cppcheck performance fixes

src/addon/addon.cpp

@@ -232,7 +232,7 @@ Addon::get_filename() const
   return get_id() + ".zip";
 }
 
-std::string
+const std::string&
 Addon::get_install_filename() const
 {
   return m_install_filename;

src/addon/addon.hpp

@@ -62,23 +62,23 @@ class Addon final
   Addon();
 
 public:
-  std::string get_id() const { return m_id; }
+  const std::string& get_id() const { return m_id; }
   int get_version() const { return m_version; }
   int get_format() const { return m_format; }
 
   Type get_type() const { return m_type; }
-  std::string get_title() const { return m_title; }
-  std::string get_author() const { return m_author; }
-  std::string get_license() const { return m_license; }
+  const std::string& get_title() const { return m_title; }
+  const std::string& get_author() const { return m_author; }
+  const std::string& get_license() const { return m_license; }
 
-  std::string get_description() const { return m_description; }
-  std::string get_url() const { return m_url; }
-  std::string get_md5() const { return m_md5; }
+  const std::string& get_description() const { return m_description; }
+  const std::string& get_url() const { return m_url; }
+  const std::string& get_md5() const { return m_md5; }
   const std::vector<std::string>& get_screenshots() const { return m_screenshots; }
   const std::vector<std::string>& get_dependencies() const { return m_dependencies; }
 
   std::string get_filename() const;
-  std::string get_install_filename() const;
+  const std::string& get_install_filename() const;
 
   bool is_installed() const;
   bool is_enabled() const;

src/audio/sound_manager.hpp

@@ -94,7 +94,7 @@ class SoundManager final : public Currenton<SoundManager>
   bool is_sound_enabled() const { return m_sound_enabled; }
 
   bool is_audio_enabled() const { return m_device != nullptr && m_context != nullptr; }
-  std::string get_current_music() const { return m_current_music; }
+  const std::string& get_current_music() const { return m_current_music; }
   void update();
 
   /** Tell soundmanager to call update() for stream_sound_source. */

src/collision/collision_movement_manager.hpp

@@ -45,12 +45,12 @@ class CollisionGroundMovementManager final
     void register_movement(CollisionObject& moving_object, const Vector& movement);
     void register_movement(TileMap& moving_tilemap, const Vector& movement);
 
-    const std::unordered_map<CollisionObject*, Vector> get_objects_map() const
+    const std::unordered_map<CollisionObject*, Vector>& get_objects_map() const
     {
       return m_moving_objects;
     }
 
-    const std::unordered_map<TileMap*, Vector> get_tilemaps_map() const
+    const std::unordered_map<TileMap*, Vector>& get_tilemaps_map() const
     {
       return m_moving_tilemaps;
     }

src/editor/editor.hpp

@@ -103,7 +103,7 @@ class Editor final : public Screen,
   int get_tileselect_select_mode() const;
   int get_tileselect_move_mode() const;
 
-  std::string get_levelfile() const { return m_levelfile; }
+  const std::string& get_levelfile() const { return m_levelfile; }
 
   void set_level(const std::string& levelfile_) {
     m_levelfile = levelfile_;

src/editor/object_group.hpp

@@ -32,7 +32,7 @@ class ObjectGroup final
 
   void add_icon(const std::string& object, const std::string& icon_path);
 
-  std::string get_name() const { return m_name; }
+  const std::string& get_name() const { return m_name; }
 
   bool is_worldmap() const { return m_for_worldmap;  }
 

src/editor/object_icon.hpp

@@ -35,7 +35,7 @@ class ObjectIcon
   virtual void draw(DrawingContext& context, const Vector& pos);
   virtual void draw(DrawingContext& context, const Vector& pos, int pixels_shown);
 
-  std::string get_object_class() const { return m_object_class; }
+  const std::string& get_object_class() const { return m_object_class; }
 
   ObjectIcon(const ObjectIcon&) = default;
   ObjectIcon& operator=(const ObjectIcon&) = default;

src/editor/tilebox.hpp

@@ -84,7 +84,7 @@ class EditorTilebox final : public Widget
   void set_input_type(InputType input_type) { m_input_type = input_type; }
 
   TileSelection* get_tiles() const { return m_tiles.get(); }
-  std::string get_object() const { return m_object; }
+  const std::string& get_object() const { return m_object; }
   void set_object(const std::string& object) { m_object = object; }
 
   float get_tiles_height() const;

src/interface/control_textbox.cpp

@@ -354,7 +354,7 @@ ControlTextbox::revert_value()
   recenter_offset();
 }
 
-std::string
+const std::string&
 ControlTextbox::get_string() const
 {
   return m_internal_string_backup;

src/interface/control_textbox.hpp

@@ -42,7 +42,7 @@ class ControlTextbox : public InterfaceControl
   void bind_string(std::string* value) { m_string = value; }
 
   /** Returns the full string held in m_charlist */
-  std::string get_string() const;
+  const std::string& get_string() const;
 
   /** Gets at which (absolute) index, in the text, corresponds an on-screen point */
   int get_text_position(const Vector& pos) const;

src/interface/label.hpp

@@ -36,7 +36,7 @@ class InterfaceLabel : public Widget
   Rectf get_rect() const { return m_rect; }
 
   void set_label(const std::string& label) { m_label = label; }
-  std::string get_label() const { return m_label; }
+  const std::string& get_label() const { return m_label; }
 
   bool fits(const std::string& text) const;
   std::string get_truncated_text() const;

src/object/background.hpp

@@ -60,7 +60,7 @@ class Background final : public GameObject,
 
   void draw_image(DrawingContext& context, const Vector& pos);
 
-  std::string get_image() const { return m_imagefile; }
+  const std::string& get_image() const { return m_imagefile; }
   float get_speed() const { return m_parallax_speed.x; }
   int get_layer() const { return m_layer; }
 

src/object/music_object.cpp

@@ -95,7 +95,7 @@ MusicObject::set_music(const std::string& music)
   m_music = music;
 }
 
-std::string
+const std::string&
 MusicObject::get_music() const
 {
   return m_music;

src/object/music_object.hpp

@@ -50,7 +50,7 @@ class MusicObject : public GameObject
   MusicType get_music_type() const;
 
   void set_music(const std::string& music);
-  std::string get_music() const;
+  const std::string& get_music() const;
 
 private:
   MusicType m_currentmusic;

src/object/particle_zone.hpp

@@ -75,7 +75,7 @@ class ParticleZone final :
   void set_particle_name(std::string& particle_name) {m_particle_name = particle_name;}
 
   /** Returns the name of the particle object for this area */
-  std::string get_particle_name() const {return m_particle_name;}
+  const std::string& get_particle_name() const { return m_particle_name; }
 
   /** Move the area around. Multiple calls stack (e. g. calling one before
    *  the other finished will play both movements simultaneously)
@@ -116,7 +116,7 @@ class ParticleZone final :
 
     Rectf get_rect() const {return m_rect;}
     ParticleZoneType get_type() const {return m_type;}
-    std::string get_particle_name() const {return m_particle_name;}
+    const std::string& get_particle_name() const {return m_particle_name;}
   };
 
   ZoneDetails get_details() {

src/squirrel/squirrel_environment.cpp

@@ -112,7 +112,7 @@ SquirrelEnvironment::unexpose(const std::string& name)
   SQInteger oldtop = sq_gettop(m_vm.get_vm());
   sq_pushobject(m_vm.get_vm(), m_table);
   try {
-    unexpose_object(m_vm.get_vm(), -1, name.c_str());
+    unexpose_object(m_vm.get_vm(), -1, name);
   } catch(std::exception& e) {
     log_warning << "Couldn't unregister object: " << e.what() << std::endl;
   }

src/supertux/game_session.hpp

@@ -121,7 +121,7 @@ class GameSession final : public Screen,
    * resources for the current level/world
    */
   std::string get_working_directory() const;
-  std::string get_level_file() const { return m_levelfile; }
+  const std::string& get_level_file() const { return m_levelfile; }
   bool has_active_sequence() const;
   int restart_level(bool after_death = false, bool preserve_music = false);
 

src/supertux/level.hpp

@@ -57,7 +57,7 @@ class Level final
 
   std::vector<Player*> get_players() const;
 
-  std::string get_tileset() const { return m_tileset; }
+  const std::string& get_tileset() const { return m_tileset; }
 
   int get_total_coins() const;
   int get_total_badguys() const;
@@ -67,7 +67,7 @@ class Level final
 
   bool is_worldmap() const { return m_is_worldmap; }
 
-  std::string get_license() const { return m_license; }
+  const std::string& get_license() const { return m_license; }
 
 private:
   void initialize();

src/supertux/profile.hpp

@@ -36,8 +36,8 @@ class Profile final
   std::string get_basedir() const;
 
   int get_id() const { return m_id; }
-  std::string get_name() const { return m_name; }
-  std::string get_last_world() const { return m_last_world; }
+  const std::string& get_name() const { return m_name; }
+  const std::string& get_last_world() const { return m_last_world; }
 
   void set_name(const std::string& name) { m_name = name; }
   void set_last_world(const std::string& world) { m_last_world = world; }

src/supertux/world.hpp

@@ -38,17 +38,17 @@ class World final
 
 public:
   std::string get_basename() const;
-  std::string get_basedir() const { return m_basedir; }
-  std::string get_title() const { return m_title; }
-  std::string get_description() const { return m_description; }
+  const std::string& get_basedir() const { return m_basedir; }
+  const std::string& get_title() const { return m_title; }
+  const std::string& get_description() const { return m_description; }
 
   bool hide_from_contribs() const { return m_hide_from_contribs && !g_config->developer_mode; }
 
   bool is_levelset() const { return m_is_levelset; }
   bool is_worldmap() const { return !m_is_levelset; }
 
-  std::string get_contrib_type() const { return m_contrib_type; }
-  std::string get_title_level() const { return m_title_level; }
+  const std::string& get_contrib_type() const { return m_contrib_type; }
+  const std::string& get_title_level() const { return m_title_level; }
 
   std::string get_worldmap_filename() const;
 

src/util/reader_document.cpp

@@ -57,7 +57,7 @@ ReaderDocument::get_root() const
   return ReaderObject(*this, m_sx);
 }
 
-std::string
+const std::string&
 ReaderDocument::get_filename() const
 {
   return m_filename;

src/util/reader_document.hpp

@@ -37,7 +37,7 @@ class ReaderDocument final
   ReaderObject get_root() const;
 
   /** Returns the filename of the document */
-  std::string get_filename() const;
+  const std::string& get_filename() const;
 
   /** Returns the directory of the document */
   std::string get_directory() const;

src/video/surface.hpp

@@ -55,7 +55,7 @@ class Surface final
   int get_width() const;
   int get_height() const;
   Flip get_flip() const { return m_flip; }
-  std::string get_filename() const { return m_source_filename; }
+  const std::string& get_filename() const { return m_source_filename; }
 
 private:
   const TexturePtr m_diffuse_texture;

src/worldmap/level_tile.hpp

@@ -49,11 +49,11 @@ class LevelTile final : public WorldMapObject
 
   void update_sprite_action();
 
-  std::string get_title() const { return m_title; }
-  std::string get_level_filename() const { return m_level_filename; }
-  std::string get_basedir() const { return m_basedir; }
+  const std::string& get_title() const { return m_title; }
+  const std::string& get_level_filename() const { return m_level_filename; }
+  const std::string& get_basedir() const { return m_basedir; }
   Color get_title_color() const { return m_title_color; }
-  std::string get_extro_script() const { return m_extro_script; }
+  const std::string& get_extro_script() const { return m_extro_script; }
   float get_target_time() const { return m_target_time; }
   bool is_auto_play() const { return m_auto_play; }
 

src/worldmap/spawn_point.hpp

@@ -32,7 +32,7 @@ class SpawnPoint final
 public:
   SpawnPoint(const ReaderMapping& mapping);
 
-  std::string get_name() const { return m_name; }
+  const std::string& get_name() const { return m_name; }
   Vector get_pos() const { return m_pos; }
   Direction get_auto_dir() const { return m_auto_dir; }
 

src/worldmap/special_tile.hpp

@@ -40,9 +40,9 @@ class SpecialTile final : public WorldMapObject
 
   virtual ObjectSettings get_settings() override;
 
-  std::string get_map_message() const { return m_map_message; }
+  const std::string& get_map_message() const { return m_map_message; }
   bool is_passive_message() const { return m_passive_message; }
-  std::string get_script() const { return m_script; }
+  const std::string& get_script() const { return m_script; }
 
   bool get_apply_action_north() const { return m_apply_action_north; }
   bool get_apply_action_east() const  { return m_apply_action_east; }

src/worldmap/worldmap.cpp

@@ -333,7 +333,7 @@ WorldMap::set_sector(const std::string& name, const std::string& spawnpoint,
     m_sector->move_to_spawnpoint(spawnpoint);
 }
 
-std::string
+const std::string&
 WorldMap::get_filename() const
 {
   return m_map_filename;

src/worldmap/worldmap.hpp

@@ -86,7 +86,7 @@ class WorldMap final : public Currenton<WorldMap>
   void set_sector(const std::string& name, const std::string& spawnpoint = "",
                   bool perform_full_setup = true);
 
-  std::string get_filename() const;
+  const std::string& get_filename() const;
 
 private:
   void on_escape_press();