scummvm/backends/plugins/elf-provider.h

/* 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 BACKENDS_PLUGINS_ELF_PROVIDER_H
#define BACKENDS_PLUGINS_ELF_PROVIDER_H

#include "base/plugins.h"
#include "backends/plugins/dynamic-plugin.h"
#include "common/fs.h"

#include "backends/plugins/elf-loader.h"

#if defined(DYNAMIC_MODULES) && defined(ELF_LOADER_TARGET)

class ELFPlugin : public DynamicPlugin {
protected:
	DLObject *_dlHandle;
	Common::String _filename;

	//FIXME: The code for this method should be in elf-provider.cpp,
	//		 but VoidFunc isn't recognized if we do that as is.
	virtual VoidFunc findSymbol(const char *symbol) {
		void *func;
			bool handleNull;
			if (_dlHandle == NULL) {
				func = NULL;
				handleNull = true;
			} else {
				func = _dlHandle->symbol(symbol);
			}
			if (!func) {
				if (handleNull) {
					warning("Failed loading symbol '%s' from plugin '%s' (Handle is NULL)", symbol, _filename.c_str());
				} else {
					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:
	ELFPlugin(const Common::String &filename)
		: _dlHandle(0), _filename(filename) {}

	~ELFPlugin() {
		if (_dlHandle)
			unloadPlugin();
	}

	bool loadPlugin();
	void unloadPlugin();

};

class ELFPluginProvider : public FilePluginProvider {
protected:
	Plugin* createPlugin(const Common::FSNode &node) const;

	bool isPluginFilename(const Common::FSNode &node) const;

};

#endif // defined(DYNAMIC_MODULES) && defined(ELF_LOADER_TARGET)

#endif /* BACKENDS_PLUGINS_ELF_PROVIDER_H */