules/markup/internal"
+	giteaUtil "code.gitea.io/gitea/modules/util"
+
+	gast "github.com/yuin/goldmark/ast"
+	"github.com/yuin/goldmark/renderer"
+	"github.com/yuin/goldmark/util"
+)
+
+// Block render output:
+// 	<pre class="code-block is-loading"><code class="language-math display">...</code></pre>
+//
+// Keep in mind that there is another "code block" render in "func (r *GlodmarkRender) highlightingRenderer"
+// "highlightingRenderer" outputs the math block with extra "chroma" class:
+// 	<pre class="code-block is-loading"><code class="chroma language-math display">...</code></pre>
+//
+// Special classes:
+// * "is-loading": show a loading indicator
+// * "display": used by JS to decide to render as a block, otherwise render as inline
+
+// BlockRenderer represents a renderer for math Blocks
+type BlockRenderer struct {
+	renderInternal *internal.RenderInternal
+}
+
+// NewBlockRenderer creates a new renderer for math Blocks
+func NewBlockRenderer(renderInternal *internal.RenderInternal) renderer.NodeRenderer {
+	return &BlockRenderer{renderInternal: renderInternal}
+}
+
+// RegisterFuncs registers the renderer for math Blocks
+func (r *BlockRenderer) RegisterFuncs(reg renderer.NodeRendererFuncRegisterer) {
+	reg.Register(KindBlock, r.renderBlock)
+}
+
+func (r *BlockRenderer) writeLines(w util.BufWriter, source []byte, n gast.Node) {
+	l := n.Lines().Len()
+	for i := range l {
+		line := n.Lines().At(i)
+		_, _ = w.Write(util.EscapeHTML(line.Value(source)))
+	}
+}
+
+func (r *BlockRenderer) renderBlock(w util.BufWriter, source []byte, node gast.Node, entering bool) (gast.WalkStatus, error) {
+	n := node.(*Block)
+	if entering {
+		codeHTML := giteaUtil.Iif[template.HTML](n.Inline, "", `<pre class="code-block is-loading">`) + `<code class="language-math display">`
+		_, _ = w.WriteString(string(r.renderInternal.ProtectSafeAttrs(codeHTML)))
+		r.writeLines(w, source, n)
+	} else {
+		_, _ = w.WriteString(`</code>` + giteaUtil.Iif(n.Inline, "", `</pre>`) + "\n")
+	}
+	return gast.WalkContinue, nil
+}

modules/markup/markdown/math/inline_node.go

@@ -0,0 +1,48 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package math
+
+import (
+	"github.com/yuin/goldmark/ast"
+	"github.com/yuin/goldmark/util"
+)
+
+// Inline struct represents inline math e.g. $...$ or \(...\)
+type Inline struct {
+	ast.BaseInline
+}
+
+// Inline implements Inline.Inline.
+func (n *Inline) Inline() {}
+
+// IsBlank returns if this inline node is empty
+func (n *Inline) IsBlank(source []byte) bool {
+	for c := n.FirstChild(); c != nil; c = c.NextSibling() {
+		text := c.(*ast.Text).Segment
+		if !util.IsBlank(text.Value(source)) {
+			return false
+		}
+	}
+	return true
+}
+
+// Dump renders this inline math as debug
+func (n *Inline) Dump(source []byte, level int) {
+	ast.DumpHelper(n, source, level, nil, nil)
+}
+
+// KindInline is the kind for math inline
+var KindInline = ast.NewNodeKind("MathInline")
+
+// Kind returns KindInline
+func (n *Inline) Kind() ast.NodeKind {
+	return KindInline
+}
+
+// NewInline creates a new ast math inline node
+func NewInline() *Inline {
+	return &Inline{
+		BaseInline: ast.BaseInline{},
+	}
+}

modules/markup/markdown/math/inline_parser.go

@@ -0,0 +1,169 @@
+// 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"
+)
+
+type inlineParser struct {
+	trigger              []byte
+	endBytesSingleDollar []byte
+	endBytesDoubleDollar []byte
+	endBytesParentheses  []byte
+	enableInlineDollar   bool
+}
+
+func NewInlineDollarParser(enableInlineDollar bool) parser.InlineParser {
+	return &inlineParser{
+		trigger:              []byte{'$'},
+		endBytesSingleDollar: []byte{'$'},
+		endBytesDoubleDollar: []byte{'$', '$'},
+		enableInlineDollar:   enableInlineDollar,
+	}
+}
+
+var defaultInlineParenthesesParser = &inlineParser{
+	trigger:             []byte{'\\', '('},
+	endBytesParentheses: []byte{'\\', ')'},
+}
+
+func NewInlineParenthesesParser() parser.InlineParser {
+	return defaultInlineParenthesesParser
+}
+
+// Trigger triggers this parser on $ or \
+func (parser *inlineParser) Trigger() []byte {
+	return parser.trigger
+}
+
+func isPunctuation(b byte) bool {
+	return b == '.' || b == '!' || b == '?' || b == ',' || b == ';' || b == ':'
+}
+
+func isParenthesesClose(b byte) bool {
+	return b == ')'
+}
+
+func isAlphanumeric(b byte) bool {
+	return (b >= 'a' && b <= 'z') || (b >= 'A' && b <= 'Z') || (b >= '0' && b <= '9')
+}
+
+// Parse parses the current line and returns a result of parsing.
+func (parser *inlineParser) Parse(parent ast.Node, block text.Reader, pc parser.Context) ast.Node {
+	line, _ := block.PeekLine()
+
+	if !bytes.HasPrefix(line, parser.trigger) {
+		// We'll catch this one on the next time round
+		return nil
+	}
+
+	var startMarkLen int
+	var stopMark []byte
+	checkSurrounding := true
+	if line[0] == '$' {
+		startMarkLen = 1
+		stopMark = parser.endBytesSingleDollar
+		if len(line) > 1 {
+			switch line[1] {
+			case '$':
+				startMarkLen = 2
+				stopMark = parser.endBytesDoubleDollar
+			case '`':
+				pos := 1
+				for ; pos < len(line) && line[pos] == '`'; pos++ {
+				}
+				startMarkLen = pos
+				stopMark = bytes.Repeat([]byte{'`'}, pos)
+				stopMark[len(stopMark)-1] = '$'
+				checkSurrounding = false
+			}
+		}
+	} else {
+		startMarkLen = 2
+		stopMark = parser.endBytesParentheses
+	}
+
+	if line[0] == '$' && !parser.enableInlineDollar && (len(line) == 1 || line[1] != '`') {
+		return nil
+	}
+
+	if checkSurrounding {
+		precedingCharacter := block.PrecendingCharacter()
+		if precedingCharacter < 256 && (isAlphanumeric(byte(precedingCharacter)) || isPunctuation(byte(precedingCharacter))) {
+			// need to exclude things like `a$` from being considered a start
+			return nil
+		}
+	}
+
+	// move the opener marker point at the start of the text
+	opener := startMarkLen
+
+	// Now look for an ending line
+	depth := 0
+	ender := -1
+	for i := opener; i < len(line); i++ {
+		if depth == 0 && bytes.HasPrefix(line[i:], stopMark) {
+			succeedingCharacter := byte(0)
+			if i+len(stopMark) < len(line) {
+				succeedingCharacter = line[i+len(stopMark)]
+			}
+			// check valid ending character
+			isValidEndingChar := isPunctuation(succeedingCharacter) || isParenthesesClose(succeedingCharacter) ||
+				succeedingCharacter == ' ' || succeedingCharacter == '\n' || succeedingCharacter == 0
+			if checkSurrounding && !isValidEndingChar {
+				break
+			}
+			ender = i
+			break
+		}
+		if line[i] == '\\' {
+			i++
+			continue
+		}
+		switch line[i] {
+		case '{':
+			depth++
+		case '}':
+			depth--
+		}
+	}
+	if ender == -1 {
+		return nil
+	}
+
+	block.Advance(opener)
+	_, pos := block.Position()
+	node := NewInline()
+
+	segment := pos.WithStop(pos.Start + ender - opener)
+	node.AppendChild(node, ast.NewRawTextSegment(segment))
+	block.Advance(ender - opener + len(stopMark))
+	trimBlock(node, block)
+	return node
+}
+
+func trimBlock(node *Inline, block text.Reader) {
+	if node.IsBlank(block.Source()) {
+		return
+	}
+
+	// trim first space and last space
+	first := node.FirstChild().(*ast.Text)
+	if !(!first.Segment.IsEmpty() && block.Source()[first.Segment.Start] == ' ') {
+		return
+	}
+
+	last := node.LastChild().(*ast.Text)
+	if !(!last.Segment.IsEmpty() && block.Source()[last.Segment.Stop-1] == ' ') {
+		return
+	}
+
+	first.Segment = first.Segment.WithStart(first.Segment.Start + 1)
+	last.Segment = last.Segment.WithStop(last.Segment.Stop - 1)
+}

modules/markup/markdown/math/inline_renderer.go

@@ -0,0 +1,53 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package math
+
+import (
+	"bytes"
+
+	"code.gitea.io/gitea/modules/markup/internal"
+
+	"github.com/yuin/goldmark/ast"
+	"github.com/yuin/goldmark/renderer"
+	"github.com/yuin/goldmark/util"
+)
+
+// Inline render output:
+// <code class="language-math">...</code>
+
+// InlineRenderer is an inline renderer
+type InlineRenderer struct {
+	renderInternal *internal.RenderInternal
+}
+
+// NewInlineRenderer returns a new renderer for inline math
+func NewInlineRenderer(renderInternal *internal.RenderInternal) renderer.NodeRenderer {
+	return &InlineRenderer{renderInternal: renderInternal}
+}
+
+func (r *InlineRenderer) renderInline(w util.BufWriter, source []byte, n ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		_, _ = w.WriteString(string(r.renderInternal.ProtectSafeAttrs(`<code class="language-math">`)))
+		for c := n.FirstChild(); c != nil; c = c.NextSibling() {
+			segment := c.(*ast.Text).Segment
+			value := util.EscapeHTML(segment.Value(source))
+			if bytes.HasSuffix(value, []byte("\n")) {
+				_, _ = w.Write(value[:len(value)-1])
+				if c != n.LastChild() {
+					_, _ = w.Write([]byte(" "))
+				}
+			} else {
+				_, _ = w.Write(value)
+			}
+		}
+		return ast.WalkSkipChildren, nil
+	}
+	_, _ = w.WriteString(`</code>`)
+	return ast.WalkContinue, nil
+}
+
+// RegisterFuncs registers the renderer for inline math nodes
+func (r *InlineRenderer) RegisterFuncs(reg renderer.NodeRendererFuncRegisterer) {
+	reg.Register(KindInline, r.renderInline)
+}

modules/markup/markdown/math/math.go

@@ -0,0 +1,60 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package math
+
+import (
+	"code.gitea.io/gitea/modules/markup/internal"
+	giteaUtil "code.gitea.io/gitea/modules/util"
+
+	"github.com/yuin/goldmark"
+	"github.com/yuin/goldmark/parser"
+	"github.com/yuin/goldmark/renderer"
+	"github.com/yuin/goldmark/util"
+)
+
+type Options struct {
+	Enabled                  bool
+	ParseInlineDollar        bool // inline $$ xxx $$ text
+	ParseInlineParentheses   bool // inline \( xxx \) text
+	ParseBlockDollar         bool // block $$ multiple-line $$ text
+	ParseBlockSquareBrackets bool // block \[ multiple-line \] text
+}
+
+// Extension is a math extension
+type Extension struct {
+	renderInternal *internal.RenderInternal
+	options        Options
+}
+
+// NewExtension creates a new math extension with the provided options
+func NewExtension(renderInternal *internal.RenderInternal, opts ...Options) *Extension {
+	opt := giteaUtil.OptionalArg(opts)
+	r := &Extension{
+		renderInternal: renderInternal,
+		options:        opt,
+	}
+	return r
+}
+
+// Extend extends goldmark with our parsers and renderers
+func (e *Extension) Extend(m goldmark.Markdown) {
+	if !e.options.Enabled {
+		return
+	}
+
+	var inlines []util.PrioritizedValue
+	if e.options.ParseInlineParentheses {
+		inlines = append(inlines, util.Prioritized(NewInlineParenthesesParser(), 501))
+	}
+	inlines = append(inlines, util.Prioritized(NewInlineDollarParser(e.options.ParseInlineDollar), 502))
+
+	m.Parser().AddOptions(parser.WithInlineParsers(inlines...))
+	m.Parser().AddOptions(parser.WithBlockParsers(
+		util.Prioritized(NewBlockParser(e.options.ParseBlockDollar, e.options.ParseBlockSquareBrackets), 701),
+	))
+	m.Renderer().AddOptions(renderer.WithNodeRenderers(
+		util.Prioritized(NewBlockRenderer(e.renderInternal), 501),
+		util.Prioritized(NewInlineRenderer(e.renderInternal), 502),
+	))
+}