hugo/helpers/pygments.go
Ruben Vermeersch e8ca8602c0 Hash all pygments parameters.
Ensures that Hugo rehighlights source code whenever one of the
highlighting options changes.
2015-03-29 13:01:44 +02:00

108 lines
2.5 KiB
Go

// Copyright © 2013-14 Steve Francia <spf@spf13.com>.
//
// Licensed under the Simple Public 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://opensource.org/licenses/Simple-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"
"strings"
"github.com/spf13/hugo/hugofs"
jww "github.com/spf13/jwalterweatherman"
"github.com/spf13/viper"
)
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 string, lexer string) string {
if !HasPygments() {
jww.WARN.Println("Highlighting requires Pygments to be installed and in the path")
return code
}
fs := hugofs.OsFs
style := viper.GetString("PygmentsStyle")
noclasses := "true"
if viper.GetBool("PygmentsUseClasses") {
noclasses = "false"
}
// Try to read from cache first
hash := sha1.New()
io.WriteString(hash, lexer)
io.WriteString(hash, code)
io.WriteString(hash, style)
io.WriteString(hash, noclasses)
cachefile := fmt.Sprintf("%s/pygments-%x", viper.GetString("CacheDir"), 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
cmd := exec.Command(pygmentsBin, "-l"+lexer, "-fhtml", "-O",
fmt.Sprintf("style=%s,noclasses=%s,encoding=utf8", style, noclasses))
cmd.Stdin = strings.NewReader(code)
cmd.Stdout = &out
cmd.Stderr = &stderr
if err := cmd.Run(); err != nil {
jww.ERROR.Print(stderr.String())
return code
}
// Write cache file
if err := WriteToDisk(cachefile, bytes.NewReader(out.Bytes()), fs); err != nil {
jww.ERROR.Print(stderr.String())
}
return out.String()
}