/* This file is part of the KDE libraries
Copyright (C) 1999 Torben Weis <weis@kde.org>
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 <qobject.h>
#include <qstring.h>
#include <qstringlist.h>
#include <qasciidict.h>
#include <qlist.h>
#include "ltdl.h"
class KInstance;
class QTimer;
class KLibFactoryPrivate;
class KLibLoaderPrivate;
class KLibraryPrivate;
/**
* If you develop a library that is to be loaded dynamically at runtime, then
* you should provide a function that returns a pointer to your factory like this:
* <pre>
* extern "C"
* {
* void* init_libkspread()
* {
* return new KSpreadFactory;
* }
* };
* </pre>
* You should especially see that the function must follow the naming pattern
* "init_libname".
*
* In the constructor of your factory you should create an instance of @ref KInstance
* like this:
* <pre>
* s_global = new KInstance( "kspread" );
* </pre>
* This @ref KInstance is compareable to @ref KGlobal used by normal applications.
* It allows you to find ressource files (images, XML, sound etc.) belonging
* to the library.
* Furthermore if you provide any QObject derived classes, you must call
* @ref setMocClasses() with an array of names of these classes. To generate
* that list automatically use am_edit.
*
* 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 <weis@kde.org>
*/
class KLibFactory : public QObject
{
Q_OBJECT
public:
/**
* Create a new factory.
*/
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 @ref KoDocument. But
* if asked for a "QWidget", it could create a wrapper widget,
* that encapsulates the Koffice specific features.
*
* Never reimplement this function. Instead, reimplement @ref
* createObject().
*
* 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.
*
* This function is virtual for compatibility reasons only.
*/
virtual QObject* create( QObject* parent = 0, const char* name = 0, const char* classname = "QObject", const QStringList &args = QStringList() );
signals:
/**
* Emitted in @ref create
*/
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 @ref KoDocument. But
* if asked for a "QWidget", it could create a wrapper widget,
* that encapsulates the Koffice specific features.
*
* This function is called by @ref create()
*/
virtual QObject* createObject( QObject* parent = 0, const char* name = 0, const char* classname = "QObject", const QStringList &args = QStringList() );
private:
KLibFactoryPrivate *d;
};
/**
* @short Represents a dynamically loaded library.
*
* KLibrary allows you to look up symbols of the shared library.
*
* @author Torben Weis <weis@kde.org>
*/
class KLibrary : public QObject
{
Q_OBJECT
public:
KLibrary( const QString& libname, const QString& filename, lt_dlhandle handel );
~KLibrary();
/**
* @return The name of the library like "libkspread".
*/
QString name() const;
/**
* @return The filename of the library, for example "/opt/kde2&/lib/libkspread.la"
*/
QString fileName() const;
/**
* @return The factory of the library if there is any.
*/
KLibFactory* factory();
/**
* Looks up a symbol from the library. This is a very low level
* function that you usually dont want to use.
*/
void* symbol( const char* name );
private slots:
void slotObjectCreated( QObject *obj );
void slotObjectDestroyed();
void slotTimeout();
private:
QString m_libname;
QString m_filename;
KLibFactory* m_factory;
lt_dlhandle m_handle;
QList<QObject> m_objs;
QTimer *m_timer;
KLibraryPrivate *d;
};
/**
* The KLibLoader allows you to load libraries dynamically at runtime.
* Dependend 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.
*
* @author Torben Weis <weis@kde.org>
*/
class KLibLoader : public QObject
{
Q_OBJECT
public:
/**
* You should NEVER destruct an instance of KLibLoader
* until you know what you are doing. This will release
* the loaded library.
*/
~KLibLoader();
/**
* Loads and initializes a library. Loading a library multiple times is
* handled gracefully.
*
* This is a convenience function that returns the factory immediately
*
* @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 :)
*
* @see #factory
*/
virtual KLibrary* library( const char* libname );
virtual void unloadLibrary( const char *libname );
/**
* @return a pointer to the loader. If no loader exists until now
* then one is created.
*/
static KLibLoader* self();
/**
* @internal method, called by the KApplication destructor
* 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();
protected:
KLibLoader( QObject* parent = 0, const char* name = 0 );
private slots:
void slotLibraryDestroyed();
private:
QAsciiDict<KLibrary> m_libs;
static KLibLoader* s_self;
KLibLoaderPrivate *d;
};
#endif
| Generated by: dfaure on Tue Feb 27 12:46:10 2001, using kdoc 2.0a50. |