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1/* This file is part of the KDE libraries
2 Copyright (C) 1999 Torben Weis <weis@kde.org>
3
4 This library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Library General Public
6 License version 2 as published by the Free Software Foundation.
7
8 This library is distributed in the hope that it will be useful,
9 but WITHOUT ANY WARRANTY; without even the implied warranty of
10 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 Library General Public License for more details.
12
13 You should have received a copy of the GNU Library General Public License
14 along with this library; see the file COPYING.LIB. If not, write to
15 the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 Boston, MA 02111-1307, USA.
17*/
18#ifndef KLIBLOADER_H
19#define KLIBLOADER_H
20
21#include <qobject.h>
22#include <qstring.h>
23#include <qstringlist.h>
24#include <qasciidict.h>
25#include <qptrlist.h>
26#include <kglobal.h>
27
28#include <stdlib.h> // For backwards compatibility
29
30class KInstance;
31class QTimer;
32class KLibrary;
33class KLibFactory;
34class KLibFactoryPrivate;
35class KLibLoaderPrivate;
36class KLibraryPrivate;
37
38class QLibrary;
39
40#define K_EXPORT_COMPONENT_FACTORY( libname, factory ) \
41 extern "C" { void *init_##libname() { return new factory; } }
42
43/**
44 * @short Represents a dynamically loaded library.
45 *
46 * KLibrary allows you to look up symbols of the shared library.
47 * Use @ref KLibLoader to create a new instance of KLibrary.
48 *
49 * @see KLibLoader
50 * @author Torben Weis <weis@kde.org>
51 */
52class KLibrary : public QObject
53{
54 friend class KLibLoader;
55 friend class QAsciiDict<KLibrary>;
56
57 Q_OBJECT
58public:
59 /**
60 * @internal
61 * Don't create KLibrary objects on your own. Instead use @ref KLibLoader.
62 */
63//US KLibrary( const QString& libname, const QString& filename, void * handle );
64 KLibrary( const QString& libname, const QString& filename, QLibrary* handle );
65
66 /**
67 * Returns the name of the library.
68 * @return The name of the library like "libkspread".
69 */
70 QString name() const;
71
72 /**
73 * Returns the file name of the library.
74 * @return The filename of the library, for example "/opt/kde2&/lib/libkspread.la"
75 */
76 QString fileName() const;
77
78 /**
79 * Returns the factory of the library.
80 * @return The factory of the library if there is any, otherwise 0
81 */
82 KLibFactory* factory();
83
84 /**
85 * Looks up a symbol from the library. This is a very low level
86 * function that you usually don't want to use. Usually you should
87 * check using @ref hasSymbol() whether the symbol actually exists,
88 * otherwise a warning will be printed.
89 * @param name the name of the symbol to look up
90 * @return the address of the symbol, or 0 if it does not exist
91 * @see #hasSymbol
92 */
93 void* symbol( const char* name ) const;
94
95 /**
96 * Looks up a symbol from the library. This is a very low level
97 * function that you usually don't want to use.
98 * Unlike @ref symbol(), this method doesn't warn if the symbol doesn't exist,
99 * so if the symbol might or might not exist, better use hasSymbol() before symbol().
100 * @param name the name of the symbol to check
101 * @return true if the symbol exists
102 * @since 3.1
103 */
104 bool hasSymbol( const char* name ) const;
105
106 /**
107 * Unloads the library.
108 * This typically results in the deletion of this object. You should
109 * not reference its pointer after calling this function.
110 */
111 void unload() const;
112
113private slots:
114 void slotObjectCreated( QObject *obj );
115 void slotObjectDestroyed();
116 void slotTimeout();
117
118private:
119 /**
120 * @internal
121 * Don't destruct KLibrary objects yourself. Instead use @ref unload() instead.
122 */
123 ~KLibrary();
124
125 QString m_libname;
126 QString m_filename;
127 KLibFactory* m_factory;
128//US void * m_handle;
129 QLibrary* m_handle;
130 QPtrList<QObject> m_objs;
131 QTimer *m_timer;
132 KLibraryPrivate *d;
133};
134
135class KLibWrapPrivate;
136
137/**
138 * The KLibLoader allows you to load libraries dynamically at runtime.
139 * Dependent libraries are loaded automatically.
140 *
141 * KLibLoader follows the singleton pattern. You can not create multiple
142 * instances. Use @ref self() to get a pointer to the loader.
143 *
144 * @see KLibrary
145 * @author Torben Weis <weis@kde.org>
146 */
147class KLibLoader : public QObject
148{
149 friend class KLibrary;
150
151 Q_OBJECT
152public:
153 /**
154 * You should NEVER destruct an instance of KLibLoader
155 * until you know what you are doing. This will release
156 * the loaded libraries.
157 */
158 ~KLibLoader();
159
160 /**
161 * Loads and initializes a library. Loading a library multiple times is
162 * handled gracefully.
163 *
164 * This is a convenience function that returns the factory immediately
165 * @param libname This is the library name without extension. Usually that is something like
166 * "libkspread". The function will then search for a file named
167 * "libkspread.la" in the KDE library paths.
168 * The *.la files are created by libtool and contain
169 * important information especially about the libraries dependencies
170 * on other shared libs. Loading a "libfoo.so" could not solve the
171 * dependencies problem.
172 *
173 * You can, however, give a library name ending in ".so"
174 * (or whatever is used on your platform), and the library
175 * will be loaded without resolving dependencies. USE WITH CARE :)
176 * @return the @ref KLibFactory, or 0 if the library does not exist or it does
177 * not have a factory
178 * @see #library
179 */
180 KLibFactory* factory( const char* libname );
181
182 /**
183 * Loads and initializes a library. Loading a library multiple times is
184 * handled gracefully.
185 *
186 * @param libname This is the library name without extension. Usually that is something like
187 * "libkspread". The function will then search for a file named
188 * "libkspread.la" in the KDE library paths.
189 * The *.la files are created by libtool and contain
190 * important information especially about the libraries dependencies
191 * on other shared libs. Loading a "libfoo.so" could not solve the
192 * dependencies problem.
193 *
194 * You can, however, give a library name ending in ".so"
195 * (or whatever is used on your platform), and the library
196 * will be loaded without resolving dependencies. USE WITH CARE :)
197 * @return @ref KLibrary is invalid (0) when the library couldn't be dlopened. in such
198 * a case you can retrieve the error message by calling KLibLoader::lastErrorMessage()
199 *
200 * @see #factory
201 */
202 virtual KLibrary* library( const char* libname );
203
204 /**
205 * Loads and initializes a library. Loading a library multiple times is
206 * handled gracefully. The library is loaded such that the symbols are
207 * globally accessible so libraries with dependencies can be loaded
208 * sequentially.
209 *
210 * @param name This is the library name without extension. Usually that is something like
211 * "libkspread". The function will then search for a file named
212 * "libkspread.la" in the KDE library paths.
213 * The *.la files are created by libtool and contain
214 * important information especially about the libraries dependencies
215 * on other shared libs. Loading a "libfoo.so" could not solve the
216 * dependencies problem.
217 *
218 * You can, however, give a library name ending in ".so"
219 * (or whatever is used on your platform), and the library
220 * will be loaded without resolving dependencies. USE WITH CARE :)
221 * @return KLibrariy is invalid (0) when the library couldn't be dlopened. in such
222 * a case you can retrieve the error message by calling KLibLoader::lastErrorMessage()
223 *
224 * @see #factory
225 */
226 KLibrary* globalLibrary( const char *name );
227
228 /*
229 * Returns an error message that can be useful to debug the problem.
230 * Returns QString::null if the last call to @ref #library() was successful.
231 * You can call this function more than once. The error message is only
232 * reset by a new call to library().
233 * @return the last error message, or QString::null if there was no error
234 */
235 QString lastErrorMessage() const;
236
237 /**
238 * Unloads the library with the given name.
239 * @param libname This is the library name without extension. Usually that is something like
240 * "libkspread". The function will then search for a file named
241 * "libkspread.la" in the KDE library paths.
242 * The *.la files are created by libtool and contain
243 * important information especially about the libraries dependencies
244 * on other shared libs. Loading a "libfoo.so" could not solve the
245 * dependencies problem.
246 *
247 * You can, however, give a library name ending in ".so"
248 * (or whatever is used on your platform), and the library
249 * will be loaded without resolving dependencies. USE WITH CARE :)
250 */
251 virtual void unloadLibrary( const char *libname );
252
253 /**
254 * Returns a pointer to the factory. Use this function to get an instance
255 * of KLibLoader.
256 * @return a pointer to the loader. If no loader exists until now
257 * then one is created.
258 */
259 static KLibLoader* self();
260
261 /**
262 * @internal
263 * Internal Method, called by the KApplication destructor.
264 * Do not call it.
265 * This is what makes it possible to rely on ~KLibFactory
266 * being called in all cases, whether the library is unloaded
267 * while the application is running or when exiting.
268 */
269 static void cleanUp();
270
271 /**
272 * Helper method which looks for a library in the standard paths
273 * ("module" and "lib" resources).
274 * Made public for code that doesn't use KLibLoader itself, but still
275 * wants to open modules.
276 * @param name of the library. If it is not a path, the function searches in
277 * the "module" and "lib" resources. If there is no extension,
278 * ".la" will be appended.
279 * @param instance a KInstance used to get the standard paths
280 */
281 static QString findLibrary( const char * name/*US , const KInstance * instance = KGlobal::instance()*/ );
282
283protected:
284 KLibLoader( QObject* parent = 0, const char* name = 0 );
285
286private slots:
287 void slotLibraryDestroyed();
288private:
289 void close_pending( KLibWrapPrivate * );
290 QAsciiDict<KLibWrapPrivate> m_libs;
291
292 static KLibLoader* s_self;
293
294protected:
295 virtual void virtual_hook( int id, void* data );
296private:
297 KLibLoaderPrivate *d;
298};
299
300/**
301 * If you develop a library that is to be loaded dynamically at runtime, then
302 * you should return a pointer to your factory. The K_EXPORT_COMPONENT_FACTORY
303 * macro is provided for this purpose:
304 * <pre>
305 * K_EXPORT_COMPONENT_FACTORY( libkspread, KSpreadFactory )
306 * </pre>
307 *
308 * The first macro argument is the name of your library, the second specifies the name
309 * of your factory.
310 *
311 * In the constructor of your factory you should create an instance of @ref KInstance
312 * like this:
313 * <pre>
314 * s_global = new KInstance( "kspread" );
315 * </pre>
316 * This @ref KInstance is comparable to @ref KGlobal used by normal applications.
317 * It allows you to find resource files (images, XML, sound etc.) belonging
318 * to the library.
319 *
320 * If you want to load a library, use @ref KLibLoader. You can query @ref KLibLoader
321 * directly for a pointer to the libraries factory by using the @ref KLibLoader::factory()
322 * function.
323 *
324 * The KLibFactory is used to create the components, the library has to offer.
325 * The factory of KSpread for example will create instances of KSpreadDoc,
326 * while the Konqueror factory will create KonqView widgets.
327 * All objects created by the factory must be derived from @ref QObject, since @ref QObject
328 * offers type safe casting.
329 *
330 * KLibFactory is an abstract class. Reimplement the @ref
331 * createObject() method to give it functionality.
332 *
333 * @author Torben Weis <weis@kde.org>
334 */
335class KLibFactory : public QObject
336{
337 Q_OBJECT
338public:
339 /**
340 * Create a new factory.
341 * @param parent the parent of the QObject, 0 for no parent
342 * @param name the name of the QObject, 0 for no name
343 */
344 KLibFactory( QObject* parent = 0, const char* name = 0 );
345 virtual ~KLibFactory();
346
347 /**
348 * Creates a new object. The returned object has to be derived from
349 * the requested classname.
350 *
351 * It is valid behavior to create different kinds of objects
352 * depending on the requested @p classname. For example a koffice
353 * library may usually return a pointer to KoDocument. But
354 * if asked for a "QWidget", it could create a wrapper widget,
355 * that encapsulates the Koffice specific features.
356 *
357 * create() automatically emits a signal @ref objectCreated to tell
358 * the library about its newly created object. This is very
359 * important for reference counting, and allows unloading the
360 * library automatically once all its objects have been destroyed.
361 *
362 * @param parent the parent of the QObject, 0 for no parent
363 * @param name the name of the QObject, 0 for no name
364 * @param classname the name of the class
365 * @param args a list of arguments
366 */
367
368 QObject* create( QObject* parent = 0, const char* name = 0, const char* classname = "QObject", const QStringList &args = QStringList() );
369
370signals:
371 /**
372 * Emitted in #create
373 * @param obj the new object
374 */
375 void objectCreated( QObject *obj );
376
377
378protected:
379
380 /**
381 * Creates a new object. The returned object has to be derived from
382 * the requested classname.
383 *
384 * It is valid behavior to create different kinds of objects
385 * depending on the requested @p classname. For example a koffice
386 * library may usually return a pointer to KoDocument. But
387 * if asked for a "QWidget", it could create a wrapper widget,
388 * that encapsulates the Koffice specific features.
389 *
390 * This function is called by #create()
391 * @param parent the parent of the QObject, 0 for no parent
392 * @param name the name of the QObject, 0 for no name
393 * @param classname the name of the class
394 * @param args a list of arguments
395 */
396 virtual QObject* createObject( QObject* parent = 0, const char* name = 0, const char* classname = "QObject", const QStringList &args = QStringList() ) = 0;
397
398
399protected:
400 virtual void virtual_hook( int id, void* data );
401private:
402 KLibFactoryPrivate *d;
403};
404
405#endif