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path: root/library/qlibrary.cpp
authorkergoth <kergoth>2002-01-25 22:14:26 (UTC)
committer kergoth <kergoth>2002-01-25 22:14:26 (UTC)
commit15318cad33835e4e2dc620d033e43cd930676cdd (patch) (side-by-side diff)
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+/**********************************************************************
+** Copyright (C) 2000 Trolltech AS. All rights reserved.
+**
+** This file is part of 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
+}
+
+/*!
+ \class QLibrary qlibrary.h
+
+ \brief The QLibrary class provides a wrapper for handling shared libraries.
+
+ This class is temporarily copied from Qt 3.0.
+*/
+
+/*!
+ \enum QLibrary::Policy
+
+ This enum type defines the various policies a QLibrary can have with respect to
+ loading and unloading the shared library.
+
+ The \e policy can be:
+
+ \value Delayed The library get's loaded as soon as needed and unloaded in the destructor
+ \value Immediately The library is loaded immediately and unloaded in the destructor
+ \value Manual Like delayed, and library has to be unloaded manually
+*/
+
+/*!
+ Creates a QLibrary object for the shared library \a filename.
+ The library get's loaded if \a pol is Immediately.
+
+ Note that \a filename does not need to include the (platform specific)
+ file extension, so calling
+
+ \code
+ QLibrary lib( "mylib" );
+ \endcode
+
+ would be equivalent to
+
+ \code
+ QLibrary lib( "mylib.dll" );
+ \endcode
+
+ on Windows. But \e "mylib.dll" will obviously not work on other platforms.
+
+ \sa setPolicy(), unload()
+*/
+QLibrary::QLibrary( const QString& filename, Policy pol )
+ : libfile( filename ), libPol( pol ), entry( 0 )
+{
+ d = new QLibraryPrivate( this );
+ if ( pol == Immediately )
+ load();
+}
+
+/*!
+ Deletes the QLibrary object.
+ The library will be unloaded if the policy is not Manual.
+
+ \sa unload(), setPolicy()
+*/
+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();
+ }
+ }
+}
+
+/*!
+ Returns the address of the exported symbol \a symb. The library gets
+ loaded if necessary. The function returns NULL if the symbol could
+ not be resolved, or if loading the library failed.
+
+ \code
+ typedef int (*addProc)( int, int );
+
+ addProc add = (addProc) library->resolve( "add" );
+ if ( add )
+ return add( 5, 8 );
+ else
+ return 5 + 8;
+ \endcode
+
+ \sa queryInterface()
+*/
+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;
+}
+
+/*!
+ \overload
+
+ Loads the library \a filename and returns the address of the exported symbol \a symb.
+ Note that like for the constructor, \a filename does not need to include the (platform specific)
+ file extension. The library staying loaded until the process exits.
+
+ The function returns a null pointer if the symbol could not be resolved or if loading
+ the library failed.
+*/
+void *QLibrary::resolve( const QString &filename, const char *symb )
+{
+ QLibrary lib( filename, Manual );
+ return lib.resolve( symb );
+}
+
+/*!
+ Returns whether the library is loaded.
+
+ \sa unload()
+*/
+bool QLibrary::isLoaded() const
+{
+ return d->pHnd != 0;
+}
+
+/*!
+ Loads the library.
+*/
+bool QLibrary::load()
+{
+ return d->loadLibrary();
+}
+
+/*!
+ Releases the component and unloads the library when successful.
+ Returns TRUE if the library could be unloaded, otherwise FALSE.
+ If the component implements the QLibraryInterface, the cleanup()
+ function of this interface will be called. The unloading will be
+ cancelled if the subsequent call to canUnload() returns FALSE.
+
+ This function gets called automatically in the destructor if
+ the policy is not Manual.
+
+ \warning
+ If \a force is set to TRUE, the library gets unloaded at any cost,
+ which is in most cases a segmentation fault, so you should know what
+ you're doing!
+
+ \sa queryInterface(), resolve()
+*/
+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
+}
+
+/*!
+ Sets the current policy to \a pol.
+ The library is loaded if \a pol is set to Immediately.
+*/
+void QLibrary::setPolicy( Policy pol )
+{
+ libPol = pol;
+
+ if ( libPol == Immediately && !d->pHnd )
+ load();
+}
+
+/*!
+ Returns the current policy.
+
+ \sa setPolicy()
+*/
+QLibrary::Policy QLibrary::policy() const
+{
+ return libPol;
+}
+
+/*!
+ Returns the filename of the shared library this QLibrary object handles,
+ including the platform specific file extension.
+
+ \code
+ QLibrary lib( "mylib" );
+ QString str = lib.library();
+ \endcode
+
+ will set \e str to "mylib.dll" on Windows, and "libmylib.so" on Linux.
+*/
+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;
+}
+
+/*!
+ Forwards the query to the component and returns the result. \a request and \a iface
+ are propagated to the component's queryInterface implementation.
+
+ The library gets loaded if necessary.
+*/
+QRESULT QLibrary::queryInterface( const QUuid& request, QUnknownInterface** iface )
+{
+ if ( !entry ) {
+ createInstanceInternal();
+ }
+
+ return entry ? entry->queryInterface( request, iface ) : QE_NOINTERFACE;
+}
+
+#endif // QT_NO_COMPONENT