Add more options to highlight

Fixes #1021

1 files changed, 80 insertions, 16 deletions

diff --git a/helpers/pygments.go b/helpers/pygments.go
index 8223759c5..74327c6f5 100644
--- a/helpers/pygments.go
+++ b/helpers/pygments.go
@@ -17,15 +17,15 @@ 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"
-
-	"github.com/spf13/hugo/hugofs"
-	jww "github.com/spf13/jwalterweatherman"
-	"github.com/spf13/viper"
 )
 
 const pygmentsBin = "pygmentize"
@@ -40,30 +40,30 @@ func HasPygments() bool {
 }
 
 // Highlight takes some code and returns highlighted code.
-func Highlight(code string, lexer string) string {
+func Highlight(code, lang, optsStr 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")
+	options, err := parsePygmentsOpts(optsStr)
 
-	noclasses := "true"
-	if viper.GetBool("PygmentsUseClasses") {
-		noclasses = "false"
+	if err != nil {
+		jww.ERROR.Print(err.Error())
+		return code
 	}
 
 	// 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)
+	io.WriteString(hash, lang)
+	io.WriteString(hash, options)
 
 	cachefile := filepath.Join(viper.GetString("CacheDir"), fmt.Sprintf("pygments-%x", hash.Sum(nil)))
+
+	fs := hugofs.OsFs
+
 	exists, err := Exists(cachefile, fs)
 	if err != nil {
 		jww.ERROR.Print(err.Error())
@@ -89,8 +89,7 @@ func Highlight(code string, lexer string) string {
 	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 := exec.Command(pygmentsBin, "-l"+lang, "-fhtml", "-O", options)
 	cmd.Stdin = strings.NewReader(code)
 	cmd.Stdout = &out
 	cmd.Stderr = &stderr
@@ -107,3 +106,68 @@ func Highlight(code string, lexer string) string {
 
 	return out.String()
 }
+
+var pygmentsKeywords = make(map[string]bool)
+
+func init() {
+	pygmentsKeywords["style"] = true
+	pygmentsKeywords["encoding"] = true
+	pygmentsKeywords["noclasses"] = true
+	pygmentsKeywords["hl_lines"] = true
+	pygmentsKeywords["linenos"] = true
+}
+
+func parsePygmentsOpts(in string) (string, error) {
+
+	in = strings.Trim(in, " ")
+
+	style := viper.GetString("PygmentsStyle")
+
+	noclasses := "true"
+	if viper.GetBool("PygmentsUseClasses") {
+		noclasses = "false"
+	}
+
+	if len(in) == 0 {
+		return fmt.Sprintf("style=%s,noclasses=%s,encoding=utf8", style, noclasses), nil
+	}
+
+	options := make(map[string]string)
+
+	o := strings.Split(in, ",")
+	for _, v := range o {
+		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]
+	}
+
+	if _, ok := options["style"]; !ok {
+		options["style"] = style
+	}
+
+	if _, ok := options["noclasses"]; !ok {
+		options["noclasses"] = noclasses
+	}
+
+	if _, ok := options["encoding"]; !ok {
+		options["encoding"] = "utf8"
+	}
+
+	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, nil
+}