Experimental-ish rollback functionality

src/rollback.cpp

@@ -0,0 +1,293 @@
+/*
+Minetest-c55
+Copyright (C) 2012 celeron55, Perttu Ahola <celeron55@gmail.com>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#include "rollback.h"
+#include <fstream>
+#include <list>
+#include <sstream>
+#include "log.h"
+#include "mapnode.h"
+#include "gamedef.h"
+#include "nodedef.h"
+#include "util/serialize.h"
+#include "util/string.h"
+#include "strfnd.h"
+#include "inventorymanager.h" // deserializing InventoryLocations
+
+#define PP(x) "("<<(x).X<<","<<(x).Y<<","<<(x).Z<<")"
+
+class RollbackManager: public IRollbackManager
+{
+public:
+	// IRollbackManager interface
+
+	void reportAction(const RollbackAction &action_)
+	{
+		// Ignore if not important
+		if(!action_.isImportant(m_gamedef))
+			return;
+		RollbackAction action = action_;
+		action.unix_time = time(0);
+		action.actor = m_current_actor;
+		infostream<<"RollbackManager::reportAction():"
+				<<" time="<<action.unix_time
+				<<" actor=\""<<action.actor<<"\""
+				<<" action="<<action.toString()
+				<<std::endl;
+		addAction(action);
+	}
+	std::string getActor()
+	{
+		return m_current_actor;
+	}
+	void setActor(const std::string &actor)
+	{
+		m_current_actor = actor;
+	}
+	void flush()
+	{
+		infostream<<"RollbackManager::flush()"<<std::endl;
+		std::ofstream of(m_filepath.c_str(), std::ios::app);
+		if(!of.good()){
+			errorstream<<"RollbackManager::flush(): Could not open file "
+					<<"for appending: \""<<m_filepath<<"\""<<std::endl;
+			return;
+		}
+		for(std::list<RollbackAction>::const_iterator
+				i = m_action_todisk_buffer.begin();
+				i != m_action_todisk_buffer.end(); i++)
+		{
+			// Do not save stuff that does not have an actor
+			if(i->actor == "")
+				continue;
+			of<<i->unix_time;
+			of<<" ";
+			of<<serializeJsonString(i->actor);
+			of<<" ";
+			std::string action_s = i->toString();
+			of<<action_s<<std::endl;
+		}
+		m_action_todisk_buffer.clear();
+	}
+	
+	// Other
+
+	RollbackManager(const std::string &filepath, IGameDef *gamedef):
+		m_filepath(filepath),
+		m_gamedef(gamedef)
+	{
+		infostream<<"RollbackManager::RollbackManager("<<filepath<<")"
+				<<std::endl;
+	}
+	~RollbackManager()
+	{
+		infostream<<"RollbackManager::~RollbackManager()"<<std::endl;
+		flush();
+	}
+
+	void addAction(const RollbackAction &action)
+	{
+		m_action_todisk_buffer.push_back(action);
+		m_action_latest_buffer.push_back(action);
+
+		// Flush to disk sometimes
+		if(m_action_todisk_buffer.size() >= 100)
+			flush();
+	}
+	
+	bool readFile(std::list<RollbackAction> &dst)
+	{
+		// Load whole file to memory
+		std::ifstream f(m_filepath.c_str(), std::ios::in);
+		if(!f.good()){
+			errorstream<<"RollbackManager::readFile(): Could not open "
+					<<"file for reading: \""<<m_filepath<<"\""<<std::endl;
+			return false;
+		}
+		for(;;){
+			if(f.eof() || !f.good())
+				break;
+			std::string line;
+			std::getline(f, line);
+			line = trim(line);
+			if(line == "")
+				continue;
+			std::istringstream is(line);
+			
+			try{
+				std::string action_time_raw;
+				std::getline(is, action_time_raw, ' ');
+				std::string action_actor;
+				try{
+					action_actor = deSerializeJsonString(is);
+				}catch(SerializationError &e){
+					errorstream<<"RollbackManager: Error deserializing actor: "
+							<<e.what()<<std::endl;
+					throw e;
+				}
+				RollbackAction action;
+				action.unix_time = stoi(action_time_raw);
+				action.actor = action_actor;
+				int c = is.get();
+				if(c != ' '){
+					is.putback(c);
+					throw SerializationError("readFile(): second ' ' not found");
+				}
+				action.fromStream(is);
+				/*infostream<<"RollbackManager::readFile(): Action from disk: "
+						<<action.toString()<<std::endl;*/
+				dst.push_back(action);
+			}
+			catch(SerializationError &e){
+				errorstream<<"RollbackManager: Error on line: "<<line<<std::endl;
+				errorstream<<"RollbackManager: ^ error: "<<e.what()<<std::endl;
+			}
+		}
+		return true;
+	}
+
+	std::list<RollbackAction> getEntriesSince(int first_time)
+	{
+		infostream<<"RollbackManager::getEntriesSince("<<first_time<<")"<<std::endl;
+		// Collect enough data to this buffer
+		std::list<RollbackAction> action_buffer;
+		// Use the latest buffer if it is long enough
+		if(!m_action_latest_buffer.empty() &&
+				m_action_latest_buffer.begin()->unix_time <= first_time){
+			action_buffer = m_action_latest_buffer;
+		}
+		else
+		{
+			// Save all remaining stuff
+			flush();
+			// Load whole file to memory
+			bool good = readFile(action_buffer);
+			if(!good){
+				errorstream<<"RollbackManager::getEntriesSince(): Failed to"
+						<<" open file; using data in memory."<<std::endl;
+				action_buffer = m_action_latest_buffer;
+			}
+		}
+		return action_buffer;
+	}
+	
+	std::string getLastNodeActor(v3s16 p, int range, int seconds,
+			v3s16 *act_p, int *act_seconds)
+	{
+		infostream<<"RollbackManager::getLastNodeActor("<<PP(p)
+				<<", "<<seconds<<")"<<std::endl;
+		// Figure out time
+		int cur_time = time(0);
+		int first_time = cur_time - seconds;
+
+		std::list<RollbackAction> action_buffer = getEntriesSince(first_time);
+		
+		std::list<RollbackAction> result;
+
+		for(std::list<RollbackAction>::const_reverse_iterator
+				i = action_buffer.rbegin();
+				i != action_buffer.rend(); i++)
+		{
+			if(i->unix_time < first_time)
+				break;
+
+			// Find position of action or continue
+			v3s16 action_p;
+
+			if(i->type == RollbackAction::TYPE_SET_NODE)
+			{
+				action_p = i->p;
+			}
+			else if(i->type == RollbackAction::TYPE_MODIFY_INVENTORY_STACK)
+			{
+				InventoryLocation loc;
+				loc.deSerialize(i->inventory_location);
+				if(loc.type != InventoryLocation::NODEMETA)
+					continue;
+				action_p = loc.p;
+			}
+			else
+				continue;
+
+			if(range == 0){
+				if(action_p != p)
+					continue;
+			} else {
+				if(abs(action_p.X - p.X) > range ||
+						abs(action_p.Y - p.Y) > range ||
+						abs(action_p.Z - p.Z) > range)
+					continue;
+			}
+			
+			if(act_p)
+				*act_p = action_p;
+			if(act_seconds)
+				*act_seconds = cur_time - i->unix_time;
+			return i->actor;
+		}
+		return "";
+	}
+
+	std::list<RollbackAction> getRevertActions(const std::string &actor_filter,
+			int seconds)
+	{
+		infostream<<"RollbackManager::getRevertActions("<<actor_filter
+				<<", "<<seconds<<")"<<std::endl;
+		// Figure out time
+		int cur_time = time(0);
+		int first_time = cur_time - seconds;
+		
+		std::list<RollbackAction> action_buffer = getEntriesSince(first_time);
+		
+		std::list<RollbackAction> result;
+
+		for(std::list<RollbackAction>::const_reverse_iterator
+				i = action_buffer.rbegin();
+				i != action_buffer.rend(); i++)
+		{
+			if(i->unix_time < first_time)
+				break;
+			if(i->actor != actor_filter)
+				continue;
+			const RollbackAction &action = *i;
+			/*infostream<<"RollbackManager::revertAction(): Should revert"
+					<<" time="<<action.unix_time
+					<<" actor=\""<<action.actor<<"\""
+					<<" action="<<action.toString()
+					<<std::endl;*/
+			result.push_back(action);
+		}
+
+		return result;
+	}
+
+private:
+	std::string m_filepath;
+	IGameDef *m_gamedef;
+	std::string m_current_actor;
+	std::list<RollbackAction> m_action_todisk_buffer;
+	std::list<RollbackAction> m_action_latest_buffer;
+};
+
+IRollbackManager *createRollbackManager(const std::string &filepath, IGameDef *gamedef)
+{
+	return new RollbackManager(filepath, gamedef);
+}
+
+