/* 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. * */ #ifndef BASE_PLUGINS_H #define BASE_PLUGINS_H #include "common/array.h" #include "common/fs.h" #include "common/str.h" #include "backends/plugins/elf/version.h" #define INCLUDED_FROM_BASE_PLUGINS_H #include "base/internal_plugins.h" #undef INCLUDED_FROM_BASE_PLUGINS_H /** * @page pagePlugins An overview of the ScummVM plugin system * This is a brief overview of how plugins (dynamically loadable code modules) * work in ScummVM. We will explain how to write plugins, how they work internally, * and sketch how porters can add support for them in their ports. * * \section secPluginImpl Implementing a plugin * TODO * * \section secPluginUse Using plugins * TODO * * \section secPluginInternals How plugins work internally * TODO * * \section secPluginBackend How to add support for dynamic plugins to a port * TODO */ // Plugin versioning /** Global Plugin API version */ #define PLUGIN_VERSION 1 enum PluginType { PLUGIN_TYPE_ENGINE = 0, PLUGIN_TYPE_MUSIC, /* PLUGIN_TYPE_SCALER, */ // TODO: Add graphics scaler plugins PLUGIN_TYPE_MAX }; // TODO: Make the engine API version depend on ScummVM's version // because of the backlinking (posibly from the checkout revision) #define PLUGIN_TYPE_ENGINE_VERSION 1 #define PLUGIN_TYPE_MUSIC_VERSION 1 extern int pluginTypeVersions[PLUGIN_TYPE_MAX]; // Plugin linking // see comments in backends/plugins/elf/elf-provider.cpp #if defined(USE_ELF_LOADER) && defined(ELF_LOADER_CXA_ATEXIT) #define PLUGIN_DYNAMIC_DSO_HANDLE \ uint32 __dso_handle __attribute__((visibility("hidden"))) = 0; #else #define PLUGIN_DYNAMIC_DSO_HANDLE #endif #ifdef USE_ELF_LOADER #define PLUGIN_DYNAMIC_BUILD_DATE \ PLUGIN_EXPORT const char *PLUGIN_getBuildDate() { return gScummVMPluginBuildDate; } #else #define PLUGIN_DYNAMIC_BUILD_DATE #endif /** * 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_DYNAMIC_DSO_HANDLE \ PLUGIN_DYNAMIC_BUILD_DATE \ 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. An existing PluginObject refers to an executable file * loaded in memory and ready to run. The plugin, on the other hand, is just * a handle to the file/object, whether it's loaded in memory or not. */ 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. This class refers to a plugin which may or may not be loaded in * memory. */ class Plugin { protected: PluginObject *_pluginObject; PluginType _type; public: Plugin() : _pluginObject(0), _type(PLUGIN_TYPE_MAX) {} 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() ? /** * The following functions query information from the plugin object once * it's loaded into memory. **/ PluginType getType() const; const char *getName() const; template T &get() const { T *pluginObject = dynamic_cast(_pluginObject); if (!pluginObject) { error("Invalid cast of plugin %s", getName()); } return *pluginObject; } /** * The getFileName() function gets the name of the plugin file for those * plugins that have files (ie. not static). It doesn't require the plugin * object to be loaded into memory, unlike getName() **/ virtual const char *getFileName() const { return 0; } }; /** List of Plugin instances. */ typedef Common::Array PluginList; /** * 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. * * @return a list of Plugin instances */ virtual PluginList getPlugins() = 0; /** * @return whether or not object is a FilePluginProvider. */ virtual bool isFilePluginProvider() { return false; } }; #ifdef DYNAMIC_MODULES /** * 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: /** * Return a list of Plugin objects loaded via createPlugin from disk. * For this, a list of directories is searched for plugin objects: * The current dir and its "plugins" subdirectory (if present), a list * of custom search dirs (see addCustomDirectories) and finally the * directory specified via the "pluginspath" config variable (if any). * * @return a list of Plugin instances */ virtual PluginList getPlugins(); /** * @return whether or not object is a FilePluginProvider. */ bool isFilePluginProvider() { return true; } 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 node the FSNode of the loadable code module * @return a pointer to a Plugin instance, or 0 if an error occurred. */ virtual Plugin *createPlugin(const Common::FSNode &node) const = 0; /** * Check if the supplied file corresponds to a loadable plugin file in * the current platform. Usually, this will just check the file name. * * @param node the FSNode of the file to check * @return true if the filename corresponds to a plugin, false otherwise */ virtual bool isPluginFilename(const Common::FSNode &node) const; /** * Optionally add to the list of directories to be searched for * plugins by getPlugins(). * * @param dirs the reference to the list of directories to be used when * searching for plugins. */ virtual void addCustomDirectories(Common::FSList &dirs) const; }; #endif // DYNAMIC_MODULES #define PluginMan PluginManager::instance() /** * Singleton class which manages all plugins, including loading them, * managing all Plugin class instances, and unloading them. */ class PluginManager { protected: typedef Common::Array ProviderList; PluginList _pluginsInMem[PLUGIN_TYPE_MAX]; ProviderList _providers; bool tryLoadPlugin(Plugin *plugin); void addToPluginsInMemList(Plugin *plugin); static PluginManager *_instance; PluginManager(); public: virtual ~PluginManager(); static void destroy() { delete _instance; _instance = 0; } static PluginManager &instance(); void addPluginProvider(PluginProvider *pp); // Functions used by the uncached PluginManager virtual void init() {} virtual void loadFirstPlugin() {} virtual bool loadNextPlugin() { return false; } virtual bool loadPluginFromEngineId(const Common::String &engineId) { return false; } virtual void updateConfigWithFileName(const Common::String &engineId) {} // Functions used only by the cached PluginManager virtual void loadAllPlugins(); virtual void loadAllPluginsOfType(PluginType type); void unloadAllPlugins(); void unloadPluginsExcept(PluginType type, const Plugin *plugin, bool deletePlugin = true); const PluginList &getPlugins(PluginType t) { return _pluginsInMem[t]; } }; /** * Uncached version of plugin manager * Keeps only one dynamic plugin in memory at a time **/ class PluginManagerUncached : public PluginManager { protected: friend class PluginManager; PluginList _allEnginePlugins; PluginList::iterator _currentPlugin; PluginManagerUncached() {} bool loadPluginByFileName(const Common::String &filename); public: virtual void init(); virtual void loadFirstPlugin(); virtual bool loadNextPlugin(); virtual bool loadPluginFromEngineId(const Common::String &engineId); virtual void updateConfigWithFileName(const Common::String &engineId); virtual void loadAllPlugins() {} // we don't allow these virtual void loadAllPluginsOfType(PluginType type) {} }; #endif