placeholder for html entity

go-gitea · wxiaoguang · Jul 23, 2022 · Jun 13, 2022 · Jun 13, 2022 · Jun 13, 2022
commit 90c644096b89f78cd1c5e5f1305adda9e76eb7f4
diff --git a/services/gitdiff/gitdiff.go b/services/gitdiff/gitdiff.go
@@ -283,187 +283,6 @@ func DiffInlineWithHighlightCode(fileName, language, code string) DiffInline {
 	return DiffInline{EscapeStatus: status, Content: template.HTML(content)}
 }
 
-// highlightCodeDiff is used to do diff with highlighted HTML code.
-// It totally depends on Chroma's valid HTML output and its structure, do not use these functions for other purposes.
-// The HTML tags will be replaced by Unicode placeholders: "<span>{TEXT}</span>" => "\uE000{TEXT}\uE001"
-// These Unicode placeholders are friendly to the diff.
-// Then after diff, the placeholders in diff result will be recovered to the HTML tags.
-// It's guaranteed that the tags in final diff result are paired correctly.
-type highlightCodeDiff struct {
-	placeholderBegin    rune
-	placeholderMaxCount int
-	placeholderIndex    int
-	placeholderTagMap   map[rune]string
-	tagPlaceholderMap   map[string]rune
-
-	placeholderOverflowCount int
-
-	lineWrapperTags []string
-}
-
-func newHighlightCodeDiff() *highlightCodeDiff {
-	return &highlightCodeDiff{
-		placeholderBegin:    rune(0xE000), // Private Use Unicode: U+E000..U+F8FF, BMP(0), 6400
-		placeholderMaxCount: 6400,
-		placeholderTagMap:   map[rune]string{},
-		tagPlaceholderMap:   map[string]rune{},
-	}
-}
-
-// nextPlaceholder returns 0 if no more placeholder can be used
-// the diff is done line by line, usually there are only a few (no more than 10) placeholders in one line
-// so the placeholderMaxCount is impossible to be exhausted in real cases.
-func (hcd *highlightCodeDiff) nextPlaceholder() rune {
-	for hcd.placeholderIndex < hcd.placeholderMaxCount {
-		r := hcd.placeholderBegin + rune(hcd.placeholderIndex)
-		hcd.placeholderIndex++
-		// only use non-existing (not used by code) rune as placeholders
-		if _, ok := hcd.placeholderTagMap[r]; !ok {
-			return r
-		}
-	}
-	return 0 // no more available placeholder
-}
-
-func (hcd *highlightCodeDiff) isInPlaceholderRange(r rune) bool {
-	return hcd.placeholderBegin <= r && r < hcd.placeholderBegin+rune(hcd.placeholderMaxCount)
-}
-
-func (hcd *highlightCodeDiff) collectUsedRunes(code string) {
-	for _, r := range code {
-		if hcd.isInPlaceholderRange(r) {
-			// put the existing rune (used by code) in map, then this rune won't be used a placeholder anymore.
-			hcd.placeholderTagMap[r] = ""
-		}
-	}
-}
-
-func (hcd *highlightCodeDiff) diffWithHighlight(filename, language, codeA, codeB string) []diffmatchpatch.Diff {
-	hcd.collectUsedRunes(codeA)
-	hcd.collectUsedRunes(codeB)
-
-	highlightCodeA := highlight.Code(filename, language, codeA)
-	highlightCodeB := highlight.Code(filename, language, codeB)
-
-	highlightCodeA = hcd.convertToPlaceholders(highlightCodeA)
-	highlightCodeB = hcd.convertToPlaceholders(highlightCodeB)
-
-	diffs := diffMatchPatch.DiffMain(highlightCodeA, highlightCodeB, true)
-	diffs = diffMatchPatch.DiffCleanupEfficiency(diffs)
-
-	for i := range diffs {
-		hcd.recoverOneDiff(&diffs[i])
-	}
-	return diffs
-}
-
-func (hcd *highlightCodeDiff) convertToPlaceholders(htmlCode string) string {
-	var tagStack []string
-	res := strings.Builder{}
-
-	firstRunForLineTags := hcd.lineWrapperTags == nil
-
-	// the standard chroma highlight HTML is "<span class="line [hl]"><span class="cl"> ... </span></span>"
-	for {
-		// find the next HTML tag
-		pos1 := strings.IndexByte(htmlCode, '<')
-		pos2 := strings.IndexByte(htmlCode, '>')
-		if pos1 == -1 || pos2 == -1 || pos2 < pos1 {
-			break
-		}
-		tag := htmlCode[pos1 : pos2+1]
-
-		// write the content before the tag into result string, and consume the tag in the string
-		res.WriteString(htmlCode[:pos1])
-		htmlCode = htmlCode[pos2+1:]
-
-		// the line wrapper tags should be removed before diff
-		if strings.HasPrefix(tag, `<span class="line`) || strings.HasPrefix(tag, `<span class="cl"`) {
-			if firstRunForLineTags {
-				// if this is the first run for converting, save the line wrapper tags for later use, they should be added back
-				hcd.lineWrapperTags = append(hcd.lineWrapperTags, tag)
-			}
-			htmlCode = strings.TrimSuffix(htmlCode, "</span>")
-			continue
-		}
-
-		var tagInMap string
-		if tag[1] == '/' { // for closed tag
-			if len(tagStack) == 0 {
-				break // invalid diff result, no open tag but see close tag
-			}
-			// make sure the closed tag in map is related to the open tag, to make the diff algorithm can match the open/closed tags
-			// the closed tag will be recorded in the map by key "</span><!-- <span the-open> -->" for "<span the-open>"
-			tagInMap = tag + "<!-- " + tagStack[len(tagStack)-1] + "-->"
-			tagStack = tagStack[:len(tagStack)-1]
-		} else { // for open tag
-			tagInMap = tag
-			tagStack = append(tagStack, tag)
-		}
-
-		// remember the placeholder and tag in the map
-		placeholder, ok := hcd.tagPlaceholderMap[tagInMap]
-		if !ok {
-			placeholder = hcd.nextPlaceholder()
-			if placeholder != 0 {
-				hcd.tagPlaceholderMap[tagInMap] = placeholder
-				hcd.placeholderTagMap[placeholder] = tagInMap
-			}
-		}
-
-		if placeholder != 0 {
-			res.WriteRune(placeholder) // use the placeholder to replace the tag
-		} else {
-			// unfortunately, all private use runes has been exhausted, no more placeholder could be used, no more converting
-			// usually, the exhausting won't occur in real cases, the magnitude of used placeholders is not larger than that of the CSS classes outputted by chroma.
-			hcd.placeholderOverflowCount++
-		}
-	}
-	// write the remaining string
-	res.WriteString(htmlCode)
-	return res.String()
-}
-
-func (hcd *highlightCodeDiff) recoverOneDiff(diff *diffmatchpatch.Diff) {
-	sb := strings.Builder{}
-	var tagStack []string
-
-	for _, r := range diff.Text {
-		tag, ok := hcd.placeholderTagMap[r]
-		if !ok || tag == "" {
-			sb.WriteRune(r) // if the rune is not a placeholder, write it as it is
-			continue
-		}
-		var tagToRecover string
-		if tag[1] == '/' { // Closing tag
-			// only get the tag itself, ignore the trailing comment (for how the comment is generated, see the code in `convert` function)
-			tagToRecover = tag[:strings.IndexByte(tag, '>')+1]
-			if len(tagStack) == 0 {
-				continue // if no open tag in stack yet, skip the closed tag
-			}
-			tagStack = tagStack[:len(tagStack)-1]
-		} else {
-			tagToRecover = tag
-			tagStack = append(tagStack, tag)
-		}
-		sb.WriteString(tagToRecover)
-	}
-
-	if len(tagStack) > 0 {
-		// close all open tags
-		for i := len(tagStack) - 1; i >= 0; i-- {
-			tagToClose := tagStack[i]
-			// get the closed tag "</span>" from "<span class=...>" or "<span>"
-			pos := strings.IndexAny(tagToClose, " >")
-			if pos != -1 {
-				sb.WriteString("</" + tagToClose[1:pos] + ">")
-			} // else: impossible. every tag was pushed into the stack by the code above and is valid HTML open tag
-		}
-	}
-
-	diff.Text = sb.String()
-}
-
 // GetComputedInlineDiffFor computes inline diff for the given line.
 func (diffSection *DiffSection) GetComputedInlineDiffFor(diffLine *DiffLine) DiffInline {
 	if setting.Git.DisableDiffHighlight {

diff --git a/services/gitdiff/gitdiff_test.go b/services/gitdiff/gitdiff_test.go
@@ -644,71 +644,6 @@ func TestGetDiffRangeWithWhitespaceBehavior(t *testing.T) {
 	}
 }
 
-func TestDiffWithHighlight(t *testing.T) {
-	hcd := newHighlightCodeDiff()
-	diffs := hcd.diffWithHighlight(
-		"main.v", "",
-		"		run('<>')\n",
-		"		run(db)\n",
-	)
-
-	expected := `		<span class="n">run</span><span class="o">(</span><span class="removed-code"><span class="k">&#39;</span><span class="o">&lt;</span><span class="o">&gt;</span><span class="k">&#39;</span></span><span class="o">)</span>` + "\n"
-	output := diffToHTML(nil, diffs, DiffLineDel)
-	assert.Equal(t, expected, output)
-
-	expected = `		<span class="n">run</span><span class="o">(</span><span class="added-code"><span class="n">db</span></span><span class="o">)</span>` + "\n"
-	output = diffToHTML(nil, diffs, DiffLineAdd)
-	assert.Equal(t, expected, output)
-}
-
-func TestDiffWithHighlightPlaceholder(t *testing.T) {
-	hcd := newHighlightCodeDiff()
-	diffs := hcd.diffWithHighlight(
-		"main.js", "",
-		"a='\uE000'",
-		"a='\uF8FF'",
-	)
-	assert.Equal(t, "", hcd.placeholderTagMap[0xE000])
-	assert.Equal(t, "", hcd.placeholderTagMap[0xF8FF])
-
-	expected := fmt.Sprintf(`<span class="line"><span class="cl"><span class="nx">a</span><span class="o">=</span><span class="s1">&#39;</span><span class="removed-code">%s</span>&#39;</span></span>`, "\uE000")
-	output := diffToHTML(hcd.lineWrapperTags, diffs, DiffLineDel)
-	assert.Equal(t, expected, output)
-
-	hcd = newHighlightCodeDiff()
-	diffs = hcd.diffWithHighlight(
-		"main.js", "",
-		"a='\uE000'",
-		"a='\uF8FF'",
-	)
-	expected = fmt.Sprintf(`<span class="nx">a</span><span class="o">=</span><span class="s1">&#39;</span><span class="added-code">%s</span>&#39;`, "\uF8FF")
-	output = diffToHTML(nil, diffs, DiffLineAdd)
-	assert.Equal(t, expected, output)
-
-	totalOverflow := 0
-	for i := 0; i < 100; i++ {
-		hcd = newHighlightCodeDiff()
-		hcd.placeholderMaxCount = i
-		diffs = hcd.diffWithHighlight(
-			"main.js", "",
-			"a='1'",
-			"b='2'",
-		)
-		totalOverflow += hcd.placeholderOverflowCount
-
-		output = diffToHTML(nil, diffs, DiffLineDel)
-		c1 := strings.Count(output, "<span")
-		c2 := strings.Count(output, "</span")
-		assert.Equal(t, c1, c2)
-
-		output = diffToHTML(nil, diffs, DiffLineAdd)
-		c1 = strings.Count(output, "<span")
-		c2 = strings.Count(output, "</span")
-		assert.Equal(t, c1, c2)
-	}
-	assert.NotZero(t, totalOverflow)
-}
-
 func TestNoCrashes(t *testing.T) {
 	type testcase struct {
 		gitdiff string