michael@0: /* -*- Mode: c++; tab-width: 2; indent-tabs-mode: nil; -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef nsBaseAppShell_h__
michael@0: #define nsBaseAppShell_h__
michael@0: 
michael@0: #include "mozilla/Atomics.h"
michael@0: #include "nsIAppShell.h"
michael@0: #include "nsIThreadInternal.h"
michael@0: #include "nsIObserver.h"
michael@0: #include "nsIRunnable.h"
michael@0: #include "nsCOMPtr.h"
michael@0: #include "nsTArray.h"
michael@0: #include "prinrval.h"
michael@0: 
michael@0: /**
michael@0:  * A singleton that manages the UI thread's event queue.  Subclass this class
michael@0:  * to enable platform-specific event queue support.
michael@0:  */
michael@0: class nsBaseAppShell : public nsIAppShell, public nsIThreadObserver,
michael@0:                        public nsIObserver
michael@0: {
michael@0: public:
michael@0:   NS_DECL_THREADSAFE_ISUPPORTS
michael@0:   NS_DECL_NSIAPPSHELL
michael@0:   NS_DECL_NSITHREADOBSERVER
michael@0:   NS_DECL_NSIOBSERVER
michael@0: 
michael@0:   nsBaseAppShell();
michael@0: 
michael@0: protected:
michael@0:   virtual ~nsBaseAppShell();
michael@0: 
michael@0:   /**
michael@0:    * This method is called by subclasses when the app shell singleton is
michael@0:    * instantiated.
michael@0:    */
michael@0:   nsresult Init();
michael@0: 
michael@0:   /**
michael@0:    * Called by subclasses from a native event. See ScheduleNativeEventCallback.
michael@0:    */
michael@0:   void NativeEventCallback();
michael@0: 
michael@0:   /**
michael@0:    * Make a decision as to whether or not NativeEventCallback will
michael@0:    * trigger gecko event processing when there are pending gecko
michael@0:    * events.
michael@0:    */
michael@0:   virtual void DoProcessMoreGeckoEvents();
michael@0: 
michael@0:   /**
michael@0:    * Implemented by subclasses.  Invoke NativeEventCallback from a native
michael@0:    * event.  This method may be called on any thread.
michael@0:    */
michael@0:   virtual void ScheduleNativeEventCallback() = 0;
michael@0: 
michael@0:   /**
michael@0:    * Implemented by subclasses.  Process the next native event.  Only wait for
michael@0:    * the next native event if mayWait is true.  This method is only called on
michael@0:    * the main application thread.
michael@0:    *
michael@0:    * @param mayWait
michael@0:    *   If "true", then this method may wait if necessary for the next available
michael@0:    *   native event.  DispatchNativeEvent may be called to unblock a call to
michael@0:    *   ProcessNextNativeEvent that is waiting.
michael@0:    * @return
michael@0:    *   This method returns "true" if a native event was processed.
michael@0:    */
michael@0:   virtual bool ProcessNextNativeEvent(bool mayWait) = 0;
michael@0: 
michael@0:   int32_t mSuspendNativeCount;
michael@0:   uint32_t mEventloopNestingLevel;
michael@0: 
michael@0: private:
michael@0:   bool DoProcessNextNativeEvent(bool mayWait, uint32_t recursionDepth);
michael@0: 
michael@0:   bool DispatchDummyEvent(nsIThread* target);
michael@0: 
michael@0:   void IncrementEventloopNestingLevel();
michael@0:   void DecrementEventloopNestingLevel();
michael@0: 
michael@0:   /**
michael@0:    * Runs all synchronous sections which are queued up in mSyncSections.
michael@0:    */
michael@0:   void RunSyncSectionsInternal(bool stable, uint32_t threadRecursionLevel);
michael@0: 
michael@0:   void RunSyncSections(bool stable, uint32_t threadRecursionLevel)
michael@0:   {
michael@0:     if (!mSyncSections.IsEmpty()) {
michael@0:       RunSyncSectionsInternal(stable, threadRecursionLevel);
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   void ScheduleSyncSection(nsIRunnable* runnable, bool stable);
michael@0: 
michael@0:   struct SyncSection {
michael@0:     SyncSection()
michael@0:     : mStable(false), mEventloopNestingLevel(0), mThreadRecursionLevel(0)
michael@0:     { }
michael@0: 
michael@0:     void Forget(SyncSection* other) {
michael@0:       other->mStable = mStable;
michael@0:       other->mEventloopNestingLevel = mEventloopNestingLevel;
michael@0:       other->mThreadRecursionLevel = mThreadRecursionLevel;
michael@0:       other->mRunnable = mRunnable.forget();
michael@0:     }
michael@0: 
michael@0:     bool mStable;
michael@0:     uint32_t mEventloopNestingLevel;
michael@0:     uint32_t mThreadRecursionLevel;
michael@0:     nsCOMPtr<nsIRunnable> mRunnable;
michael@0:   };
michael@0: 
michael@0:   nsCOMPtr<nsIRunnable> mDummyEvent;
michael@0:   /**
michael@0:    * mBlockedWait points back to a slot that controls the wait loop in
michael@0:    * an outer OnProcessNextEvent invocation.  Nested calls always set
michael@0:    * it to false to unblock an outer loop, since all events may
michael@0:    * have been consumed by the inner event loop(s).
michael@0:    */
michael@0:   bool *mBlockedWait;
michael@0:   int32_t mFavorPerf;
michael@0:   mozilla::Atomic<bool> mNativeEventPending;
michael@0:   PRIntervalTime mStarvationDelay;
michael@0:   PRIntervalTime mSwitchTime;
michael@0:   PRIntervalTime mLastNativeEventTime;
michael@0:   enum EventloopNestingState {
michael@0:     eEventloopNone,  // top level thread execution
michael@0:     eEventloopXPCOM, // innermost native event loop is ProcessNextNativeEvent
michael@0:     eEventloopOther  // innermost native event loop is a native library/plugin etc
michael@0:   };
michael@0:   EventloopNestingState mEventloopNestingState;
michael@0:   nsTArray<SyncSection> mSyncSections;
michael@0:   bool mRunning;
michael@0:   bool mExiting;
michael@0:   /**
michael@0:    * mBlockNativeEvent blocks the appshell from processing native events.
michael@0:    * It is set to true while a nested native event loop (eEventloopOther)
michael@0:    * is processing gecko events in NativeEventCallback(), thus queuing up
michael@0:    * native events until we return to that loop (bug 420148).
michael@0:    * We force mBlockNativeEvent to false in case handling one of the gecko
michael@0:    * events spins up a nested XPCOM event loop (eg. modal window) which would
michael@0:    * otherwise lead to a "deadlock" where native events aren't processed at all.
michael@0:    */
michael@0:   bool mBlockNativeEvent;
michael@0:   /**
michael@0:    * Tracks whether we have processed any gecko events in NativeEventCallback so
michael@0:    * that we can avoid erroneously entering a blocking loop waiting for gecko
michael@0:    * events to show up during OnProcessNextEvent.  This is required because on
michael@0:    * OS X ProcessGeckoEvents may be invoked inside the context of
michael@0:    * ProcessNextNativeEvent and may result in NativeEventCallback being invoked
michael@0:    * and in turn invoking NS_ProcessPendingEvents.  Because
michael@0:    * ProcessNextNativeEvent may be invoked prior to the NS_HasPendingEvents
michael@0:    * waiting loop, this is the only way to make the loop aware that events may
michael@0:    * have been processed.
michael@0:    *
michael@0:    * This variable is set to false in OnProcessNextEvent prior to the first
michael@0:    * call to DoProcessNextNativeEvent.  It is set to true by
michael@0:    * NativeEventCallback after calling NS_ProcessPendingEvents.
michael@0:    */
michael@0:   bool mProcessedGeckoEvents;
michael@0: };
michael@0: 
michael@0: #endif // nsBaseAppShell_h__