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