OSX fix empty message queue handling

For some (unknown) reason [NSApp postEvent: ... atStart: NO]
doesn't append the event, if the message queue is empty
(AKA [NSApp nextEventMatchingMask .. ] returns nil).
Due to nextEventMatchingMask usage, these postEvents have to
run in the main thread.

Using performSelectorOnMainThread deadlocks, since the calling
thread may have locked the Yield mutex, so we simply defer the
call using an NSEvent, like the Windows backend.

So we have to peek at the queue and if it's empty simply prepend
the event using [.. atStart: YES].

In the end this make the vcl_timer unit test pass on OSX.

Change-Id: Ib41186425b2f76faa0e9f116f47fdcd60d878099

1 files changed, 16 insertions, 2 deletions

diff --git a/vcl/inc/osx/saltimer.h b/vcl/inc/osx/saltimer.h
index f9a6acb7a02f..86964115d648 100644
--- a/vcl/inc/osx/saltimer.h
+++ b/vcl/inc/osx/saltimer.h
@@ -26,10 +26,24 @@
 
 #include "saltimer.hxx"
 
-class AquaSalTimer : public SalTimer
+/**
+ * if NO == bAtStart, then it has to be run in the main thread,
+ * e.g. via performSelectorOnMainThread!
+ **/
+void ImplNSAppPostEvent( short nEventId, BOOL bAtStart, int nUserData = 0 );
+
+class ReleasePoolHolder
 {
-  public:
+    NSAutoreleasePool* mpPool;
+
+public:
+    ReleasePoolHolder() : mpPool( [[NSAutoreleasePool alloc] init] ) {}
+    ~ReleasePoolHolder() { [mpPool release]; }
+};
 
+class AquaSalTimer : public SalTimer
+{
+public:
     AquaSalTimer();
     virtual ~AquaSalTimer() override;