Before I start re-coding; I have some multi-threading questions…
I read that Applescript Studio is not so good at multi-threading. But I want to speed up some of my apps. How do I properly “fake multi-threading is Applescript Studio”?
My Applescript studio app.
Currently I search for files and populate a table with them. I authenticate, then selected files (via checkbox) are deleted and removed from the table in a loop.
What is the ‘Best method for speed and proper coding technique in applescript studio to handle this situation?’
Stay in applesscript studio [do nothing to change speed]
if rowChecked then
set theResult to do shell script ("rm -R '" & theLocation & "'") password "" with administrator privileges
delete (item rowIndex of selectedDataRows)
end if
Same as #2 above but add “&” at the end to make a background task.
Write selected files to a /tmp file and execute shell script to delete files in a loop in the background.
Some other way.
My concern is that any background task will be canceled before completion if the Applescript Studio app is quit.
Thank you for any response.
The AppleScript language doesn’t support the creation or use of multiple threads; you’d need to use some other language for that.
Have you profiled your code to see where the performance bottlenecks are? I don’t think using multiple threads will make your app go faster (why do you think they would?); might make it more responsive while files are being deleted, but the actual file deletion bit will take as long as it takes.
BTW, your do shell script (“rm -R '” & theLocation & “'”) is completely unsafe; use do shell script ("rm -R " as Unicode text & quoted form of theLocation)
Just how unresponsive is it anyway? If it’s only a few seconds delay, or if there’s really not much other useful work the user can be doing meantime, then I’d suggest just living with it. Studio’s hardly an ideal choice for writing sophisticated high-performance apps anyway.
Assuming you do decide to pursue it further, have you profiled your app to see where the performance problems are? That’s the very first thing to do - you can’t provide a proper solution until you’ve worked out what the problem actually is. It may be that you’ve a lousy algorithm somewhere that’s causing it to take far longer than it actually needs to, in which case you should fix that first. Or it might be that the GUI code is just naturally slow, in which case threads won’t help you.
If it is the file deletion stuff that’s the major time consumer then that’s something that could be offloaded to a second thread/process to avoid blocking your main thread. Since you’re working in AppleScript the simplest thing would be to spawn a background process via ‘do shell script’ that handles all the file deletions as a single batch operation, with progress/completion being communicated back to the main process one way or another. It’ll be fairly clumsy however you do it; neither AppleScript nor Studio make this sort of thing simple or convenient.
Since filesystem deletions can also be handled individually, another option is to handle file deletions one at a time from the main event loop. Stick pending deletions into a queue, then have the application’s idle handler process these queued jobs one at a time. That’ll allow you to do everything from the main thread without blocking other GUI events for a lengthy period. The only disadvantage IIRC is that Studio’s idle handler has a minimum delay of 1 sec; ideally you’d want something like 1/10 sec so deletions are handled fairly snappily. Still, you could compromise by deleting several files at a time; the GUI should remain moderately responsive and file deletion will progress at a reasonable rate.