Use const ref instead of string copy

Author: joto

src/properties.cpp

@@ -83,7 +83,8 @@ bool properties_t::get_bool(std::string const &property,
                     property);
 }
 
-void properties_t::set_string(std::string property, std::string value)
+void properties_t::set_string(std::string const &property,
+                              std::string const &value)
 {
     m_properties[property] = value;
     m_to_update[property] = value;

src/properties.hpp

@@ -54,7 +54,7 @@ class properties_t
      * \param property Name of the property
      * \param value Value of the property
      */
-    void set_string(std::string property, std::string value);
+    void set_string(std::string const &property, std::string const &value);
 
     /**
      * Set property to integer value. The integer will be converted to a string