aboutsummaryrefslogtreecommitdiff
path: root/backends/plugins/dc/dc-provider.cpp
blob: 00471b790d513e414f1efdfea9fdc7afbb7bb07a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
/* 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.
 *
 * $URL$
 * $Id$
 *
 */

#if defined(DYNAMIC_MODULES) && defined(__DC__)

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

#include "dcloader.h"
#define PLUGIN_DIRECTORY	"/"
#define PLUGIN_PREFIX		""
#define PLUGIN_SUFFIX		".PLG"


class DCPlugin : public DynamicPlugin {
protected:
	void *_dlHandle;
	Common::String _filename;

	virtual VoidFunc findSymbol(const char *symbol) {
		void *func = dlsym(_dlHandle, symbol);
		if (!func)
			warning("Failed loading symbol '%s' from plugin '%s' (%s)", symbol, _filename.c_str(), dlerror());

		// 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:
	DCPlugin(const Common::String &filename)
		: _dlHandle(0), _filename(filename) {}

	bool loadPlugin() {
		assert(!_dlHandle);
		_dlHandle = dlopen(_filename.c_str(), RTLD_LAZY);

		if (!_dlHandle) {
			warning("Failed loading plugin '%s' (%s)", _filename.c_str(), dlerror());
			return false;
		}

		bool ret = DynamicPlugin::loadPlugin();

		if (ret)
			dlforgetsyms(_dlHandle);

		return ret;
	}
	void unloadPlugin() {
		if (_dlHandle) {
			if (dlclose(_dlHandle) != 0)
				warning("Failed unloading plugin '%s' (%s)", _filename.c_str(), dlerror());
			_dlHandle = 0;
		}
	}
};


DCPluginProvider::DCPluginProvider() {
}

DCPluginProvider::~DCPluginProvider() {
}

PluginList DCPluginProvider::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.getChildren(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->getName());
		if (name.hasPrefix(PLUGIN_PREFIX) && name.hasSuffix(PLUGIN_SUFFIX)) {
			pl.push_back(new DCPlugin(i->getPath()));
		}
	}


	return pl;
}


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