while(1)
{
wxAutoNSAutoreleasePool pool;
+ /* NOTE: It may be better to use something like
+ NSEventTrackingRunLoopMode since we don't necessarily want all
+ timers/sources/observers to run, only those which would
+ run while tracking events. However, it should be noted that
+ NSEventTrackingRunLoopMode is in the common set of modes
+ so it may not effectively make much of a difference.
+ */
NSEvent *event = [GetNSApplication()
nextEventMatchingMask:NSAnyEventMask
untilDate:[NSDate distantPast]
[GetNSApplication() sendEvent: event];
}
+ /*
+ Because we just told NSApplication to avoid blocking it will in turn
+ run the CFRunLoop with a timeout of 0 seconds. In that case, our
+ run loop observer on kCFRunLoopBeforeWaiting never fires because
+ no waiting occurs. Therefore, no idle events are sent.
+
+ Believe it or not, this is actually desirable because we do not want
+ to process idle from here. However, we do want to process pending
+ events because some user code expects to do work in a thread while
+ the main thread waits and then notify the main thread by posting
+ an event.
+ */
+ ProcessPendingEvents();
+
#if wxUSE_LOG
// let the logs be flashed again
wxLog::Resume();
void wxApp::WakeUpIdle()
{
+ /* When called from the main thread the NSAutoreleasePool managed by
+ the [NSApplication run] method would ordinarily be in place and so
+ one would think a pool here would be unnecessary.
+
+ However, when called from a different thread there is usually no
+ NSAutoreleasePool in place because wxThread has no knowledge of
+ wxCocoa. The pool here is generally only ever going to contain
+ the NSEvent we create with the factory method. As soon as we add
+ it to the main event queue with postEvent:atStart: it is retained
+ and so safe for our pool to release.
+ */
+ wxAutoNSAutoreleasePool pool;
+ /* NOTE: This is a little heavy handed. What this does is cause an
+ AppKit NSEvent to be added to NSApplication's queue (which is always
+ on the main thread). This will cause the main thread runloop to
+ exit which returns control to nextEventMatchingMask which returns
+ the event which is then sent with sendEvent: and essentially dropped
+ since it's not for a window (windowNumber 0) and NSApplication
+ certainly doesn't understand it.
+
+ With the exception of wxEventLoop::Exit which uses us to cause the
+ runloop to exit and return to the NSApplication event loop, most
+ callers only need wx idle to happen, or more specifically only really
+ need to ensure that ProcessPendingEvents is called which is currently
+ done without exiting the runloop.
+
+ Be careful if you decide to change the implementation of this method
+ as wxEventLoop::Exit depends on the current behavior.
+ */
[m_cocoaApp postEvent:[NSEvent otherEventWithType:NSApplicationDefined
location:NSZeroPoint modifierFlags:NSAnyEventMask
timestamp:0 windowNumber:0 context:nil
static int sg_cApplicationWillUpdate = 0;
#endif
+/*!
+ Invoked from the applicationWillUpdate notification observer. See the
+ NSApplication documentation for the official statement on when this
+ will be called. Since it can be hard to understand for a Cocoa newbie
+ I'll try to explain it here as it relates to wxCocoa.
+
+ Basically, we get called from within nextEventMatchingMask if and only
+ if any user code told the application to send the update notification
+ (sort of like a request for idle events). However, unlike wx idle events,
+ this notification is sent quite often, nearly every time through the loop
+ because nearly every control tells the application to send it.
+
+ Because wx idle events are only supposed to be sent when the event loop
+ is about to block we instead schedule a function to be called just
+ before the run loop waits and send the idle events from there.
+
+ It also has the desirable effect of only sending the wx idle events when
+ the event loop is actualy going to block. If the event loop is being
+ pumped manualy (e.g. like a PeekMessage) then the kCFRunLoopBeforeWaiting
+ observer never fires. Our Yield() method depends on this because sending
+ idle events from within Yield would be bad.
+
+ Normally you might think that we could just set the observer up once and
+ leave it attached. However, this is problematic because our run loop
+ observer calls user code (the idle handlers) which can actually display
+ modal dialogs. Displaying a modal dialog causes reentry of the event
+ loop, usually in a different run loop mode than the main loop (e.g. in
+ modal-dialog mode instead of default mode). Because we only register the
+ observer with the run loop mode at the time of this call, it won't be
+ called from a modal loop.
+
+ We want it to be called and thus we need a new observer.
+ */
void wxApp::CocoaDelegate_applicationWillUpdate()
{
wxLogTrace(wxTRACE_COCOA,wxT("applicationWillUpdate"));
CFRunLoopRef cfRunLoop = CFRunLoopGetCurrent();
wxCFRef<CFStringRef> cfRunLoopMode(CFRunLoopCopyCurrentMode(cfRunLoop));
+ /* If we have an observer and that observer is for the wrong run loop
+ mode then invalidate it and release it.
+ */
if(m_cfRunLoopIdleObserver != NULL && m_cfObservedRunLoopMode != cfRunLoopMode)
{
CFRunLoopObserverInvalidate(m_cfRunLoopIdleObserver);
#if 0
++sg_cApplicationWillUpdate;
#endif
+ /* This will be true either on the first call or when the above code has
+ invalidated and released the exisiting observer.
+ */
if(m_cfRunLoopIdleObserver == NULL)
{
// Enable idle event handling
, NULL
, NULL
};
+ /* NOTE: I can't recall why we don't just let the observer repeat
+ instead of invalidating itself each time it fires thus requiring
+ it to be recreated for each shot but there was if I remember
+ some good (but very obscure) reason for it.
+
+ On the other hand, I could be wrong so don't take that as gospel.
+ */
m_cfRunLoopIdleObserver.reset(CFRunLoopObserverCreate(kCFAllocatorDefault, kCFRunLoopBeforeWaiting, /*repeats*/FALSE, /*priority*/0, ObserveMainRunLoopBeforeWaiting, &observerContext));
m_cfObservedRunLoopMode = cfRunLoopMode;
CFRunLoopAddObserver(cfRunLoop, m_cfRunLoopIdleObserver, m_cfObservedRunLoopMode);
#endif
}
+/*!
+ Called by CFRunLoop just before waiting. This is the appropriate time to
+ send idle events. Unlike other ports, we don't peek the queue for events
+ and stop idling if there is one. Instead, if the user requests more idle
+ events we tell Cocoa to send us an applicationWillUpdate notification
+ which will cause our observer of that notification to tell CFRunLoop to
+ call us before waiting which will cause us to be fired again but only
+ after exhausting the event queue.
+
+ The reason we do it this way is that peeking for an event causes CFRunLoop
+ to reenter and fire off its timers, observers, and sources which we're
+ better off avoiding. Doing it this way, we basically let CFRunLoop do the
+ work of peeking for the next event which is much nicer.
+ */
void wxApp::CF_ObserveMainRunLoopBeforeWaiting(CFRunLoopObserverRef observer, int activity)
{
- // Ensure that the app knows we've been invalidated
+ // Ensure that CocoaDelegate_applicationWillUpdate will recreate us.
+ // We've already been invalidated by CFRunLoop because we are one-shot.
m_cfRunLoopIdleObserver.reset();
#if 0
wxLogTrace(wxTRACE_COCOA,wxT("Idle BEGIN (%d)"), sg_cApplicationWillUpdate);
m_isInAssert = false;
}
#endif // __WXDEBUG__
+
+/* A note about Cocoa's event loops vs. run loops:
+
+ It's important to understand that Cocoa has a two-level event loop. The
+ outer level is run by NSApplication and can only ever happen on the main
+ thread. The nextEventMatchingMask:untilDate:inMode:dequeue: method returns
+ the next event which is then given to sendEvent: to send it. These
+ methods are defined in NSApplication and are thus part of AppKit.
+
+ Events (NSEvent) are only sent due to actual user actions like clicking
+ the mouse or moving the mouse or pressing a key and so on. There are no
+ paint events; there are no timer events; there are no socket events; there
+ are no idle events.
+
+ All of those types of "events" have nothing to do with the GUI at all.
+ That is why Cocoa's AppKit doesn't implement them. Instead, they are
+ implemented in Foundation's NSRunLoop which on OS X uses CFRunLoop
+ to do the actual work.
+
+ How NSApplication uses NSRunLoop is rather interesting. Basically, it
+ interacts with NSRunLoop only from within the nextEventMatchingMask
+ method. It passes its inMode: argument almost directly to NSRunLoop
+ and thus CFRunLoop. The run loop then runs (e.g. loops) until it
+ is told to exit. The run loop calls the callout functions directly.
+ From within those callout functions the run loop is considered to
+ be running. Presumably, the AppKit installs a run loop source to
+ receive messages from the window server over the mach port (like a
+ socket). For some messages (e.g. need to paint) the AppKit will
+ call application code like drawRect: without exiting the run loop.
+ For other messages (ones that can be encapsulated in an NSEvent)
+ the AppKit tells the run loop to exit which returns control to
+ the nextEventMatchingMask method which then returns the NSEvent
+ object. It's important to note that once the runloop has exited
+ it is no longer considered running and thus if you ask it which
+ mode it is running in it will return nil.
+
+ When manually pumping the event loop care should be taken to
+ tell it to run in the correct mode. For instance, if you are
+ using it to run a modal dialog then you want to run it in
+ the modal panel run loop mode. AppKit presumably has sources
+ or timers or observers that specifically don't listen on this
+ mode. Another interesting mode is the connection reply mode.
+ This allows Cocoa to wait for a response from a distributed
+ objects message without firing off user code that may result
+ in a DO call being made thus recursing. So basically, the
+ mode is a way for Cocoa to attempt to avoid run loop recursion
+ but to allow it under certain circumstances.
+ */
+
projects / wxWidgets.git / commitdiff
