The Tor Browser: widget/cocoa/nsAppShell.mm@6474c204b198 (annotated)

widget/cocoa/nsAppShell.mm@6474c204b198 (annotated)

widget/cocoa/nsAppShell.mm

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* -*- Mode: c++; tab-width: 2; indent-tabs-mode: nil; -*- */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 /*
  * Runs the main native Cocoa run loop, interrupting it as needed to process
  * Gecko events.
  */
 #import <Cocoa/Cocoa.h>
 #include <dlfcn.h>
 #include "CustomCocoaEvents.h"
 #include "mozilla/WidgetTraceEvent.h"
 #include "nsAppShell.h"
 #include "nsCOMPtr.h"
 #include "nsIFile.h"
 #include "nsDirectoryServiceDefs.h"
 #include "nsString.h"
 #include "nsIRollupListener.h"
 #include "nsIWidget.h"
 #include "nsThreadUtils.h"
 #include "nsIWindowMediator.h"
 #include "nsServiceManagerUtils.h"
 #include "nsIInterfaceRequestor.h"
 #include "nsIWebBrowserChrome.h"
 #include "nsObjCExceptions.h"
 #include "nsCocoaFeatures.h"
 #include "nsCocoaUtils.h"
 #include "nsChildView.h"
 #include "nsToolkit.h"
 #include "TextInputHandler.h"
 #include "mozilla/HangMonitor.h"
 #include "GeckoProfiler.h"
 #include "pratom.h"
 #include "npapi.h"
 using namespace mozilla::widget;
 // defined in nsCocoaWindow.mm
 extern int32_t             gXULModalLevel;
 static bool gAppShellMethodsSwizzled = false;
 // List of current Cocoa app-modal windows (nested if more than one).
 nsCocoaAppModalWindowList *gCocoaAppModalWindowList = NULL;
 // Push a Cocoa app-modal window onto the top of our list.
 nsresult nsCocoaAppModalWindowList::PushCocoa(NSWindow *aWindow, NSModalSession aSession)
 {
   NS_ENSURE_STATE(aWindow && aSession);
   mList.AppendElement(nsCocoaAppModalWindowListItem(aWindow, aSession));
   return NS_OK;
 }
 // Pop the topmost Cocoa app-modal window off our list.  aWindow and aSession
 // are just used to check that it's what we expect it to be.
 nsresult nsCocoaAppModalWindowList::PopCocoa(NSWindow *aWindow, NSModalSession aSession)
 {
   NS_ENSURE_STATE(aWindow && aSession);
   for (int i = mList.Length(); i > 0; --i) {
     nsCocoaAppModalWindowListItem &item = mList.ElementAt(i - 1);
     if (item.mSession) {
       NS_ASSERTION((item.mWindow == aWindow) && (item.mSession == aSession),
                    "PopCocoa() called without matching call to PushCocoa()!");
       mList.RemoveElementAt(i - 1);
       return NS_OK;
     }
   }
   NS_ERROR("PopCocoa() called without matching call to PushCocoa()!");
   return NS_ERROR_FAILURE;
 }
 // Push a Gecko-modal window onto the top of our list.
 nsresult nsCocoaAppModalWindowList::PushGecko(NSWindow *aWindow, nsCocoaWindow *aWidget)
 {
   NS_ENSURE_STATE(aWindow && aWidget);
   mList.AppendElement(nsCocoaAppModalWindowListItem(aWindow, aWidget));
   return NS_OK;
 }
 // Pop the topmost Gecko-modal window off our list.  aWindow and aWidget are
 // just used to check that it's what we expect it to be.
 nsresult nsCocoaAppModalWindowList::PopGecko(NSWindow *aWindow, nsCocoaWindow *aWidget)
 {
   NS_ENSURE_STATE(aWindow && aWidget);
   for (int i = mList.Length(); i > 0; --i) {
     nsCocoaAppModalWindowListItem &item = mList.ElementAt(i - 1);
     if (item.mWidget) {
       NS_ASSERTION((item.mWindow == aWindow) && (item.mWidget == aWidget),
                    "PopGecko() called without matching call to PushGecko()!");
       mList.RemoveElementAt(i - 1);
       return NS_OK;
     }
   }
   NS_ERROR("PopGecko() called without matching call to PushGecko()!");
   return NS_ERROR_FAILURE;
 }
 // The "current session" is normally the "session" corresponding to the
 // top-most Cocoa app-modal window (both on the screen and in our list).
 // But because Cocoa app-modal dialog can be "interrupted" by a Gecko-modal
 // dialog, the top-most Cocoa app-modal dialog may already have finished
 // (and no longer be visible).  In this case we need to check the list for
 // the "next" visible Cocoa app-modal window (and return its "session"), or
 // (if no Cocoa app-modal window is visible) return nil.  This way we ensure
 // (as we need to) that all nested Cocoa app-modal sessions are dealt with
 // before we get to any Gecko-modal session(s).  See nsAppShell::
 // ProcessNextNativeEvent() below.
 NSModalSession nsCocoaAppModalWindowList::CurrentSession()
 {
   if (![NSApp _isRunningAppModal])
     return nil;
   NSModalSession currentSession = nil;
   for (int i = mList.Length(); i > 0; --i) {
     nsCocoaAppModalWindowListItem &item = mList.ElementAt(i - 1);
     if (item.mSession && [item.mWindow isVisible]) {
       currentSession = item.mSession;
       break;
     }
   }
   return currentSession;
 }
 // Has a Gecko modal dialog popped up over a Cocoa app-modal dialog?
 bool nsCocoaAppModalWindowList::GeckoModalAboveCocoaModal()
 {
   if (mList.IsEmpty())
     return false;
   nsCocoaAppModalWindowListItem &topItem = mList.ElementAt(mList.Length() - 1);
   return (topItem.mWidget != nullptr);
 }
 @implementation GeckoNSApplication
 - (void)sendEvent:(NSEvent *)anEvent
 {
   mozilla::HangMonitor::NotifyActivity();
   if ([anEvent type] == NSApplicationDefined &&
       [anEvent subtype] == kEventSubtypeTrace) {
     mozilla::SignalTracerThread();
     return;
   }
   [super sendEvent:anEvent];
 }
 - (NSEvent*)nextEventMatchingMask:(NSUInteger)mask
                         untilDate:(NSDate*)expiration
                            inMode:(NSString*)mode
                           dequeue:(BOOL)flag
 {
   if (expiration) {
     mozilla::HangMonitor::Suspend();
   }
   return [super nextEventMatchingMask:mask
           untilDate:expiration inMode:mode dequeue:flag];
 }
 @end
 // AppShellDelegate
 //
 // Cocoa bridge class.  An object of this class is registered to receive
 // notifications.
 //
 @interface AppShellDelegate : NSObject
 {
   @private
     nsAppShell* mAppShell;
 }
 - (id)initWithAppShell:(nsAppShell*)aAppShell;
 - (void)applicationWillTerminate:(NSNotification*)aNotification;
 - (void)beginMenuTracking:(NSNotification*)aNotification;
 @end
 // nsAppShell implementation
 NS_IMETHODIMP
 nsAppShell::ResumeNative(void)
 {
   nsresult retval = nsBaseAppShell::ResumeNative();
   if (NS_SUCCEEDED(retval) && (mSuspendNativeCount == 0) &&
       mSkippedNativeCallback)
   {
     mSkippedNativeCallback = false;
     ScheduleNativeEventCallback();
   }
   return retval;
 }
 nsAppShell::nsAppShell()
 : mAutoreleasePools(nullptr)
 , mDelegate(nullptr)
 , mCFRunLoop(NULL)
 , mCFRunLoopSource(NULL)
 , mRunningEventLoop(false)
 , mStarted(false)
 , mTerminated(false)
 , mSkippedNativeCallback(false)
 , mHadMoreEventsCount(0)
 , mRecursionDepth(0)
 , mNativeEventCallbackDepth(0)
 , mNativeEventScheduledDepth(0)
 {
   // A Cocoa event loop is running here if (and only if) we've been embedded
   // by a Cocoa app (like Camino).
   mRunningCocoaEmbedded = [NSApp isRunning] ? true : false;
 }
 nsAppShell::~nsAppShell()
 {
   NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
   if (mCFRunLoop) {
     if (mCFRunLoopSource) {
       ::CFRunLoopRemoveSource(mCFRunLoop, mCFRunLoopSource,
                               kCFRunLoopCommonModes);
       ::CFRelease(mCFRunLoopSource);
     }
     ::CFRelease(mCFRunLoop);
   }
   if (mAutoreleasePools) {
     NS_ASSERTION(::CFArrayGetCount(mAutoreleasePools) == 0,
                  "nsAppShell destroyed without popping all autorelease pools");
     ::CFRelease(mAutoreleasePools);
   }
   [mDelegate release];
   NS_OBJC_END_TRY_ABORT_BLOCK
 }
 // An undocumented CoreGraphics framework method, present in the same form
 // since at least OS X 10.5.
 extern "C" CGError CGSSetDebugOptions(int options);
 // Init
 //
 // Loads the nib (see bug 316076c21) and sets up the CFRunLoopSource used to
 // interrupt the main native run loop.
 //
 // public
 nsresult
 nsAppShell::Init()
 {
   NS_OBJC_BEGIN_TRY_ABORT_BLOCK_NSRESULT;
   // No event loop is running yet (unless Camino is running, or another
   // embedding app that uses NSApplicationMain()).
   NSAutoreleasePool* localPool = [[NSAutoreleasePool alloc] init];
   // mAutoreleasePools is used as a stack of NSAutoreleasePool objects created
   // by |this|.  CFArray is used instead of NSArray because NSArray wants to
   // retain each object you add to it, and you can't retain an
   // NSAutoreleasePool.
   mAutoreleasePools = ::CFArrayCreateMutable(nullptr, 0, nullptr);
   NS_ENSURE_STATE(mAutoreleasePools);
   // Get the path of the nib file, which lives in the GRE location
   nsCOMPtr<nsIFile> nibFile;
   nsresult rv = NS_GetSpecialDirectory(NS_GRE_DIR, getter_AddRefs(nibFile));
   NS_ENSURE_SUCCESS(rv, rv);
   nibFile->AppendNative(NS_LITERAL_CSTRING("res"));
   nibFile->AppendNative(NS_LITERAL_CSTRING("MainMenu.nib"));
   nsAutoCString nibPath;
   rv = nibFile->GetNativePath(nibPath);
   NS_ENSURE_SUCCESS(rv, rv);
   // This call initializes NSApplication unless:
   // 1) we're using xre -- NSApp's already been initialized by
   //    MacApplicationDelegate.mm's EnsureUseCocoaDockAPI().
   // 2) Camino is running (or another embedding app that uses
   //    NSApplicationMain()) -- NSApp's already been initialized and
   //    its main run loop is already running.
   [NSBundle loadNibFile:
                      [NSString stringWithUTF8String:(const char*)nibPath.get()]
       externalNameTable:
            [NSDictionary dictionaryWithObject:[GeckoNSApplication sharedApplication]
                                        forKey:@"NSOwner"]
                withZone:NSDefaultMallocZone()];
   mDelegate = [[AppShellDelegate alloc] initWithAppShell:this];
   NS_ENSURE_STATE(mDelegate);
   // Add a CFRunLoopSource to the main native run loop.  The source is
   // responsible for interrupting the run loop when Gecko events are ready.
   mCFRunLoop = [[NSRunLoop currentRunLoop] getCFRunLoop];
   NS_ENSURE_STATE(mCFRunLoop);
   ::CFRetain(mCFRunLoop);
   CFRunLoopSourceContext context;
   bzero(&context, sizeof(context));
   // context.version = 0;
   context.info = this;
   context.perform = ProcessGeckoEvents;
   mCFRunLoopSource = ::CFRunLoopSourceCreate(kCFAllocatorDefault, 0, &context);
   NS_ENSURE_STATE(mCFRunLoopSource);
   ::CFRunLoopAddSource(mCFRunLoop, mCFRunLoopSource, kCFRunLoopCommonModes);
   rv = nsBaseAppShell::Init();
 #ifndef __LP64__
   TextInputHandler::InstallPluginKeyEventsHandler();
 #endif
   gCocoaAppModalWindowList = new nsCocoaAppModalWindowList;
   if (!gAppShellMethodsSwizzled) {
     nsToolkit::SwizzleMethods([NSApplication class], @selector(beginModalSessionForWindow:),
                               @selector(nsAppShell_NSApplication_beginModalSessionForWindow:));
     nsToolkit::SwizzleMethods([NSApplication class], @selector(endModalSession:),
                               @selector(nsAppShell_NSApplication_endModalSession:));
     // We should only replace the original terminate: method if we're not
     // running in a Cocoa embedder (like Camino).  See bug 604901.
     if (!mRunningCocoaEmbedded) {
       nsToolkit::SwizzleMethods([NSApplication class], @selector(terminate:),
                                 @selector(nsAppShell_NSApplication_terminate:));
     }
     gAppShellMethodsSwizzled = true;
   }
   if (nsCocoaFeatures::OnYosemiteOrLater()) {
     // Explicitly turn off CGEvent logging.  This works around bug 1092855.
     // If there are already CGEvents in the log, turning off logging also
     // causes those events to be written to disk.  But at this point no
     // CGEvents have yet been processed.  CGEvents are events (usually
     // input events) pulled from the WindowServer.  An option of 0x80000008
     // turns on CGEvent logging.
     CGSSetDebugOptions(0x80000007);
   }
   [localPool release];
   return rv;
   NS_OBJC_END_TRY_ABORT_BLOCK_NSRESULT;
 }
 // ProcessGeckoEvents
 //
 // The "perform" target of mCFRunLoop, called when mCFRunLoopSource is
 // signalled from ScheduleNativeEventCallback.
 //
 // Arrange for Gecko events to be processed on demand (in response to a call
 // to ScheduleNativeEventCallback(), if processing of Gecko events via "native
 // methods" hasn't been suspended).  This happens in NativeEventCallback().
 //
 // protected static
 void
 nsAppShell::ProcessGeckoEvents(void* aInfo)
 {
   NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
   PROFILER_LABEL("Events", "ProcessGeckoEvents");
   nsAppShell* self = static_cast<nsAppShell*> (aInfo);
   if (self->mRunningEventLoop) {
     self->mRunningEventLoop = false;
     // The run loop may be sleeping -- [NSRunLoop runMode:...]
     // won't return until it's given a reason to wake up.  Awaken it by
     // posting a bogus event.  There's no need to make the event
     // presentable.
     //
     // But _don't_ set windowNumber to '-1' -- that can lead to nasty
     // wierdness like bmo bug 397039 (a crash in [NSApp sendEvent:] on one of
     // these fake events, because the -1 has gotten changed into the number
     // of an actual NSWindow object, and that NSWindow object has just been
     // destroyed).  Setting windowNumber to '0' seems to work fine -- this
     // seems to prevent the OS from ever trying to associate our bogus event
     // with a particular NSWindow object.
     [NSApp postEvent:[NSEvent otherEventWithType:NSApplicationDefined
                                         location:NSMakePoint(0,0)
                                    modifierFlags:0
                                        timestamp:0
                                     windowNumber:0
                                          context:NULL
                                          subtype:kEventSubtypeNone
                                            data1:0
                                            data2:0]
              atStart:NO];
   }
   if (self->mSuspendNativeCount <= 0) {
     ++self->mNativeEventCallbackDepth;
     self->NativeEventCallback();
     --self->mNativeEventCallbackDepth;
   } else {
     self->mSkippedNativeCallback = true;
   }
   // Still needed to fix bug 343033 ("5-10 second delay or hang or crash
   // when quitting Cocoa Firefox").
   [NSApp postEvent:[NSEvent otherEventWithType:NSApplicationDefined
                                       location:NSMakePoint(0,0)
                                  modifierFlags:0
                                      timestamp:0
                                   windowNumber:0
                                        context:NULL
                                        subtype:kEventSubtypeNone
                                          data1:0
                                          data2:0]
            atStart:NO];
   // Normally every call to ScheduleNativeEventCallback() results in
   // exactly one call to ProcessGeckoEvents().  So each Release() here
   // normally balances exactly one AddRef() in ScheduleNativeEventCallback().
   // But if Exit() is called just after ScheduleNativeEventCallback(), the
   // corresponding call to ProcessGeckoEvents() will never happen.  We check
   // for this possibility in two different places -- here and in Exit()
   // itself.  If we find here that Exit() has been called (that mTerminated
   // is true), it's because we've been called recursively, that Exit() was
   // called from self->NativeEventCallback() above, and that we're unwinding
   // the recursion.  In this case we'll never be called again, and we balance
   // here any extra calls to ScheduleNativeEventCallback().
   //
   // When ProcessGeckoEvents() is called recursively, it's because of a
   // call to ScheduleNativeEventCallback() from NativeEventCallback().  We
   // balance the "extra" AddRefs here (rather than always in Exit()) in order
   // to ensure that 'self' stays alive until the end of this method.  We also
   // make sure not to finish the balancing until all the recursion has been
   // unwound.
   if (self->mTerminated) {
     int32_t releaseCount = 0;
     if (self->mNativeEventScheduledDepth > self->mNativeEventCallbackDepth) {
       releaseCount = PR_ATOMIC_SET(&self->mNativeEventScheduledDepth,
                                    self->mNativeEventCallbackDepth);
     }
     while (releaseCount-- > self->mNativeEventCallbackDepth)
       self->Release();
   } else {
     // As best we can tell, every call to ProcessGeckoEvents() is triggered
     // by a call to ScheduleNativeEventCallback().  But we've seen a few
     // (non-reproducible) cases of double-frees that *might* have been caused
     // by spontaneous calls (from the OS) to ProcessGeckoEvents().  So we
     // deal with that possibility here.
     if (PR_ATOMIC_DECREMENT(&self->mNativeEventScheduledDepth) < 0) {
       PR_ATOMIC_SET(&self->mNativeEventScheduledDepth, 0);
       NS_WARNING("Spontaneous call to ProcessGeckoEvents()!");
     } else {
       self->Release();
     }
   }
   NS_OBJC_END_TRY_ABORT_BLOCK;
 }
 // WillTerminate
 //
 // Called by the AppShellDelegate when an NSApplicationWillTerminate
 // notification is posted.  After this method is called, native events should
 // no longer be processed.  The NSApplicationWillTerminate notification is
 // only posted when [NSApp terminate:] is called, which doesn't happen on a
 // "normal" application quit.
 //
 // public
 void
 nsAppShell::WillTerminate()
 {
   if (mTerminated)
     return;
   // Make sure that the nsAppExitEvent posted by nsAppStartup::Quit() (called
   // from [MacApplicationDelegate applicationShouldTerminate:]) gets run.
   NS_ProcessPendingEvents(NS_GetCurrentThread());
   mTerminated = true;
 }
 // ScheduleNativeEventCallback
 //
 // Called (possibly on a non-main thread) when Gecko has an event that
 // needs to be processed.  The Gecko event needs to be processed on the
 // main thread, so the native run loop must be interrupted.
 //
 // In nsBaseAppShell.cpp, the mNativeEventPending variable is used to
 // ensure that ScheduleNativeEventCallback() is called no more than once
 // per call to NativeEventCallback().  ProcessGeckoEvents() can skip its
 // call to NativeEventCallback() if processing of Gecko events by native
 // means is suspended (using nsIAppShell::SuspendNative()), which will
 // suspend calls from nsBaseAppShell::OnDispatchedEvent() to
 // ScheduleNativeEventCallback().  But when Gecko event processing by
 // native means is resumed (in ResumeNative()), an extra call is made to
 // ScheduleNativeEventCallback() (from ResumeNative()).  This triggers
 // another call to ProcessGeckoEvents(), which calls NativeEventCallback(),
 // and nsBaseAppShell::OnDispatchedEvent() resumes calling
 // ScheduleNativeEventCallback().
 //
 // protected virtual
 void
 nsAppShell::ScheduleNativeEventCallback()
 {
   NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
   if (mTerminated)
     return;
   // Each AddRef() here is normally balanced by exactly one Release() in
   // ProcessGeckoEvents().  But there are exceptions, for which see
   // ProcessGeckoEvents() and Exit().
   NS_ADDREF_THIS();
   PR_ATOMIC_INCREMENT(&mNativeEventScheduledDepth);
   // This will invoke ProcessGeckoEvents on the main thread.
   ::CFRunLoopSourceSignal(mCFRunLoopSource);
   ::CFRunLoopWakeUp(mCFRunLoop);
   NS_OBJC_END_TRY_ABORT_BLOCK;
 }
 // ProcessNextNativeEvent
 //
 // If aMayWait is false, process a single native event.  If it is true, run
 // the native run loop until stopped by ProcessGeckoEvents.
 //
 // Returns true if more events are waiting in the native event queue.
 //
 // But (now that we're using [NSRunLoop runMode:beforeDate:]) it's too
 // expensive to call ProcessNextNativeEvent() many times in a row (in a
 // tight loop), so we never return true more than kHadMoreEventsCountMax
 // times in a row.  This doesn't seem to cause native event starvation.
 //
 // protected virtual
 bool
 nsAppShell::ProcessNextNativeEvent(bool aMayWait)
 {
   bool moreEvents = false;
   NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
   bool eventProcessed = false;
   NSString* currentMode = nil;
   if (mTerminated)
     return false;
   // We don't want any native events to be processed here (via Gecko) while
   // Cocoa is displaying an app-modal dialog (as opposed to a window-modal
   // "sheet" or a Gecko-modal dialog).  Otherwise Cocoa event-processing loops
   // may be interrupted, and inappropriate events may get through to the
   // browser window(s) underneath.  This resolves bmo bugs 419668 and 420967.
   //
   // But we need more complex handling (we need to make an exception) if a
   // Gecko modal dialog is running above the Cocoa app-modal dialog -- for
   // which see below.
   if ([NSApp _isRunningAppModal] &&
       (!gCocoaAppModalWindowList || !gCocoaAppModalWindowList->GeckoModalAboveCocoaModal()))
     return false;
   bool wasRunningEventLoop = mRunningEventLoop;
   mRunningEventLoop = aMayWait;
   NSDate* waitUntil = nil;
   if (aMayWait)
     waitUntil = [NSDate distantFuture];
   NSRunLoop* currentRunLoop = [NSRunLoop currentRunLoop];
   do {
     // No autorelease pool is provided here, because OnProcessNextEvent
     // and AfterProcessNextEvent are responsible for maintaining it.
     NS_ASSERTION(mAutoreleasePools && ::CFArrayGetCount(mAutoreleasePools),
                  "No autorelease pool for native event");
     // If an event is waiting to be processed, run the main event loop
     // just long enough to process it.  For some reason, using [NSApp
     // nextEventMatchingMask:...] to dequeue the event and [NSApp sendEvent:]
     // to "send" it causes trouble, so we no longer do that.  (The trouble
     // was very strange, and only happened while processing Gecko events on
     // demand (via ProcessGeckoEvents()), as opposed to processing Gecko
     // events in a tight loop (via nsBaseAppShell::Run()):  Particularly in
     // Camino, mouse-down events sometimes got dropped (or mis-handled), so
     // that (for example) you sometimes needed to click more than once on a
     // button to make it work (the zoom button was particularly susceptible).
     // You also sometimes had to ctrl-click or right-click multiple times to
     // bring up a context menu.)
     // Now that we're using [NSRunLoop runMode:beforeDate:], it's too
     // expensive to call ProcessNextNativeEvent() many times in a row, so we
     // never return true more than kHadMoreEventsCountMax in a row.  I'm not
     // entirely sure why [NSRunLoop runMode:beforeDate:] is too expensive,
     // since it and its cousin [NSRunLoop acceptInputForMode:beforeDate:] are
     // designed to be called in a tight loop.  Possibly the problem is due to
     // combining [NSRunLoop runMode:beforeDate] with [NSApp
     // nextEventMatchingMask:...].
     // We special-case timer events (events of type NSPeriodic) to avoid
     // starving them.  Apple's documentation is very scanty, and it's now
     // more scanty than it used to be.  But it appears that [NSRunLoop
     // acceptInputForMode:beforeDate:] doesn't process timer events at all,
     // that it is called from [NSRunLoop runMode:beforeDate:], and that
     // [NSRunLoop runMode:beforeDate:], though it does process timer events,
     // doesn't return after doing so.  To get around this, when aWait is
     // false we check for timer events and process them using [NSApp
     // sendEvent:].  When aWait is true [NSRunLoop runMode:beforeDate:]
     // will only return on a "real" event.  But there's code in
     // ProcessGeckoEvents() that should (when need be) wake us up by sending
     // a "fake" "real" event.  (See Apple's current doc on [NSRunLoop
     // runMode:beforeDate:] and a quote from what appears to be an older
     // version of this doc at
     // http://lists.apple.com/archives/cocoa-dev/2001/May/msg00559.html.)
     // If the current mode is something else than NSDefaultRunLoopMode, look
     // for events in that mode.
     currentMode = [currentRunLoop currentMode];
     if (!currentMode)
       currentMode = NSDefaultRunLoopMode;
     NSEvent* nextEvent = nil;
     if (aMayWait) {
       mozilla::HangMonitor::Suspend();
     }
     // If we're running modal (or not in a Gecko "main" event loop) we still
     // need to use nextEventMatchingMask and sendEvent -- otherwise (in
     // Minefield) the modal window (or non-main event loop) won't receive key
     // events or most mouse events.
     //
     // Add aMayWait to minimize the number of calls to -[NSApp sendEvent:]
     // made from nsAppShell::ProcessNextNativeEvent() (and indirectly from
     // nsBaseAppShell::OnProcessNextEvent()), to work around bug 959281.
     if ([NSApp _isRunningModal] || (aMayWait && !InGeckoMainEventLoop())) {
       if ((nextEvent = [NSApp nextEventMatchingMask:NSAnyEventMask
                                           untilDate:waitUntil
                                              inMode:currentMode
                                             dequeue:YES])) {
         // If we're in a Cocoa app-modal session that's been interrupted by a
         // Gecko-modal dialog, send the event to the Cocoa app-modal dialog's
         // session.  This ensures that the app-modal session won't be starved
         // of events, and fixes bugs 463473 and 442442.  (The case of an
         // ordinary Cocoa app-modal dialog has been dealt with above.)
         //
         // Otherwise (if we're in an ordinary Gecko-modal dialog, or if we're
         // otherwise not in a Gecko main event loop), process the event as
         // expected.
         NSModalSession currentAppModalSession = nil;
         if (gCocoaAppModalWindowList)
           currentAppModalSession = gCocoaAppModalWindowList->CurrentSession();
         mozilla::HangMonitor::NotifyActivity();
         if (currentAppModalSession) {
           [NSApp _modalSession:currentAppModalSession sendEvent:nextEvent];
         } else {
           [NSApp sendEvent:nextEvent];
         }
         eventProcessed = true;
       }
     } else {
       if (aMayWait ||
           (nextEvent = [NSApp nextEventMatchingMask:NSAnyEventMask
                                           untilDate:nil
                                              inMode:currentMode
                                             dequeue:NO])) {
         if (nextEvent && ([nextEvent type] == NSPeriodic)) {
           nextEvent = [NSApp nextEventMatchingMask:NSAnyEventMask
                                          untilDate:waitUntil
                                             inMode:currentMode
                                            dequeue:YES];
           [NSApp sendEvent:nextEvent];
         } else {
           [currentRunLoop runMode:currentMode beforeDate:waitUntil];
         }
         eventProcessed = true;
       }
     }
   } while (mRunningEventLoop);
   if (eventProcessed && (mHadMoreEventsCount < kHadMoreEventsCountMax)) {
     moreEvents = ([NSApp nextEventMatchingMask:NSAnyEventMask
                                      untilDate:nil
                                         inMode:currentMode
                                        dequeue:NO] != nil);
   }
   if (moreEvents) {
     // Once this reaches kHadMoreEventsCountMax, it will be reset to 0 the
     // next time through (whether or not we process any events then).
     ++mHadMoreEventsCount;
   } else {
     mHadMoreEventsCount = 0;
   }
   mRunningEventLoop = wasRunningEventLoop;
   NS_OBJC_END_TRY_ABORT_BLOCK;
   if (!moreEvents) {
     nsChildView::UpdateCurrentInputEventCount();
   }
   return moreEvents;
 }
 // Returns true if Gecko events are currently being processed in its "main"
 // event loop (or one of its "main" event loops).  Returns false if Gecko
 // events are being processed in a "nested" event loop, or if we're not
 // running in any sort of Gecko event loop.  How we process native events in
 // ProcessNextNativeEvent() turns on our decision (and if we make the wrong
 // choice, the result may be a hang).
 //
 // We define the "main" event loop(s) as the place (or places) where Gecko
 // event processing "normally" takes place, and all other Gecko event loops
 // as "nested".  The "nested" event loops are normally processed while a call
 // from a "main" event loop is on the stack ... but not always.  For example,
 // the Venkman JavaScript debugger runs a "nested" event loop (in jsdService::
 // EnterNestedEventLoop()) whenever it breaks into the current script.  But
 // if this happens as the result of the user pressing a key combination, there
 // won't be any other Gecko event-processing call on the stack (e.g.
 // NS_ProcessNextEvent() or NS_ProcessPendingEvents()).  (In the current
 // nsAppShell implementation, what counts as the "main" event loop is what
 // nsBaseAppShell::NativeEventCallback() does to process Gecko events.  We
 // don't currently use nsBaseAppShell::Run().)
 bool
 nsAppShell::InGeckoMainEventLoop()
 {
   if ((gXULModalLevel > 0) || (mRecursionDepth > 0))
     return false;
   if (mNativeEventCallbackDepth <= 0)
     return false;
   return true;
 }
 // Run
 //
 // Overrides the base class's Run() method to call [NSApp run] (which spins
 // the native run loop until the application quits).  Since (unlike the base
 // class's Run() method) we don't process any Gecko events here, they need
 // to be processed elsewhere (in NativeEventCallback(), called from
 // ProcessGeckoEvents()).
 //
 // Camino calls [NSApp run] on its own (via NSApplicationMain()), and so
 // doesn't call nsAppShell::Run().
 //
 // public
 NS_IMETHODIMP
 nsAppShell::Run(void)
 {
   NS_ASSERTION(!mStarted, "nsAppShell::Run() called multiple times");
   if (mStarted || mTerminated)
     return NS_OK;
   mStarted = true;
   NS_OBJC_TRY_ABORT([NSApp run]);
   return NS_OK;
 }
 NS_IMETHODIMP
 nsAppShell::Exit(void)
 {
   NS_OBJC_BEGIN_TRY_ABORT_BLOCK_NSRESULT;
   // This method is currently called more than once -- from (according to
   // mento) an nsAppExitEvent dispatched by nsAppStartup::Quit() and from an
   // XPCOM shutdown notification that nsBaseAppShell has registered to
   // receive.  So we need to ensure that multiple calls won't break anything.
   // But we should also complain about it (since it isn't quite kosher).
   if (mTerminated) {
     NS_WARNING("nsAppShell::Exit() called redundantly");
     return NS_OK;
   }
   mTerminated = true;
   delete gCocoaAppModalWindowList;
   gCocoaAppModalWindowList = NULL;
 #ifndef __LP64__
   TextInputHandler::RemovePluginKeyEventsHandler();
 #endif
   // Quoting from Apple's doc on the [NSApplication stop:] method (from their
   // doc on the NSApplication class):  "If this method is invoked during a
   // modal event loop, it will break that loop but not the main event loop."
   // nsAppShell::Exit() shouldn't be called from a modal event loop.  So if
   // it is we complain about it (to users of debug builds) and call [NSApp
   // stop:] one extra time.  (I'm not sure if modal event loops can be nested
   // -- Apple's docs don't say one way or the other.  But the return value
   // of [NSApp _isRunningModal] doesn't change immediately after a call to
   // [NSApp stop:], so we have to assume that one extra call to [NSApp stop:]
   // will do the job.)
   BOOL cocoaModal = [NSApp _isRunningModal];
   NS_ASSERTION(!cocoaModal,
                "Don't call nsAppShell::Exit() from a modal event loop!");
   if (cocoaModal)
     [NSApp stop:nullptr];
   [NSApp stop:nullptr];
   // A call to Exit() just after a call to ScheduleNativeEventCallback()
   // prevents the (normally) matching call to ProcessGeckoEvents() from
   // happening.  If we've been called from ProcessGeckoEvents() (as usually
   // happens), we take care of it there.  But if we have an unbalanced call
   // to ScheduleNativeEventCallback() and ProcessGeckoEvents() isn't on the
   // stack, we need to take care of the problem here.
   if (!mNativeEventCallbackDepth && mNativeEventScheduledDepth) {
     int32_t releaseCount = PR_ATOMIC_SET(&mNativeEventScheduledDepth, 0);
     while (releaseCount-- > 0)
       NS_RELEASE_THIS();
   }
   return nsBaseAppShell::Exit();
   NS_OBJC_END_TRY_ABORT_BLOCK_NSRESULT;
 }
 // OnProcessNextEvent
 //
 // This nsIThreadObserver method is called prior to processing an event.
 // Set up an autorelease pool that will service any autoreleased Cocoa
 // objects during this event.  This includes native events processed by
 // ProcessNextNativeEvent.  The autorelease pool will be popped by
 // AfterProcessNextEvent, it is important for these two methods to be
 // tightly coupled.
 //
 // public
 NS_IMETHODIMP
 nsAppShell::OnProcessNextEvent(nsIThreadInternal *aThread, bool aMayWait,
                                uint32_t aRecursionDepth)
 {
   NS_OBJC_BEGIN_TRY_ABORT_BLOCK_NSRESULT;
   mRecursionDepth = aRecursionDepth;
   NS_ASSERTION(mAutoreleasePools,
                "No stack on which to store autorelease pool");
   NSAutoreleasePool* pool = [[NSAutoreleasePool alloc] init];
   ::CFArrayAppendValue(mAutoreleasePools, pool);
   return nsBaseAppShell::OnProcessNextEvent(aThread, aMayWait, aRecursionDepth);
   NS_OBJC_END_TRY_ABORT_BLOCK_NSRESULT;
 }
 // AfterProcessNextEvent
 //
 // This nsIThreadObserver method is called after event processing is complete.
 // The Cocoa implementation cleans up the autorelease pool create by the
 // previous OnProcessNextEvent call.
 //
 // public
 NS_IMETHODIMP
 nsAppShell::AfterProcessNextEvent(nsIThreadInternal *aThread,
                                   uint32_t aRecursionDepth,
                                   bool aEventWasProcessed)
 {
   NS_OBJC_BEGIN_TRY_ABORT_BLOCK_NSRESULT;
   mRecursionDepth = aRecursionDepth;
   CFIndex count = ::CFArrayGetCount(mAutoreleasePools);
   NS_ASSERTION(mAutoreleasePools && count,
                "Processed an event, but there's no autorelease pool?");
   const NSAutoreleasePool* pool = static_cast<const NSAutoreleasePool*>
     (::CFArrayGetValueAtIndex(mAutoreleasePools, count - 1));
   ::CFArrayRemoveValueAtIndex(mAutoreleasePools, count - 1);
   [pool release];
   return nsBaseAppShell::AfterProcessNextEvent(aThread, aRecursionDepth,
                                                aEventWasProcessed);
   NS_OBJC_END_TRY_ABORT_BLOCK_NSRESULT;
 }
 // AppShellDelegate implementation
 @implementation AppShellDelegate
 // initWithAppShell:
 //
 // Constructs the AppShellDelegate object
 - (id)initWithAppShell:(nsAppShell*)aAppShell
 {
   NS_OBJC_BEGIN_TRY_ABORT_BLOCK_NIL;
   if ((self = [self init])) {
     mAppShell = aAppShell;
     [[NSNotificationCenter defaultCenter] addObserver:self
                                              selector:@selector(applicationWillTerminate:)
                                                  name:NSApplicationWillTerminateNotification
                                                object:NSApp];
     [[NSNotificationCenter defaultCenter] addObserver:self
                                              selector:@selector(applicationDidBecomeActive:)
                                                  name:NSApplicationDidBecomeActiveNotification
                                                object:NSApp];
     [[NSDistributedNotificationCenter defaultCenter] addObserver:self
                                                         selector:@selector(beginMenuTracking:)
                                                             name:@"com.apple.HIToolbox.beginMenuTrackingNotification"
                                                           object:nil];
   }
   return self;
   NS_OBJC_END_TRY_ABORT_BLOCK_NIL;
 }
 - (void)dealloc
 {
   NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
   [[NSNotificationCenter defaultCenter] removeObserver:self];
   [[NSDistributedNotificationCenter defaultCenter] removeObserver:self];
   [super dealloc];
   NS_OBJC_END_TRY_ABORT_BLOCK;
 }
 // applicationWillTerminate:
 //
 // Notify the nsAppShell that native event processing should be discontinued.
 - (void)applicationWillTerminate:(NSNotification*)aNotification
 {
   NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
   mAppShell->WillTerminate();
   NS_OBJC_END_TRY_ABORT_BLOCK;
 }
 // applicationDidBecomeActive
 //
 // Make sure TextInputHandler::sLastModifierState is updated when we become
 // active (since we won't have received [ChildView flagsChanged:] messages
 // while inactive).
 - (void)applicationDidBecomeActive:(NSNotification*)aNotification
 {
   NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
   // [NSEvent modifierFlags] is valid on every kind of event, so we don't need
   // to worry about getting an NSInternalInconsistencyException here.
   NSEvent* currentEvent = [NSApp currentEvent];
   if (currentEvent) {
     TextInputHandler::sLastModifierState =
       [currentEvent modifierFlags] & NSDeviceIndependentModifierFlagsMask;
   }
   NS_OBJC_END_TRY_ABORT_BLOCK;
 }
 // beginMenuTracking
 //
 // Roll up our context menu (if any) when some other app (or the OS) opens
 // any sort of menu.  But make sure we don't do this for notifications we
 // send ourselves (whose 'sender' will be @"org.mozilla.gecko.PopupWindow").
 - (void)beginMenuTracking:(NSNotification*)aNotification
 {
   NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
   NSString *sender = [aNotification object];
   if (!sender || ![sender isEqualToString:@"org.mozilla.gecko.PopupWindow"]) {
     nsIRollupListener* rollupListener = nsBaseWidget::GetActiveRollupListener();
     nsCOMPtr<nsIWidget> rollupWidget = rollupListener->GetRollupWidget();
     if (rollupWidget)
       rollupListener->Rollup(0, nullptr, nullptr);
   }
   NS_OBJC_END_TRY_ABORT_BLOCK;
 }
 @end
 // We hook beginModalSessionForWindow: and endModalSession: in order to
 // maintain a list of Cocoa app-modal windows (and the "sessions" to which
 // they correspond).  We need this in order to deal with the consequences
 // of a Cocoa app-modal dialog being "interrupted" by a Gecko-modal dialog.
 // See nsCocoaAppModalWindowList::CurrentSession() and
 // nsAppShell::ProcessNextNativeEvent() above.
 //
 // We hook terminate: in order to make OS-initiated termination work nicely
 // with Gecko's shutdown sequence.  (Two ways to trigger OS-initiated
 // termination:  1) Quit from the Dock menu; 2) Log out from (or shut down)
 // your computer while the browser is active.)
 @interface NSApplication (MethodSwizzling)
 - (NSModalSession)nsAppShell_NSApplication_beginModalSessionForWindow:(NSWindow *)aWindow;
 - (void)nsAppShell_NSApplication_endModalSession:(NSModalSession)aSession;
 - (void)nsAppShell_NSApplication_terminate:(id)sender;
 @end
 @implementation NSApplication (MethodSwizzling)
 // Called if and only if a Cocoa app-modal session is beginning.  Always call
 // gCocoaAppModalWindowList->PushCocoa() here (if gCocoaAppModalWindowList is
 // non-nil).
 - (NSModalSession)nsAppShell_NSApplication_beginModalSessionForWindow:(NSWindow *)aWindow
 {
   NSModalSession session =
     [self nsAppShell_NSApplication_beginModalSessionForWindow:aWindow];
   if (gCocoaAppModalWindowList)
     gCocoaAppModalWindowList->PushCocoa(aWindow, session);
   return session;
 }
 // Called to end any Cocoa modal session (app-modal or otherwise).  Only call
 // gCocoaAppModalWindowList->PopCocoa() when an app-modal session is ending
 // (and when gCocoaAppModalWindowList is non-nil).
 - (void)nsAppShell_NSApplication_endModalSession:(NSModalSession)aSession
 {
   BOOL wasRunningAppModal = [NSApp _isRunningAppModal];
   NSWindow *prevAppModalWindow = [NSApp modalWindow];
   [self nsAppShell_NSApplication_endModalSession:aSession];
   if (gCocoaAppModalWindowList &&
       wasRunningAppModal && (prevAppModalWindow != [NSApp modalWindow]))
     gCocoaAppModalWindowList->PopCocoa(prevAppModalWindow, aSession);
 }
 // Called by the OS after [MacApplicationDelegate applicationShouldTerminate:]
 // has returned NSTerminateNow.  This method "subclasses" and replaces the
 // OS's original implementation.  The only thing the orginal method does which
 // we need is that it posts NSApplicationWillTerminateNotification.  Everything
 // else is unneeded (because it's handled elsewhere), or actively interferes
 // with Gecko's shutdown sequence.  For example the original terminate: method
 // causes the app to exit() inside [NSApp run] (called from nsAppShell::Run()
 // above), which means that nothing runs after the call to nsAppStartup::Run()
 // in XRE_Main(), which in particular means that ScopedXPCOMStartup's destructor
 // and NS_ShutdownXPCOM() never get called.
 - (void)nsAppShell_NSApplication_terminate:(id)sender
 {
   [[NSNotificationCenter defaultCenter] postNotificationName:NSApplicationWillTerminateNotification
                                                       object:NSApp];
 }
 @end

The Tor Browser / annotate

widget/cocoa/nsAppShell.mm@6474c204b198 (annotated)

widget/cocoa/nsAppShell.mm