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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 BASE_PLUGINS_H
#define BASE_PLUGINS_H
#include "common/error.h"
#include "common/list.h"
#include "common/singleton.h"
#include "base/game.h"
// Plugin versioning
/** Global Plugin API version */
#define PLUGIN_VERSION 1
enum PluginType {
PLUGIN_TYPE_ENGINE = 0,
PLUGIN_TYPE_MAX
};
// TODO: Make the engine API version depend on ScummVM's version
// because of the backlinking
#define PLUGIN_TYPE_ENGINE_VERSION 1
extern int pluginTypeVersions[PLUGIN_TYPE_MAX];
// Plugin linking
#define STATIC_PLUGIN 1
#define DYNAMIC_PLUGIN 2
#define PLUGIN_ENABLED_STATIC(ID) \
(defined(ENABLE_##ID) && !PLUGIN_ENABLED_DYNAMIC(ID))
// HACK for MSVC
#if defined(_MSC_VER)
#undef PLUGIN_ENABLED_STATIC
#define PLUGIN_ENABLED_STATIC(ID) 1
#endif
#define PLUGIN_ENABLED_DYNAMIC(ID) \
(defined(ENABLE_##ID) && (ENABLE_##ID == DYNAMIC_PLUGIN) && defined(DYNAMIC_MODULES))
/**
* REGISTER_PLUGIN_STATIC is a convenience macro which is used to declare
* the plugin interface for static plugins. Code (such as game engines)
* which needs to implement a static plugin can simply invoke this macro
* with a plugin ID, plugin type and PluginObject subclass, and the correct
* wrapper code will be inserted.
*
* @see REGISTER_PLUGIN_DYNAMIC
*/
#define REGISTER_PLUGIN_STATIC(ID,TYPE,PLUGINCLASS) \
PluginType g_##ID##_type = TYPE; \
PluginObject *g_##ID##_getObject() { \
return new PLUGINCLASS(); \
} \
void dummyFuncToAllowTrailingSemicolon()
#ifdef DYNAMIC_MODULES
/**
* REGISTER_PLUGIN_DYNAMIC is a convenience macro which is used to declare
* the plugin interface for dynamically loadable plugins. Code (such as game engines)
* which needs to implement a dynamic plugin can simply invoke this macro
* with a plugin ID, plugin type and PluginObject subclass, and the correct
* wrapper code will be inserted.
*
* @see REGISTER_PLUGIN_STATIC
*/
#define REGISTER_PLUGIN_DYNAMIC(ID,TYPE,PLUGINCLASS) \
extern "C" { \
PLUGIN_EXPORT int32 PLUGIN_getVersion() { return PLUGIN_VERSION; } \
PLUGIN_EXPORT int32 PLUGIN_getType() { return TYPE; } \
PLUGIN_EXPORT int32 PLUGIN_getTypeVersion() { return TYPE##_VERSION; } \
PLUGIN_EXPORT PluginObject *PLUGIN_getObject() { \
return new PLUGINCLASS(); \
} \
} \
void dummyFuncToAllowTrailingSemicolon()
#endif // DYNAMIC_MODULES
// Abstract plugins
/**
* Abstract base class for the plugin objects which handle plugins
* instantiation. Subclasses for this may be used for engine plugins
* and other types of plugins.
*/
class PluginObject {
public:
virtual ~PluginObject() {}
/** Returns the name of the plugin. */
virtual const char *getName() const = 0;
};
/**
* Abstract base class for the plugin system.
* Subclasses for this can be used to wrap both static and dynamic
* plugins.
*/
class Plugin {
protected:
PluginObject *_pluginObject;
PluginType _type;
public:
Plugin() : _pluginObject(0) {}
virtual ~Plugin() {
//if (isLoaded())
//unloadPlugin();
}
// virtual bool isLoaded() const = 0; // TODO
virtual bool loadPlugin() = 0; // TODO: Rename to load() ?
virtual void unloadPlugin() = 0; // TODO: Rename to unload() ?
PluginType getType() const;
const char *getName() const;
};
/** List of Plugin instances. */
typedef Common::Array<Plugin *> PluginList;
/**
* Convenience template to make it easier defining normal Plugin
* subclasses. Namely, the PluginSubclass will manage PluginObjects
* of a type specified via the PO_t template parameter.
*/
template<class PO_t>
class PluginSubclass : public Plugin {
public:
PO_t *operator->() const {
return (PO_t *)_pluginObject;
}
typedef Common::Array<PluginSubclass *> list;
};
/**
* Abstract base class for Plugin factories. Subclasses of this
* are responsible for creating plugin objects, e.g. by loading
* loadable modules from storage media; by creating "fake" plugins
* from static code; or whatever other means.
*/
class PluginProvider {
public:
virtual ~PluginProvider() {}
/**
* Return a list of Plugin objects. The caller is responsible for actually
* loading/unloading them (by invoking the appropriate Plugin methods).
* Furthermore, the caller is responsible for deleting these objects
* eventually.
*/
virtual PluginList getPlugins() = 0;
};
/**
* Abstract base class for Plugin factories which load binary code from files.
* Subclasses only have to implement the createPlugin() method, and optionally
* can overload the other protected methods to achieve custom behavior.
*/
class FilePluginProvider : public PluginProvider {
public:
virtual PluginList getPlugins();
protected:
/**
* Create a Plugin instance from a loadable code module with the specified name.
* Subclasses of FilePluginProvider have to at least overload this method.
* If the file is not found, or does not contain loadable code, 0 is returned instead.
*
* @param filename the name of the loadable code module
* @return a pointer to a Plugin instance, or 0 if an error occured.
*/
virtual Plugin* createPlugin(const Common::String &filename) const = 0;
virtual const char* getPrefix() const;
virtual const char* getSuffix() const;
virtual void addCustomDirectories(Common::StringList &dirs) const;
};
/**
* Singleton class which manages all plugins, including loading them,
* managing all Plugin class instances, and unloading them.
*/
class PluginManager : public Common::Singleton<PluginManager> {
typedef Common::List<PluginProvider *> ProviderList;
private:
PluginList _plugins[PLUGIN_TYPE_MAX];
ProviderList _providers;
bool tryLoadPlugin(Plugin *plugin);
friend class Common::Singleton<SingletonBaseType>;
PluginManager();
public:
~PluginManager();
void addPluginProvider(PluginProvider *pp);
void loadPlugins();
void unloadPlugins();
void unloadPluginsExcept(PluginType type, const Plugin *plugin);
const PluginList &getPlugins(PluginType t) { return _plugins[t]; }
};
#endif
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