Configurable undo history

Note: Each undo adds 16.7 MB of RAM usage, max is 200 (3.4GB), but don't set it to this

src/gui/game/GameController.cpp

@@ -260,7 +260,7 @@ void GameController::HistorySnapshot()
 			history.pop_back();
 			delete snap;
 		}
-		if (history.size() >= 1)
+		if (history.size() >= gameModel->GetUndoHistoryLimit())
 		{
 			Snapshot * snap = history.front();
 			history.pop_front();

src/gui/game/GameModel.cpp

@@ -134,6 +134,11 @@ GameModel::GameModel():
 	colourPresets.push_back(ui::Colour(0, 255, 0));
 	colourPresets.push_back(ui::Colour(0, 0, 255));
 	colourPresets.push_back(ui::Colour(0, 0, 0));
+
+	undoHistoryLimit = Client::Ref().GetPrefInteger("UndoHistoryLimit", 1);
+	// cap due to memory usage (this is about 3.4GB of RAM)
+	if (undoHistoryLimit > 200)
+		undoHistoryLimit = 200;
 }
 
 GameModel::~GameModel()
@@ -161,6 +166,8 @@ GameModel::~GameModel()
 	Client::Ref().SetPref("Decoration.Blue", (int)colour.Blue);
 	Client::Ref().SetPref("Decoration.Alpha", (int)colour.Alpha);
 
+	Client::Ref().SetPref("UndoHistoryLimit", undoHistoryLimit);
+
 	Favorite::Ref().SaveFavoritesToPrefs();
 
 	for (size_t i = 0; i < menuList.size(); i++)
@@ -451,6 +458,16 @@ void GameModel::SetRedoHistory(Snapshot * redo)
 	redoHistory = redo;
 }
 
+unsigned int GameModel::GetUndoHistoryLimit()
+{
+	return undoHistoryLimit;
+}
+
+void GameModel::SetUndoHistoryLimit(unsigned int undoHistoryLimit_)
+{
+	undoHistoryLimit = undoHistoryLimit_;
+}
+
 void GameModel::SetVote(int direction)
 {
 	if(currentSave)

src/gui/game/GameModel.h

@@ -67,6 +67,7 @@ class GameModel
 	std::deque<Snapshot*> history;
 	Snapshot *redoHistory;
 	unsigned int historyPosition;
+	unsigned int undoHistoryLimit;
 
 	size_t activeColourPreset;
 	std::vector<ui::Colour> colourPresets;
@@ -136,6 +137,8 @@ class GameModel
 	void SetHistoryPosition(unsigned int newHistoryPosition);
 	Snapshot * GetRedoHistory();
 	void SetRedoHistory(Snapshot * redo);
+	unsigned int GetUndoHistoryLimit();
+	void SetUndoHistoryLimit(unsigned int undoHistoryLimit_);
 
 	void UpdateQuickOptions();