From kde-devel Sun Oct 17 15:10:50 2004 From: "Oliver Oppitz" Date: Sun, 17 Oct 2004 15:10:50 +0000 To: kde-devel Subject: Re: Execution replay for Qt/KDE applications Message-Id: X-MARC-Message: https://marc.info/?l=kde-devel&m=109802590310559 >> cool. I really interested in this kind of possibility. Maybe this can >> be merged into Qt in the future? Most of the project does not need modifications to Qt itself, its just additional classes. However, to get a _guaranteed_ correct replay, minimal changes to the Qt eventLoop are necessary. This is to synchronize the QEvents I post during the replay with the call graph like it was during the execution: e.g. the events handled in the say 42nd invocation of the Qt eventLoop during the execution phase, need to be handled in the 42nd invocation in the replay phase. For most applications this does not matter: it is irrelevant how fast you type, so we replay events with roughly the same timing. Indeed this synchronisation _should_ never matter, otherwise you have a bad design if your application depends on it. However, for debugging we want to have _identical_ behaviour as in the original run. I have an editor that works nicely, but once I open some 25 (!) windows (showing the same buffer) and insert characters via keyrepeat ("fast") the cursor misses to advance its position now and then. This is clearly some timing/reentrancy problem due to the massive slow down of the 25 windows (my X-server is a lightning-fast 600 Mhz Via C3 machine: slow machines do have advantages ;-). For debugging this a recording/replay tool would be _really_ handy: the events are recorded in _real time_ but they can be replayed in _non real time_ (assuming the little fix to the Qt event loop). You can then even set break points during the replay. Is that neat or what? ;-) >> What about setting up a project in the SF? I will make it public within the week, though it is really early. Currently it only captures keystrokes. > Or just putting it in kdenonbeta I do not know about kdennonbeta yet. I need to check this out. Cheers for now, Oliver -- ---------------------------------------------------------------------------- "To dare is to lose foothold a moment not to dare os to lose one self" by S.Kierkegaard >> Visit http://mail.kde.org/mailman/listinfo/kde-devel#unsub to unsubscribe <<