dynamic-plugin.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 3 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, see <http://www.gnu.org/licenses/>.
 *
 */

#ifndef BACKENDS_PLUGINS_DYNAMICPLUGIN_H
#define BACKENDS_PLUGINS_DYNAMICPLUGIN_H

#include "base/plugins.h"
#include "common/textconsole.h"


class DynamicPlugin : public Plugin {
protected:
    typedef int32 (*IntFunc)();
    typedef void (*VoidFunc)();
    typedef PluginObject *(*GetObjectFunc)();

    virtual VoidFunc findSymbol(const char *symbol) = 0;

    const Common::Path _filename;

public:
    DynamicPlugin(const Common::Path &filename) :
        _filename(filename) {}

    bool loadPlugin() override {
        // Validate the plugin API version
        IntFunc verFunc = (IntFunc)findSymbol("PLUGIN_getVersion");
        if (!verFunc) {
            unloadPlugin();
            return false;
        }
        if (verFunc() != PLUGIN_VERSION) {
            warning("Plugin uses a different API version (you have: '%d', needed is: '%d')", verFunc(), PLUGIN_VERSION);
            unloadPlugin();
            return false;
        }

        // Get the type of the plugin
        IntFunc typeFunc = (IntFunc)findSymbol("PLUGIN_getType");
        if (!typeFunc) {
            unloadPlugin();
            return false;
        }
        _type = (PluginType)typeFunc();
        if (_type >= PLUGIN_TYPE_MAX) {
            warning("Plugin type unknown: %d", _type);
            unloadPlugin();
            return false;
        }

        // Validate the plugin type API version
        IntFunc typeVerFunc = (IntFunc)findSymbol("PLUGIN_getTypeVersion");
        if (!typeVerFunc) {
            unloadPlugin();
            return false;
        }
        if (typeVerFunc() != pluginTypeVersions[_type]) {
            warning("Plugin uses a different type API version (you have: '%d', needed is: '%d')", typeVerFunc(), pluginTypeVersions[_type]);
            unloadPlugin();
            return false;
        }

        // Get the plugin's instantiator object
        GetObjectFunc getObject = (GetObjectFunc)findSymbol("PLUGIN_getObject");
        if (!getObject) {
            unloadPlugin();
            return false;
        }

        // Get the plugin object
        _pluginObject = getObject();
        if (!_pluginObject) {
            warning("Couldn't get the plugin object");
            unloadPlugin();
            return false;
        }

        return true;
    }

    void unloadPlugin() override {
        delete _pluginObject;
        _pluginObject = nullptr;
    }

    Common::Path getFileName() const override {
        return _filename;
    }
};

#endif