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/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* 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 General Public License for more details.
*
* You should have received a copy of the GNU 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.
*
* $URL$
* $Id$
*/
#ifndef ENGINES_METAENGINE_H
#define ENGINES_METAENGINE_H
#include "common/scummsys.h"
#include "common/str.h"
#include "common/error.h"
#include "base/game.h"
#include "base/plugins.h"
class Engine;
class OSystem;
namespace Common {
class FSList;
}
/**
* A meta engine is essentially a factory for Engine instances with the
* added ability of listing and detecting supported games.
* Every engine "plugin" provides a hook to get an instance of a MetaEngine
* subclass for that "engine plugin". E.g. SCUMM povides ScummMetaEngine.
* This is then in turn used by the frontend code to detect games,
* and instantiate actual Engine objects.
*/
class MetaEngine : public PluginObject {
public:
virtual ~MetaEngine() {}
/** Returns some copyright information about the engine. */
virtual const char *getCopyright() const = 0;
/** Returns a list of games supported by this engine. */
virtual GameList getSupportedGames() const = 0;
/** Query the engine for a GameDescriptor for the specified gameid, if any. */
virtual GameDescriptor findGame(const char *gameid) const = 0;
/**
* Runs the engine's game detector on the given list of files, and returns a
* (possibly empty) list of games supported by the engine which it was able
* to detect amongst the given files.
*/
virtual GameList detectGames(const Common::FSList &fslist) const = 0;
/**
* Tries to instantiate an engine instance based on the settings of
* the currently active ConfMan target. That is, the MetaEngine should
* query the ConfMan singleton for the target, gameid, path etc. data.
*
* @param syst Pointer to the global OSystem object
* @param engine Pointer to a pointer which the MetaEngine sets to
* the newly create Engine, or 0 in case of an error
* @return a PluginError describing the error which occurred, or kNoError
*/
virtual PluginError createInstance(OSystem *syst, Engine **engine) const = 0;
/**
* Return a list of all save states associated with the given target.
*
* The caller has to ensure that this (Meta)Engine is responsible
* for the specified target (by using findGame on it respectively
* on the associated gameid from the relevant ConfMan entry, if present).
*
* The default implementation returns an empty list.
*
* @param target name of a config manager target
* @return a list of save state descriptors
*/
virtual SaveStateList listSaves(const char *target) const {
return SaveStateList();
}
/**
* Remove the specified save state.
*
* For most engines this just amounts to calling _saveFileMan->removeSaveFile().
* Engines which keep an index file will also update it accordingly.
*
* @param target name of a config manager target
* @param slot slot number of the save state to be removed
*/
virtual void removeSaveState(const char *target, int slot) const {};
/**
* Loads a thumbnail from the specified save state.
*
* This can return '0' to indicate that no thumbnail was found.
* If it returns a valid Graphics::Surface object, it must be the same
* format as the overlay.
*
* @param target name of a config manager target
* @param slot slot number of the save state
*/
virtual Graphics::Surface *loadThumbnailFromSlot(const char *target, int slot) const { return 0; }
/** @name MetaEngineFeature flags */
//@{
/**
* A feature in this context means an ability of the engine which can be
* either available or not.
*/
enum MetaEngineFeature {
/** 'Return to launcher' feature (i.e. EVENT_RTL is handled) */
kSupportsRTL = 0,
/**
* Listing Save States (i.e. implements the listSaves() method;
* used for --list-saves support)
*/
kSupportsListSaves = 1,
/** Loading from the Launcher / command line (-x) */
kSupportsDirectLoad = 2,
/**
* Deleting Saves from the Launcher (i.e. implements the
* removeSaveState() method)
*/
kSupportsDeleteSave = 3,
/**
* Features a thumbnail in savegames (i.e. implements the
* loadThumbnailFromSlot method)
*/
kSupportsThumbnails = 4
};
/**
* Determine whether the engine supports the specified MetaEngine feature.
* Used by e.g. the launcher to determine whether to enable the "Load" button.
*/
virtual bool hasFeature(MetaEngineFeature f) const { return false; };
//@}
};
// Engine plugins
typedef PluginSubclass<MetaEngine> EnginePlugin;
/**
* Singleton class which manages all Engine plugins.
*/
class EngineManager : public Common::Singleton<EngineManager> {
private:
friend class Common::Singleton<SingletonBaseType>;
public:
GameDescriptor findGame(const Common::String &gameName, const EnginePlugin **plugin = NULL) const;
GameList detectGames(const Common::FSList &fslist) const;
const EnginePlugin::List &getPlugins() const;
};
/** Convenience shortcut for accessing the engine manager. */
#define EngineMan EngineManager::instance()
#endif
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