componentfactory.h

#ifndef __tdeparts_componentfactory_h__
#define __tdeparts_componentfactory_h__
 
#include <tdeparts/factory.h>
#include <tdeparts/part.h>
#include <ktrader.h>
#include <tqmetaobject.h>
 
namespace KParts
{
 
    // this is a namespace and not a class because stupid egcs 1.1.2 doesn't grok
    // static template methods in classes. !@%@#$!
    namespace ComponentFactory
    {
        enum ComponentLoadingError { ErrNoServiceFound = 1,
                                     ErrServiceProvidesNoLibrary,
                                     ErrNoLibrary,
                                     ErrNoFactory,
                                     ErrNoComponent };
 
        template <class T>
        static T *createInstanceFromFactory( KLibFactory *factory, TQObject *parent = 0,
                                             const char *name = 0,
                                             const TQStringList &args = TQStringList() )
        {
            TQObject *object = factory->create( parent, name,
                                               T::staticMetaObject()->className(),
                                               args );
 
            T *result = dynamic_cast<T *>( object );
            if ( !result )
                    delete object;
            return result;
        }
 
        template <class T>
        static T *createPartInstanceFromFactory( KParts::Factory *factory,
                                                 TQWidget *parentWidget = 0,
                                                 const char *widgetName = 0,
                                                 TQObject *parent = 0,
                                                 const char *name = 0,
                                                 const TQStringList &args = TQStringList() )
        {
            KParts::Part *object = factory->createPart( parentWidget, widgetName,
                                                        parent, name,
                                                        T::staticMetaObject()->className(),
                                                        args );
 
            T *result = dynamic_cast<T *>( object );
            if ( !result )
                delete object;
            return result;
        }
 
        template <class T>
        static T *createInstanceFromLibrary( const char *libraryName, TQObject *parent = 0,
                                             const char *name = 0,
                                             const TQStringList &args = TQStringList(),
                                             int *error = 0 )
        {
            KLibrary *library = KLibLoader::self()->library( libraryName );
            if ( !library )
            {
                if ( error )
                    *error = ErrNoLibrary;
                return 0;
            }
            KLibFactory *factory = library->factory();
            if ( !factory )
            {
                library->unload();
                if ( error )
                    *error = ErrNoFactory;
                return 0;
            }
            T *res = createInstanceFromFactory<T>( factory, parent, name, args );
            if ( !res )
            {
                library->unload();
                if ( error )
                    *error = ErrNoComponent;
            }
            return res;
        }
 
        template <class T>
        static T *createPartInstanceFromLibrary( const char *libraryName,
                                                 TQWidget *parentWidget = 0,
                                                 const char *widgetName = 0,
                                                 TQObject *parent = 0,
                                                 const char *name = 0,
                                                 const TQStringList &args = TQStringList(),
                                                 int *error = 0 )
        {
            KLibrary *library = KLibLoader::self()->library( libraryName );
            if ( !library )
            {
                if ( error )
                    *error = ErrNoLibrary;
                return 0;
            }
            KLibFactory *factory = library->factory();
            if ( !factory )
            {
                library->unload();
                if ( error )
                    *error = ErrNoFactory;
                return 0;
            }
            KParts::Factory *partFactory = dynamic_cast<KParts::Factory *>( factory );
            if ( !partFactory )
            {
                library->unload();
                if ( error )
                    *error = ErrNoFactory;
                return 0;
            }
            T *res = createPartInstanceFromFactory<T>( partFactory, parentWidget,
                                                       widgetName, parent, name, args );
            if ( !res )
            {
                library->unload();
                if ( error )
                    *error = ErrNoComponent;
            }
            return res;
        }
 
        template <class T>
        static T *createInstanceFromService( const KService::Ptr &service,
                                             TQObject *parent = 0,
                                             const char *name = 0,
                                             const TQStringList &args = TQStringList(),
                                             int *error = 0 )
        {
            TQString library = service->library();
            if ( library.isEmpty() )
            {
                if ( error )
                    *error = ErrServiceProvidesNoLibrary;
                return 0;
            }
 
            return createInstanceFromLibrary<T>( library.local8Bit().data(), parent,
                             name, args, error );
        }
 
        template <class T>
        static T *createPartInstanceFromService( const KService::Ptr &service,
                                                 TQWidget *parentWidget = 0,
                                                 const char *widgetName = 0,
                                                 TQObject *parent = 0,
                                                 const char *name = 0,
                                                 const TQStringList &args = TQStringList(),
                                                 int *error = 0 )
        {
            TQString library = service->library();
            if ( library.isEmpty() )
            {
                if ( error )
                    *error = ErrServiceProvidesNoLibrary;
                return 0;
            }
 
            return createPartInstanceFromLibrary<T>( library.local8Bit().data(), parentWidget,
                                                     widgetName, parent, name, args, error );
        }
 
        template <class T, class ServiceIterator>
        static T *createInstanceFromServices( ServiceIterator begin, ServiceIterator end,
                                              TQObject *parent = 0,
                                              const char *name = 0,
                                              const TQStringList &args = TQStringList(),
                                              int *error = 0 )
        {
            for (; begin != end; ++begin )
            {
                KService::Ptr service = *begin;
 
                if ( error )
                    *error = 0;
 
                T *component = createInstanceFromService<T>( service, parent, name,
                                                             args, error );
                if ( component )
                    return component;
            }
 
            if ( error )
                *error = ErrNoServiceFound;
 
            return 0;
 
        }
 
        template <class T, class ServiceIterator>
        static T *createPartInstanceFromServices( ServiceIterator begin,
                                                  ServiceIterator end,
                                                  TQWidget *parentWidget = 0,
                                                  const char *widgetName = 0,
                                                  TQObject *parent = 0,
                                                  const char *name = 0,
                                                  const TQStringList &args = TQStringList(),
                                                  int *error = 0 )
         {
            for (; begin != end; ++begin )
            {
                KService::Ptr service = *begin;
 
                if ( error )
                    *error = 0;
 
                T *component = createPartInstanceFromService<T>( service, parentWidget,
                                                                 widgetName, parent,
                                                                 name, args, error );
                if ( component )
                    return component;
            }
 
            if ( error )
                *error = ErrNoServiceFound;
 
            return 0;
 
        }
 
        template <class T>
        static T *createInstanceFromQuery( const TQString &serviceType,
                                           const TQString &constraint = TQString::null,
                                           TQObject *parent = 0,
                                           const char *name = 0,
                                           const TQStringList &args = TQStringList(),
                                           int *error = 0 )
        {
            TDETrader::OfferList offers = TDETrader::self()->query( serviceType, constraint );
            if ( offers.isEmpty() )
            {
                if ( error )
                    *error = ErrNoServiceFound;
                return 0;
            }
 
            return createInstanceFromServices<T>( offers.begin(),
                                                  offers.end(),
                                                  parent, name, args, error );
        }
 
        template <class T>
        static T *createPartInstanceFromQuery( const TQString &serviceType,
                                               const TQString &constraint,
                                               TQWidget *parentWidget = 0,
                                               const char *widgetName = 0,
                                               TQObject *parent = 0,
                                               const char *name = 0,
                                               const TQStringList &args = TQStringList(),
                                               int *error = 0 )
        {
            TDETrader::OfferList offers = TDETrader::self()->query( serviceType, TQString::fromLatin1("KParts/ReadOnlyPart"), constraint, TQString::null );
            if ( offers.isEmpty() )
            {
                if ( error )
                    *error = ErrNoServiceFound;
                return 0;
            }
 
            return createPartInstanceFromServices<T>( offers.begin(), offers.end(),
                                                      parentWidget, widgetName,
                                                      parent, name, args, error );
        }
 
    }
 
}
 
#endif