/* -*- 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/. */ #ifndef nsBaseAppShell_h__ #define nsBaseAppShell_h__ #include "mozilla/Atomics.h" #include "nsIAppShell.h" #include "nsIThreadInternal.h" #include "nsIObserver.h" #include "nsIRunnable.h" #include "nsCOMPtr.h" #include "nsTArray.h" #include "prinrval.h" /** * A singleton that manages the UI thread's event queue. Subclass this class * to enable platform-specific event queue support. */ class nsBaseAppShell : public nsIAppShell, public nsIThreadObserver, public nsIObserver { public: NS_DECL_THREADSAFE_ISUPPORTS NS_DECL_NSIAPPSHELL NS_DECL_NSITHREADOBSERVER NS_DECL_NSIOBSERVER nsBaseAppShell(); protected: virtual ~nsBaseAppShell(); /** * This method is called by subclasses when the app shell singleton is * instantiated. */ nsresult Init(); /** * Called by subclasses from a native event. See ScheduleNativeEventCallback. */ void NativeEventCallback(); /** * Make a decision as to whether or not NativeEventCallback will * trigger gecko event processing when there are pending gecko * events. */ virtual void DoProcessMoreGeckoEvents(); /** * Implemented by subclasses. Invoke NativeEventCallback from a native * event. This method may be called on any thread. */ virtual void ScheduleNativeEventCallback() = 0; /** * Implemented by subclasses. Process the next native event. Only wait for * the next native event if mayWait is true. This method is only called on * the main application thread. * * @param mayWait * If "true", then this method may wait if necessary for the next available * native event. DispatchNativeEvent may be called to unblock a call to * ProcessNextNativeEvent that is waiting. * @return * This method returns "true" if a native event was processed. */ virtual bool ProcessNextNativeEvent(bool mayWait) = 0; int32_t mSuspendNativeCount; uint32_t mEventloopNestingLevel; private: bool DoProcessNextNativeEvent(bool mayWait); bool DispatchDummyEvent(nsIThread* target); void IncrementEventloopNestingLevel(); void DecrementEventloopNestingLevel(); nsCOMPtr<nsIRunnable> mDummyEvent; /** * mBlockedWait points back to a slot that controls the wait loop in * an outer OnProcessNextEvent invocation. Nested calls always set * it to false to unblock an outer loop, since all events may * have been consumed by the inner event loop(s). */ bool *mBlockedWait; int32_t mFavorPerf; mozilla::Atomic<bool> mNativeEventPending; PRIntervalTime mStarvationDelay; PRIntervalTime mSwitchTime; PRIntervalTime mLastNativeEventTime; enum EventloopNestingState { eEventloopNone, // top level thread execution eEventloopXPCOM, // innermost native event loop is ProcessNextNativeEvent eEventloopOther // innermost native event loop is a native library/plugin etc }; EventloopNestingState mEventloopNestingState; bool mRunning; bool mExiting; /** * mBlockNativeEvent blocks the appshell from processing native events. * It is set to true while a nested native event loop (eEventloopOther) * is processing gecko events in NativeEventCallback(), thus queuing up * native events until we return to that loop (bug 420148). * We force mBlockNativeEvent to false in case handling one of the gecko * events spins up a nested XPCOM event loop (eg. modal window) which would * otherwise lead to a "deadlock" where native events aren't processed at all. */ bool mBlockNativeEvent; /** * Tracks whether we have processed any gecko events in NativeEventCallback so * that we can avoid erroneously entering a blocking loop waiting for gecko * events to show up during OnProcessNextEvent. This is required because on * OS X ProcessGeckoEvents may be invoked inside the context of * ProcessNextNativeEvent and may result in NativeEventCallback being invoked * and in turn invoking NS_ProcessPendingEvents. Because * ProcessNextNativeEvent may be invoked prior to the NS_HasPendingEvents * waiting loop, this is the only way to make the loop aware that events may * have been processed. * * This variable is set to false in OnProcessNextEvent prior to the first * call to DoProcessNextNativeEvent. It is set to true by * NativeEventCallback after calling NS_ProcessPendingEvents. */ bool mProcessedGeckoEvents; }; #endif // nsBaseAppShell_h__