Show syntax lexer name in file view/blame (#21814)

Show which Chroma Lexer is used to highlight the file in the file
header. It's useful for development to see what was detected, and I
think it's not bad info to have for the user:

<img width="233" alt="Screenshot 2022-11-14 at 22 31 16"
src="https://user-images.githubusercontent.com/115237/201770854-44933dfc-70a4-487c-8457-1bb3cc43ea62.png">
<img width="226" alt="Screenshot 2022-11-14 at 22 36 06"
src="https://user-images.githubusercontent.com/115237/201770856-9260ce6f-6c0f-442c-92b5-201e5b113188.png">
<img width="194" alt="Screenshot 2022-11-14 at 22 36 26"
src="https://user-images.githubusercontent.com/115237/201770857-6f56591b-80ea-42cc-8ea5-21b9156c018b.png">

Also, I improved the way this header overflows on small screens:

<img width="354" alt="Screenshot 2022-11-14 at 22 44 36"
src="https://user-images.githubusercontent.com/115237/201774828-2ddbcde1-da15-403f-bf7a-6248449fa2c5.png">

Co-authored-by: delvh <dev.lh@web.de>
Co-authored-by: Lauris BH <lauris@nix.lv>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: John Olheiser <john.olheiser@gmail.com>

modules/highlight/highlight.go

@@ -18,6 +18,7 @@ import (
 	"code.gitea.io/gitea/modules/analyze"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/util"
 
 	"github.com/alecthomas/chroma/v2"
 	"github.com/alecthomas/chroma/v2/formatters/html"
@@ -56,18 +57,18 @@ func NewContext() {
 	})
 }
 
-// Code returns a HTML version of code string with chroma syntax highlighting classes
-func Code(fileName, language, code string) string {
+// Code returns a HTML version of code string with chroma syntax highlighting classes and the matched lexer name
+func Code(fileName, language, code string) (string, string) {
 	NewContext()
 
 	// diff view newline will be passed as empty, change to literal '\n' so it can be copied
 	// preserve literal newline in blame view
 	if code == "" || code == "\n" {
-		return "\n"
+		return "\n", ""
 	}
 
 	if len(code) > sizeLimit {
-		return code
+		return code, ""
 	}
 
 	var lexer chroma.Lexer
@@ -103,7 +104,10 @@ func Code(fileName, language, code string) string {
 		}
 		cache.Add(fileName, lexer)
 	}
-	return CodeFromLexer(lexer, code)
+
+	lexerName := formatLexerName(lexer.Config().Name)
+
+	return CodeFromLexer(lexer, code), lexerName
 }
 
 // CodeFromLexer returns a HTML version of code string with chroma syntax highlighting classes
@@ -134,12 +138,12 @@ func CodeFromLexer(lexer chroma.Lexer, code string) string {
 	return strings.TrimSuffix(htmlbuf.String(), "\n")
 }
 
-// File returns a slice of chroma syntax highlighted HTML lines of code
-func File(fileName, language string, code []byte) ([]string, error) {
+// File returns a slice of chroma syntax highlighted HTML lines of code and the matched lexer name
+func File(fileName, language string, code []byte) ([]string, string, error) {
 	NewContext()
 
 	if len(code) > sizeLimit {
-		return PlainText(code), nil
+		return PlainText(code), "", nil
 	}
 
 	formatter := html.New(html.WithClasses(true),
@@ -172,9 +176,11 @@ func File(fileName, language string, code []byte) ([]string, error) {
 		}
 	}
 
+	lexerName := formatLexerName(lexer.Config().Name)
+
 	iterator, err := lexer.Tokenise(nil, string(code))
 	if err != nil {
-		return nil, fmt.Errorf("can't tokenize code: %w", err)
+		return nil, "", fmt.Errorf("can't tokenize code: %w", err)
 	}
 
 	tokensLines := chroma.SplitTokensIntoLines(iterator.Tokens())
@@ -185,13 +191,13 @@ func File(fileName, language string, code []byte) ([]string, error) {
 		iterator = chroma.Literator(tokens...)
 		err = formatter.Format(htmlBuf, styles.GitHub, iterator)
 		if err != nil {
-			return nil, fmt.Errorf("can't format code: %w", err)
+			return nil, "", fmt.Errorf("can't format code: %w", err)
 		}
 		lines = append(lines, htmlBuf.String())
 		htmlBuf.Reset()
 	}
 
-	return lines, nil
+	return lines, lexerName, nil
 }
 
 // PlainText returns non-highlighted HTML for code
@@ -212,3 +218,11 @@ func PlainText(code []byte) []string {
 	}
 	return m
 }
+
+func formatLexerName(name string) string {
+	if name == "fallback" {
+		return "Plaintext"
+	}
+
+	return util.ToTitleCaseNoLower(name)
+}

modules/highlight/highlight_test.go

@@ -20,31 +20,49 @@ func TestFile(t *testing.T) {
 		name      string
 		code      string
 		want      []string
+		lexerName string
 	}{
 		{
 			name:      "empty.py",
 			code:      "",
 			want:      lines(""),
+			lexerName: "Python",
+		},
+		{
+			name:      "empty.js",
+			code:      "",
+			want:      lines(""),
+			lexerName: "JavaScript",
+		},
+		{
+			name:      "empty.yaml",
+			code:      "",
+			want:      lines(""),
+			lexerName: "YAML",
 		},
 		{
 			name:      "tags.txt",
 			code:      "<>",
 			want:      lines("&lt;&gt;"),
+			lexerName: "Plaintext",
 		},
 		{
 			name:      "tags.py",
 			code:      "<>",
 			want:      lines(`<span class="o">&lt;</span><span class="o">&gt;</span>`),
+			lexerName: "Python",
 		},
 		{
 			name:      "eol-no.py",
 			code:      "a=1",
 			want:      lines(`<span class="n">a</span><span class="o">=</span><span class="mi">1</span>`),
+			lexerName: "Python",
 		},
 		{
 			name:      "eol-newline1.py",
 			code:      "a=1\n",
 			want:      lines(`<span class="n">a</span><span class="o">=</span><span class="mi">1</span>\n`),
+			lexerName: "Python",
 		},
 		{
 			name: "eol-newline2.py",
@@ -54,6 +72,7 @@ func TestFile(t *testing.T) {
 \n
 			`,
 			),
+			lexerName: "Python",
 		},
 		{
 			name: "empty-line-with-space.py",
@@ -73,17 +92,19 @@ c=2
     \n
 <span class="n">c</span><span class="o">=</span><span class="mi">2</span>`,
 			),
+			lexerName: "Python",
 		},
 	}
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			out, err := File(tt.name, "", []byte(tt.code))
+			out, lexerName, err := File(tt.name, "", []byte(tt.code))
 			assert.NoError(t, err)
 			expected := strings.Join(tt.want, "\n")
 			actual := strings.Join(out, "\n")
 			assert.Equal(t, strings.Count(actual, "<span"), strings.Count(actual, "</span>"))
 			assert.EqualValues(t, expected, actual)
+			assert.Equal(t, tt.lexerName, lexerName)
 		})
 	}
 }

modules/indexer/code/search.go

@@ -94,6 +94,9 @@ func searchResult(result *SearchResult, startIndex, endIndex int) (*Result, erro
 		lineNumbers[i] = startLineNum + i
 		index += len(line)
 	}
+
+	highlighted, _ := highlight.Code(result.Filename, "", formattedLinesBuffer.String())
+
 	return &Result{
 		RepoID:         result.RepoID,
 		Filename:       result.Filename,
@@ -102,7 +105,7 @@ func searchResult(result *SearchResult, startIndex, endIndex int) (*Result, erro
 		Language:       result.Language,
 		Color:          result.Color,
 		LineNumbers:    lineNumbers,
-		FormattedLines: highlight.Code(result.Filename, "", formattedLinesBuffer.String()),
+		FormattedLines: highlighted,
 	}, nil
 }
 

modules/util/util.go

@@ -186,13 +186,21 @@ func ToUpperASCII(s string) string {
 	return string(b)
 }
 
-var titleCaser = cases.Title(language.English)
+var (
+	titleCaser        = cases.Title(language.English)
+	titleCaserNoLower = cases.Title(language.English, cases.NoLower)
+)
 
 // ToTitleCase returns s with all english words capitalized
 func ToTitleCase(s string) string {
 	return titleCaser.String(s)
 }
 
+// ToTitleCaseNoLower returns s with all english words capitalized without lowercasing
+func ToTitleCaseNoLower(s string) string {
+	return titleCaserNoLower.String(s)
+}
+
 var (
 	whitespaceOnly    = regexp.MustCompile("(?m)^[ \t]+$")
 	leadingWhitespace = regexp.MustCompile("(?m)(^[ \t]*)(?:[^ \t\n])")

routers/web/repo/blame.go

@@ -100,6 +100,8 @@ func RefBlame(ctx *context.Context) {
 	ctx.Data["FileName"] = blob.Name()
 
 	ctx.Data["NumLines"], err = blob.GetBlobLineCount()
+	ctx.Data["NumLinesSet"] = true
+
 	if err != nil {
 		ctx.NotFound("GetBlobLineCount", err)
 		return
@@ -237,6 +239,8 @@ func renderBlame(ctx *context.Context, blameParts []git.BlamePart, commitNames m
 	rows := make([]*blameRow, 0)
 	escapeStatus := &charset.EscapeStatus{}
 
+	var lexerName string
+
 	i := 0
 	commitCnt := 0
 	for _, part := range blameParts {
@@ -278,7 +282,13 @@ func renderBlame(ctx *context.Context, blameParts []git.BlamePart, commitNames m
 				line += "\n"
 			}
 			fileName := fmt.Sprintf("%v", ctx.Data["FileName"])
-			line = highlight.Code(fileName, language, line)
+			line, lexerNameForLine := highlight.Code(fileName, language, line)
+
+			// set lexer name to the first detected lexer. this is certainly suboptimal and
+			// we should instead highlight the whole file at once
+			if lexerName == "" {
+				lexerName = lexerNameForLine
+			}
 
 			br.EscapeStatus, line = charset.EscapeControlHTML(line, ctx.Locale)
 			br.Code = gotemplate.HTML(line)
@@ -290,4 +300,5 @@ func renderBlame(ctx *context.Context, blameParts []git.BlamePart, commitNames m
 	ctx.Data["EscapeStatus"] = escapeStatus
 	ctx.Data["BlameRows"] = rows
 	ctx.Data["CommitCnt"] = commitCnt
+	ctx.Data["LexerName"] = lexerName
 }

routers/web/repo/view.go

@@ -568,7 +568,8 @@ func renderFile(ctx *context.Context, entry *git.TreeEntry, treeLink, rawLink st
 					language = ""
 				}
 			}
-			fileContent, err := highlight.File(blob.Name(), language, buf)
+			fileContent, lexerName, err := highlight.File(blob.Name(), language, buf)
+			ctx.Data["LexerName"] = lexerName
 			if err != nil {
 				log.Error("highlight.File failed, fallback to plain text: %v", err)
 				fileContent = highlight.PlainText(buf)

services/gitdiff/gitdiff.go

@@ -280,7 +280,8 @@ func DiffInlineWithUnicodeEscape(s template.HTML, locale translation.Locale) Dif
 
 // DiffInlineWithHighlightCode makes a DiffInline with code highlight and hidden unicode characters escaped
 func DiffInlineWithHighlightCode(fileName, language, code string, locale translation.Locale) DiffInline {
-	status, content := charset.EscapeControlHTML(highlight.Code(fileName, language, code), locale)
+	highlighted, _ := highlight.Code(fileName, language, code)
+	status, content := charset.EscapeControlHTML(highlighted, locale)
 	return DiffInline{EscapeStatus: status, Content: template.HTML(content)}
 }
 

services/gitdiff/highlightdiff.go

@@ -91,8 +91,8 @@ func (hcd *highlightCodeDiff) diffWithHighlight(filename, language, codeA, codeB
 	hcd.collectUsedRunes(codeA)
 	hcd.collectUsedRunes(codeB)
 
-	highlightCodeA := highlight.Code(filename, language, codeA)
-	highlightCodeB := highlight.Code(filename, language, codeB)
+	highlightCodeA, _ := highlight.Code(filename, language, codeA)
+	highlightCodeB, _ := highlight.Code(filename, language, codeB)
 
 	highlightCodeA = hcd.convertToPlaceholders(highlightCodeA)
 	highlightCodeB = hcd.convertToPlaceholders(highlightCodeB)

templates/repo/blame.tmpl

@@ -1,14 +1,9 @@
 <div class="{{TabSizeClass .Editorconfig .FileName}} non-diff-file-content">
-	<h4 class="file-header ui top attached header df ac sb">
-		<div class="file-header-left df ac">
-			<div class="file-info text grey normal mono">
-				<div class="file-info-entry">
-					{{.NumLines}} {{.locale.TrN .NumLines "repo.line" "repo.lines"}}
+	<h4 class="file-header ui top attached header df ac sb fw">
+		<div class="file-header-left df ac py-3 pr-4">
+			{{template "repo/file_info" .}}
 		</div>
-				<div class="file-info-entry">{{FileSize .FileSize}}</div>
-			</div>
-		</div>
-		<div class="file-header-right file-actions df ac">
+		<div class="file-header-right file-actions df ac fw">
 			<div class="ui buttons">
 				<a class="ui tiny button" href="{{$.RawFileLink}}">{{.locale.Tr "repo.file_raw"}}</a>
 				{{if not .IsViewCommit}}

templates/repo/file_info.tmpl

@@ -0,0 +1,28 @@
+<div class="file-info text grey normal mono">
+	{{if .FileIsSymlink}}
+		<div class="file-info-entry">
+			{{.locale.Tr "repo.symbolic_link"}}
+		</div>
+	{{end}}
+	{{if .NumLinesSet}}{{/* Explicit attribute needed to show 0 line changes */}}
+		<div class="file-info-entry">
+			{{.NumLines}} {{.locale.TrN .NumLines "repo.line" "repo.lines"}}
+		</div>
+	{{end}}
+	{{if .FileSize}}
+		<div class="file-info-entry">
+			{{FileSize .FileSize}}{{if .IsLFSFile}} ({{.locale.Tr "repo.stored_lfs"}}){{end}}
+		</div>
+	{{end}}
+	{{if .LFSLock}}
+		<div class="file-info-entry ui tooltip" data-content="{{.LFSLockHint}}">
+			{{svg "octicon-lock" 16 "mr-2"}}
+			<a href="{{.LFSLockOwnerHomeLink}}">{{.LFSLockOwner}}</a>
+		</div>
+	{{end}}
+	{{if .LexerName}}
+		<div class="file-info-entry">
+			{{.LexerName}}
+		</div>
+	{{end}}
+</div>

templates/repo/view_file.tmpl

@@ -6,38 +6,16 @@
 			</div>
 		</div>
 	{{end}}
-	<h4 class="file-header ui top attached header df ac sb">
-		<div class="file-header-left df ac pr-4">
+	<h4 class="file-header ui top attached header df ac sb fw">
+		<div class="file-header-left df ac py-3 pr-4">
 			{{if .ReadmeInList}}
 				{{svg "octicon-book" 16 "mr-3"}}
 				<strong>{{.FileName}}</strong>
 			{{else}}
-				<div class="file-info text grey normal mono">
-					{{if .FileIsSymlink}}
-						<div class="file-info-entry">
-							{{.locale.Tr "repo.symbolic_link"}}
-						</div>
-					{{end}}
-					{{if .NumLinesSet}}
-						<div class="file-info-entry">
-							{{.NumLines}} {{.locale.TrN .NumLines "repo.line" "repo.lines"}}
-						</div>
-					{{end}}
-					{{if .FileSize}}
-						<div class="file-info-entry">
-							{{FileSize .FileSize}}{{if .IsLFSFile}} ({{.locale.Tr "repo.stored_lfs"}}){{end}}
-						</div>
-					{{end}}
-					{{if .LFSLock}}
-						<div class="file-info-entry ui tooltip" data-content="{{.LFSLockHint}}">
-							{{svg "octicon-lock" 16 "mr-2"}}
-							<a href="{{.LFSLockOwnerHomeLink}}">{{.LFSLockOwner}}</a>
-						</div>
+				{{template "repo/file_info" .}}
 			{{end}}
 		</div>
-			{{end}}
-		</div>
-		<div class="file-header-right file-actions df ac">
+		<div class="file-header-right file-actions df ac fw">
 			{{if .HasSourceRenderedToggle}}
 				<div class="ui compact icon buttons two-toggle-buttons">
 					<a href="{{$.Link}}?display=source" class="ui mini basic button tooltip {{if .IsDisplayingSource}}active{{end}}" data-content="{{.locale.Tr "repo.file_view_source"}}" data-position="bottom center">{{svg "octicon-code" 15}}</a>