[KPhotoAlbum] Crash from the latest svn

[Robert Krawitz]

The latest svn crashed when I attempted to resize the thumbnail grid
with the mouse middle button.

(Personally, I think that that should be disabled with the new
thumbnail code -- accidentally changing the thumbnail size is
presumably a much more expensive operation now.

I also vaguely recall that we had a similar performance issue in the
KDE3 version that was resolved, at least partially, by using a quick
and dirty resampling algorithm rather than rescaling.  This made the
thumbnails less attractive but much faster to load.)

Application: KPhotoAlbum (kphotoalbum), signal: Segmentation fault
[Current thread is 1 (Thread 0x7f238ba76790 (LWP 7437))]

Thread 3 (Thread 0x7f2377973950 (LWP 7475)):
#0  0x00007f2387dc0d59 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
#1  0x00007f238804dd69 in QWaitCondition::wait (this=0xc001e68, mutex=0xc001e70, time=18446744073709551615) at thread/qwaitcondition_unix.cpp:87
#2  0x00000000004f7612 in ImageManager::Manager::next (this=0xc001e30) at /home/rlk/sandbox/kpa4/kphotoalbum/ImageManager/Manager.cpp:101
#3  0x00000000004f694d in ImageManager::ImageLoader::run (this=0xc0a0550) at /home/rlk/sandbox/kpa4/kphotoalbum/ImageManager/ImageLoader.cpp:56
#4  0x00007f238804ce05 in QThreadPrivate::start (arg=0xc0a0550) at thread/qthread_unix.cpp:248
#5  0x00007f2387dbd070 in start_thread () from /lib64/libpthread.so.0
#6  0x00007f23861f111d in clone () from /lib64/libc.so.6
#7  0x0000000000000000 in ?? ()

Thread 2 (Thread 0x7f2378174950 (LWP 7476)):
#0  0x00007f2387dc0d59 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
#1  0x00007f238804dd69 in QWaitCondition::wait (this=0xc001e68, mutex=0xc001e70, time=18446744073709551615) at thread/qwaitcondition_unix.cpp:87
#2  0x00000000004f7612 in ImageManager::Manager::next (this=0xc001e30) at /home/rlk/sandbox/kpa4/kphotoalbum/ImageManager/Manager.cpp:101
#3  0x00000000004f694d in ImageManager::ImageLoader::run (this=0xc3242d0) at /home/rlk/sandbox/kpa4/kphotoalbum/ImageManager/ImageLoader.cpp:56
#4  0x00007f238804ce05 in QThreadPrivate::start (arg=0xc3242d0) at thread/qthread_unix.cpp:248
#5  0x00007f2387dbd070 in start_thread () from /lib64/libpthread.so.0
#6  0x00007f23861f111d in clone () from /lib64/libc.so.6
#7  0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7f238ba76790 (LWP 7437)):
[KCrash Handler]
#5  0x0000000000522c6b in DB::Result::at (this=0x495a120, index=<value optimized out>) at /home/rlk/sandbox/kpa4/kphotoalbum/DB/Result.cpp:60
#6  0x000000000048fe4d in ThumbnailView::ThumbnailModel::imageAt (this=<value optimized out>, index=76914976) at /home/rlk/sandbox/kpa4/kphotoalbum/ThumbnailView/ThumbnailModel.cpp:236
#7  0x000000000048c7c1 in ThumbnailView::ThumbnailWidget::emitDateChange (this=0xc6e060) at /home/rlk/sandbox/kpa4/kphotoalbum/ThumbnailView/ThumbnailWidget.cpp:225
#8  0x000000000048ca28 in ThumbnailView::ThumbnailWidget::qt_metacall (this=0xc6e060, _c=QMetaObject::InvokeMetaMethod, _id=33, _a=0x7fffa9ceb2a0)
    at /home/rlk/sandbox/kpa4/kphotoalbum/ThumbnailWidget.moc:95
#9  0x00007f23881547b8 in QMetaObject::activate (sender=0xdc0e00, m=<value optimized out>, local_signal_index=<value optimized out>, argv=0x19854ff0) at kernel/qobject.cpp:3295
#10 0x00007f2388150da3 in QObject::event (this=0xdc0e00, e=0x495a120) at kernel/qobject.cpp:1212
#11 0x00007f23872be02d in QApplicationPrivate::notify_helper (this=0x8972e0, receiver=0xdc0e00, e=0x7fffa9cebae0) at kernel/qapplication.cpp:4302
#12 0x00007f23872c5744 in QApplication::notify (this=0x7fffa9cebf40, receiver=0xdc0e00, e=0x7fffa9cebae0) at kernel/qapplication.cpp:3706
#13 0x00007f2388f77b6b in KApplication::notify(QObject*, QEvent*) () from /usr/lib64/libkdeui.so.5
#14 0x00007f238814092c in QCoreApplication::notifyInternal (this=0x7fffa9cebf40, receiver=0xdc0e00, event=0x7fffa9cebae0) at kernel/qcoreapplication.cpp:726
#15 0x00007f238816f260 in QTimerInfoList::activateTimers (this=0x89afe0) at kernel/qcoreapplication.h:215
#16 0x00007f238816b534 in timerSourceDispatch (source=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:184
#17 0x00007f237fb1afca in g_main_context_dispatch () from /usr/lib64/libglib-2.0.so.0
#18 0x00007f237fb1e958 in g_main_context_iterate () from /usr/lib64/libglib-2.0.so.0
#19 0x00007f237fb1eb1c in g_main_context_iteration () from /usr/lib64/libglib-2.0.so.0
#20 0x00007f238816b22c in QEventDispatcherGlib::processEvents (this=0x897270, flags=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:412
#21 0x00007f238737121f in QGuiEventDispatcherGlib::processEvents (this=0x7fffa9ceb170, flags=<value optimized out>) at kernel/qguieventdispatcher_glib.cpp:204
#22 0x00007f238813f202 in QEventLoop::processEvents (this=<value optimized out>, flags={i = -1446068656}) at kernel/qeventloop.cpp:149
#23 0x00007f238813f5dc in QEventLoop::exec (this=0x7fffa9cebe90, flags={i = -1446068576}) at kernel/qeventloop.cpp:201
#24 0x00007f23881434d6 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1003
#25 0x0000000000444362 in main (argc=1, argv=0x7fffa9cec658) at /home/rlk/sandbox/kpa4/kphotoalbum/main.cpp:86