On 08.10.2012 11:31, Camillo Bruni wrote:
Just from the deleted wiki page on our google code project site:
Squeak startup and shutdown lists are iterated too often, and startup is ignored by the network classes.
= Introduction = == Squeak/Pharo Problems == Squeak's startup and shutdown lists are not used as such. Each snapshot forces a shutdown and then a startup. This is not only inefficient, it is unfair to things like open sockets, database connections, etc. Platform windows will not be well served: imagine shutting down the entire IDE for a snapshot; something needs to be done. This is false, using startUp:/shutDown: serves exactly this purpose.
Dolphin does not free external resources on a snapshot. Resources are freed on shutdown (by registering for the shutdown events) and pointers/handles are cleared on *startup*. Having worked with it for years, I have gone from considering it strange to believing it is the correct design.
== First Steps Toward a Fix == It became clear that my life would be easier given a singleton SessionManager that triggers #sessionStarted and #sessionStopped. The open question was whether Squeak's startup and shutdown lists with the quitting and resuming flags would be enough to reproduce Dolphin's behavior, which is to trigger #sessionStarted and #sessionStopped when *and only when* the image starts and stops, respectively. Somewhat surprisingly, it appears to be. I am left wondering why people have tolerated the need to litter images with #initializeNetwork sends; that should be done once every time the image starts. And this is true, you can achieve the same using startUp:/shutDown: as you can in Dolphin. Whether that is the best interface, or a manager/announcer would be better is a different question.
Ironically, the session object Igor describes would necessitate the same kind of intrusive checks as #initializeNetwork. IMO, lazily checking whether the image has been restarted whenever you want to do something stinks. Registering to be notified when image starts/stops is a lot better. Cheers, Henry