ref: 8483b53aefc3c6b52f9917e6e5af9c4d2e98df66
dir: /helpers/pygments.go/
// Copyright 2019 The Hugo Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package helpers
import (
"bytes"
"crypto/sha1"
"fmt"
"io"
"io/ioutil"
"os/exec"
"path/filepath"
"regexp"
"sort"
"strconv"
"strings"
"github.com/alecthomas/chroma"
"github.com/alecthomas/chroma/formatters"
"github.com/alecthomas/chroma/formatters/html"
"github.com/alecthomas/chroma/lexers"
"github.com/alecthomas/chroma/styles"
bp "github.com/gohugoio/hugo/bufferpool"
"github.com/gohugoio/hugo/config"
"github.com/gohugoio/hugo/hugofs"
jww "github.com/spf13/jwalterweatherman"
)
const pygmentsBin = "pygmentize"
// hasPygments checks to see if Pygments is installed and available
// on the system.
func hasPygments() bool {
if _, err := exec.LookPath(pygmentsBin); err != nil {
return false
}
return true
}
type highlighters struct {
cs *ContentSpec
ignoreCache bool
cacheDir string
}
func newHiglighters(cs *ContentSpec) highlighters {
return highlighters{cs: cs, ignoreCache: cs.Cfg.GetBool("ignoreCache"), cacheDir: cs.Cfg.GetString("cacheDir")}
}
func (h highlighters) chromaHighlight(code, lang, optsStr string) (string, error) {
opts, err := h.cs.parsePygmentsOpts(optsStr)
if err != nil {
jww.ERROR.Print(err.Error())
return code, err
}
style, found := opts["style"]
if !found || style == "" {
style = "friendly"
}
f, err := h.cs.chromaFormatterFromOptions(opts)
if err != nil {
jww.ERROR.Print(err.Error())
return code, err
}
b := bp.GetBuffer()
defer bp.PutBuffer(b)
err = chromaHighlight(b, code, lang, style, f)
if err != nil {
jww.ERROR.Printf("Highlight failed: %s\nLang: %q\nCode: \n%s", err, lang, code)
return code, err
}
return h.injectCodeTag(`<div class="highlight">`+b.String()+"</div>", lang), nil
}
func (h highlighters) pygmentsHighlight(code, lang, optsStr string) (string, error) {
options, err := h.cs.createPygmentsOptionsString(optsStr)
if err != nil {
jww.ERROR.Print(err.Error())
return code, nil
}
// Try to read from cache first
hash := sha1.New()
io.WriteString(hash, code)
io.WriteString(hash, lang)
io.WriteString(hash, options)
fs := hugofs.Os
var cachefile string
if !h.ignoreCache && h.cacheDir != "" {
cachefile = filepath.Join(h.cacheDir, fmt.Sprintf("pygments-%x", hash.Sum(nil)))
exists, err := Exists(cachefile, fs)
if err != nil {
jww.ERROR.Print(err.Error())
return code, nil
}
if exists {
f, err := fs.Open(cachefile)
if err != nil {
jww.ERROR.Print(err.Error())
return code, nil
}
s, err := ioutil.ReadAll(f)
if err != nil {
jww.ERROR.Print(err.Error())
return code, nil
}
return string(s), nil
}
}
// No cache file, render and cache it
var out bytes.Buffer
var stderr bytes.Buffer
var langOpt string
if lang == "" {
langOpt = "-g" // Try guessing the language
} else {
langOpt = "-l" + lang
}
cmd := exec.Command(pygmentsBin, langOpt, "-fhtml", "-O", options)
cmd.Stdin = strings.NewReader(code)
cmd.Stdout = &out
cmd.Stderr = &stderr
if err := cmd.Run(); err != nil {
jww.ERROR.Print(stderr.String())
return code, err
}
str := string(normalizeExternalHelperLineFeeds(out.Bytes()))
str = h.injectCodeTag(str, lang)
if !h.ignoreCache && cachefile != "" {
// Write cache file
if err := WriteToDisk(cachefile, strings.NewReader(str), fs); err != nil {
jww.ERROR.Print(stderr.String())
}
}
return str, nil
}
var preRe = regexp.MustCompile(`(?s)(.*?<pre.*?>)(.*?)(</pre>)`)
func (h highlighters) injectCodeTag(code, lang string) string {
if lang == "" {
return code
}
codeTag := fmt.Sprintf(`<code class="language-%s" data-lang="%s">`, lang, lang)
return preRe.ReplaceAllString(code, fmt.Sprintf("$1%s$2</code>$3", codeTag))
}
func chromaHighlight(w io.Writer, source, lexer, style string, f chroma.Formatter) error {
l := lexers.Get(lexer)
if l == nil {
l = lexers.Analyse(source)
}
if l == nil {
l = lexers.Fallback
}
l = chroma.Coalesce(l)
if f == nil {
f = formatters.Fallback
}
s := styles.Get(style)
if s == nil {
s = styles.Fallback
}
it, err := l.Tokenise(nil, source)
if err != nil {
return err
}
return f.Format(w, s, it)
}
var pygmentsKeywords = make(map[string]bool)
func init() {
pygmentsKeywords["encoding"] = true
pygmentsKeywords["outencoding"] = true
pygmentsKeywords["nowrap"] = true
pygmentsKeywords["full"] = true
pygmentsKeywords["title"] = true
pygmentsKeywords["style"] = true
pygmentsKeywords["noclasses"] = true
pygmentsKeywords["classprefix"] = true
pygmentsKeywords["cssclass"] = true
pygmentsKeywords["cssstyles"] = true
pygmentsKeywords["prestyles"] = true
pygmentsKeywords["linenos"] = true
pygmentsKeywords["hl_lines"] = true
pygmentsKeywords["linenostart"] = true
pygmentsKeywords["linenostep"] = true
pygmentsKeywords["linenospecial"] = true
pygmentsKeywords["nobackground"] = true
pygmentsKeywords["lineseparator"] = true
pygmentsKeywords["lineanchors"] = true
pygmentsKeywords["linespans"] = true
pygmentsKeywords["anchorlinenos"] = true
pygmentsKeywords["startinline"] = true
}
func parseOptions(defaults map[string]string, in string) (map[string]string, error) {
in = strings.Trim(in, " ")
opts := make(map[string]string)
for k, v := range defaults {
opts[k] = v
}
if in == "" {
return opts, nil
}
for _, v := range strings.Split(in, ",") {
keyVal := strings.Split(v, "=")
key := strings.ToLower(strings.Trim(keyVal[0], " "))
if len(keyVal) != 2 || !pygmentsKeywords[key] {
return opts, fmt.Errorf("invalid Pygments option: %s", key)
}
opts[key] = keyVal[1]
}
return opts, nil
}
func createOptionsString(options map[string]string) string {
var keys []string
for k := range options {
keys = append(keys, k)
}
sort.Strings(keys)
var optionsStr string
for i, k := range keys {
optionsStr += fmt.Sprintf("%s=%s", k, options[k])
if i < len(options)-1 {
optionsStr += ","
}
}
return optionsStr
}
func parseDefaultPygmentsOpts(cfg config.Provider) (map[string]string, error) {
options, err := parseOptions(nil, cfg.GetString("pygmentsOptions"))
if err != nil {
return nil, err
}
if cfg.IsSet("pygmentsStyle") {
options["style"] = cfg.GetString("pygmentsStyle")
}
if cfg.IsSet("pygmentsUseClasses") {
if cfg.GetBool("pygmentsUseClasses") {
options["noclasses"] = "false"
} else {
options["noclasses"] = "true"
}
}
if _, ok := options["encoding"]; !ok {
options["encoding"] = "utf8"
}
return options, nil
}
func (cs *ContentSpec) chromaFormatterFromOptions(pygmentsOpts map[string]string) (chroma.Formatter, error) {
var options = []html.Option{html.TabWidth(4)}
if pygmentsOpts["noclasses"] == "false" {
options = append(options, html.WithClasses())
}
lineNumbers := pygmentsOpts["linenos"]
if lineNumbers != "" {
options = append(options, html.WithLineNumbers())
if lineNumbers != "inline" {
options = append(options, html.LineNumbersInTable())
}
}
startLineStr := pygmentsOpts["linenostart"]
var startLine = 1
if startLineStr != "" {
line, err := strconv.Atoi(strings.TrimSpace(startLineStr))
if err == nil {
startLine = line
options = append(options, html.BaseLineNumber(startLine))
}
}
hlLines := pygmentsOpts["hl_lines"]
if hlLines != "" {
ranges, err := hlLinesToRanges(startLine, hlLines)
if err == nil {
options = append(options, html.HighlightLines(ranges))
}
}
return html.New(options...), nil
}
func (cs *ContentSpec) parsePygmentsOpts(in string) (map[string]string, error) {
opts, err := parseOptions(cs.defatultPygmentsOpts, in)
if err != nil {
return nil, err
}
return opts, nil
}
func (cs *ContentSpec) createPygmentsOptionsString(in string) (string, error) {
opts, err := cs.parsePygmentsOpts(in)
if err != nil {
return "", err
}
return createOptionsString(opts), nil
}
// startLine compansates for https://github.com/alecthomas/chroma/issues/30
func hlLinesToRanges(startLine int, s string) ([][2]int, error) {
var ranges [][2]int
s = strings.TrimSpace(s)
if s == "" {
return ranges, nil
}
// Variants:
// 1 2 3 4
// 1-2 3-4
// 1-2 3
// 1 3-4
// 1 3-4
fields := strings.Split(s, " ")
for _, field := range fields {
field = strings.TrimSpace(field)
if field == "" {
continue
}
numbers := strings.Split(field, "-")
var r [2]int
first, err := strconv.Atoi(numbers[0])
if err != nil {
return ranges, err
}
first = first + startLine - 1
r[0] = first
if len(numbers) > 1 {
second, err := strconv.Atoi(numbers[1])
if err != nil {
return ranges, err
}
second = second + startLine - 1
r[1] = second
} else {
r[1] = first
}
ranges = append(ranges, r)
}
return ranges, nil
}