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Started to refactor the plugin code (moving backend specific stuff into backends/plugins/)

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svn-id: r24148
This commit is contained in:
Max Horn 2006-10-07 00:22:48 +00:00
parent 1373686c34
commit 26e4e16800
6 changed files with 478 additions and 282 deletions
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126
backends/plugins/dynamic-plugin.h Normal file
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/* 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.
*
* $URL$
* $Id$
*
*/
#ifndef BACKENDS_PLUGINS_DYNAMICPLUGIN_H
#define BACKENDS_PLUGINS_DYNAMICPLUGIN_H
#include "common/stdafx.h"
#include "base/plugins.h"
/** Type of factory functions which make new Engine objects. */
typedef PluginError (*EngineFactory)(OSystem *syst, Engine **engine);
typedef const char *(*NameFunc)();
typedef GameDescriptor (*GameIDQueryFunc)(const char *gameid);
typedef GameList (*GameIDListFunc)();
typedef DetectedGameList (*DetectFunc)(const FSList &fslist);
class DynamicPlugin : public Plugin {
protected:
typedef void (*VoidFunc)();
Common::String _name;
Common::String _copyright;
GameIDQueryFunc _qf;
EngineFactory _ef;
DetectFunc _df;
GameList _games;
virtual VoidFunc findSymbol(const char *symbol) = 0;
public:
DynamicPlugin() : _qf(0), _ef(0), _df(0), _games() {}
const char *getName() const { return _name.c_str(); }
const char *getCopyright() const { return _copyright.c_str(); }
PluginError createInstance(OSystem *syst, Engine **engine) const {
assert(_ef);
return (*_ef)(syst, engine);
}
GameList getSupportedGames() const { return _games; }
GameDescriptor findGame(const char *gameid) const {
assert(_qf);
return (*_qf)(gameid);
}
DetectedGameList detectGames(const FSList &fslist) const {
assert(_df);
return (*_df)(fslist);
}
virtual bool loadPlugin() {
// Query the plugin's name
NameFunc nameFunc = (NameFunc)findSymbol("PLUGIN_name");
if (!nameFunc) {
unloadPlugin();
return false;
}
_name = nameFunc();
// Query the plugin's copyright
nameFunc = (NameFunc)findSymbol("PLUGIN_copyright");
if (!nameFunc) {
unloadPlugin();
return false;
}
_copyright = nameFunc();
// Query the plugin for the game ids it supports
GameIDListFunc gameListFunc = (GameIDListFunc)findSymbol("PLUGIN_gameIDList");
if (!gameListFunc) {
unloadPlugin();
return false;
}
_games = gameListFunc();
// Retrieve the gameid query function
_qf = (GameIDQueryFunc)findSymbol("PLUGIN_findGameID");
if (!_qf) {
unloadPlugin();
return false;
}
// Retrieve the factory function
_ef = (EngineFactory)findSymbol("PLUGIN_createEngine");
if (!_ef) {
unloadPlugin();
return false;
}
// Retrieve the detector function
_df = (DetectFunc)findSymbol("PLUGIN_detectGames");
if (!_df) {
unloadPlugin();
return false;
}
return true;
}
};
#endif

178
backends/plugins/posix/posix-provider.cpp Normal file
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/* 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/posix/posix-provider.h"
#include "backends/plugins/dynamic-plugin.h"
#include "common/fs.h"
#include "common/util.h"
#if defined(UNIX)
#include <dlfcn.h>
#define PLUGIN_DIRECTORY "plugins/"
#elif defined(__DC__)
#include "dcloader.h"
#define PLUGIN_DIRECTORY "/"
#define PLUGIN_PREFIX ""
#define PLUGIN_SUFFIX ".PLG"
#elif defined(_WIN32)
#define PLUGIN_DIRECTORY ""
#define PLUGIN_PREFIX ""
#define PLUGIN_SUFFIX ".dll"
#else
#error No support for loading plugins on non-unix systems at this point!
#endif
class POSIXPlugin : public DynamicPlugin {
protected:
void *_dlHandle;
Common::String _filename;
virtual VoidFunc findSymbol(const char *symbol) {
#if defined(UNIX) || defined(__DC__)
void *func = dlsym(_dlHandle, symbol);
if (!func)
warning("Failed loading symbol '%s' from plugin '%s' (%s)", symbol, _filename.c_str(), dlerror());
#else
#if defined(_WIN32)
void *func = (void *)GetProcAddress((HMODULE)_dlHandle, symbol);
if (!func)
warning("Failed loading symbol '%s' from plugin '%s'", symbol, _filename.c_str());
#else
#error TODO
#endif
#endif
// 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:
POSIXPlugin(const Common::String &filename)
: _dlHandle(0), _filename(filename) {}
bool loadPlugin() {
assert(!_dlHandle);
#if defined(UNIX) || defined(__DC__)
_dlHandle = dlopen(_filename.c_str(), RTLD_LAZY);
if (!_dlHandle) {
warning("Failed loading plugin '%s' (%s)", _filename.c_str(), dlerror());
return false;
}
#else
#if defined(_WIN32)
_dlHandle = LoadLibrary(_filename.c_str());
if (!_dlHandle) {
warning("Failed loading plugin '%s'", _filename.c_str());
return false;
}
#else
#error TODO
#endif
#endif
bool ret = DynamicPlugin::loadPlugin();
#ifdef __DC__
if (ret)
dlforgetsyms(_dlHandle);
#endif
return ret;
}
void unloadPlugin() {
if (_dlHandle) {
#if defined(UNIX) || defined(__DC__)
if (dlclose(_dlHandle) != 0)
warning("Failed unloading plugin '%s' (%s)", _filename.c_str(), dlerror());
#elif defined(_WIN32)
if (!FreeLibrary((HMODULE)_dlHandle))
warning("Failed unloading plugin '%s'", _filename.c_str());
#else
#error TODO
#endif
}
}
};
POSIXPluginProvider::POSIXPluginProvider() {
}
POSIXPluginProvider::~POSIXPluginProvider() {
}
PluginList POSIXPluginProvider::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 POSIXPlugin(i->path()));
}
}
return pl;
}
#endif // DYNAMIC_MODULES

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backends/plugins/posix/posix-provider.h Normal file
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/* 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.
*
* $URL$
* $Id$
*
*/
#ifndef BACKENDS_PLUGINS_POSIX_H
#define BACKENDS_PLUGINS_POSIX_H
#include "common/stdafx.h"
#include "base/plugins.h"
#ifdef DYNAMIC_MODULES
class POSIXPluginProvider : public PluginProvider {
public:
POSIXPluginProvider();
~POSIXPluginProvider();
virtual PluginList getPlugins();
};
#endif
#endif