27757714d0
* Move to goldmark Markdown rendering moved from blackfriday to the goldmark. Multiple subtle changes required to the goldmark extensions to keep current rendering and defaults. Can go further with goldmark linkify and have this work within markdown rendering making the link processor unnecessary. Need to think about how to go about allowing extensions - at present it seems that these would be hard to do without recompilation. * linter fixes Co-authored-by: Lauris BH <lauris@nix.lv>
133 lines
3.2 KiB
Go
133 lines
3.2 KiB
Go
// Copyright 2019 The Gitea Authors. All rights reserved.
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// Use of this source code is governed by a MIT-style
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// license that can be found in the LICENSE file.
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package mdstripper
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import (
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"bytes"
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"sync"
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"io"
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"code.gitea.io/gitea/modules/log"
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"code.gitea.io/gitea/modules/markup/common"
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"github.com/yuin/goldmark"
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"github.com/yuin/goldmark/ast"
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"github.com/yuin/goldmark/extension"
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"github.com/yuin/goldmark/parser"
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"github.com/yuin/goldmark/renderer"
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"github.com/yuin/goldmark/renderer/html"
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"github.com/yuin/goldmark/text"
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)
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type stripRenderer struct {
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links []string
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empty bool
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}
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func (r *stripRenderer) Render(w io.Writer, source []byte, doc ast.Node) error {
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return ast.Walk(doc, func(n ast.Node, entering bool) (ast.WalkStatus, error) {
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if !entering {
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return ast.WalkContinue, nil
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}
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switch v := n.(type) {
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case *ast.Text:
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if !v.IsRaw() {
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_, prevSibIsText := n.PreviousSibling().(*ast.Text)
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coalesce := prevSibIsText
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r.processString(
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w,
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v.Text(source),
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coalesce)
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if v.SoftLineBreak() {
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r.doubleSpace(w)
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}
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}
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return ast.WalkContinue, nil
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case *ast.Link:
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r.processLink(w, v.Destination)
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return ast.WalkSkipChildren, nil
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case *ast.AutoLink:
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r.processLink(w, v.URL(source))
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return ast.WalkSkipChildren, nil
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}
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return ast.WalkContinue, nil
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})
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}
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func (r *stripRenderer) doubleSpace(w io.Writer) {
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if !r.empty {
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_, _ = w.Write([]byte{'\n'})
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}
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}
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func (r *stripRenderer) processString(w io.Writer, text []byte, coalesce bool) {
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// Always break-up words
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if !coalesce {
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r.doubleSpace(w)
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}
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_, _ = w.Write(text)
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r.empty = false
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}
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func (r *stripRenderer) processLink(w io.Writer, link []byte) {
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// Links are processed out of band
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r.links = append(r.links, string(link))
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}
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// GetLinks returns the list of link data collected while parsing
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func (r *stripRenderer) GetLinks() []string {
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return r.links
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}
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// AddOptions adds given option to this renderer.
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func (r *stripRenderer) AddOptions(...renderer.Option) {
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// no-op
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}
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// StripMarkdown parses markdown content by removing all markup and code blocks
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// in order to extract links and other references
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func StripMarkdown(rawBytes []byte) (string, []string) {
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buf, links := StripMarkdownBytes(rawBytes)
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return string(buf), links
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}
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var stripParser parser.Parser
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var once = sync.Once{}
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// StripMarkdownBytes parses markdown content by removing all markup and code blocks
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// in order to extract links and other references
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func StripMarkdownBytes(rawBytes []byte) ([]byte, []string) {
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once.Do(func() {
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gdMarkdown := goldmark.New(
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goldmark.WithExtensions(extension.Table,
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extension.Strikethrough,
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extension.TaskList,
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extension.DefinitionList,
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common.FootnoteExtension,
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common.Linkify,
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),
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goldmark.WithParserOptions(
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parser.WithAttribute(),
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parser.WithAutoHeadingID(),
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),
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goldmark.WithRendererOptions(
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html.WithUnsafe(),
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),
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)
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stripParser = gdMarkdown.Parser()
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})
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stripper := &stripRenderer{
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links: make([]string, 0, 10),
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empty: true,
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}
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reader := text.NewReader(rawBytes)
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doc := stripParser.Parse(reader)
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var buf bytes.Buffer
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if err := stripper.Render(&buf, rawBytes, doc); err != nil {
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log.Error("Unable to strip: %v", err)
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}
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return buf.Bytes(), stripper.GetLinks()
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}
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