/* This file is part of the KDE libraries Copyright (C) 1999 Torben Weis This library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License version 2 as published by the Free Software Foundation. This library 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 Library General Public License for more details. You should have received a copy of the GNU Library General Public License along with this library; see the file COPYING.LIB. If not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #ifndef KLIBLOADER_H #define KLIBLOADER_H #include #include #include #include #include #include #include // For backwards compatibility class KInstance; class QTimer; class KLibrary; class KLibFactory; class KLibFactoryPrivate; class KLibLoaderPrivate; class KLibraryPrivate; class QLibrary; #define K_EXPORT_COMPONENT_FACTORY( libname, factory ) \ extern "C" { void *init_##libname() { return new factory; } } /** * @short Represents a dynamically loaded library. * * KLibrary allows you to look up symbols of the shared library. * Use @ref KLibLoader to create a new instance of KLibrary. * * @see KLibLoader * @author Torben Weis */ class KLibrary : public QObject { friend class KLibLoader; friend class QAsciiDict; Q_OBJECT public: /** * @internal * Don't create KLibrary objects on your own. Instead use @ref KLibLoader. */ //US KLibrary( const QString& libname, const QString& filename, void * handle ); KLibrary( const QString& libname, const QString& filename, QLibrary* handle ); /** * Returns the name of the library. * @return The name of the library like "libkspread". */ QString name() const; /** * Returns the file name of the library. * @return The filename of the library, for example "/opt/kde2&/lib/libkspread.la" */ QString fileName() const; /** * Returns the factory of the library. * @return The factory of the library if there is any, otherwise 0 */ KLibFactory* factory(); /** * Looks up a symbol from the library. This is a very low level * function that you usually don't want to use. Usually you should * check using @ref hasSymbol() whether the symbol actually exists, * otherwise a warning will be printed. * @param name the name of the symbol to look up * @return the address of the symbol, or 0 if it does not exist * @see #hasSymbol */ void* symbol( const char* name ) const; /** * Looks up a symbol from the library. This is a very low level * function that you usually don't want to use. * Unlike @ref symbol(), this method doesn't warn if the symbol doesn't exist, * so if the symbol might or might not exist, better use hasSymbol() before symbol(). * @param name the name of the symbol to check * @return true if the symbol exists * @since 3.1 */ bool hasSymbol( const char* name ) const; /** * Unloads the library. * This typically results in the deletion of this object. You should * not reference its pointer after calling this function. */ void unload() const; private slots: void slotObjectCreated( QObject *obj ); void slotObjectDestroyed(); void slotTimeout(); private: /** * @internal * Don't destruct KLibrary objects yourself. Instead use @ref unload() instead. */ ~KLibrary(); QString m_libname; QString m_filename; KLibFactory* m_factory; //US void * m_handle; QLibrary* m_handle; QPtrList m_objs; QTimer *m_timer; KLibraryPrivate *d; }; class KLibWrapPrivate; /** * The KLibLoader allows you to load libraries dynamically at runtime. * Dependent libraries are loaded automatically. * * KLibLoader follows the singleton pattern. You can not create multiple * instances. Use @ref self() to get a pointer to the loader. * * @see KLibrary * @author Torben Weis */ class KLibLoader : public QObject { friend class KLibrary; Q_OBJECT public: /** * You should NEVER destruct an instance of KLibLoader * until you know what you are doing. This will release * the loaded libraries. */ ~KLibLoader(); /** * Loads and initializes a library. Loading a library multiple times is * handled gracefully. * * This is a convenience function that returns the factory immediately * @param libname This is the library name without extension. Usually that is something like * "libkspread". The function will then search for a file named * "libkspread.la" in the KDE library paths. * The *.la files are created by libtool and contain * important information especially about the libraries dependencies * on other shared libs. Loading a "libfoo.so" could not solve the * dependencies problem. * * You can, however, give a library name ending in ".so" * (or whatever is used on your platform), and the library * will be loaded without resolving dependencies. USE WITH CARE :) * @return the @ref KLibFactory, or 0 if the library does not exist or it does * not have a factory * @see #library */ KLibFactory* factory( const char* libname ); /** * Loads and initializes a library. Loading a library multiple times is * handled gracefully. * * @param libname This is the library name without extension. Usually that is something like * "libkspread". The function will then search for a file named * "libkspread.la" in the KDE library paths. * The *.la files are created by libtool and contain * important information especially about the libraries dependencies * on other shared libs. Loading a "libfoo.so" could not solve the * dependencies problem. * * You can, however, give a library name ending in ".so" * (or whatever is used on your platform), and the library * will be loaded without resolving dependencies. USE WITH CARE :) * @return @ref KLibrary is invalid (0) when the library couldn't be dlopened. in such * a case you can retrieve the error message by calling KLibLoader::lastErrorMessage() * * @see #factory */ virtual KLibrary* library( const char* libname ); /** * Loads and initializes a library. Loading a library multiple times is * handled gracefully. The library is loaded such that the symbols are * globally accessible so libraries with dependencies can be loaded * sequentially. * * @param name This is the library name without extension. Usually that is something like * "libkspread". The function will then search for a file named * "libkspread.la" in the KDE library paths. * The *.la files are created by libtool and contain * important information especially about the libraries dependencies * on other shared libs. Loading a "libfoo.so" could not solve the * dependencies problem. * * You can, however, give a library name ending in ".so" * (or whatever is used on your platform), and the library * will be loaded without resolving dependencies. USE WITH CARE :) * @return KLibrariy is invalid (0) when the library couldn't be dlopened. in such * a case you can retrieve the error message by calling KLibLoader::lastErrorMessage() * * @see #factory */ KLibrary* globalLibrary( const char *name ); /* * Returns an error message that can be useful to debug the problem. * Returns QString::null if the last call to @ref #library() was successful. * You can call this function more than once. The error message is only * reset by a new call to library(). * @return the last error message, or QString::null if there was no error */ QString lastErrorMessage() const; /** * Unloads the library with the given name. * @param libname This is the library name without extension. Usually that is something like * "libkspread". The function will then search for a file named * "libkspread.la" in the KDE library paths. * The *.la files are created by libtool and contain * important information especially about the libraries dependencies * on other shared libs. Loading a "libfoo.so" could not solve the * dependencies problem. * * You can, however, give a library name ending in ".so" * (or whatever is used on your platform), and the library * will be loaded without resolving dependencies. USE WITH CARE :) */ virtual void unloadLibrary( const char *libname ); /** * Returns a pointer to the factory. Use this function to get an instance * of KLibLoader. * @return a pointer to the loader. If no loader exists until now * then one is created. */ static KLibLoader* self(); /** * @internal * Internal Method, called by the KApplication destructor. * Do not call it. * This is what makes it possible to rely on ~KLibFactory * being called in all cases, whether the library is unloaded * while the application is running or when exiting. */ static void cleanUp(); /** * Helper method which looks for a library in the standard paths * ("module" and "lib" resources). * Made public for code that doesn't use KLibLoader itself, but still * wants to open modules. * @param name of the library. If it is not a path, the function searches in * the "module" and "lib" resources. If there is no extension, * ".la" will be appended. * @param instance a KInstance used to get the standard paths */ static QString findLibrary( const char * name/*US , const KInstance * instance = KGlobal::instance()*/ ); protected: KLibLoader( QObject* parent = 0, const char* name = 0 ); private slots: void slotLibraryDestroyed(); private: void close_pending( KLibWrapPrivate * ); QAsciiDict m_libs; static KLibLoader* s_self; protected: virtual void virtual_hook( int id, void* data ); private: KLibLoaderPrivate *d; }; /** * If you develop a library that is to be loaded dynamically at runtime, then * you should return a pointer to your factory. The K_EXPORT_COMPONENT_FACTORY * macro is provided for this purpose: * 
 *   K_EXPORT_COMPONENT_FACTORY( libkspread, KSpreadFactory )
 *
* * The first macro argument is the name of your library, the second specifies the name * of your factory. * * In the constructor of your factory you should create an instance of @ref KInstance * like this: * 
 *     s_global = new KInstance( "kspread" );
 *
* This @ref KInstance is comparable to @ref KGlobal used by normal applications. * It allows you to find resource files (images, XML, sound etc.) belonging * to the library. * * If you want to load a library, use @ref KLibLoader. You can query @ref KLibLoader * directly for a pointer to the libraries factory by using the @ref KLibLoader::factory() * function. * * The KLibFactory is used to create the components, the library has to offer. * The factory of KSpread for example will create instances of KSpreadDoc, * while the Konqueror factory will create KonqView widgets. * All objects created by the factory must be derived from @ref QObject, since @ref QObject * offers type safe casting. * * KLibFactory is an abstract class. Reimplement the @ref * createObject() method to give it functionality. * * @author Torben Weis */ class KLibFactory : public QObject { Q_OBJECT public: /** * Create a new factory. * @param parent the parent of the QObject, 0 for no parent * @param name the name of the QObject, 0 for no name */ KLibFactory( QObject* parent = 0, const char* name = 0 ); virtual ~KLibFactory(); /** * Creates a new object. The returned object has to be derived from * the requested classname. * * It is valid behavior to create different kinds of objects * depending on the requested @p classname. For example a koffice * library may usually return a pointer to KoDocument. But * if asked for a "QWidget", it could create a wrapper widget, * that encapsulates the Koffice specific features. * * create() automatically emits a signal @ref objectCreated to tell * the library about its newly created object. This is very * important for reference counting, and allows unloading the * library automatically once all its objects have been destroyed. * * @param parent the parent of the QObject, 0 for no parent * @param name the name of the QObject, 0 for no name * @param classname the name of the class * @param args a list of arguments */ QObject* create( QObject* parent = 0, const char* name = 0, const char* classname = "QObject", const QStringList &args = QStringList() ); signals: /** * Emitted in #create * @param obj the new object */ void objectCreated( QObject *obj ); protected: /** * Creates a new object. The returned object has to be derived from * the requested classname. * * It is valid behavior to create different kinds of objects * depending on the requested @p classname. For example a koffice * library may usually return a pointer to KoDocument. But * if asked for a "QWidget", it could create a wrapper widget, * that encapsulates the Koffice specific features. * * This function is called by #create() * @param parent the parent of the QObject, 0 for no parent * @param name the name of the QObject, 0 for no name * @param classname the name of the class * @param args a list of arguments */ virtual QObject* createObject( QObject* parent = 0, const char* name = 0, const char* classname = "QObject", const QStringList &args = QStringList() ) = 0; protected: virtual void virtual_hook( int id, void* data ); private: KLibFactoryPrivate *d; }; #endif