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Diffstat (limited to 'src/gvcore/busylevelmanager.cpp')
| -rw-r--r-- | src/gvcore/busylevelmanager.cpp | 108 |
1 files changed, 108 insertions, 0 deletions
diff --git a/src/gvcore/busylevelmanager.cpp b/src/gvcore/busylevelmanager.cpp new file mode 100644 index 0000000..adfdf55 --- /dev/null +++ b/src/gvcore/busylevelmanager.cpp @@ -0,0 +1,108 @@ +// vim: set tabstop=4 shiftwidth=4 noexpandtab +/* +Gwenview - A simple image viewer for KDE +Copyright 2000-2004 Aurélien Gâteau + + This program is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public License + as published by the Free Software Foundation; either version 2 + of the License, or (at your option) any later version. + + This program 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 General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + +*/ + +// Qt +#include <qtimer.h> + +// KDE +#include <kdebug.h> + +// Local +#include "busylevelmanager.moc" +namespace Gwenview { + +#undef ENABLE_LOG +#undef LOG +//#define ENABLE_LOG +#ifdef ENABLE_LOG +#define LOG(x) kdDebug() << k_funcinfo << x << endl +#else +#define LOG(x) ; +#endif + +BusyLevelManager::BusyLevelManager() +: mCurrentBusyLevel( BUSY_NONE ) +{ + connect( &mDelayedBusyLevelTimer, SIGNAL( timeout()), + this, SLOT( delayedBusyLevelChanged())); +} + +BusyLevelManager* BusyLevelManager::instance() { + static BusyLevelManager manager; + return &manager; +} + +// How the busy level stuff works: +// This system allows suspending less important tasks while more important +// task are active, i.e. no thumbnails are generated when the viewed +// image is being loaded and painted. +// All objects responsible for operations set their busy level +// to the matching value when the operation starts and reset their busy +// level when the operation is done. They all connect to busyLevelChanged() +// signal and suspend their operation if the current busy level is higher +// than the busy level of their operation. If a new operation is started, +// it needs to be immediatelly suspended if the current busy level is higher! +// Note that there can be only one level per object, +// so if one object is responsible for more operations, +// it needs to use helper objects for setBusyLevel(). + +void BusyLevelManager::setBusyLevel( QObject* obj, BusyLevel level ) { + LOG("BUSY:" << level << ":" << obj << ":" << obj->className() ); + if( level > BUSY_NONE ) { + if( mBusyLevels.contains( obj ) && mBusyLevels[ obj ] == level ) return; + if( !mBusyLevels.contains( obj )) { + connect( obj, SIGNAL( destroyed( QObject* )), this, SLOT( objectDestroyed( QObject* ))); + } + mBusyLevels[ obj ] = level; + } else { + mBusyLevels.remove( obj ); + disconnect( obj, SIGNAL( destroyed( QObject* )), this, SLOT( objectDestroyed( QObject* ))); + } + mDelayedBusyLevelTimer.start( 0, true ); +} + +void BusyLevelManager::objectDestroyed( QObject* obj ) { + LOG("DESTROYED:" << obj ); + mBusyLevels.remove( obj ); + mDelayedBusyLevelTimer.start( 0, true ); +} + +void BusyLevelManager::delayedBusyLevelChanged() { + BusyLevel newLevel = BUSY_NONE; + for( QMap< QObject*, BusyLevel >::ConstIterator it = mBusyLevels.begin(); + it != mBusyLevels.end(); + ++it ) { + newLevel = QMAX( newLevel, *it ); + } + + if( newLevel != mCurrentBusyLevel ) { + LOG("CHANGED BUSY:" << newLevel); + mCurrentBusyLevel = newLevel; + emit busyLevelChanged( newLevel ); + } +} + +BusyLevel BusyLevelManager::busyLevel() const { + return mCurrentBusyLevel; +} + + +} // namespace |