Add data files support in themes

If duplicate keys, the main data dir wins.

Fixes #892

helpers/general.go

@@ -19,13 +19,13 @@ import (
 	"encoding/hex"
 	"errors"
 	"fmt"
+	bp "github.com/spf13/hugo/bufferpool"
+	"github.com/spf13/viper"
 	"io"
 	"net"
 	"path/filepath"
 	"reflect"
 	"strings"
-
-	bp "github.com/spf13/hugo/bufferpool"
 )
 
 // Filepath separator defined by os.Separator.
@@ -100,6 +100,10 @@ func BytesToReader(in []byte) io.Reader {
 	return bytes.NewReader(in)
 }
 
+func ThemeSet() bool {
+	return viper.GetString("theme") != ""
+}
+
 // SliceToLower goes through the source slice and lowers all values.
 func SliceToLower(s []string) []string {
 	if s == nil {

helpers/path.go

@@ -178,6 +178,29 @@ func GetStaticDirPath() string {
 	return AbsPathify(viper.GetString("StaticDir"))
 }
 
+// GetThemeStaticDirPath returns the theme's static dir path if theme is set.
+// If theme is set and the static dir doesn't exist, an error is returned.
+func GetThemeStaticDirPath() (string, error) {
+	return getThemeDirPath("static")
+}
+
+// GetThemeStaticDirPath returns the theme's data dir path if theme is set.
+// If theme is set and the data dir doesn't exist, an error is returned.
+func GetThemeDataDirPath() (string, error) {
+	return getThemeDirPath("data")
+}
+
+func getThemeDirPath(path string) (string, error) {
+	var themeDir string
+	if ThemeSet() {
+		themeDir = AbsPathify("themes/"+viper.GetString("theme")) + FilePathSeparator + path
+		if _, err := os.Stat(themeDir); os.IsNotExist(err) {
+			return "", fmt.Errorf("Unable to find %s directory for theme %s in %s", path, viper.GetString("theme"), themeDir)
+		}
+	}
+	return themeDir, nil
+}
+
 func GetThemesDirPath() string {
 	return AbsPathify(filepath.Join("themes", viper.GetString("theme"), "static"))
 }