Merge commit 'ad273dbe5dba7bd0e901270464e25fc1f030a5b5' as 'backend/goldmark'
This commit is contained in:
@@ -0,0 +1,962 @@
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// Package html implements renderer that outputs HTMLs.
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package html
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import (
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"bytes"
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"fmt"
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"strconv"
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"unicode"
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"unicode/utf8"
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"github.com/yuin/goldmark/ast"
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"github.com/yuin/goldmark/renderer"
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"github.com/yuin/goldmark/util"
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)
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// A Config struct has configurations for the HTML based renderers.
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type Config struct {
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Writer Writer
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HardWraps bool
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EastAsianLineBreaks EastAsianLineBreaks
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XHTML bool
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Unsafe bool
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}
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// NewConfig returns a new Config with defaults.
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func NewConfig() Config {
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return Config{
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Writer: DefaultWriter,
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HardWraps: false,
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EastAsianLineBreaks: EastAsianLineBreaksNone,
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XHTML: false,
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Unsafe: false,
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}
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}
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// SetOption implements renderer.NodeRenderer.SetOption.
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func (c *Config) SetOption(name renderer.OptionName, value any) {
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switch name {
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case optHardWraps:
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c.HardWraps = value.(bool)
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case optEastAsianLineBreaks:
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c.EastAsianLineBreaks = value.(EastAsianLineBreaks)
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case optXHTML:
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c.XHTML = value.(bool)
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case optUnsafe:
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c.Unsafe = value.(bool)
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case optTextWriter:
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c.Writer = value.(Writer)
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}
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}
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// An Option interface sets options for HTML based renderers.
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type Option interface {
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SetHTMLOption(*Config)
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}
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// TextWriter is an option name used in WithWriter.
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const optTextWriter renderer.OptionName = "Writer"
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type withWriter struct {
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value Writer
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}
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func (o *withWriter) SetConfig(c *renderer.Config) {
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c.Options[optTextWriter] = o.value
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}
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func (o *withWriter) SetHTMLOption(c *Config) {
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c.Writer = o.value
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}
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// WithWriter is a functional option that allow you to set the given writer to
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// the renderer.
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func WithWriter(writer Writer) interface {
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renderer.Option
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Option
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} {
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return &withWriter{writer}
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}
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// HardWraps is an option name used in WithHardWraps.
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const optHardWraps renderer.OptionName = "HardWraps"
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type withHardWraps struct {
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}
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func (o *withHardWraps) SetConfig(c *renderer.Config) {
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c.Options[optHardWraps] = true
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}
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func (o *withHardWraps) SetHTMLOption(c *Config) {
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c.HardWraps = true
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}
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// WithHardWraps is a functional option that indicates whether softline breaks
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// should be rendered as '<br>'.
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func WithHardWraps() interface {
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renderer.Option
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Option
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} {
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return &withHardWraps{}
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}
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// EastAsianLineBreaks is an option name used in WithEastAsianLineBreaks.
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const optEastAsianLineBreaks renderer.OptionName = "EastAsianLineBreaks"
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// A EastAsianLineBreaks is a style of east asian line breaks.
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type EastAsianLineBreaks int
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const (
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//EastAsianLineBreaksNone renders line breaks as it is.
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EastAsianLineBreaksNone EastAsianLineBreaks = iota
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// EastAsianLineBreaksSimple follows east_asian_line_breaks in Pandoc.
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EastAsianLineBreaksSimple
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// EastAsianLineBreaksCSS3Draft follows CSS text level3 "Segment Break Transformation Rules" with some enhancements.
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EastAsianLineBreaksCSS3Draft
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)
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func (b EastAsianLineBreaks) softLineBreak(thisLastRune rune, siblingFirstRune rune) bool {
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switch b {
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case EastAsianLineBreaksNone:
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return false
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case EastAsianLineBreaksSimple:
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return !(util.IsEastAsianWideRune(thisLastRune) && util.IsEastAsianWideRune(siblingFirstRune))
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case EastAsianLineBreaksCSS3Draft:
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return eastAsianLineBreaksCSS3DraftSoftLineBreak(thisLastRune, siblingFirstRune)
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}
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return false
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}
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func eastAsianLineBreaksCSS3DraftSoftLineBreak(thisLastRune rune, siblingFirstRune rune) bool {
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// Implements CSS text level3 Segment Break Transformation Rules with some enhancements.
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// References:
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// - https://www.w3.org/TR/2020/WD-css-text-3-20200429/#line-break-transform
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// - https://github.com/w3c/csswg-drafts/issues/5086
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// Rule1:
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// If the character immediately before or immediately after the segment break is
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// the zero-width space character (U+200B), then the break is removed, leaving behind the zero-width space.
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if thisLastRune == '\u200B' || siblingFirstRune == '\u200B' {
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return false
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}
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// Rule2:
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// Otherwise, if the East Asian Width property of both the character before and after the segment break is
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// F, W, or H (not A), and neither side is Hangul, then the segment break is removed.
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thisLastRuneEastAsianWidth := util.EastAsianWidth(thisLastRune)
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siblingFirstRuneEastAsianWidth := util.EastAsianWidth(siblingFirstRune)
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if (thisLastRuneEastAsianWidth == "F" ||
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thisLastRuneEastAsianWidth == "W" ||
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thisLastRuneEastAsianWidth == "H") &&
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(siblingFirstRuneEastAsianWidth == "F" ||
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siblingFirstRuneEastAsianWidth == "W" ||
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siblingFirstRuneEastAsianWidth == "H") {
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return unicode.Is(unicode.Hangul, thisLastRune) || unicode.Is(unicode.Hangul, siblingFirstRune)
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}
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// Rule3:
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// Otherwise, if either the character before or after the segment break belongs to
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// the space-discarding character set and it is a Unicode Punctuation (P*) or U+3000,
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// then the segment break is removed.
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if util.IsSpaceDiscardingUnicodeRune(thisLastRune) ||
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unicode.IsPunct(thisLastRune) ||
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thisLastRune == '\u3000' ||
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util.IsSpaceDiscardingUnicodeRune(siblingFirstRune) ||
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unicode.IsPunct(siblingFirstRune) ||
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siblingFirstRune == '\u3000' {
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return false
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}
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// Rule4:
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// Otherwise, the segment break is converted to a space (U+0020).
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return true
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}
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type withEastAsianLineBreaks struct {
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eastAsianLineBreaksStyle EastAsianLineBreaks
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}
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func (o *withEastAsianLineBreaks) SetConfig(c *renderer.Config) {
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c.Options[optEastAsianLineBreaks] = o.eastAsianLineBreaksStyle
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}
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func (o *withEastAsianLineBreaks) SetHTMLOption(c *Config) {
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c.EastAsianLineBreaks = o.eastAsianLineBreaksStyle
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}
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// WithEastAsianLineBreaks is a functional option that indicates whether softline breaks
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// between east asian wide characters should be ignored.
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func WithEastAsianLineBreaks(e EastAsianLineBreaks) interface {
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renderer.Option
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Option
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} {
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return &withEastAsianLineBreaks{e}
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}
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// XHTML is an option name used in WithXHTML.
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const optXHTML renderer.OptionName = "XHTML"
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type withXHTML struct {
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}
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func (o *withXHTML) SetConfig(c *renderer.Config) {
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c.Options[optXHTML] = true
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}
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func (o *withXHTML) SetHTMLOption(c *Config) {
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c.XHTML = true
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}
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// WithXHTML is a functional option indicates that nodes should be rendered in
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// xhtml instead of HTML5.
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func WithXHTML() interface {
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Option
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renderer.Option
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} {
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return &withXHTML{}
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}
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// Unsafe is an option name used in WithUnsafe.
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const optUnsafe renderer.OptionName = "Unsafe"
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type withUnsafe struct {
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}
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func (o *withUnsafe) SetConfig(c *renderer.Config) {
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c.Options[optUnsafe] = true
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}
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func (o *withUnsafe) SetHTMLOption(c *Config) {
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c.Unsafe = true
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}
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// WithUnsafe is a functional option that renders dangerous contents
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// (raw htmls and potentially dangerous links) as it is.
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func WithUnsafe() interface {
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renderer.Option
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Option
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} {
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return &withUnsafe{}
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}
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// A Renderer struct is an implementation of renderer.NodeRenderer that renders
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// nodes as (X)HTML.
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type Renderer struct {
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Config
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}
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// NewRenderer returns a new Renderer with given options.
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func NewRenderer(opts ...Option) renderer.NodeRenderer {
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r := &Renderer{
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Config: NewConfig(),
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}
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for _, opt := range opts {
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opt.SetHTMLOption(&r.Config)
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}
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return r
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}
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// RegisterFuncs implements NodeRenderer.RegisterFuncs .
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func (r *Renderer) RegisterFuncs(reg renderer.NodeRendererFuncRegisterer) {
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// blocks
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reg.Register(ast.KindDocument, r.renderDocument)
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reg.Register(ast.KindHeading, r.renderHeading)
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reg.Register(ast.KindBlockquote, r.renderBlockquote)
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reg.Register(ast.KindCodeBlock, r.renderCodeBlock)
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reg.Register(ast.KindFencedCodeBlock, r.renderFencedCodeBlock)
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reg.Register(ast.KindHTMLBlock, r.renderHTMLBlock)
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reg.Register(ast.KindList, r.renderList)
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reg.Register(ast.KindListItem, r.renderListItem)
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reg.Register(ast.KindParagraph, r.renderParagraph)
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reg.Register(ast.KindTextBlock, r.renderTextBlock)
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reg.Register(ast.KindThematicBreak, r.renderThematicBreak)
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reg.Register(ast.KindLinkReferenceDefinition, func(
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_ util.BufWriter, _ []byte, _ ast.Node, _ bool) (ast.WalkStatus, error) {
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return ast.WalkSkipChildren, nil
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})
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// inlines
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reg.Register(ast.KindAutoLink, r.renderAutoLink)
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reg.Register(ast.KindCodeSpan, r.renderCodeSpan)
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reg.Register(ast.KindEmphasis, r.renderEmphasis)
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reg.Register(ast.KindImage, r.renderImage)
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reg.Register(ast.KindLink, r.renderLink)
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reg.Register(ast.KindRawHTML, r.renderRawHTML)
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reg.Register(ast.KindText, r.renderText)
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reg.Register(ast.KindString, r.renderString)
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}
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func (r *Renderer) writeLines(w util.BufWriter, source []byte, n ast.Node) {
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l := n.Lines().Len()
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for i := range l {
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line := n.Lines().At(i)
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r.Writer.RawWrite(w, line.Value(source))
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}
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}
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// GlobalAttributeFilter defines attribute names which any elements can have.
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var GlobalAttributeFilter = util.NewBytesFilterString(`accesskey,autocapitalize,autofocus,class,contenteditable,dir,draggable,enterkeyhint,hidden,id,inert,inputmode,is,itemid,itemprop,itemref,itemscope,itemtype,lang,part,role,slot,spellcheck,style,tabindex,title,translate`) // nolint:lll
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func (r *Renderer) renderDocument(
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w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
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// nothing to do
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return ast.WalkContinue, nil
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}
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// HeadingAttributeFilter defines attribute names which heading elements can have.
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var HeadingAttributeFilter = GlobalAttributeFilter
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func (r *Renderer) renderHeading(
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w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
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n := node.(*ast.Heading)
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if entering {
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_, _ = w.WriteString("<h")
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_ = w.WriteByte("0123456"[n.Level])
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if n.Attributes() != nil {
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RenderAttributes(w, node, HeadingAttributeFilter)
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}
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_ = w.WriteByte('>')
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} else {
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_, _ = w.WriteString("</h")
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_ = w.WriteByte("0123456"[n.Level])
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_, _ = w.WriteString(">\n")
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}
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return ast.WalkContinue, nil
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}
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// BlockquoteAttributeFilter defines attribute names which blockquote elements can have.
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var BlockquoteAttributeFilter = GlobalAttributeFilter.ExtendString(`cite`)
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func (r *Renderer) renderBlockquote(
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w util.BufWriter, source []byte, n ast.Node, entering bool) (ast.WalkStatus, error) {
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if entering {
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if n.Attributes() != nil {
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_, _ = w.WriteString("<blockquote")
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RenderAttributes(w, n, BlockquoteAttributeFilter)
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_ = w.WriteByte('>')
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} else {
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_, _ = w.WriteString("<blockquote>\n")
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}
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} else {
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_, _ = w.WriteString("</blockquote>\n")
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}
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return ast.WalkContinue, nil
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}
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func (r *Renderer) renderCodeBlock(w util.BufWriter, source []byte, n ast.Node, entering bool) (ast.WalkStatus, error) {
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if entering {
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_, _ = w.WriteString("<pre><code>")
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r.writeLines(w, source, n)
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} else {
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_, _ = w.WriteString("</code></pre>\n")
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}
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return ast.WalkContinue, nil
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}
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func (r *Renderer) renderFencedCodeBlock(
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w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
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n := node.(*ast.FencedCodeBlock)
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if entering {
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_, _ = w.WriteString("<pre><code")
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language := n.Language(source)
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if language != nil {
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_, _ = w.WriteString(" class=\"language-")
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r.Writer.Write(w, language)
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_, _ = w.WriteString("\"")
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}
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_ = w.WriteByte('>')
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r.writeLines(w, source, n)
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} else {
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_, _ = w.WriteString("</code></pre>\n")
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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 *Renderer) renderHTMLBlock(
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w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
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n := node.(*ast.HTMLBlock)
|
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if entering {
|
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if r.Unsafe {
|
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l := n.Lines().Len()
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for i := range l {
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line := n.Lines().At(i)
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r.Writer.SecureWrite(w, line.Value(source))
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}
|
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} else {
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_, _ = w.WriteString("<!-- raw HTML omitted -->\n")
|
||||
}
|
||||
} else {
|
||||
if n.HasClosure() {
|
||||
if r.Unsafe {
|
||||
closure := n.ClosureLine
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r.Writer.SecureWrite(w, closure.Value(source))
|
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} else {
|
||||
_, _ = w.WriteString("<!-- raw HTML omitted -->\n")
|
||||
}
|
||||
}
|
||||
}
|
||||
return ast.WalkContinue, nil
|
||||
}
|
||||
|
||||
// ListAttributeFilter defines attribute names which list elements can have.
|
||||
var ListAttributeFilter = GlobalAttributeFilter.ExtendString(`start,reversed,type`)
|
||||
|
||||
func (r *Renderer) renderList(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
|
||||
n := node.(*ast.List)
|
||||
tag := "ul"
|
||||
if n.IsOrdered() {
|
||||
tag = "ol"
|
||||
}
|
||||
if entering {
|
||||
_ = w.WriteByte('<')
|
||||
_, _ = w.WriteString(tag)
|
||||
if n.IsOrdered() && n.Start != 1 {
|
||||
_, _ = fmt.Fprintf(w, " start=\"%d\"", n.Start)
|
||||
}
|
||||
if n.Attributes() != nil {
|
||||
RenderAttributes(w, n, ListAttributeFilter)
|
||||
}
|
||||
_, _ = w.WriteString(">\n")
|
||||
} else {
|
||||
_, _ = w.WriteString("</")
|
||||
_, _ = w.WriteString(tag)
|
||||
_, _ = w.WriteString(">\n")
|
||||
}
|
||||
return ast.WalkContinue, nil
|
||||
}
|
||||
|
||||
// ListItemAttributeFilter defines attribute names which list item elements can have.
|
||||
var ListItemAttributeFilter = GlobalAttributeFilter.ExtendString(`value`)
|
||||
|
||||
func (r *Renderer) renderListItem(w util.BufWriter, source []byte, n ast.Node, entering bool) (ast.WalkStatus, error) {
|
||||
if entering {
|
||||
if n.Attributes() != nil {
|
||||
_, _ = w.WriteString("<li")
|
||||
RenderAttributes(w, n, ListItemAttributeFilter)
|
||||
_ = w.WriteByte('>')
|
||||
} else {
|
||||
_, _ = w.WriteString("<li>")
|
||||
}
|
||||
fc := n.FirstChild()
|
||||
if fc != nil {
|
||||
if _, ok := fc.(*ast.TextBlock); !ok {
|
||||
_ = w.WriteByte('\n')
|
||||
}
|
||||
}
|
||||
} else {
|
||||
_, _ = w.WriteString("</li>\n")
|
||||
}
|
||||
return ast.WalkContinue, nil
|
||||
}
|
||||
|
||||
// ParagraphAttributeFilter defines attribute names which paragraph elements can have.
|
||||
var ParagraphAttributeFilter = GlobalAttributeFilter
|
||||
|
||||
func (r *Renderer) renderParagraph(w util.BufWriter, source []byte, n ast.Node, entering bool) (ast.WalkStatus, error) {
|
||||
if entering {
|
||||
if n.Attributes() != nil {
|
||||
_, _ = w.WriteString("<p")
|
||||
RenderAttributes(w, n, ParagraphAttributeFilter)
|
||||
_ = w.WriteByte('>')
|
||||
} else {
|
||||
_, _ = w.WriteString("<p>")
|
||||
}
|
||||
} else {
|
||||
_, _ = w.WriteString("</p>\n")
|
||||
}
|
||||
return ast.WalkContinue, nil
|
||||
}
|
||||
|
||||
func (r *Renderer) renderTextBlock(w util.BufWriter, source []byte, n ast.Node, entering bool) (ast.WalkStatus, error) {
|
||||
if !entering {
|
||||
if n.NextSibling() != nil && n.FirstChild() != nil {
|
||||
_ = w.WriteByte('\n')
|
||||
}
|
||||
}
|
||||
return ast.WalkContinue, nil
|
||||
}
|
||||
|
||||
// ThematicAttributeFilter defines attribute names which hr elements can have.
|
||||
var ThematicAttributeFilter = GlobalAttributeFilter.ExtendString(`align,color,noshade,size,width`)
|
||||
|
||||
func (r *Renderer) renderThematicBreak(
|
||||
w util.BufWriter, source []byte, n ast.Node, entering bool) (ast.WalkStatus, error) {
|
||||
if !entering {
|
||||
return ast.WalkContinue, nil
|
||||
}
|
||||
_, _ = w.WriteString("<hr")
|
||||
if n.Attributes() != nil {
|
||||
RenderAttributes(w, n, ThematicAttributeFilter)
|
||||
}
|
||||
if r.XHTML {
|
||||
_, _ = w.WriteString(" />\n")
|
||||
} else {
|
||||
_, _ = w.WriteString(">\n")
|
||||
}
|
||||
return ast.WalkContinue, nil
|
||||
}
|
||||
|
||||
// LinkAttributeFilter defines attribute names which link elements can have.
|
||||
var LinkAttributeFilter = GlobalAttributeFilter.ExtendString(`download,href,lang,media,ping,referrerpolicy,rel,shape,target`) // nolint:lll
|
||||
|
||||
func (r *Renderer) renderAutoLink(
|
||||
w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
|
||||
n := node.(*ast.AutoLink)
|
||||
if !entering {
|
||||
return ast.WalkContinue, nil
|
||||
}
|
||||
_, _ = w.WriteString(`<a href="`)
|
||||
url := util.URLEscape(n.URL(source), false)
|
||||
label := n.Label(source)
|
||||
if n.AutoLinkType == ast.AutoLinkEmail && !bytes.HasPrefix(bytes.ToLower(url), []byte("mailto:")) {
|
||||
_, _ = w.WriteString("mailto:")
|
||||
}
|
||||
if r.Unsafe || !IsDangerousURL(url) {
|
||||
_, _ = w.Write(util.EscapeHTML(url))
|
||||
}
|
||||
if n.Attributes() != nil {
|
||||
_ = w.WriteByte('"')
|
||||
RenderAttributes(w, n, LinkAttributeFilter)
|
||||
_ = w.WriteByte('>')
|
||||
} else {
|
||||
_, _ = w.WriteString(`">`)
|
||||
}
|
||||
_, _ = w.Write(util.EscapeHTML(label))
|
||||
_, _ = w.WriteString(`</a>`)
|
||||
return ast.WalkContinue, nil
|
||||
}
|
||||
|
||||
// CodeAttributeFilter defines attribute names which code elements can have.
|
||||
var CodeAttributeFilter = GlobalAttributeFilter
|
||||
|
||||
func (r *Renderer) renderCodeSpan(w util.BufWriter, source []byte, n ast.Node, entering bool) (ast.WalkStatus, error) {
|
||||
if entering {
|
||||
if n.Attributes() != nil {
|
||||
_, _ = w.WriteString("<code")
|
||||
RenderAttributes(w, n, CodeAttributeFilter)
|
||||
_ = w.WriteByte('>')
|
||||
} else {
|
||||
_, _ = w.WriteString("<code>")
|
||||
}
|
||||
for c := n.FirstChild(); c != nil; c = c.NextSibling() {
|
||||
segment := c.(*ast.Text).Segment
|
||||
value := segment.Value(source)
|
||||
if bytes.HasSuffix(value, []byte("\n")) {
|
||||
r.Writer.RawWrite(w, value[:len(value)-1])
|
||||
r.Writer.RawWrite(w, []byte(" "))
|
||||
} else {
|
||||
r.Writer.RawWrite(w, value)
|
||||
}
|
||||
}
|
||||
return ast.WalkSkipChildren, nil
|
||||
}
|
||||
_, _ = w.WriteString("</code>")
|
||||
return ast.WalkContinue, nil
|
||||
}
|
||||
|
||||
// EmphasisAttributeFilter defines attribute names which emphasis elements can have.
|
||||
var EmphasisAttributeFilter = GlobalAttributeFilter
|
||||
|
||||
func (r *Renderer) renderEmphasis(
|
||||
w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
|
||||
n := node.(*ast.Emphasis)
|
||||
tag := "em"
|
||||
if n.Level == 2 {
|
||||
tag = "strong"
|
||||
}
|
||||
if entering {
|
||||
_ = w.WriteByte('<')
|
||||
_, _ = w.WriteString(tag)
|
||||
if n.Attributes() != nil {
|
||||
RenderAttributes(w, n, EmphasisAttributeFilter)
|
||||
}
|
||||
_ = w.WriteByte('>')
|
||||
} else {
|
||||
_, _ = w.WriteString("</")
|
||||
_, _ = w.WriteString(tag)
|
||||
_ = w.WriteByte('>')
|
||||
}
|
||||
return ast.WalkContinue, nil
|
||||
}
|
||||
|
||||
func (r *Renderer) renderLink(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
|
||||
n := node.(*ast.Link)
|
||||
if entering {
|
||||
_, _ = w.WriteString("<a href=\"")
|
||||
dest := util.URLEscape(n.Destination, true)
|
||||
if r.Unsafe || !IsDangerousURL(dest) {
|
||||
_, _ = w.Write(util.EscapeHTML(dest))
|
||||
}
|
||||
_ = w.WriteByte('"')
|
||||
if n.Title != nil {
|
||||
_, _ = w.WriteString(` title="`)
|
||||
r.Writer.Write(w, n.Title)
|
||||
_ = w.WriteByte('"')
|
||||
}
|
||||
if n.Attributes() != nil {
|
||||
RenderAttributes(w, n, LinkAttributeFilter)
|
||||
}
|
||||
_ = w.WriteByte('>')
|
||||
} else {
|
||||
_, _ = w.WriteString("</a>")
|
||||
}
|
||||
return ast.WalkContinue, nil
|
||||
}
|
||||
|
||||
// ImageAttributeFilter defines attribute names which image elements can have.
|
||||
var ImageAttributeFilter = GlobalAttributeFilter.ExtendString(`align,border,crossorigin,decoding,height,importance,intrinsicsize,ismap,loading,referrerpolicy,sizes,srcset,usemap,width`) // nolint: lll
|
||||
|
||||
func (r *Renderer) renderImage(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
|
||||
if !entering {
|
||||
return ast.WalkContinue, nil
|
||||
}
|
||||
n := node.(*ast.Image)
|
||||
_, _ = w.WriteString("<img src=\"")
|
||||
dest := util.URLEscape(n.Destination, true)
|
||||
if r.Unsafe || !IsDangerousURL(dest) {
|
||||
_, _ = w.Write(util.EscapeHTML(dest))
|
||||
}
|
||||
_, _ = w.WriteString(`" alt="`)
|
||||
r.renderTexts(w, source, n)
|
||||
_ = w.WriteByte('"')
|
||||
if n.Title != nil {
|
||||
_, _ = w.WriteString(` title="`)
|
||||
r.Writer.Write(w, n.Title)
|
||||
_ = w.WriteByte('"')
|
||||
}
|
||||
if n.Attributes() != nil {
|
||||
RenderAttributes(w, n, ImageAttributeFilter)
|
||||
}
|
||||
if r.XHTML {
|
||||
_, _ = w.WriteString(" />")
|
||||
} else {
|
||||
_, _ = w.WriteString(">")
|
||||
}
|
||||
return ast.WalkSkipChildren, nil
|
||||
}
|
||||
|
||||
func (r *Renderer) renderRawHTML(
|
||||
w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
|
||||
if !entering {
|
||||
return ast.WalkSkipChildren, nil
|
||||
}
|
||||
if r.Unsafe {
|
||||
n := node.(*ast.RawHTML)
|
||||
l := n.Segments.Len()
|
||||
for i := range l {
|
||||
segment := n.Segments.At(i)
|
||||
_, _ = w.Write(segment.Value(source))
|
||||
}
|
||||
return ast.WalkSkipChildren, nil
|
||||
}
|
||||
_, _ = w.WriteString("<!-- raw HTML omitted -->")
|
||||
return ast.WalkSkipChildren, nil
|
||||
}
|
||||
|
||||
func (r *Renderer) renderText(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
|
||||
if !entering {
|
||||
return ast.WalkContinue, nil
|
||||
}
|
||||
n := node.(*ast.Text)
|
||||
segment := n.Segment
|
||||
if n.IsRaw() {
|
||||
r.Writer.RawWrite(w, segment.Value(source))
|
||||
} else {
|
||||
value := segment.Value(source)
|
||||
r.Writer.Write(w, value)
|
||||
if n.HardLineBreak() || (n.SoftLineBreak() && r.HardWraps) {
|
||||
if r.XHTML {
|
||||
_, _ = w.WriteString("<br />\n")
|
||||
} else {
|
||||
_, _ = w.WriteString("<br>\n")
|
||||
}
|
||||
} else if n.SoftLineBreak() {
|
||||
if r.EastAsianLineBreaks != EastAsianLineBreaksNone && len(value) != 0 {
|
||||
sibling := node.NextSibling()
|
||||
if sibling != nil && sibling.Kind() == ast.KindText {
|
||||
if siblingText := sibling.(*ast.Text).Value(source); len(siblingText) != 0 {
|
||||
thisLastRune := util.ToRune(value, len(value)-1)
|
||||
siblingFirstRune, _ := utf8.DecodeRune(siblingText)
|
||||
if r.EastAsianLineBreaks.softLineBreak(thisLastRune, siblingFirstRune) {
|
||||
_ = w.WriteByte('\n')
|
||||
}
|
||||
}
|
||||
}
|
||||
} else {
|
||||
_ = w.WriteByte('\n')
|
||||
}
|
||||
}
|
||||
}
|
||||
return ast.WalkContinue, nil
|
||||
}
|
||||
|
||||
func (r *Renderer) renderString(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
|
||||
if !entering {
|
||||
return ast.WalkContinue, nil
|
||||
}
|
||||
n := node.(*ast.String)
|
||||
if n.IsCode() {
|
||||
_, _ = w.Write(n.Value)
|
||||
} else {
|
||||
if n.IsRaw() {
|
||||
r.Writer.RawWrite(w, n.Value)
|
||||
} else {
|
||||
r.Writer.Write(w, n.Value)
|
||||
}
|
||||
}
|
||||
return ast.WalkContinue, nil
|
||||
}
|
||||
|
||||
func (r *Renderer) renderTexts(w util.BufWriter, source []byte, n ast.Node) {
|
||||
for c := n.FirstChild(); c != nil; c = c.NextSibling() {
|
||||
if s, ok := c.(*ast.String); ok {
|
||||
_, _ = r.renderString(w, source, s, true)
|
||||
} else if t, ok := c.(*ast.Text); ok {
|
||||
_, _ = r.renderText(w, source, t, true)
|
||||
} else {
|
||||
r.renderTexts(w, source, c)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
var dataPrefix = []byte("data-")
|
||||
|
||||
// RenderAttributes renders given node's attributes.
|
||||
// You can specify attribute names to render by the filter.
|
||||
// If filter is nil, RenderAttributes renders all attributes.
|
||||
func RenderAttributes(w util.BufWriter, node ast.Node, filter util.BytesFilter) {
|
||||
for _, attr := range node.Attributes() {
|
||||
if filter != nil && !filter.Contains(attr.Name) {
|
||||
if !bytes.HasPrefix(attr.Name, dataPrefix) {
|
||||
continue
|
||||
}
|
||||
}
|
||||
_, _ = w.WriteString(" ")
|
||||
_, _ = w.Write(attr.Name)
|
||||
_, _ = w.WriteString(`="`)
|
||||
// TODO: convert numeric values to strings
|
||||
var value []byte
|
||||
switch typed := attr.Value.(type) {
|
||||
case []byte:
|
||||
value = typed
|
||||
case string:
|
||||
value = util.StringToReadOnlyBytes(typed)
|
||||
}
|
||||
_, _ = w.Write(util.EscapeHTML(value))
|
||||
_ = w.WriteByte('"')
|
||||
}
|
||||
}
|
||||
|
||||
// A Writer interface writes textual contents to a writer.
|
||||
type Writer interface {
|
||||
// Write writes the given source to writer with resolving references and unescaping
|
||||
// backslash escaped characters.
|
||||
Write(writer util.BufWriter, source []byte)
|
||||
|
||||
// RawWrite writes the given source to writer without resolving references and
|
||||
// unescaping backslash escaped characters.
|
||||
RawWrite(writer util.BufWriter, source []byte)
|
||||
|
||||
// SecureWrite writes the given source to writer with replacing insecure characters.
|
||||
SecureWrite(writer util.BufWriter, source []byte)
|
||||
}
|
||||
|
||||
var replacementCharacter = []byte("\ufffd")
|
||||
|
||||
// A WriterConfig struct has configurations for the HTML based writers.
|
||||
type WriterConfig struct {
|
||||
// EscapedSpace is an option that indicates that a '\' escaped half-space(0x20) should not be rendered.
|
||||
EscapedSpace bool
|
||||
}
|
||||
|
||||
// A WriterOption interface sets options for HTML based writers.
|
||||
type WriterOption func(*WriterConfig)
|
||||
|
||||
// WithEscapedSpace is a WriterOption indicates that a '\' escaped half-space(0x20) should not be rendered.
|
||||
func WithEscapedSpace() WriterOption {
|
||||
return func(c *WriterConfig) {
|
||||
c.EscapedSpace = true
|
||||
}
|
||||
}
|
||||
|
||||
type defaultWriter struct {
|
||||
WriterConfig
|
||||
}
|
||||
|
||||
// NewWriter returns a new Writer.
|
||||
func NewWriter(opts ...WriterOption) Writer {
|
||||
w := &defaultWriter{}
|
||||
for _, opt := range opts {
|
||||
opt(&w.WriterConfig)
|
||||
}
|
||||
return w
|
||||
}
|
||||
|
||||
func escapeRune(writer util.BufWriter, r rune) {
|
||||
if r < 256 {
|
||||
v := util.EscapeHTMLByte(byte(r))
|
||||
if v != nil {
|
||||
_, _ = writer.Write(v)
|
||||
return
|
||||
}
|
||||
}
|
||||
_, _ = writer.WriteRune(util.ToValidRune(r))
|
||||
}
|
||||
|
||||
func (d *defaultWriter) SecureWrite(writer util.BufWriter, source []byte) {
|
||||
n := 0
|
||||
l := len(source)
|
||||
for i := range l {
|
||||
if source[i] == '\u0000' {
|
||||
_, _ = writer.Write(source[i-n : i])
|
||||
n = 0
|
||||
_, _ = writer.Write(replacementCharacter)
|
||||
continue
|
||||
}
|
||||
n++
|
||||
}
|
||||
if n != 0 {
|
||||
_, _ = writer.Write(source[l-n:])
|
||||
}
|
||||
}
|
||||
|
||||
func (d *defaultWriter) RawWrite(writer util.BufWriter, source []byte) {
|
||||
n := 0
|
||||
l := len(source)
|
||||
for i := range l {
|
||||
v := util.EscapeHTMLByte(source[i])
|
||||
if v != nil {
|
||||
_, _ = writer.Write(source[i-n : i])
|
||||
n = 0
|
||||
_, _ = writer.Write(v)
|
||||
continue
|
||||
}
|
||||
n++
|
||||
}
|
||||
if n != 0 {
|
||||
_, _ = writer.Write(source[l-n:])
|
||||
}
|
||||
}
|
||||
|
||||
func (d *defaultWriter) Write(writer util.BufWriter, source []byte) {
|
||||
escaped := false
|
||||
var ok bool
|
||||
limit := len(source)
|
||||
n := 0
|
||||
for i := 0; i < limit; i++ {
|
||||
c := source[i]
|
||||
if escaped {
|
||||
if util.IsPunct(c) {
|
||||
d.RawWrite(writer, source[n:i-1])
|
||||
n = i
|
||||
escaped = false
|
||||
continue
|
||||
}
|
||||
if d.EscapedSpace && c == ' ' {
|
||||
d.RawWrite(writer, source[n:i-1])
|
||||
n = i + 1
|
||||
escaped = false
|
||||
continue
|
||||
}
|
||||
}
|
||||
if c == '\x00' {
|
||||
d.RawWrite(writer, source[n:i])
|
||||
d.RawWrite(writer, replacementCharacter)
|
||||
n = i + 1
|
||||
escaped = false
|
||||
continue
|
||||
}
|
||||
if c == '&' {
|
||||
pos := i
|
||||
next := i + 1
|
||||
if next < limit && source[next] == '#' {
|
||||
nnext := next + 1
|
||||
if nnext < limit {
|
||||
nc := source[nnext]
|
||||
// code point like #x22;
|
||||
if nnext < limit && nc == 'x' || nc == 'X' {
|
||||
start := nnext + 1
|
||||
i, ok = util.ReadWhile(source, [2]int{start, limit}, util.IsHexDecimal)
|
||||
if ok && i < limit && source[i] == ';' && i-start < 7 {
|
||||
v, _ := strconv.ParseUint(util.BytesToReadOnlyString(source[start:i]), 16, 32)
|
||||
d.RawWrite(writer, source[n:pos])
|
||||
n = i + 1
|
||||
escapeRune(writer, rune(v))
|
||||
continue
|
||||
}
|
||||
// code point like #1234;
|
||||
} else if nc >= '0' && nc <= '9' {
|
||||
start := nnext
|
||||
i, ok = util.ReadWhile(source, [2]int{start, limit}, util.IsNumeric)
|
||||
if ok && i < limit && i-start < 8 && source[i] == ';' {
|
||||
v, _ := strconv.ParseUint(util.BytesToReadOnlyString(source[start:i]), 10, 32)
|
||||
d.RawWrite(writer, source[n:pos])
|
||||
n = i + 1
|
||||
escapeRune(writer, rune(v))
|
||||
continue
|
||||
}
|
||||
}
|
||||
}
|
||||
} else {
|
||||
start := next
|
||||
i, ok = util.ReadWhile(source, [2]int{start, limit}, util.IsAlphaNumeric)
|
||||
// entity reference
|
||||
if ok && i < limit && source[i] == ';' {
|
||||
name := util.BytesToReadOnlyString(source[start:i])
|
||||
entity, ok := util.LookUpHTML5EntityByName(name)
|
||||
if ok {
|
||||
d.RawWrite(writer, source[n:pos])
|
||||
n = i + 1
|
||||
d.RawWrite(writer, entity.Characters)
|
||||
continue
|
||||
}
|
||||
}
|
||||
}
|
||||
i = next - 1
|
||||
}
|
||||
if c == '\\' {
|
||||
escaped = true
|
||||
continue
|
||||
}
|
||||
escaped = false
|
||||
}
|
||||
d.RawWrite(writer, source[n:])
|
||||
}
|
||||
|
||||
// DefaultWriter is a default instance of the Writer.
|
||||
var DefaultWriter = NewWriter()
|
||||
|
||||
var bDataImage = []byte("data:image/")
|
||||
var bPng = []byte("png;")
|
||||
var bGif = []byte("gif;")
|
||||
var bJpeg = []byte("jpeg;")
|
||||
var bWebp = []byte("webp;")
|
||||
var bSvg = []byte("svg+xml;")
|
||||
var bJs = []byte("javascript:")
|
||||
var bVb = []byte("vbscript:")
|
||||
var bFile = []byte("file:")
|
||||
var bData = []byte("data:")
|
||||
|
||||
func hasPrefix(s, prefix []byte) bool {
|
||||
return len(s) >= len(prefix) && bytes.Equal(bytes.ToLower(s[0:len(prefix)]), bytes.ToLower(prefix))
|
||||
}
|
||||
|
||||
// IsDangerousURL returns true if the given url seems a potentially dangerous url,
|
||||
// otherwise false.
|
||||
func IsDangerousURL(url []byte) bool {
|
||||
if hasPrefix(url, bDataImage) && len(url) >= 11 {
|
||||
v := url[11:]
|
||||
if hasPrefix(v, bPng) || hasPrefix(v, bGif) ||
|
||||
hasPrefix(v, bJpeg) || hasPrefix(v, bWebp) ||
|
||||
hasPrefix(v, bSvg) {
|
||||
return false
|
||||
}
|
||||
return true
|
||||
}
|
||||
return hasPrefix(url, bJs) || hasPrefix(url, bVb) ||
|
||||
hasPrefix(url, bFile) || hasPrefix(url, bData)
|
||||
}
|
||||
Reference in New Issue
Block a user