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// Copyright 2015 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"
"github.com/spf13/hugo/hugofs"
jww "github.com/spf13/jwalterweatherman"
"github.com/spf13/viper"
"io"
"io/ioutil"
"os/exec"
"path/filepath"
"sort"
"strings"
)
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
}
// Highlight takes some code and returns highlighted code.
func Highlight(code, lang, optsStr string) string {
if !HasPygments() {
jww.WARN.Println("Highlighting requires Pygments to be installed and in the path")
return code
}
options, err := parsePygmentsOpts(optsStr)
if err != nil {
jww.ERROR.Print(err.Error())
return code
}
// Try to read from cache first
hash := sha1.New()
io.WriteString(hash, code)
io.WriteString(hash, lang)
io.WriteString(hash, options)
fs := hugofs.OsFs
cacheDir := viper.GetString("CacheDir")
var cachefile string
if cacheDir != "" {
cachefile = filepath.Join(cacheDir, fmt.Sprintf("pygments-%x", hash.Sum(nil)))
exists, err := Exists(cachefile, fs)
if err != nil {
jww.ERROR.Print(err.Error())
return code
}
if exists {
f, err := fs.Open(cachefile)
if err != nil {
jww.ERROR.Print(err.Error())
return code
}
s, err := ioutil.ReadAll(f)
if err != nil {
jww.ERROR.Print(err.Error())
return code
}
return string(s)
}
}
// 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
}
str := out.String()
// inject code tag into Pygments output
if lang != "" && strings.Contains(str, "<pre>") {
codeTag := fmt.Sprintf(`<pre><code class="language-%s" data-lang="%s">`, lang, lang)
str = strings.Replace(str, "<pre>", codeTag, 1)
str = strings.Replace(str, "</pre>", "</code></pre>", 1)
}
if cachefile != "" {
// Write cache file
if err := WriteToDisk(cachefile, strings.NewReader(str), fs); err != nil {
jww.ERROR.Print(stderr.String())
}
}
return str
}
var pygmentsKeywords = make(map[string]bool)
func init() {
pygmentsKeywords["style"] = true
pygmentsKeywords["encoding"] = true
pygmentsKeywords["noclasses"] = true
pygmentsKeywords["hl_lines"] = true
pygmentsKeywords["linenos"] = true
pygmentsKeywords["classprefix"] = true
pygmentsKeywords["startinline"] = true
}
func parseOptions(options map[string]string, in string) error {
in = strings.Trim(in, " ")
if in != "" {
for _, v := range strings.Split(in, ",") {
keyVal := strings.Split(v, "=")
key := strings.ToLower(strings.Trim(keyVal[0], " "))
if len(keyVal) != 2 || !pygmentsKeywords[key] {
return fmt.Errorf("invalid Pygments option: %s", key)
}
options[key] = keyVal[1]
}
}
return 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() (map[string]string, error) {
options := make(map[string]string)
err := parseOptions(options, viper.GetString("PygmentsOptions"))
if err != nil {
return nil, err
}
if viper.IsSet("PygmentsStyle") {
options["style"] = viper.GetString("PygmentsStyle")
}
if viper.IsSet("PygmentsUseClasses") {
if viper.GetBool("PygmentsUseClasses") {
options["noclasses"] = "false"
} else {
options["noclasses"] = "true"
}
}
if _, ok := options["encoding"]; !ok {
options["encoding"] = "utf8"
}
return options, nil
}
func parsePygmentsOpts(in string) (string, error) {
options, err := parseDefaultPygmentsOpts()
if err != nil {
return "", err
}
err = parseOptions(options, in)
if err != nil {
return "", err
}
return createOptionsString(options), nil
}
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