Added plugin providers for Win32 and DC

svn-id: r24149

backends/plugins/win32/win32-provider.cpp

@@ -0,0 +1,124 @@
+/* ScummVM - Scumm Interpreter
+ * Copyright (C) 2001  Ludvig Strigeus
+ * Copyright (C) 2001-2006 The ScummVM project
+ *
+ * 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.
+ *
+ * $URL$
+ * $Id$
+ *
+ */
+
+#ifdef DYNAMIC_MODULES
+
+#include "backends/plugins/win32/win32-provider.h"
+#include "backends/plugins/dynamic-plugin.h"
+#include "common/fs.h"
+
+#define PLUGIN_DIRECTORY	""
+#define PLUGIN_PREFIX		""
+#define PLUGIN_SUFFIX		".dll"
+
+
+class Win32Plugin : public DynamicPlugin {
+protected:
+	void *_dlHandle;
+	Common::String _filename;
+
+	virtual VoidFunc findSymbol(const char *symbol) {
+		void *func = (void *)GetProcAddress((HMODULE)_dlHandle, symbol);
+		if (!func)
+			warning("Failed loading symbol '%s' from plugin '%s'", symbol, _filename.c_str());
+	
+		// FIXME HACK: This is a HACK to circumvent a clash between the ISO C++
+		// standard and POSIX: ISO C++ disallows casting between function pointers
+		// and data pointers, but dlsym always returns a void pointer. For details,
+		// see e.g. <http://www.trilithium.com/johan/2004/12/problem-with-dlsym/>.
+		assert(sizeof(VoidFunc) == sizeof(func));
+		VoidFunc tmp;
+		memcpy(&tmp, &func, sizeof(VoidFunc));
+		return tmp;
+	}
+
+public:
+	Win32Plugin(const Common::String &filename)
+		: _dlHandle(0), _filename(filename) {}
+
+	bool loadPlugin() {
+		assert(!_dlHandle);
+		_dlHandle = LoadLibrary(_filename.c_str());
+	
+		if (!_dlHandle) {
+			warning("Failed loading plugin '%s'", _filename.c_str());
+			return false;
+		}
+
+		return DynamicPlugin::loadPlugin();
+	}
+	void unloadPlugin() {
+		if (_dlHandle) {
+			if (!FreeLibrary((HMODULE)_dlHandle))
+				warning("Failed unloading plugin '%s'", _filename.c_str());
+		}
+	}
+};
+
+
+Win32PluginProvider::Win32PluginProvider() {
+}
+
+Win32PluginProvider::~Win32PluginProvider() {
+}
+
+PluginList Win32PluginProvider::getPlugins() {
+	PluginList pl;
+	
+	
+	// Load dynamic plugins
+	// TODO... this is right now just a nasty hack.
+	// This should search one or multiple directories for all plugins it can
+	// find (to this end, we maybe should use a special prefix/suffix; e.g.
+	// instead of libscumm.so, use scumm.engine or scumm.plugin etc.).
+	//
+	// The list of directories to search could be e.g.:
+	// User specified (via config file), ".", "./plugins", "$(prefix)/lib".
+	//
+	// We also need to add code which ensures what we are looking at is
+	// a) a ScummVM engine and b) matches the version of the executable.
+	// Hence one more symbol should be exported by plugins which returns
+	// the "ABI" version the plugin was built for, and we can compare that
+	// to the ABI version of the executable.
+
+	// Load all plugins.
+	// Scan for all plugins in this directory
+	FilesystemNode dir(PLUGIN_DIRECTORY);
+	FSList files;
+	if (!dir.listDir(files, FilesystemNode::kListFilesOnly)) {
+		error("Couldn't open plugin directory '%s'", PLUGIN_DIRECTORY);
+	}
+
+	for (FSList::const_iterator i = files.begin(); i != files.end(); ++i) {
+		Common::String name(i->name());
+		if (name.hasPrefix(PLUGIN_PREFIX) && name.hasSuffix(PLUGIN_SUFFIX)) {
+			pl.push_back(new Win32Plugin(i->path()));
+		}
+	}
+	
+	
+	return pl;
+}
+
+
+#endif // DYNAMIC_MODULES