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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-10-11 10:27:00 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-10-11 10:27:00 +0000 |
commit | 65aa53fc52ff15efe54df4147564828d535837f8 (patch) | |
tree | 31c51dad04fdcca80e6d3043c8bd49d2f1a51f83 /modules/markup/markdown/markdown.go | |
parent | Initial commit. (diff) | |
download | forgejo-upstream.tar.xz forgejo-upstream.zip |
Adding upstream version 8.0.3.HEADupstream/8.0.3upstreamdebian
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'modules/markup/markdown/markdown.go')
-rw-r--r-- | modules/markup/markdown/markdown.go | 305 |
1 files changed, 305 insertions, 0 deletions
diff --git a/modules/markup/markdown/markdown.go b/modules/markup/markdown/markdown.go new file mode 100644 index 00000000..77c876df --- /dev/null +++ b/modules/markup/markdown/markdown.go @@ -0,0 +1,305 @@ +// Copyright 2014 The Gogs Authors. All rights reserved. +// Copyright 2018 The Gitea Authors. All rights reserved. +// SPDX-License-Identifier: MIT + +package markdown + +import ( + "fmt" + "html/template" + "io" + "strings" + "sync" + + "code.gitea.io/gitea/modules/log" + "code.gitea.io/gitea/modules/markup" + "code.gitea.io/gitea/modules/markup/common" + "code.gitea.io/gitea/modules/markup/markdown/callout" + "code.gitea.io/gitea/modules/markup/markdown/math" + "code.gitea.io/gitea/modules/setting" + giteautil "code.gitea.io/gitea/modules/util" + + chromahtml "github.com/alecthomas/chroma/v2/formatters/html" + "github.com/yuin/goldmark" + highlighting "github.com/yuin/goldmark-highlighting/v2" + meta "github.com/yuin/goldmark-meta" + "github.com/yuin/goldmark/extension" + "github.com/yuin/goldmark/parser" + "github.com/yuin/goldmark/renderer" + "github.com/yuin/goldmark/renderer/html" + "github.com/yuin/goldmark/util" +) + +var ( + specMarkdown goldmark.Markdown + specMarkdownOnce sync.Once +) + +var ( + renderContextKey = parser.NewContextKey() + renderConfigKey = parser.NewContextKey() +) + +type limitWriter struct { + w io.Writer + sum int64 + limit int64 +} + +// Write implements the standard Write interface: +func (l *limitWriter) Write(data []byte) (int, error) { + leftToWrite := l.limit - l.sum + if leftToWrite < int64(len(data)) { + n, err := l.w.Write(data[:leftToWrite]) + l.sum += int64(n) + if err != nil { + return n, err + } + return n, fmt.Errorf("rendered content too large - truncating render") + } + n, err := l.w.Write(data) + l.sum += int64(n) + return n, err +} + +// newParserContext creates a parser.Context with the render context set +func newParserContext(ctx *markup.RenderContext) parser.Context { + pc := parser.NewContext(parser.WithIDs(newPrefixedIDs())) + pc.Set(renderContextKey, ctx) + return pc +} + +// SpecializedMarkdown sets up the Gitea specific markdown extensions +func SpecializedMarkdown() goldmark.Markdown { + specMarkdownOnce.Do(func() { + specMarkdown = goldmark.New( + goldmark.WithExtensions( + extension.NewTable( + extension.WithTableCellAlignMethod(extension.TableCellAlignAttribute)), + extension.Strikethrough, + extension.TaskList, + extension.DefinitionList, + common.FootnoteExtension, + highlighting.NewHighlighting( + highlighting.WithFormatOptions( + chromahtml.WithClasses(true), + chromahtml.PreventSurroundingPre(true), + ), + highlighting.WithWrapperRenderer(func(w util.BufWriter, c highlighting.CodeBlockContext, entering bool) { + if entering { + language, _ := c.Language() + if language == nil { + language = []byte("text") + } + + languageStr := string(language) + + preClasses := []string{"code-block"} + if languageStr == "mermaid" || languageStr == "math" { + preClasses = append(preClasses, "is-loading") + } + + _, err := w.WriteString(`<pre class="` + strings.Join(preClasses, " ") + `">`) + if err != nil { + return + } + + // include language-x class as part of commonmark spec + // the "display" class is used by "js/markup/math.js" to render the code element as a block + _, err = w.WriteString(`<code class="chroma language-` + string(language) + ` display">`) + if err != nil { + return + } + } else { + _, err := w.WriteString("</code></pre>") + if err != nil { + return + } + } + }), + ), + math.NewExtension( + math.Enabled(setting.Markdown.EnableMath), + ), + meta.Meta, + ), + goldmark.WithParserOptions( + parser.WithAttribute(), + parser.WithAutoHeadingID(), + parser.WithASTTransformers( + util.Prioritized(&callout.GitHubLegacyCalloutTransformer{}, 8000), + util.Prioritized(&callout.GitHubCalloutTransformer{}, 9000), + util.Prioritized(&ASTTransformer{}, 10000), + ), + ), + goldmark.WithRendererOptions( + html.WithUnsafe(), + ), + ) + + // Override the original Tasklist renderer! + specMarkdown.Renderer().AddOptions( + renderer.WithNodeRenderers( + util.Prioritized(callout.NewGitHubCalloutHTMLRenderer(), 10), + util.Prioritized(NewHTMLRenderer(), 10), + ), + ) + }) + return specMarkdown +} + +// actualRender renders Markdown to HTML without handling special links. +func actualRender(ctx *markup.RenderContext, input io.Reader, output io.Writer) error { + converter := SpecializedMarkdown() + lw := &limitWriter{ + w: output, + limit: setting.UI.MaxDisplayFileSize * 3, + } + + // FIXME: should we include a timeout to abort the renderer if it takes too long? + defer func() { + err := recover() + if err == nil { + return + } + + log.Warn("Unable to render markdown due to panic in goldmark: %v", err) + if log.IsDebug() { + log.Debug("Panic in markdown: %v\n%s", err, log.Stack(2)) + } + }() + + // FIXME: Don't read all to memory, but goldmark doesn't support + pc := newParserContext(ctx) + buf, err := io.ReadAll(input) + if err != nil { + log.Error("Unable to ReadAll: %v", err) + return err + } + buf = giteautil.NormalizeEOL(buf) + + // Preserve original length. + bufWithMetadataLength := len(buf) + + rc := &RenderConfig{ + Meta: renderMetaModeFromString(string(ctx.RenderMetaAs)), + Icon: "table", + Lang: "", + } + buf, _ = ExtractMetadataBytes(buf, rc) + + metaLength := bufWithMetadataLength - len(buf) + if metaLength < 0 { + metaLength = 0 + } + rc.metaLength = metaLength + + pc.Set(renderConfigKey, rc) + + if err := converter.Convert(buf, lw, parser.WithContext(pc)); err != nil { + log.Error("Unable to render: %v", err) + return err + } + + return nil +} + +// Note: The output of this method must get sanitized. +func render(ctx *markup.RenderContext, input io.Reader, output io.Writer) error { + defer func() { + err := recover() + if err == nil { + return + } + + log.Warn("Unable to render markdown due to panic in goldmark - will return raw bytes") + if log.IsDebug() { + log.Debug("Panic in markdown: %v\n%s", err, log.Stack(2)) + } + _, err = io.Copy(output, input) + if err != nil { + log.Error("io.Copy failed: %v", err) + } + }() + return actualRender(ctx, input, output) +} + +// MarkupName describes markup's name +var MarkupName = "markdown" + +func init() { + markup.RegisterRenderer(Renderer{}) +} + +// Renderer implements markup.Renderer +type Renderer struct{} + +var _ markup.PostProcessRenderer = (*Renderer)(nil) + +// Name implements markup.Renderer +func (Renderer) Name() string { + return MarkupName +} + +// NeedPostProcess implements markup.PostProcessRenderer +func (Renderer) NeedPostProcess() bool { return true } + +// Extensions implements markup.Renderer +func (Renderer) Extensions() []string { + return setting.Markdown.FileExtensions +} + +// SanitizerRules implements markup.Renderer +func (Renderer) SanitizerRules() []setting.MarkupSanitizerRule { + return []setting.MarkupSanitizerRule{} +} + +// Render implements markup.Renderer +func (Renderer) Render(ctx *markup.RenderContext, input io.Reader, output io.Writer) error { + return render(ctx, input, output) +} + +// Render renders Markdown to HTML with all specific handling stuff. +func Render(ctx *markup.RenderContext, input io.Reader, output io.Writer) error { + if ctx.Type == "" { + ctx.Type = MarkupName + } + return markup.Render(ctx, input, output) +} + +// RenderString renders Markdown string to HTML with all specific handling stuff and return string +func RenderString(ctx *markup.RenderContext, content string) (template.HTML, error) { + var buf strings.Builder + if err := Render(ctx, strings.NewReader(content), &buf); err != nil { + return "", err + } + return template.HTML(buf.String()), nil +} + +// RenderRaw renders Markdown to HTML without handling special links. +func RenderRaw(ctx *markup.RenderContext, input io.Reader, output io.Writer) error { + rd, wr := io.Pipe() + defer func() { + _ = rd.Close() + _ = wr.Close() + }() + + go func() { + if err := render(ctx, input, wr); err != nil { + _ = wr.CloseWithError(err) + return + } + _ = wr.Close() + }() + + return markup.SanitizeReader(rd, "", output) +} + +// RenderRawString renders Markdown to HTML without handling special links and return string +func RenderRawString(ctx *markup.RenderContext, content string) (string, error) { + var buf strings.Builder + if err := RenderRaw(ctx, strings.NewReader(content), &buf); err != nil { + return "", err + } + return buf.String(), nil +} |