src/rollback_interface.h

/*
Minetest
Copyright (C) 2010-2013 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.
*/

#pragma once

#include <unordered_set>
#include "irrlichttypes_bloated.h"
#include "activeobject.h"
#include "inventorymanager.h"
#include "itemgroup.h"
#include "util/container.h"

/*

Some planning
-------------

* Server environment adds an active object, which gets the id 1
* The active object list is scanned for each client once in a while,
  and it finds out what objects have been added that are not known
  by the client yet. This scan is initiated by the Server class and
  the result ends up directly to the server.
* A network packet is created with the info and sent to the client.
* Environment converts objects to static data and static data to
  objects, based on how close players are to them.

*/

class ServerEnvironment;
struct ItemStack;
struct ToolCapabilities;
struct ObjectProperties;
struct PlayerHPChangeReason;

class ServerActiveObject : public ActiveObject
{
public:
	/*
		NOTE: m_env can be NULL, but step() isn't called if it is.
		Prototypes are used that way.
	*/
	ServerActiveObject(ServerEnvironment *env, v3f pos);
	virtual ~ServerActiveObject() = default;

	virtual ActiveObjectType getSendType() const
	{ return getType(); }

	// Called after id has been set and has been inserted in environment
	virtual void addedToEnvironment(u32 dtime_s){};
	// Called before removing from environment
	virtual void removingFromEnvironment(){};
	// Returns true if object's deletion is the job of the
	// environment
	virtual bool environmentDeletes() const
	{ return true; }

	// Create a certain type of ServerActiveObject
	static ServerActiveObject* create(ActiveObjectType type,
			ServerEnvironment *env, u16 id, v3f pos,
			const std::string &data);

	/*
		Some simple getters/setters
	*/
	v3f getBasePosition() const { return m_base_position; }
	void setBasePosition(v3f pos){ m_base_position = pos; }
	ServerEnvironment* getEnv(){ return m_env; }

	/*
		Some more dynamic interface
	*/

	virtual void setPos(const v3f &pos)
		{ setBasePosition(pos); }
	// continuous: if true, object does not stop immediately at pos
	virtual void moveTo(v3f pos, bool continuous)
		{ setBasePosition(pos); }
	// If object has moved less than this and data has not changed,
	// saving to disk may be omitted
	virtual float getMinimumSavedMovement();

	virtual std::string getDescription(){return "SAO";}

	/*
		Step object in time.
		Messages added to messages are sent to client over network.

		send_recommended:
			True at around 5-10 times a second, same for all objects.
			This is used to let objects send most of the data at the
			same time so that the data can be combined in a single
			packet.
	*/
	virtual void step(float dtime, bool send_recommended){}

	/*
		The return value of this is passed to the client-side object
		when it is created
	*/
	virtual std::string getClientInitializationData(u16 protocol_version){return "";}

	/*
		The return value of this is passed to the server-side object
		when it is created (converted from static to active - actually
		the data is the static form)
	*/
	virtual void getStaticData(std::string *result) const
	{
		assert(isStaticAllowed());
		*result = "";
	}
	/*
		Return false in here to never save and instead remove object
		on unload. getStaticData() will not be called in that case.
	*/
	virtual bool isStaticAllowed() const
	{return true;}

	// Returns tool wear
	virtual u16 punch(v3f dir,
			const ToolCapabilities *toolcap = nullptr,
			ServerActiveObject *puncher = nullptr,
			float time_from_last_punch = 1000000.0f)
	{ return 0; }
	virtual void rightClick(ServerActiveObject *clicker)
	{}
	virtual void setHP(s32 hp, const PlayerHPChangeReason &reason)
	{}
	virtual u16 getHP() const
	{ return 0; }

	virtual void setArmorGroups(const ItemGroupList &armor_groups)
	{}
	virtual const ItemGroupList &getArmorGroups() const
	{ static ItemGroupList rv; return rv; }
	virtual void setPhysicsOverride(float physics_override_speed, float physics_override_jump, float physics_override_gravity)
	{}
	virtual void setAnimation(v2f frames, float frame_speed, float frame_blend, bool frame_loop)
	{}
	virtual void getAnimation(v2f *frames, float *frame_speed, float *frame_blend, bool *frame_loop)
	{}
	virtual void setAnimationSpeed(float frame_speed)
	{}
	virtual void setBonePosition(const std::string &bone, v3f position, v3f rotation)
	{}
	virtual void getBonePosition(const std::string &bone, v3f *position, v3f *lotation)
	{}
	virtual const std::unordered_set<int> &getAttachmentChildIds() const
	{ static std::unordered_set<int> rv; return rv; }
	virtual ServerActiveObject *getParent() const { return nullptr; }
	virtual ObjectProperties* accessObjectProperties()
	{ return NULL; }
	virtual void notifyObjectPropertiesModified()
	{}

	// Inventory and wielded item
	virtual Inventory *getInventory() const
	{ return NULL; }
	virtual InventoryLocation getInventoryLocation() const
	{ return InventoryLocation(); }
	virtual void setInventoryModified()
	{}
	virtual std::string getWieldList() const
	{ return ""; }
	virtual u16 getWieldIndex() const
	{ return 0; }
	virtual ItemStack getWieldedItem(ItemStack *selected,
			ItemStack *hand = nullptr) const;
	virtual bool setWieldedItem(const ItemStack &item);
	inline void attachParticleSpawner(u32 id)
	{
		m_attached_particle_spawners.insert(id);
	}
	inline void detachParticleSpawner(u32 id)
	{
		m_attached_particle_spawners.erase(id);
	}


	/*
		Number of players which know about this object. Object won't be
		deleted until this is 0 to keep the id preserved for the right
		object.
	*/
	u16 m_known_by_count = 0;

	/*
		- Whether this object is to be removed when nobody knows about
		  it anymore.
		- Removal is delayed to preserve the id for the time during which
		  it could be confused to some other object by some client.
		- This is usually set to true by the step() method when the object wants
		  to be deleted but can be set by anything else too.
	*/
	bool m_pending_removal = false;

	/*
		Same purpose as m_pending_removal but for deactivation.
		deactvation = save static data in block, remove active object

		If this is set alongside with m_pending_removal, removal takes
		priority.
	*/
	bool m_pending_deactivation = false;

	/*
		A getter that unifies the above to answer the question:
		"Can the environment still interact with this object?"
	*/
	inline bool isGone() const
	{ return m_pending_removal || m_pending_deactivation; }

	/*
		Whether the object's static data has been stored to a block
	*/
	bool m_static_exists = false;
	/*
		The block from which the object was loaded from, and in which
		a copy of the static data resides.
	*/
	v3s16 m_static_block = v3s16(1337,1337,1337);

	/*
		Queue of messages to be sent to the client
	*/
	std::queue<ActiveObjectMessage> m_messages_out;

protected:
	virtual void onAttach(int parent_id) {}
	virtual void onDetach(int parent_id) {}

	// Used for creating objects based on type
	typedef ServerActiveObject* (*Factory)
			(ServerEnvironment *env, v3f pos,
			const std::string &data);
	static void registerType(u16 type, Factory f);

	ServerEnvironment *m_env;
	v3f m_base_position;
	std::unordered_set<u32> m_attached_particle_spawners;

private:
	// Used for creating objects based on type
	static std::map<u16, Factory> m_types;
};
	Commit message (Expand)	Author	Age
*	Code modernization: src/p, src/q, src/r, src/s (partial) (#6282)	Loïc Blot	2017-08-19
*	C++ modernize: Pragma once (#6264)	Loïc Blot	2017-08-17
*	Cpp11 patchset 11: continue working on constructor style migration (#6004)	Loïc Blot	2017-06-18
*	Clean up rollback	ShadowNinja	2014-11-19
*	Rollback fixes and get_node_actions	ShadowNinja	2013-11-27
*	Update Copyright Years	Sfan5	2013-02-24
*	Change Minetest-c55 to Minetest	PilzAdam	2013-02-24
*	Tweak rollback and liquids	Perttu Ahola	2012-07-27
*	Tweak rollback stuff	Perttu Ahola	2012-07-27
*	Make the rollback system VERY FUCKING GOD DAMN POWERFUL	Perttu Ahola	2012-07-27
*	Experimental-ish rollback functionality	Perttu Ahola	2012-07-27