Merge remote-tracking branch 'damfr/save-unique-id' into jgrpp

# Conflicts:
#	src/saveload/afterload.cpp
#	src/saveload/saveload.cpp

src/fios_gui.cpp

@@ -265,6 +265,8 @@ static void SortSaveGameList(FileList &file_list)
 	QSortT(file_list.Get(sort_start), s_amount, CompareFiosItems);
 }
 
+void SaveGameConfirmationCallback(Window *w, bool confirmed);
+
 struct SaveLoadWindow : public Window {
 private:
 	static const uint EDITBOX_MAX_SIZE   =  50;
@@ -281,6 +283,8 @@ private:
 	QueryString filter_editbox; ///< Filter editbox;
 	SmallVector<bool, 32> fios_items_shown; ///< Map of the filtered out fios items
 
+	friend void SaveGameConfirmationCallback(Window *w, bool confirmed);
+
 public:
 
 	/** Generate a default save filename. */
@@ -463,6 +467,14 @@ public:
 					y = DrawStringMultiLine(r.left + WD_FRAMERECT_LEFT, r.right - WD_FRAMERECT_RIGHT,
 							y, r.bottom - WD_FRAMERECT_BOTTOM, _load_check_data.error, TC_RED);
 				} else {
+					/* Warning if save unique id differ when saving */
+					if (this->fop == SLO_SAVE &&
+							_load_check_data.settings.game_creation.generation_unique_id != 0 && /* Don't warn if the save has no id (old save) */
+							_load_check_data.settings.game_creation.generation_unique_id != _settings_game.game_creation.generation_unique_id) {
+						y = DrawStringMultiLine(r.left + WD_FRAMERECT_LEFT, r.right - WD_FRAMERECT_RIGHT,
+							y, r.bottom - WD_FRAMERECT_BOTTOM, STR_SAVELOAD_DIFFERENT_ID);
+					}
+
 					/* Mapsize */
 					SetDParam(0, _load_check_data.map_size_x);
 					SetDParam(1, _load_check_data.map_size_y);
@@ -731,8 +743,15 @@ public:
 			}
 		} else if (this->IsWidgetLowered(WID_SL_SAVE_GAME)) { // Save button clicked
 			if (this->abstract_filetype == FT_SAVEGAME || this->abstract_filetype == FT_SCENARIO) {
-				_switch_mode = SM_SAVE_GAME;
+				if (_load_check_data.settings.game_creation.generation_unique_id != 0 && /* Don't warn if the save has no id (old save) */
-				FiosMakeSavegameName(_file_to_saveload.name, this->filename_editbox.text.buf, lastof(_file_to_saveload.name));
+						_load_check_data.settings.game_creation.generation_unique_id != _settings_game.game_creation.generation_unique_id) {
+					/* The save has a different id to the current game */
+					/* Show a caption box asking whether the user is sure to overwrite the save */
+					ShowQuery(STR_SAVEGAME_UNMATCHING_ID_CAPTION, STR_SAVEGAME_UNMATCHING_ID_CONFIRMATION_TEXT, this, SaveGameConfirmationCallback);
+				} else {
+					/* We can safely overwrite the save */
+					SaveGameConfirmationCallback(this, true);
+				}
 			} else {
 				_switch_mode = SM_SAVE_HEIGHTMAP;
 				FiosMakeHeightmapName(_file_to_saveload.name, this->filename_editbox.text.buf, lastof(_file_to_saveload.name));
@@ -864,6 +883,19 @@ static WindowDesc _save_dialog_desc(
 	_nested_save_dialog_widgets, lengthof(_nested_save_dialog_widgets)
 );
 
+/**
+ * Callback function for the savegame 'are you sure you want to overwrite save' window
+ * @param w Window which is calling this callback
+ * @param confirmed boolean value, true when yes was clicked, false otherwise
+ */
+void SaveGameConfirmationCallback(Window *w, bool confirmed)
+{
+	if (confirmed) {
+		_switch_mode = SM_SAVE_GAME;
+		FiosMakeSavegameName(_file_to_saveload.name, dynamic_cast<SaveLoadWindow*>(w)->filename_editbox.text.buf, lastof(_file_to_saveload.name));
+	}
+}
+
 /**
  * Launch save/load dialog in the given mode.
  * @param abstract_filetype Kind of file to handle.

src/genworld.cpp

@@ -105,6 +105,11 @@ static void _GenerateWorld(void *)
 		/* Set the Random() seed to generation_seed so we produce the same map with the same seed */
 		if (_settings_game.game_creation.generation_seed == GENERATE_NEW_SEED) _settings_game.game_creation.generation_seed = _settings_newgame.game_creation.generation_seed = InteractiveRandom();
 		_random.SetSeed(_settings_game.game_creation.generation_seed);
+
+		/* Generates a unique id for the savegame, to avoid accidentally overwriting a save */
+		/* We keep id 0 for old savegames that don't have an id */
+		_settings_game.game_creation.generation_unique_id = _interactive_random.Next(UINT32_MAX - 1) + 1; /* Generates between [1,UINT32_MAX] */
+
 		SetGeneratingWorldProgress(GWP_MAP_INIT, 2);
 		SetObjectToPlace(SPR_CURSOR_ZZZ, PAL_NONE, HT_NONE, WC_MAIN_WINDOW, 0);
 

src/lang/english.txt

@@ -3297,6 +3297,7 @@ STR_SAVELOAD_DETAIL_NOT_AVAILABLE                               :{BLACK}No infor
 STR_SAVELOAD_DETAIL_COMPANY_INDEX                               :{SILVER}{COMMA}: {WHITE}{STRING1}
 STR_SAVELOAD_DETAIL_GRFSTATUS                                   :{SILVER}NewGRF: {WHITE}{STRING}
 STR_SAVELOAD_FILTER_TITLE                                       :{BLACK}Filter string:
+STR_SAVELOAD_DIFFERENT_ID                                       :{RED}Not the same game as you are saving.
 
 STR_SAVELOAD_OSKTITLE                                           :{BLACK}Enter a name for the savegame
 
@@ -4994,6 +4995,8 @@ STR_GAME_SAVELOAD_ERROR_FILE_NOT_WRITEABLE                      :File not writea
 STR_GAME_SAVELOAD_ERROR_DATA_INTEGRITY_CHECK_FAILED             :Data integrity check failed
 STR_GAME_SAVELOAD_NOT_AVAILABLE                                 :<not available>
 STR_WARNING_LOADGAME_REMOVED_TRAMS                              :{WHITE}Game was saved in version without tram support. All trams have been removed
+STR_SAVEGAME_UNMATCHING_ID_CAPTION                              :{WHITE}Caution!
+STR_SAVEGAME_UNMATCHING_ID_CONFIRMATION_TEXT                    :{YELLOW}The savegame you are about to overwrite is not the same as the current one.{}Are you sure you want to do this?
 
 STR_GAME_SAVELOAD_ERROR_HUGE_AIRPORTS_PRESENT                   :Savegame uses huge airports
 STR_GAME_SAVELOAD_ERROR_HELI_OILRIG_BUG                         :Savegame has a helicopter on approach to a buggy oil rig

src/saveload/afterload.cpp

@@ -3597,6 +3597,12 @@ bool AfterLoadGame()
 		}
 	}
 
+	if (SlXvIsFeatureMissing(XSLFI_SAVEGAME_UNIQUE_ID)) {
+		/* Generate a random id for savegames that didn't have one */
+		/* We keep id 0 for old savegames that don't have an id */
+		_settings_game.game_creation.generation_unique_id = _interactive_random.Next(UINT32_MAX-1) + 1; /* Generates between [1;UINT32_MAX] */
+	}
+
 	/* Road stops is 'only' updating some caches */
 	AfterLoadRoadStops();
 	AfterLoadLabelMaps();

src/saveload/extended_ver_sl.cpp

@@ -93,6 +93,7 @@ const SlxiSubChunkInfo _sl_xv_sub_chunk_infos[] = {
 	{ XSLFI_BUY_LAND_RATE_LIMIT,    XSCF_NULL,                1,   1, "buy_land_rate_limit",       NULL, NULL, NULL        },
 	{ XSLFI_DUAL_RAIL_TYPES,        XSCF_NULL,                1,   1, "dual_rail_types",           NULL, NULL, NULL        },
 	{ XSLFI_CONSIST_SPEED_RD_FLAG,  XSCF_NULL,                1,   1, "consist_speed_rd_flag",     NULL, NULL, NULL        },
+	{ XSLFI_SAVEGAME_UNIQUE_ID,     XSCF_IGNORABLE_ALL,       1,   1, "savegame_unique_id",        NULL, NULL, NULL        },
 	{ XSLFI_NULL, XSCF_NULL, 0, 0, NULL, NULL, NULL, NULL },// This is the end marker
 };
 

src/saveload/extended_ver_sl.h

@@ -67,6 +67,7 @@ enum SlXvFeatureIndex {
 	XSLFI_BUY_LAND_RATE_LIMIT,                    ///< Buy land rate limit
 	XSLFI_DUAL_RAIL_TYPES,                        ///< Two rail-types per tile
 	XSLFI_CONSIST_SPEED_RD_FLAG,                  ///< Consist speed reduction flag
+	XSLFI_SAVEGAME_UNIQUE_ID,                     ///< Savegame unique ID
 
 	XSLFI_RIFF_HEADER_60_BIT,                     ///< Size field in RIFF chunk header is 60 bit
 	XSLFI_HEIGHT_8_BIT,                           ///< Map tile height is 8 bit instead of 4 bit, but savegame version may be before this became true in trunk

src/settings_type.h

@@ -330,6 +330,7 @@ struct NetworkSettings {
 /** Settings related to the creation of games. */
 struct GameCreationSettings {
 	uint32 generation_seed;                  ///< noise seed for world generation
+	uint32 generation_unique_id;             ///< random id to differentiate savegames
 	Year   starting_year;                    ///< starting date
 	uint8  map_x;                            ///< X size of map
 	uint8  map_y;                            ///< Y size of map

src/table/settings.ini

@@ -2848,6 +2848,16 @@ min      = 0
 max      = UINT32_MAX
 cat      = SC_EXPERT
 
+[SDT_VAR]
+base     = GameSettings
+var      = game_creation.generation_unique_id
+type     = SLE_UINT32
+from     = 0
+def      = 0
+min      = 0
+max      = UINT32_MAX
+patxname = ""savegame_unique_id.game_creation.generation_unique_id""
+
 [SDT_VAR]
 base     = GameSettings
 var      = game_creation.tree_placer