PLUGINS: single plugin model now saves plugin filename to config file

After searching for the right plugin once, the filename will be saved to the config file under the domain 'plugin_files'. The key is the gameid and the value is the plugin file. The backup mechanism is searching plugin by plugin.

svn-id: r55061

8 files changed, 135 insertions, 27 deletions

diff --git a/backends/plugins/dc/dc-provider.cpp b/backends/plugins/dc/dc-provider.cpp
index 67877dc9f4..86ef68828c 100644
--- a/backends/plugins/dc/dc-provider.cpp
+++ b/backends/plugins/dc/dc-provider.cpp
@@ -37,7 +37,6 @@
 class DCPlugin : public DynamicPlugin {
 protected:
 	void *_dlHandle;
-	Common::String _filename;
 
 	virtual VoidFunc findSymbol(const char *symbol) {
 		void *func = dlsym(_dlHandle, symbol);
@@ -56,7 +55,7 @@ protected:
 
 public:
 	DCPlugin(const Common::String &filename)
-		: _dlHandle(0), _filename(filename) {}
+		: DynamicPlugin(filename), _dlHandle(0) {}
 
 	bool loadPlugin() {
 		assert(!_dlHandle);
diff --git a/backends/plugins/dynamic-plugin.h b/backends/plugins/dynamic-plugin.h
index ec051c4ed7..32d411656c 100644
--- a/backends/plugins/dynamic-plugin.h
+++ b/backends/plugins/dynamic-plugin.h
@@ -37,7 +37,12 @@ protected:
 
 	virtual VoidFunc findSymbol(const char *symbol) = 0;
 
+	const Common::String _filename;
+
 public:
+	DynamicPlugin(const Common::String &filename) :
+		_filename(filename) {}
+
 	virtual bool loadPlugin() {
 		// Validate the plugin API version
 		IntFunc verFunc = (IntFunc)findSymbol("PLUGIN_getVersion");
@@ -97,6 +102,10 @@ public:
 	virtual void unloadPlugin() {
 		delete _pluginObject;
 	}
+
+	virtual const char *getFileName() const {
+		return _filename.c_str();
+	}
 };
 
 #endif
diff --git a/backends/plugins/elf/elf-provider.h b/backends/plugins/elf/elf-provider.h
index fe8346f95e..8cc9e0a996 100644
--- a/backends/plugins/elf/elf-provider.h
+++ b/backends/plugins/elf/elf-provider.h
@@ -48,15 +48,14 @@ protected:
 	typedef const char *(*CharFunc)();
 
 	DLObject *_dlHandle;
-	Common::String _filename;
 	void *_dso_handle;
 
 	virtual VoidFunc findSymbol(const char *symbol);
 
 public:
 	ELFPlugin(const Common::String &filename) :
+		DynamicPlugin(filename),
 		_dlHandle(0),
-		_filename(filename),
 		_dso_handle(0) {
 	}
 
diff --git a/backends/plugins/posix/posix-provider.cpp b/backends/plugins/posix/posix-provider.cpp
index 01e48739bd..dd3591a992 100644
--- a/backends/plugins/posix/posix-provider.cpp
+++ b/backends/plugins/posix/posix-provider.cpp
@@ -37,7 +37,6 @@
 class POSIXPlugin : public DynamicPlugin {
 protected:
 	void *_dlHandle;
-	Common::String _filename;
 
 	virtual VoidFunc findSymbol(const char *symbol) {
 		void *func = dlsym(_dlHandle, symbol);
@@ -56,7 +55,7 @@ protected:
 
 public:
 	POSIXPlugin(const Common::String &filename)
-		: _dlHandle(0), _filename(filename) {}
+		: DynamicPlugin(filename), _dlHandle(0) {}
 
 	bool loadPlugin() {
 		assert(!_dlHandle);
diff --git a/backends/plugins/sdl/sdl-provider.cpp b/backends/plugins/sdl/sdl-provider.cpp
index 51c19fcef3..5172abc4b0 100644
--- a/backends/plugins/sdl/sdl-provider.cpp
+++ b/backends/plugins/sdl/sdl-provider.cpp
@@ -36,7 +36,6 @@
 class SDLPlugin : public DynamicPlugin {
 protected:
 	void *_dlHandle;
-	Common::String _filename;
 
 	virtual VoidFunc findSymbol(const char *symbol) {
 		void *func = SDL_LoadFunction(_dlHandle, symbol);
@@ -55,7 +54,7 @@ protected:
 
 public:
 	SDLPlugin(const Common::String &filename)
-		: _dlHandle(0), _filename(filename) {}
+		: DynamicPlugin(filename), _dlHandle(0) {}
 
 	bool loadPlugin() {
 		assert(!_dlHandle);
diff --git a/backends/plugins/win32/win32-provider.cpp b/backends/plugins/win32/win32-provider.cpp
index 16532d4059..793b1bfc0c 100644
--- a/backends/plugins/win32/win32-provider.cpp
+++ b/backends/plugins/win32/win32-provider.cpp
@@ -51,7 +51,6 @@ private:
 
 protected:
 	void *_dlHandle;
-	Common::String _filename;
 
 	virtual VoidFunc findSymbol(const char *symbol) {
 		#ifndef _WIN32_WCE
@@ -67,7 +66,7 @@ protected:
 
 public:
 	Win32Plugin(const Common::String &filename)
-		: _dlHandle(0), _filename(filename) {}
+		: DynamicPlugin(filename), _dlHandle(0) {}
 
 	bool loadPlugin() {
 		assert(!_dlHandle);
diff --git a/base/plugins.cpp b/base/plugins.cpp
index 62ff15bf81..83377600af 100644
--- a/base/plugins.cpp
+++ b/base/plugins.cpp
@@ -335,16 +335,15 @@ void PluginManager::addPluginProvider(PluginProvider *pp) {
 	_providers.push_back(pp);
 }
 
-//
-// This should only be run once
+/**
+ * This should only be called once by main()
+ **/
 void PluginManagerUncached::init() {
 	unloadAllPlugins();
 	_allEnginePlugins.clear();
 	
-	// We need to resize our pluginsInMem list to prevent fragmentation
-	// Otherwise, as soon as we add our 1 engine plugin (which is all we'll have in memory at a time)
-	// We'll get an allocation in memory that will never go away
-	_pluginsInMem[PLUGIN_TYPE_ENGINE].resize(2);	// more than we need
+	// Resize our pluginsInMem list to prevent fragmentation
+	_pluginsInMem[PLUGIN_TYPE_ENGINE].resize(2);
 
 	for (ProviderList::iterator pp = _providers.begin();
 	                            pp != _providers.end();
@@ -371,6 +370,63 @@ void PluginManagerUncached::init() {
  	}
 }
 
+/**
+ * Try to load the plugin by searching in the ConfigManager for a matching
+ * gameId under the domain 'plugin_files'.
+ **/
+bool PluginManagerUncached::loadPluginFromGameId(const Common::String &gameId) {
+	Common::ConfigManager::Domain *domain = ConfMan.getDomain("plugin_files");
+
+	if (domain) {
+		if (domain->contains(gameId)) {
+			Common::String filename = (*domain)[gameId];
+
+		    if (loadPluginByFileName(filename)) {
+				return true;
+			}
+		}
+	}
+	return false;
+}
+
+/**
+ * Load a plugin with a filename taken from ConfigManager.
+ **/
+bool PluginManagerUncached::loadPluginByFileName(const Common::String &filename) {
+	if (filename.empty())
+		return false;
+	
+	unloadPluginsExcept(PLUGIN_TYPE_ENGINE, NULL, false);
+
+	PluginList::iterator i;
+	for (i = _allEnginePlugins.begin(); i != _allEnginePlugins.end(); ++i) {
+		if (Common::String((*i)->getFileName()) == filename && (*i)->loadPlugin()) {
+			addToPluginsInMemList(*i);
+			_currentPlugin = i;
+			return true;
+		}
+	}
+	return false;
+}
+
+/** 
+ * Update the config manager with a plugin file name that we found can handle
+ * the game.
+ **/
+void PluginManagerUncached::updateConfigWithFileName(const Common::String &gameId) {
+	// Check if we have a filename for the current plugin
+	if ((*_currentPlugin)->getFileName()) {
+		if (!ConfMan.hasMiscDomain("plugin_files"))
+			ConfMan.addMiscDomain("plugin_files");
+
+		Common::ConfigManager::Domain *domain = ConfMan.getDomain("plugin_files");
+		assert(domain);
+		(*domain)[gameId] = (*_currentPlugin)->getFileName();
+
+		ConfMan.flushToDisk();
+	}
+}
+
 void PluginManagerUncached::loadFirstPlugin() { 
 	unloadPluginsExcept(PLUGIN_TYPE_ENGINE, NULL, false);
 
@@ -395,6 +451,10 @@ bool PluginManagerUncached::loadNextPlugin() {
 	return false;	// no more in list
 }
 
+/**
+ * Used by only the cached plugin manager. The uncached manager can only have
+ * one plugin in memory at a time.
+ **/
 void PluginManager::loadAllPlugins() {
 	for (ProviderList::iterator pp = _providers.begin();
 	                            pp != _providers.end();
@@ -426,6 +486,9 @@ void PluginManager::unloadPluginsExcept(PluginType type, const Plugin *plugin, b
 	}
 }
 
+/*
+ * Used only by the cached plugin manager since it deletes the plugin.
+ */
 bool PluginManager::tryLoadPlugin(Plugin *plugin) {
 	assert(plugin);
 	// Try to load the plugin
@@ -439,6 +502,9 @@ bool PluginManager::tryLoadPlugin(Plugin *plugin) {
 	}
 }
 
+/**
+ * Add to the list of plugins loaded in memory.
+ */
 void PluginManager::addToPluginsInMemList(Plugin *plugin) {
 	bool found = false;
 	// The plugin is valid, see if it provides the same module as an
@@ -468,16 +534,35 @@ void PluginManager::addToPluginsInMemList(Plugin *plugin) {
 
 DECLARE_SINGLETON(EngineManager);
 
+/** 
+ * This function works for both cached and uncached PluginManagers.
+ * For the cached version, most of the logic here will short circuit.
+ *
+ * For the uncached version, we first try to find the plugin using the gameId
+ * and only if we can't find it there, we loop through the plugins.
+ **/
 GameDescriptor EngineManager::findGame(const Common::String &gameName, const EnginePlugin **plugin) const {
 	GameDescriptor result;
-
-	PluginManager::instance().loadFirstPlugin();
+	
+	// first look for the game using the gameId
+	if (PluginMan.loadPluginFromGameId(gameName))  {
+		result = findGameInLoadedPlugins(gameName, plugin); 
+		if (!result.gameid().empty()) {
+			return result;
+		}
+	}
+	
+	// We failed to find it using the gameid. Scan the list of plugins
+	PluginMan.loadFirstPlugin();
 	do {
 		result = findGameInLoadedPlugins(gameName, plugin); 
 		if (!result.gameid().empty()) {
+			// Update with new plugin file name
+			PluginMan.updateConfigWithFileName(gameName);
 			break;
 		}
-	} while (PluginManager::instance().loadNextPlugin());
+	} while (PluginMan.loadNextPlugin());
+
 	return result;
 }
 
diff --git a/base/plugins.h b/base/plugins.h
index 928be85c32..4f6d37ac86 100644
--- a/base/plugins.h
+++ b/base/plugins.h
@@ -152,11 +152,11 @@ extern int pluginTypeVersions[PLUGIN_TYPE_MAX];
 // 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.
- *
- * FIXME: This class needs better documentation, esp. how it differs from class Plugin
+ * 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:
@@ -169,9 +169,8 @@ public:
 /**
  * Abstract base class for the plugin system.
  * Subclasses for this can be used to wrap both static and dynamic
- * plugins.
- *
- * FIXME: This class needs better documentation, esp. how it differs from class PluginObject
+ * plugins. This class refers to a plugin which may or may not be loaded in
+ * memory.
  */
 class Plugin {
 protected:
@@ -189,8 +188,19 @@ public:
 	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;
+
+	/**
+	 * 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. */
@@ -294,6 +304,8 @@ protected:
 
 #endif // DYNAMIC_MODULES
 
+#define PluginMan PluginManager::instance()
+
 /**
  * Singleton class which manages all plugins, including loading them,
  * managing all Plugin class instances, and unloading them.
@@ -319,10 +331,14 @@ public:
 
 	void addPluginProvider(PluginProvider *pp);
 
+	// Functions used by the uncached PluginManager
 	virtual void init()	{}
 	virtual void loadFirstPlugin() {}
 	virtual bool loadNextPlugin() { return false; }
+	virtual bool loadPluginFromGameId(const Common::String &gameId) { return false; } 
+	virtual void updateConfigWithFileName(const Common::String &gameId) {} 
 	
+	// Functions used only by the cached PluginManager
 	virtual void loadAllPlugins();
 	void unloadAllPlugins();
 
@@ -342,11 +358,14 @@ protected:
 	PluginList::iterator _currentPlugin;
 
 	PluginManagerUncached() {}
+	bool loadPluginByFileName(const Common::String &filename); 
 
 public:
 	virtual void init();
 	virtual void loadFirstPlugin();
 	virtual bool loadNextPlugin();
+	virtual bool loadPluginFromGameId(const Common::String &gameId); 
+	virtual void updateConfigWithFileName(const Common::String &gameId); 
 	
 	virtual void loadAllPlugins() {} 	// we don't allow this
 };