[Vm-dev] OSX VM doesn't generate events for modifier keypresses (shift, ctrl, etc)

[Ben Coman]

AliakseiSyrel reported that the OSX VM doesn't generate events on 
shift/ctrl/command/options/capslock keypress, but Win32 and Linux do.
(https://pharo.fogbugz.com/default.asp?14521)

I've submitted a fix to pharo-vm, but thought it might also be useful to 
others, and was hoping for some review and discussion here...
A diff can be seen here...
https://github.com/pharo-project/pharo-vm/pull/67/files

I discovered "recordCharEvent:fromView:" and "keyDown:" do not receive 
modifier keypresses, however "flagsChanged:" does - as described by the 
AppKit Reference "flagsChanged: informs the receiver that the user has 
pressed or released a modifier key (Shift, Control, and so on)."

Just above "flagsChanged:" I noticed...
     -(void)keyUp:(NSEvent*)theEvent {
         [(sqSqueakOSXApplication *) gDelegateApp.squeakApplication
             recordKeyUpEvent: theEvent fromView: self];
     }

So I duplicated recordKeyUpEvent:fromView:
as recordKeyDownEvent:fromView:
changing only...
         evt.pressCode = EventKeyUp;
to...
         evt.pressCode = EventKeyDown;

and called it from the bottom of flagsChanged:

============
Now in a test image, adding a debug Transcript after primGetNextEvent:
     InputEventFetcher>>eventLoop
         ...
     [true] whileTrue: [
         self waitForInput.
         [self primGetNextEvent: eventBuffer.
             Transcript crShow: Time now ; tab ; show: eventBuffer.

shows...

11:41:18.9594 pm    #(2 182714 56 1 1 0 0 1) Shift down
11:41:18.959581 pm    #(0 0 0 0 0 0 0 0)
11:41:19.19321 pm    #(2 182948 56 1 0 0 0 1) Shift up
11:41:19.193543 pm    #(0 0 0 0 0 0 0 0)
11:41:21.04326 pm    #(2 184798 59 1 2 0 0 1) Control down
11:41:21.043494 pm    #(0 0 0 0 0 0 0 0)
11:41:21.346713 pm    #(2 185102 59 1 0 0 0 1) Control up
11:41:21.346934 pm    #(0 0 0 0 0 0 0 0)
11:41:21.814845 pm    #(2 185569 58 1 4 0 0 1) Option down
11:41:21.815136 pm    #(0 0 0 0 0 0 0 0)
11:41:22.137117 pm    #(2 185892 58 1 0 0 0 1) Option up
11:41:22.137374 pm    #(0 0 0 0 0 0 0 0)
11:43:28.593666 pm    #(2 312348 55 1 8 0 0 1) Cmd down
11:43:28.593854 pm    #(0 0 0 0 0 0 0 0)
11:43:29.014829 pm    #(2 312770 55 1 0 0 0 1) Cmd up
11:43:29.015011 pm    #(0 0 0 0 0 0 0 0)
11:41:43.762799 pm    #(2 207517 57 1 0 0 0 1) CapsLock down

CapsLock does not get a up-event per...
https://bugzilla.mozilla.org/show_bug.cgi?id=259059

It perhaps can be simulated like...
https://developer.apple.com/library/mac/qa/qa1519/_index.html

Thoughts?