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-rw-r--r--widget/nsBaseAppShell.h140
1 files changed, 140 insertions, 0 deletions
diff --git a/widget/nsBaseAppShell.h b/widget/nsBaseAppShell.h
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+/* -*- 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();
+
+ /**
+ * Called by subclasses. Reset the internal timezone when the user's system
+ * timezone changes.
+ */
+ static void OnSystemTimezoneChange();
+
+ 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;
+ mozilla::Atomic<bool> mNativeEventPending;
+ PRIntervalTime mGeckoTaskBurstStartTime;
+ 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__