// Main thread via OnProcessNextEvent below
bool
nsBaseAppShell::DoProcessNextNativeEvent(bool mayWait, uint32_t recursionDepth)
{
// The next native event to be processed may trigger our NativeEventCallback,
// in which case we do not want it to process any thread events since we'll
// do that when this function returns.
//
// If the next native event is not our NativeEventCallback, then we may end
// up recursing into this function.
//
// However, if the next native event is not our NativeEventCallback, but it
// results in another native event loop, then our NativeEventCallback could
// fire and it will see mEventloopNestingState as eEventloopOther.
//
EventloopNestingState prevVal = mEventloopNestingState;
mEventloopNestingState = eEventloopXPCOM;
IncrementEventloopNestingLevel();
bool result = ProcessNextNativeEvent(mayWait);
// Make sure that any sync sections registered during this most recent event
// are run now. This is not considered a stable state because we're not back
// to the event loop yet.
RunSyncSections(false, recursionDepth);
DecrementEventloopNestingLevel();
mEventloopNestingState = prevVal;
return result;
}
// Called by nsAppShell's native event callback
void
nsBaseAppShell::NativeEventCallback()
{
if (!mNativeEventPending.exchange(false))
return;
// If DoProcessNextNativeEvent is on the stack, then we assume that we can
// just unwind and let nsThread::ProcessNextEvent process the next event.
// However, if we are called from a nested native event loop (maybe via some
// plug-in or library function), then go ahead and process Gecko events now.
if (mEventloopNestingState == eEventloopXPCOM) {
mEventloopNestingState = eEventloopOther;
// XXX there is a tiny risk we will never get a new NativeEventCallback,
// XXX see discussion in bug 389931.
return;
}
// nsBaseAppShell::Run is not being used to pump events, so this may be
// our only opportunity to process pending gecko events.
nsIThread *thread = NS_GetCurrentThread();
bool prevBlockNativeEvent = mBlockNativeEvent;
if (mEventloopNestingState == eEventloopOther) {
if (!NS_HasPendingEvents(thread))
return;
// We're in a nested native event loop and have some gecko events to
// process. While doing that we block processing native events from the
// appshell - instead, we want to get back to the nested native event
// loop ASAP (bug 420148).
mBlockNativeEvent = true;
}
IncrementEventloopNestingLevel();
EventloopNestingState prevVal = mEventloopNestingState;
NS_ProcessPendingEvents(thread, THREAD_EVENT_STARVATION_LIMIT);
mProcessedGeckoEvents = true;
mEventloopNestingState = prevVal;
mBlockNativeEvent = prevBlockNativeEvent;
// Continue processing pending events later (we don't want to starve the
// embedders event loop).
if (NS_HasPendingEvents(thread))
DoProcessMoreGeckoEvents();
DecrementEventloopNestingLevel();
}
// Main thread via OnProcessNextEvent below
bool
nsBaseAppShell::DoProcessNextNativeEvent(bool mayWait)
{
// The next native event to be processed may trigger our NativeEventCallback,
// in which case we do not want it to process any thread events since we'll
// do that when this function returns.
//
// If the next native event is not our NativeEventCallback, then we may end
// up recursing into this function.
//
// However, if the next native event is not our NativeEventCallback, but it
// results in another native event loop, then our NativeEventCallback could
// fire and it will see mEventloopNestingState as eEventloopOther.
//
EventloopNestingState prevVal = mEventloopNestingState;
mEventloopNestingState = eEventloopXPCOM;
IncrementEventloopNestingLevel();
bool result = ProcessNextNativeEvent(mayWait);
DecrementEventloopNestingLevel();
mEventloopNestingState = prevVal;
return result;
}