SCUMM: Add a "chained games manager"

This replaces the somewhat ugly use of the config manager to store
the chained games.

base/main.cpp

@@ -529,43 +529,21 @@ extern "C" int scummvm_main(int argc, const char * const argv[]) {
 			// at. At the time of writing, this is used for the Maniac Mansion
 			// easter egg in Day of the Tentacle.
 
-			Common::String chainedGames, nextGame, saveSlot;
+			Common::String chainedGame;
+			int saveSlot = -1;
 
-			if (ConfMan.hasKey("chained_games", Common::ConfigManager::kTransientDomain)) {
-				chainedGames = ConfMan.get("chained_games", Common::ConfigManager::kTransientDomain);
-			}
+			ChainedGamesMan.pop(chainedGame, saveSlot);
 
 			// Discard any command line options. It's unlikely that the user
 			// wanted to apply them to *all* games ever launched.
 			ConfMan.getDomain(Common::ConfigManager::kTransientDomain)->clear();
 
-			if (!chainedGames.empty()) {
-				if (chainedGames.contains(',')) {
-					for (uint i = 0; i < chainedGames.size(); i++) {
-						if (chainedGames[i] == ',') {
-							chainedGames.erase(0, i + 1);
-							break;
-						}
-						nextGame += chainedGames[i];
-					}
-					ConfMan.set("chained_games", chainedGames, Common::ConfigManager::kTransientDomain);
-				} else {
-					nextGame = chainedGames;
-					chainedGames.clear();
-					ConfMan.removeKey("chained_games", Common::ConfigManager::kTransientDomain);
+			if (!chainedGame.empty()) {
+				if (saveSlot != -1) {
+					ConfMan.setInt("save_slot", saveSlot, Common::ConfigManager::kTransientDomain);
 				}
-				if (nextGame.contains(':')) {
-					for (int i = nextGame.size() - 1; i >= 0; i--) {
-						if (nextGame[i] == ':') {
-							nextGame.erase(i);
-							break;
-						}
-						saveSlot = nextGame[i] + saveSlot;
-					}
-					ConfMan.setInt("save_slot", atoi(saveSlot.c_str()), Common::ConfigManager::kTransientDomain);
-				}
-				// Start the next game
-				ConfMan.setActiveDomain(nextGame);
+				// Start the chained game
+				ConfMan.setActiveDomain(chainedGame);
 			} else {
 				// Clear the active config domain
 				ConfMan.setActiveDomain("");

engines/engine.cpp

@@ -45,6 +45,7 @@
 #include "common/taskbar.h"
 #include "common/textconsole.h"
 #include "common/translation.h"
+#include "common/singleton.h"
 
 #include "backends/keymapper/keymapper.h"
 
@@ -101,6 +102,36 @@ static void defaultErrorHandler(const char *msg) {
 	}
 }
 
+// Chained games manager
+
+ChainedGamesManager::ChainedGamesManager() {
+	clear();
+}
+
+void ChainedGamesManager::clear() {
+	_chainedGames.clear();
+}
+
+void ChainedGamesManager::push(const Common::String target, const int slot) {
+	Game game;
+	game.target = target;
+	game.slot = slot;
+	_chainedGames.push(game);
+}
+
+bool ChainedGamesManager::pop(Common::String &target, int &slot) {
+	if (_chainedGames.empty()) {
+		return false;
+	}
+	Game game = _chainedGames.pop();
+	target = game.target;
+	slot = game.slot;
+	return true;
+}
+
+namespace Common {
+DECLARE_SINGLETON(ChainedGamesManager);
+}
 
 Engine::Engine(OSystem *syst)
 	: _system(syst),

engines/engine.h

@@ -27,6 +27,8 @@
 #include "common/str.h"
 #include "common/language.h"
 #include "common/platform.h"
+#include "common/queue.h"
+#include "common/singleton.h"
 
 class OSystem;
 
@@ -334,6 +336,32 @@ protected:
 
 };
 
+// Chained games
+
+/**
+ * Singleton class which manages chained games. A chained game is one that
+ * starts automatically, optionally loading a saved game, instead of returning
+ * to the launcher.
+ */
+class ChainedGamesManager : public Common::Singleton<ChainedGamesManager> {
+private:
+	struct Game {
+		Common::String target;
+		int slot;
+	};
+
+	Common::Queue<Game> _chainedGames;
+
+public:
+	ChainedGamesManager();
+	void clear();
+	void push(const Common::String target, const int slot = -1);
+	bool pop(Common::String &target, int &slot);
+};
+
+/** Convenience shortcut for accessing the chained games manager. */
+#define ChainedGamesMan ChainedGamesManager::instance()
+
 // FIXME: HACK for MidiEmu & error()
 extern Engine *g_engine;
 

engines/scumm/scumm.cpp

@@ -2625,7 +2625,8 @@ bool ScummEngine::startManiac() {
 
 		// Set up the chanined games to Maniac Mansion, and then back
 		// to the current game again with that save slot.
-		ConfMan.set("chained_games", maniacTarget + "," + ConfMan.getActiveDomainName() + ":100", Common::ConfigManager::kTransientDomain);
+		ChainedGamesMan.push(maniacTarget);
+		ChainedGamesMan.push(ConfMan.getActiveDomainName(), 100);
 
 		// Force a return to the launcher. This will start the first
 		// chained game.