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include/framework/plugin/plugin_manager.h

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+/* -----------------------------------------------------------------------------
+	GSFramework
+	Copyright 2001-2013 Emmanuel Julien. All Rights Reserved.
+----------------------------------------------------------------------------- */
+
+
+#ifndef	__PLUGIN_MANAGER__
+#define	__PLUGIN_MANAGER__
+
+
+		#include "shared/shared_library.h"
+		#include "plugin/shared_systems.h"
+		#include "container/nlist.h"
+		#include "nstring/nstring.h"
+		#include "platform.h"
+
+
+namespace GS {
+
+static const int PluginLoadOk = 0;
+static const int PluginLoadError = 1;
+
+static const int PluginMissingClass = 2;
+static const int PluginClassError = 3;
+static const int PluginMissingVersion = 4;
+static const int PluginVersionError = 5;
+static const int PluginInterfaceError = 6;
+
+/*!
+	@short	Plugin manager
+	@author	Emmanuel Julien (ejulien@owloh.com)
+*/
+template <class T> class PluginManager
+{
+		typedef	void		SetSharedSystems(SharedSystems &);
+		typedef	T			*Factory();
+		typedef	const char	*GetPluginClass();
+		typedef	uint		GetPluginVersion();
+
+public:
+
+		struct	Plugin
+		{
+			String	path;
+			AutoPtr <ISharedLib> shared_lib;
+		};
+
+private:
+
+		AutoList <Plugin *> plugins;
+
+public:
+
+		/// Return a new instance to concrete interface the plugin implements.
+		T			*CreatePluginInterface(Plugin *p)
+		{
+			Factory *p_factory = p ? (Factory *)p->shared_lib->GetFunctionPointer("createPluginInterface") : 0;
+			return p_factory ? p_factory() : 0;
+		}
+
+		/*
+			@short	Load a plugin.
+
+			The plugin is dynamically loaded from the specified path and its
+			class and version are checked for compatibility with the host
+			interface class and version.
+
+			A return code can be passed to get more information on failure.
+		*/
+		Plugin		*LoadPlugin(const char *path, int *code = 0)
+		{
+			AutoPtr <Plugin> p(new Plugin);
+			if	(p.IsNull())
+				return 0;
+
+			if	(code)
+				*code = PluginLoadOk;
+
+			#define	Error(V) { if (code) *code = V; return 0; }
+
+			p->shared_lib = Platform::Get().LoadSharedLibrary(path);
+			if	(p->shared_lib.IsNull())
+				Error(PluginLoadError);
+
+			GetPluginClass *get_plugin_class = (GetPluginClass *)p->shared_lib->GetFunctionPointer("getPluginClass");
+			GetPluginVersion *get_plugin_version = (GetPluginVersion *)p->shared_lib->GetFunctionPointer("getPluginVersion");
+			SetSharedSystems *set_shared_systems = (SetSharedSystems *)p->shared_lib->GetFunctionPointer("setSharedSystems");
+
+			if	(!get_plugin_class)
+				Error(PluginMissingClass);
+			if (!get_plugin_version)
+				Error(PluginMissingVersion);
+			if	(!set_shared_systems)
+				Error(PluginInterfaceError);
+			if (String(T::GetPluginClass()) != get_plugin_class())
+				Error(PluginClassError);
+			if	(T::GetPluginVersion() != get_plugin_version())
+				Error(PluginVersionError);
+
+			// Set the shared platform pointer.
+			SharedSystems shared;
+			set_shared_systems(shared);
+
+			p->path = path;
+			plugins.Add(p);
+
+			return p.Detach();
+		}
+};
+
+} // GS
+
+
+#endif	// __PLUGIN_MANAGER__

include/framework/plugin/shared_systems.h

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+/* -----------------------------------------------------------------------------
+	GSFramework
+	Copyright 2001-2013 Emmanuel Julien. All Rights Reserved.
+----------------------------------------------------------------------------- */
+
+
+#ifndef	__SHARED_SYSTEMS__
+#define	__SHARED_SYSTEMS__
+
+
+namespace GS {
+	class Platform;
+	class AudioIO;
+	class PictureIO;
+	class LogSystem;
+
+class SharedSystems
+{
+		Platform	*platform;
+		LogSystem	*log_system;
+		PictureIO	*picture_io;
+		AudioIO		*audio_io;
+
+public:
+
+		/// Call from the master module responsible for instantiating plugins.
+		void		Get();
+		/// Call from a dynamically module to share the master module systems.
+		void		Set();
+
+		SharedSystems() : platform(0), log_system(0), picture_io(0), audio_io(0) { Get(); }
+};
+
+} // GS
+
+
+#endif // __SHARED_SYSTEMS__