Qtopia library API Documentation
	Overview Class Hierarchy Classes Classes (annotated) Members Source Files Todo

qlibrary.cpp

/**********************************************************************
** Copyright (C) 2000-2002 Trolltech AS.  All rights reserved.
**
** This file is part of the Qtopia Environment.
**
** This file may be distributed and/or modified under the terms of the
** GNU General Public License version 2 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.
**
** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
**
** See http://www.trolltech.com/gpl/ for GPL licensing information.
**
** Contact info@trolltech.com if any conditions of this licensing are
** not clear to you.
**
**********************************************************************/


#include "qlibrary_p.h"

// uncomment this to get error messages
//#define QT_DEBUG_COMPONENT 1 
// uncomment this to get error and success messages
//#define QT_DEBUG_COMPONENT 2

#ifndef QT_DEBUG_COMPONENT
# if defined(QT_DEBUG)
#  define QT_DEBUG_COMPONENT 1
# endif
#endif

#ifndef QT_NO_COMPONENT

// KAI C++ has at the moment problems with unloading the Qt plugins. So don't
// unload them as a workaround for now.
#if defined(Q_CC_KAI) || defined(Q_OS_MAC)
#define QT_NO_LIBRARY_UNLOAD
#endif

#if defined(Q_WS_WIN) && !defined(QT_MAKEDLL)
#define QT_NO_LIBRARY_UNLOAD
#endif

/* Platform independent QLibraryPrivate implementations */
#ifndef QT_LITE_COMPONENT

#include "qtimer.h"

extern Q_EXPORT QApplication *qApp;

QLibraryPrivate::QLibraryPrivate( QLibrary *lib )
    : QObject( 0, lib->library().latin1() ), pHnd( 0 ), libIface( 0 ), unloadTimer( 0 ), library( lib )
{
}

QLibraryPrivate::~QLibraryPrivate()
{
    if ( libIface )
    libIface->release();
    killTimer();
}

/*
  Only components that implement the QLibraryInterface can
  be unloaded automatically.
*/
void QLibraryPrivate::tryUnload()
{
    if ( library->policy() == QLibrary::Manual || !pHnd || !libIface )
    return;

    if ( !libIface->canUnload() )
    return;

#if defined(QT_DEBUG_COMPONENT) && QT_DEBUG_COMPONENT == 2
    if ( library->unload() )
    qDebug( "%s has been automatically unloaded", library->library().latin1() );
#else
    library->unload();
#endif
}

#else // QT_LITE_COMPOINENT

QLibraryPrivate::QLibraryPrivate( QLibrary *lib )
    : pHnd( 0 ), libIface( 0 ), library( lib )
{
}

#endif // QT_LITE_COMPOINENT

void QLibraryPrivate::startTimer()
{
#ifndef QT_LITE_COMPONENT
    unloadTimer = new QTimer( this );
    connect( unloadTimer, SIGNAL( timeout() ), this, SLOT( tryUnload() ) );
    unloadTimer->start( 5000, FALSE );
#endif
}

void QLibraryPrivate::killTimer()
{
#ifndef QT_LITE_COMPONENT
    delete unloadTimer;
    unloadTimer = 0;
#endif
}

QLibrary::QLibrary( const QString& filename, Policy pol )
    : libfile( filename ), libPol( pol ), entry( 0 )
{
    d = new QLibraryPrivate( this );
    if ( pol == Immediately )
    load();
}

QLibrary::~QLibrary()
{
    if ( libPol == Manual || !unload() ) {
    if ( entry ) {
        entry->release();
        entry = 0;
    }
    }
    delete d;
}

void QLibrary::createInstanceInternal()
{
    if ( libfile.isEmpty() )
    return;

    if ( !d->pHnd ) {
    ASSERT( entry == 0 );
    load();
    }

    if ( d->pHnd && !entry ) {
#if defined(QT_DEBUG_COMPONENT) && QT_DEBUG_COMPONENT == 2
    qWarning( "%s has been loaded.", library().latin1() );
#endif
    typedef QUnknownInterface* (*UCMInstanceProc)();
    UCMInstanceProc ucmInstanceProc;
    ucmInstanceProc = (UCMInstanceProc) resolve( "ucm_instantiate" );
    entry = ucmInstanceProc ? ucmInstanceProc() : 0;
    if ( entry ) {
        entry->queryInterface( IID_QLibrary, (QUnknownInterface**)&d->libIface);
        if ( d->libIface ) {
        if ( !d->libIface->init() ) {
#if defined(QT_DEBUG_COMPONENT)
            qWarning( "%s: QLibraryInterface::init() failed.", library().latin1() );
#endif
            unload();
            return;
        }

        d->killTimer();
        if ( libPol != Manual )
            d->startTimer();
        }
    } else {
#if defined(QT_DEBUG_COMPONENT)
        qWarning( "%s: No interface implemented.", library().latin1() );
#endif
        unload();
    }
    }
}

void *QLibrary::resolve( const char* symb )
{
    if ( !d->pHnd )
    load();
    if ( !d->pHnd )
    return 0;

    void *address = d->resolveSymbol( symb );
    if ( !address ) {
#if defined(QT_DEBUG_COMPONENT)
    // resolveSymbol() might give a warning; so let that warning look so fatal
    qWarning( QString("Trying to resolve symbol \"_%1\" instead").arg( symb ) );
#endif
    address = d->resolveSymbol( QString( "_" ) + symb );
    }
    return address;
}

void *QLibrary::resolve( const QString &filename, const char *symb )
{
    QLibrary lib( filename, Manual );
    return lib.resolve( symb );
}

bool QLibrary::isLoaded() const
{
    return d->pHnd != 0;
}

bool QLibrary::load()
{
    return d->loadLibrary();
}

bool QLibrary::unload( bool force )
{
    if ( !d->pHnd )
    return TRUE;

    if ( entry ) {
    if ( d->libIface ) {
        d->libIface->cleanup();

        bool can = d->libIface->canUnload();
        can = ( d->libIface->release() <= 1 ) && can;
        // the "entry" member must be the last reference to the component
        if ( can || force ) {
        d->libIface = 0;
        } else {
#if defined(QT_DEBUG_COMPONENT)
        qWarning( "%s prevents unloading!", library().latin1() );
#endif
        d->libIface->addRef();
        return FALSE;
        }
    }

    if ( entry->release() ) {
#if defined(QT_DEBUG_COMPONENT)
        qWarning( "%s is still in use!", library().latin1() );
#endif
        if ( force ) {
        delete entry;
        } else {
        entry->addRef();
        return FALSE;
        }
    }
    d->killTimer();

    entry = 0;
    }

// ### this is a hack to solve problems with plugin unloading und KAI C++
// (other compilers may have the same problem)
#if !defined(QT_NO_LIBRARY_UNLOAD)
    if ( !d->freeLibrary() ) {
#if defined(QT_DEBUG_COMPONENT)
    qWarning( "%s could not be unloaded.", library().latin1() );
#endif
    return FALSE;
#else
    return TRUE;
#endif
#if !defined(QT_NO_LIBRARY_UNLOAD)
    }

#if defined(QT_DEBUG_COMPONENT) && QT_DEBUG_COMPONENT == 2
    qWarning( "%s has been unloaded.", library().latin1() );
#endif

    d->pHnd = 0;
    return TRUE;
#endif
}

void QLibrary::setPolicy( Policy pol )
{
    libPol = pol;

    if ( libPol == Immediately && !d->pHnd )
    load();
}

QLibrary::Policy QLibrary::policy() const
{
    return libPol;
}

QString QLibrary::library() const
{
    if ( libfile.isEmpty() )
    return libfile;

    QString filename = libfile;
#if defined(Q_WS_WIN)
    if ( filename.find( ".dll" ) == -1 )
    filename += ".dll";
#elif defined(Q_OS_MACX)
    if ( filename.find( ".dylib" ) == -1 )
    filename += ".dylib";
#else
    if ( filename.find( ".so" ) == -1 )
    filename = QString( "lib%1.so" ).arg( filename );
#endif

    return filename;
}

QRESULT QLibrary::queryInterface( const QUuid& request, QUnknownInterface** iface )
{
    if ( !entry ) {
    createInstanceInternal();
    }

    return entry ? entry->queryInterface( request, iface ) : QE_NOINTERFACE;
}

#endif // QT_NO_COMPONENT

This file is part of the documentation for OPIE Version 1.5.5.

Documentation copyright © 1997-2003 the KDE developers. 2003 OPIE developers
Generated on Tue Feb 10 20:24:06 2004 by doxygen 1.3.5 written by Dimitri van Heesch, © 1997-2001