Add empty()

src/utils/variable-string.cpp

@@ -63,6 +63,12 @@ const char *StringVariable::c_str() const
 	return _resolvedValue.c_str();
 }
 
+bool StringVariable::empty() const
+{
+	Resolve();
+	return _resolvedValue.empty();
+}
+
 std::string SubstitueVariables(std::string str)
 {
 	if (!switcher) {

src/utils/variable-string.hpp

@@ -20,6 +20,7 @@ public:
 	void operator=(const char *value);
 	const char *c_str();
 	const char *c_str() const;
+	bool empty() const;
 
 	const std::string &UnresolvedValue() const { return _value; }