Directory: pass std::string&& to constructor

src/db/Directory.cxx

@@ -41,10 +41,10 @@ extern "C" {
 #include <string.h>
 #include <stdlib.h>
 
-Directory::Directory(const char *_path_utf8, Directory *_parent)
+Directory::Directory(std::string &&_path_utf8, Directory *_parent)
 	:parent(_parent),
 	 mtime(0), have_stat(false),
-	 path(_path_utf8)
+	 path(std::move(_path_utf8))
 {
 	INIT_LIST_HEAD(&children);
 	INIT_LIST_HEAD(&songs);

src/db/Directory.hxx

@@ -85,7 +85,7 @@ struct Directory {
 	std::string path;
 
 public:
-	Directory(const char *_path_utf8, Directory *_parent);
+	Directory(std::string &&_path_utf8, Directory *_parent);
 	~Directory();
 
 	/**
@@ -93,7 +93,7 @@ public:
 	 */
 	gcc_malloc
 	static Directory *NewRoot() {
-		return new Directory("", nullptr);
+		return new Directory(std::string(), nullptr);
 	}
 
 	/**