X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/e22958052da57d397f8b972f949fd80bfc678388..3e1924dd5f5744c3e2a8973de9b3e4f372b7fd85:/src/cocoa/app.mm?ds=sidebyside diff --git a/src/cocoa/app.mm b/src/cocoa/app.mm index 89a375eb1a..444cccfb89 100644 --- a/src/cocoa/app.mm +++ b/src/cocoa/app.mm @@ -1,138 +1,115 @@ ///////////////////////////////////////////////////////////////////////////// -// Name: cocoa/app.mm +// Name: src/cocoa/app.mm // Purpose: wxApp // Author: David Elliott // Modified by: // Created: 2002/11/27 // RCS-ID: $Id$ // Copyright: (c) David Elliott -// Licence: wxWindows licence +// Software 2000 Ltd. +// Licence: wxWidgets licence ///////////////////////////////////////////////////////////////////////////// -// ============================================================================ -// declarations -// ============================================================================ +#include "wx/wxprec.h" -// ---------------------------------------------------------------------------- -// headers -// ---------------------------------------------------------------------------- +#include "wx/app.h" -#include "wx/wxprec.h" #ifndef WX_PRECOMP - #include "wx/defs.h" - #include "wx/app.h" - #include "wx/frame.h" - #include "wx/dialog.h" - #include "wx/dc.h" #include "wx/intl.h" #include "wx/log.h" + #include "wx/module.h" #endif -#include "wx/module.h" - -#include "wx/cocoa/ObjcPose.h" +#include "wx/cocoa/ObjcRef.h" #include "wx/cocoa/autorelease.h" +#include "wx/cocoa/mbarman.h" +#include "wx/cocoa/NSApplication.h" -#if wxUSE_WX_RESOURCES -# include "wx/resource.h" -#endif +#include "wx/cocoa/dc.h" #import #import -#import -#import +#import +#import +#import +#import +#import -// ---------------------------------------------------------------------------- -// globals -// ---------------------------------------------------------------------------- +bool wxApp::sm_isEmbedded = false; // Normally we're not a plugin + +// wxNSApplicationObserver singleton. +static wxObjcAutoRefFromAlloc sg_cocoaAppObserver = [[WX_GET_OBJC_CLASS(wxNSApplicationObserver) alloc] init]; -wxPoseAsInitializer *wxPoseAsInitializer::sm_first = NULL; +// ======================================================================== +// wxNSApplicationDelegate +// ======================================================================== +@implementation wxNSApplicationDelegate : NSObject -@interface wxPoserNSApplication : NSApplication +// NOTE: Terminate means that the event loop does NOT return and thus +// cleanup code doesn't properly execute. Furthermore, wxWidgets has its +// own exit on frame delete mechanism. +- (BOOL)applicationShouldTerminateAfterLastWindowClosed:(NSApplication *)theApplication { + return NO; } -- (void)doIdle: (id)data; -- (void)sendEvent: (NSEvent*)anEvent; -- (BOOL)applicationShouldTerminateAfterLastWindowClosed:(NSApplication *)theApplication; -@end // wxPoserNSApplication +@end // implementation wxNSApplicationDelegate : NSObject +WX_IMPLEMENT_GET_OBJC_CLASS(wxNSApplicationDelegate,NSObject) -@implementation wxPoserNSApplication : NSApplication +// ======================================================================== +// wxNSApplicationObserver +// ======================================================================== +@implementation wxNSApplicationObserver : NSObject -- (void)doIdle: (id)data +- (void)applicationWillBecomeActive:(NSNotification *)notification { - wxASSERT(wxTheApp); - wxLogDebug("doIdle called"); - NSRunLoop *rl = [NSRunLoop currentRunLoop]; - // runMode: beforeDate returns YES if something was done - while(wxTheApp->ProcessIdle()) // FIXME: AND NO EVENTS ARE PENDING - { - wxLogDebug("Looping for idle events"); - #if 1 - if( [rl runMode:[rl currentMode] beforeDate:[NSDate distantPast]]) - { - wxLogDebug("Found actual work to do"); - break; - } - #endif - } - wxLogDebug("Idle processing complete, requesting next idle event"); - // Add ourself back into the run loop (on next event) if necessary - wxTheApp->CocoaRequestIdle(); + wxTheApp->CocoaDelegate_applicationWillBecomeActive(); } -- (void)sendEvent: (NSEvent*)anEvent +- (void)applicationDidBecomeActive:(NSNotification *)notification { - wxLogDebug("SendEvent"); - wxTheApp->CocoaInstallRequestedIdleHandler(); - [super sendEvent: anEvent]; + wxTheApp->CocoaDelegate_applicationDidBecomeActive(); } -- (BOOL)applicationShouldTerminateAfterLastWindowClosed:(NSApplication *)theApplication +- (void)applicationWillResignActive:(NSNotification *)notification { - BOOL ret = wxTheApp->GetExitOnFrameDelete(); - wxLogDebug("applicationShouldTermintaeAfterLastWindowClosed=%d",ret); - return ret; + wxTheApp->CocoaDelegate_applicationWillResignActive(); } -@end // wxPoserNSApplication -WX_IMPLEMENT_POSER(wxPoserNSApplication); - -// ============================================================================ -// functions -// ============================================================================ +- (void)applicationDidResignActive:(NSNotification *)notification +{ + wxTheApp->CocoaDelegate_applicationDidResignActive(); +} -void wxApp::Exit() +- (void)applicationWillUpdate:(NSNotification *)notification; { - wxApp::CleanUp(); + wxTheApp->CocoaDelegate_applicationWillUpdate(); +} - wxAppConsole::Exit(); +- (void)controlTintChanged:(NSNotification *)notification +{ + wxLogDebug(wxT("TODO: send EVT_SYS_COLOUR_CHANGED as appropriate")); } -// ============================================================================ -// wxApp implementation -// ============================================================================ +@end // implementation wxNSApplicationObserver : NSObject +WX_IMPLEMENT_GET_OBJC_CLASS(wxNSApplicationObserver,NSObject) + +// ======================================================================== +// wxApp +// ======================================================================== // ---------------------------------------------------------------------------- // wxApp Static member initialization // ---------------------------------------------------------------------------- - -#if !USE_SHARED_LIBRARY IMPLEMENT_DYNAMIC_CLASS(wxApp, wxEvtHandler) -BEGIN_EVENT_TABLE(wxApp, wxEvtHandler) - EVT_IDLE(wxAppBase::OnIdle) -// EVT_END_SESSION(wxApp::OnEndSession) -// EVT_QUERY_END_SESSION(wxApp::OnQueryEndSession) -END_EVENT_TABLE() -#endif // ---------------------------------------------------------------------------- // wxApp initialization/cleanup // ---------------------------------------------------------------------------- - bool wxApp::Initialize(int& argc, wxChar **argv) { wxAutoNSAutoreleasePool pool; + m_cocoaMainThread = [NSThread currentThread]; // Mac OS X passes a process serial number command line argument when // the application is launched from the Finder. This argument must be // removed from the command line arguments before being handled by the @@ -140,23 +117,62 @@ bool wxApp::Initialize(int& argc, wxChar **argv) if ( argc > 1 ) { static const wxChar *ARG_PSN = _T("-psn_"); - if ( wxStrncmp(argv[1], ARG_PSN, sizeof(ARG_PSN) - 1) == 0 ) + if ( wxStrncmp(argv[1], ARG_PSN, wxStrlen(ARG_PSN)) == 0 ) { // remove this argument - memmove(argv, argv + 1, argc--); + --argc; + memmove(argv + 1, argv + 2, argc * sizeof(wxChar *)); } } - // Posing must be completed before any instances of the Objective-C - // classes being posed as are created. - wxPoseAsInitializer::InitializePosers(); + /* + Cocoa supports -Key value options which set the user defaults key "Key" + to the value "value" Some of them are very handy for debugging like + -NSShowAllViews YES. Cocoa picks these up from the real argv so + our removal of them from the wx copy of it does not affect Cocoa's + ability to see them. + + We basically just assume that any "-NS" option and its following + argument needs to be removed from argv. We hope that user code does + not expect to see -NS options and indeed it's probably a safe bet + since most user code accepting options is probably using the + double-dash GNU-style syntax. + */ + for(int i=1; i < argc; ++i) + { + static const wxChar *ARG_NS = wxT("-NS"); + static const int ARG_NS_LEN = wxStrlen(ARG_NS); + if( wxStrncmp(argv[i], ARG_NS, ARG_NS_LEN) == 0 ) + { + // Only eat this option if it has an argument + if( (i + 1) < argc ) + { + argc -= 2; + memmove(argv + i, argv + i + 2, argc * sizeof(wxChar*)); + // drop back one position so the next run through the loop + // reprocesses the argument at our current index. + --i; + } + } + } return wxAppBase::Initialize(argc, argv); } void wxApp::CleanUp() { - wxDC::CocoaShutdownTextSystem(); + wxAutoNSAutoreleasePool pool; + + wxCocoaDCImpl::CocoaShutdownTextSystem(); + wxMenuBarManager::DestroyInstance(); + + [[NSNotificationCenter defaultCenter] removeObserver:sg_cocoaAppObserver]; + if(!sm_isEmbedded) + { + [m_cocoaApp setDelegate:nil]; + [m_cocoaAppDelegate release]; + m_cocoaAppDelegate = NULL; + } wxAppBase::CleanUp(); } @@ -164,107 +180,121 @@ void wxApp::CleanUp() // ---------------------------------------------------------------------------- // wxApp creation // ---------------------------------------------------------------------------- - wxApp::wxApp() { m_topWindow = NULL; - m_isIdle = true; -#if WXWIN_COMPATIBILITY_2_2 - m_wantDebugOutput = TRUE; -#endif +#ifdef __WXDEBUG__ + m_isInAssert = false; +#endif // __WXDEBUG__ argc = 0; +#if !wxUSE_UNICODE argv = NULL; +#endif m_cocoaApp = NULL; + m_cocoaAppDelegate = NULL; +} + +void wxApp::CocoaDelegate_applicationWillBecomeActive() +{ +} + +void wxApp::CocoaDelegate_applicationDidBecomeActive() +{ +} + +void wxApp::CocoaDelegate_applicationWillResignActive() +{ + wxTopLevelWindowCocoa::DeactivatePendingWindow(); } -void wxApp::CocoaInstallIdleHandler() +void wxApp::CocoaDelegate_applicationDidResignActive() { - // If we're supposed to be stopping, don't add more idle events - if(![m_cocoaApp isRunning]) - return; - wxLogDebug("wxApp::CocoaInstallIdleHandler"); - m_isIdle = false; - // Call doIdle for EVERYTHING dammit -// We'd need Foundation/NSConnection.h for this next constant, do we need it? - [[ NSRunLoop currentRunLoop ] performSelector:@selector(doIdle:) target:m_cocoaApp argument:NULL order:0 modes:[NSArray arrayWithObjects:NSDefaultRunLoopMode, /* NSConnectionReplyRunLoopMode,*/ NSModalPanelRunLoopMode, /**/NSEventTrackingRunLoopMode,/**/ nil] ]; } bool wxApp::OnInitGui() { wxAutoNSAutoreleasePool pool; if(!wxAppBase::OnInitGui()) - return FALSE; + return false; // Create the app using the sharedApplication method m_cocoaApp = [NSApplication sharedApplication]; - wxDC::CocoaInitializeTextSystem(); -// [ m_cocoaApp setDelegate:m_cocoaApp ]; - #if 0 - wxLogDebug("Just for kicks"); - [ m_cocoaApp performSelector:@selector(doIdle:) withObject:NULL ]; - wxLogDebug("okay.. done now"); - #endif - return TRUE; -} -bool wxApp::CallOnInit() -{ -// wxAutoNSAutoreleasePool pool; - return OnInit(); -} + if(!sm_isEmbedded) + { + // Enable response to application delegate messages + m_cocoaAppDelegate = [[WX_GET_OBJC_CLASS(wxNSApplicationDelegate) alloc] init]; + [m_cocoaApp setDelegate:m_cocoaAppDelegate]; + } -bool wxApp::OnInit() -{ - if(!wxAppBase::OnInit()) - return FALSE; + // Enable response to "delegate" messages on the notification observer + [[NSNotificationCenter defaultCenter] addObserver:sg_cocoaAppObserver + selector:@selector(applicationWillBecomeActive:) + name:NSApplicationWillBecomeActiveNotification object:nil]; - return TRUE; -} + [[NSNotificationCenter defaultCenter] addObserver:sg_cocoaAppObserver + selector:@selector(applicationDidBecomeActive:) + name:NSApplicationDidBecomeActiveNotification object:nil]; -bool wxApp::Initialized() -{ - if (GetTopWindow()) - return TRUE; - else - return FALSE; + [[NSNotificationCenter defaultCenter] addObserver:sg_cocoaAppObserver + selector:@selector(applicationWillResignActive:) + name:NSApplicationWillResignActiveNotification object:nil]; + + [[NSNotificationCenter defaultCenter] addObserver:sg_cocoaAppObserver + selector:@selector(applicationDidResignActive:) + name:NSApplicationDidResignActiveNotification object:nil]; + + [[NSNotificationCenter defaultCenter] addObserver:sg_cocoaAppObserver + selector:@selector(applicationWillUpdate:) + name:NSApplicationWillUpdateNotification object:nil]; + + // Enable response to system notifications + [[NSNotificationCenter defaultCenter] addObserver:sg_cocoaAppObserver + selector:@selector(controlTintChanged:) + name:NSControlTintDidChangeNotification object:nil]; + + if(!sm_isEmbedded) + wxMenuBarManager::CreateInstance(); + + wxCocoaDCImpl::CocoaInitializeTextSystem(); + return true; } -int wxApp::MainLoop() +wxApp::~wxApp() { - [m_cocoaApp run]; - return 0; + if(m_cfRunLoopIdleObserver != NULL) + { + // Invalidate the observer which also removes it from the run loop. + CFRunLoopObserverInvalidate(m_cfRunLoopIdleObserver); + // Release the ref as we don't need it anymore. + m_cfRunLoopIdleObserver.reset(); + } } -void wxApp::ExitMainLoop() +bool wxApp::CallOnInit() { - wxLogDebug("wxApp::ExitMailLoop m_isIdle=%d, isRunning=%d",(int)m_isIdle,(int)[m_cocoaApp isRunning]); -// CocoaInstallRequestedIdleHandler(); -// if(m_isIdle) -// [[ NSRunLoop currentRunLoop ] performSelector:@selector(doIdle:) target:m_cocoaApp argument:NULL order:0 modes:[NSArray arrayWithObjects:NSDefaultRunLoopMode, /* NSConnectionReplyRunLoopMode, NSModalPanelRunLoopMode, NSEventTrackingRunLoopMode,*/ nil] ]; -// actually.. we WANT the idle event -// or not -#if 0 - if(!m_isIdle) - [[ NSRunLoop currentRunLoop ] cancelPerformSelector:@selector(doIdle:) target:m_cocoaApp argument:NULL]; -#endif - [m_cocoaApp stop: m_cocoaApp]; +// wxAutoNSAutoreleasePool pool; + return OnInit(); } -// Is a message/event pending? -bool wxApp::Pending() +bool wxApp::OnInit() { - return 0; + if(!wxAppBase::OnInit()) + return false; + + return true; } -// Dispatch a message. -void wxApp::Dispatch() +void wxApp::Exit() { + wxApp::CleanUp(); + + wxAppConsole::Exit(); } // Yield to other processes - bool wxApp::Yield(bool onlyIfNeeded) { // MT-FIXME @@ -288,8 +318,40 @@ bool wxApp::Yield(bool onlyIfNeeded) s_inYield = true; - wxLogDebug("WARNING: SUPPOSED to have yielded!"); - // FIXME: Do something! + // Run the event loop until it is out of events + 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] + inMode:NSDefaultRunLoopMode + dequeue: YES]; + if(!event) + break; + [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 @@ -301,3 +363,232 @@ bool wxApp::Yield(bool onlyIfNeeded) return true; } +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 + subtype:0 data1:0 data2:0] atStart:NO]; +} + +extern "C" static void ObserveMainRunLoopBeforeWaiting(CFRunLoopObserverRef observer, CFRunLoopActivity activity, void *info); +extern "C" static void ObserveMainRunLoopBeforeWaiting(CFRunLoopObserverRef observer, CFRunLoopActivity activity, void *info) +{ + static_cast(info)->CF_ObserveMainRunLoopBeforeWaiting(observer, activity); +} + +#if 0 +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 = [[NSRunLoop currentRunLoop] getCFRunLoop]; + CFRunLoopRef cfRunLoop = CFRunLoopGetCurrent(); + wxCFRef 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); + m_cfRunLoopIdleObserver.reset(); + } +#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 + CFRunLoopObserverContext observerContext = + { 0 + , this + , NULL + , 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); + } +} + +static inline bool FakeNeedMoreIdle() +{ +#if 0 +// Return true on every 10th call. + static int idleCount = 0; + return ++idleCount % 10; +#else + return false; +#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 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); + sg_cApplicationWillUpdate = 0; +#else + wxLogTrace(wxTRACE_COCOA,wxT("Idle BEGIN")); +#endif + if( ProcessIdle() || FakeNeedMoreIdle() ) + { + wxLogTrace(wxTRACE_COCOA, wxT("Idle REQUEST MORE")); + [NSApp setWindowsNeedUpdate:YES]; + } + else + { + wxLogTrace(wxTRACE_COCOA, wxT("Idle END")); + } +} + +#ifdef __WXDEBUG__ +void wxApp::OnAssert(const wxChar *file, int line, const wxChar* cond, const wxChar *msg) +{ + m_isInAssert = true; + wxAppBase::OnAssert(file, line, cond, msg); + 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. + */ +