throw no more handles if a timer could not be created

[jonahgraham]

At the moment the code silently fails on calling timerExec if there are no handles left or it fails for other reasons.

Relates to #2806 where we can see that we are running out of handles, but the timerExec does not report a failure.

[jonahgraham]

This is a draft for now because it needs consideration for other platforms and whether after 25 years there is a reason that this case was allowed to fail silently on Windows.

On macOS there is a pointless null check in the same place because an NPE would have already been raised. On GTK I need to investigate more because the functions are not documented as being able to fail.

macOS:

eclipse.platform.swt/bundles/org.eclipse.swt/Eclipse SWT/cocoa/org/eclipse/swt/widgets/Display.java

Lines 5381 to 5390 in bb954ac

	NSTimer timer = NSTimer.scheduledTimerWithTimeInterval(milliseconds / 1000.0, timerDelegate, OS.sel_timerProc_, userInfo, false);
	NSRunLoop runLoop = NSRunLoop.currentRunLoop();
	runLoop.addTimer(timer, OS.NSModalPanelRunLoopMode);
	runLoop.addTimer(timer, OS.NSEventTrackingRunLoopMode);
	timer.retain();
	if (timer != null) {
	nsTimers [index] = timer;
	timerList [index] = runnable;
	}
	}

GTK:

eclipse.platform.swt/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Display.java

Lines 5750 to 5759 in 286e614

	if (GTK.GTK4) {
	timerId = OS.g_timeout_add (milliseconds, timerProc, index);
	} else {
	timerId = GDK.gdk_threads_add_timeout (milliseconds, timerProc, index);
	}
	if (timerId != 0) {
	timerIds [index] = timerId;
	timerList [index] = runnable;
	}
	}

[github-actions]

Test Results

  176 files  ±0    176 suites  ±0   29m 29s ⏱️ + 1m 32s
4 680 tests ±0  4 658 ✅ ±0  22 💤 ±0  0 ❌ ±0 
  485 runs  ±0    479 ✅ ±0   6 💤 ±0  0 ❌ ±0 

Results for commit 34e35bb. ± Comparison against base commit c6ec34e.

♻️ This comment has been updated with latest results.

[jonahgraham]

This is a draft for now because it needs consideration for other platforms and whether after 25 years there is a reason that this case was allowed to fail silently on Windows.

On macOS there is a pointless null check in the same place because an NPE would have already been raised. On GTK I need to investigate more because the functions are not documented as being able to fail.

My latest commit adds throwing no more handles on macos and gtk if the timer creation routines return 0/null so they also don't silently fail anymore.

I plan to submit this soon if there are no objections.