Dataengnies

[Petri Damstén]

On Tuesday 26 August 2008 23:38:47 Aaron J. Seigo wrote:
> and yes, if the engine is doing any sort of expensive work then the code
> needs to protect against it being called while the async job is in
> progreess.

Yes, that's true.

> doing async calls inside the DataEngine subclas itself is really not the
> best way to do things. encapsulating it inside a DataContainer subclass
> makes it waaaay easier to manage.

This was new to me :-) Converted ExecutableEngine to use custom Container 
(attached). One problem. exec is called in constructor to start process for 
the first time. checkForUpdate is called when process finished but seems that 
m_queued is false and dataUpdated is not called. On second exec (first 
updateRequested signal, which comes after first timeout) it works:
plasmoidviewer(22365) ScriptedHtml::connectToEngine: 
"/home/damu/scripted_test.py"
plasmoidviewer(22365) ExecutableEngine::sourceRequestEvent: 
"/home/damu/scripted_test.py"
plasmoidviewer(22365) ExecutableContainer::exec: "/home/damu/scripted_test.py"
plasmoidviewer(22365) ScriptedHtml::dataUpdated: "/home/damu/scripted_test.py" 
QHash()
plasmoidviewer(22365)/libplasma Plasma::DataContainer::checkForUpdate: Dirty: 
false
plasmoidviewer(22365) ExecutableContainer::finished: 
"/home/damu/scripted_test.py"
plasmoidviewer(22365)/libplasma Plasma::DataContainer::checkForUpdate: Dirty: 
true
plasmoidviewer(22365)/libplasma Plasma::SignalRelay::checkQueueing: Queued is 
false
plasmoidviewer(22365) ExecutableContainer::exec: "/home/damu/scripted_test.py"
plasmoidviewer(22365)/libplasma Plasma::SignalRelay::timerEvent: Queued set 
to: true
plasmoidviewer(22365) ExecutableContainer::finished: 
"/home/damu/scripted_test.py"
plasmoidviewer(22365)/libplasma Plasma::DataContainer::checkForUpdate: Dirty: 
true
plasmoidviewer(22365)/libplasma Plasma::SignalRelay::checkQueueing: Queued is 
true
plasmoidviewer(22365) ScriptedHtml::dataUpdated: "/home/damu/scripted_test.py" 
QHash(("stderr", QVariant(QString, "") ) ( "exit code" ,  QVariant(int, 0) ) ( 
"exit status" ,  QVariant(int, 0) ) ( "stdout" ,  QVariant(QString, 
"/home/damu/scripted_test.html
") ) )

One other thing. If query() is run first for the DataEngine doing async calls 
it won't work, but I'm not sure if that is important. Applet writer does not 
have a way to know it (if engine is async or not), though.

Petri

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