forgejo/modules/highlight/highlight.go
mrsdizzie 8d081950e6
Ensure syntax highlighting is the same inside diffs (#12205)
Make sure to end up with the same syntax highlighting inside various sections of diffs by processing the code first before detecting specific changes between the lines. Also try and make sure that when highlighting individual lines in a diff that it is tokenized the same as it would be when part of an entire file with more context.

Fixes: #12190
2020-07-11 13:43:12 +08:00

166 lines
4.1 KiB
Go

// Copyright 2015 The Gogs Authors. All rights reserved.
// Copyright 2020 The Gitea Authors. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.
package highlight
import (
"bufio"
"bytes"
"path/filepath"
"strings"
"sync"
"code.gitea.io/gitea/modules/log"
"code.gitea.io/gitea/modules/setting"
"github.com/alecthomas/chroma/formatters/html"
"github.com/alecthomas/chroma/lexers"
"github.com/alecthomas/chroma/styles"
)
// don't index files larger than this many bytes for performance purposes
const sizeLimit = 1000000
var (
// For custom user mapping
highlightMapping = map[string]string{}
once sync.Once
)
// NewContext loads custom highlight map from local config
func NewContext() {
once.Do(func() {
keys := setting.Cfg.Section("highlight.mapping").Keys()
for i := range keys {
highlightMapping[keys[i].Name()] = keys[i].Value()
}
})
}
// Code returns a HTML version of code string with chroma syntax highlighting classes
func Code(fileName, code 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"
}
if len(code) > sizeLimit {
return code
}
formatter := html.New(html.WithClasses(true),
html.WithLineNumbers(false),
html.PreventSurroundingPre(true),
)
if formatter == nil {
log.Error("Couldn't create chroma formatter")
return code
}
htmlbuf := bytes.Buffer{}
htmlw := bufio.NewWriter(&htmlbuf)
if val, ok := highlightMapping[filepath.Ext(fileName)]; ok {
//change file name to one with mapped extension so we look that up instead
fileName = "mapped." + val
}
lexer := lexers.Match(fileName)
if lexer == nil {
lexer = lexers.Fallback
}
iterator, err := lexer.Tokenise(nil, string(code))
if err != nil {
log.Error("Can't tokenize code: %v", err)
return code
}
// style not used for live site but need to pass something
err = formatter.Format(htmlw, styles.GitHub, iterator)
if err != nil {
log.Error("Can't format code: %v", err)
return code
}
htmlw.Flush()
// Chroma will add newlines for certain lexers in order to highlight them properly
// Once highlighted, strip them here so they don't cause copy/paste trouble in HTML output
return strings.TrimSuffix(htmlbuf.String(), "\n")
}
// File returns map with line lumbers and HTML version of code with chroma syntax highlighting classes
func File(numLines int, fileName string, code []byte) map[int]string {
NewContext()
if len(code) > sizeLimit {
return plainText(string(code), numLines)
}
formatter := html.New(html.WithClasses(true),
html.WithLineNumbers(false),
html.PreventSurroundingPre(true),
)
if formatter == nil {
log.Error("Couldn't create chroma formatter")
return plainText(string(code), numLines)
}
htmlbuf := bytes.Buffer{}
htmlw := bufio.NewWriter(&htmlbuf)
if val, ok := highlightMapping[filepath.Ext(fileName)]; ok {
fileName = "test." + val
}
lexer := lexers.Match(fileName)
if lexer == nil {
lexer = lexers.Analyse(string(code))
if lexer == nil {
lexer = lexers.Fallback
}
}
iterator, err := lexer.Tokenise(nil, string(code))
if err != nil {
log.Error("Can't tokenize code: %v", err)
return plainText(string(code), numLines)
}
err = formatter.Format(htmlw, styles.GitHub, iterator)
if err != nil {
log.Error("Can't format code: %v", err)
return plainText(string(code), numLines)
}
htmlw.Flush()
m := make(map[int]string, numLines)
for k, v := range strings.SplitN(htmlbuf.String(), "\n", numLines) {
line := k + 1
content := string(v)
//need to keep lines that are only \n so copy/paste works properly in browser
if content == "" {
content = "\n"
}
m[line] = content
}
return m
}
// return unhiglighted map
func plainText(code string, numLines int) map[int]string {
m := make(map[int]string, numLines)
for k, v := range strings.SplitN(string(code), "\n", numLines) {
line := k + 1
content := string(v)
//need to keep lines that are only \n so copy/paste works properly in browser
if content == "" {
content = "\n"
}
m[line] = content
}
return m
}