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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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// The basis for all native run loops on the Mac is the CFRunLoop. It can be
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// used directly, it can be used as the driving force behind the similar
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// Foundation NSRunLoop, and it can be used to implement higher-level event
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// loops such as the NSApplication event loop.
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// This file introduces a basic CFRunLoop-based implementation of the
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// MessagePump interface called CFRunLoopBase. CFRunLoopBase contains all
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// of the machinery necessary to dispatch events to a delegate, but does not
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// implement the specific run loop. Concrete subclasses must provide their
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// own DoRun and Quit implementations.
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// A concrete subclass that just runs a CFRunLoop loop is provided in
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// MessagePumpCFRunLoop. For an NSRunLoop, the similar MessagePumpNSRunLoop
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// For the application's event loop, an implementation based on AppKit's
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// NSApplication event system is provided in MessagePumpNSApplication.
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// Typically, MessagePumpNSApplication only makes sense on a Cocoa
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// application's main thread. If a CFRunLoop-based message pump is needed on
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// any other thread, one of the other concrete subclasses is preferrable.
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// MessagePumpMac::Create is defined, which returns a new NSApplication-based
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// or NSRunLoop-based MessagePump subclass depending on which thread it is
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#ifndef BASE_MESSAGE_LOOP_MESSAGE_PUMP_MAC_H_
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#define BASE_MESSAGE_LOOP_MESSAGE_PUMP_MAC_H_
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#include "base/message_loop/message_pump.h"
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#include "base/basictypes.h"
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#include <CoreFoundation/CoreFoundation.h>
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#include "base/memory/weak_ptr.h"
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#if !defined(__OBJC__)
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class NSAutoreleasePool;
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#else // !defined(__OBJC__)
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#import <Foundation/Foundation.h>
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#import <AppKit/AppKit.h>
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// Clients must subclass NSApplication and implement this protocol if they use
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@protocol CrAppProtocol
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// Must return true if -[NSApplication sendEvent:] is currently on the stack.
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// See the comment for |CreateAutoreleasePool()| in the cc file for why this is
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- (BOOL)isHandlingSendEvent;
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#endif // !defined(OS_IOS)
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#endif // !defined(__OBJC__)
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class MessagePumpInstrumentation;
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class MessagePumpCFRunLoopBase : public MessagePump {
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// Needs access to CreateAutoreleasePool.
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friend class MessagePumpScopedAutoreleasePool;
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MessagePumpCFRunLoopBase();
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virtual ~MessagePumpCFRunLoopBase();
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// Subclasses should implement the work they need to do in MessagePump::Run
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// in the DoRun method. MessagePumpCFRunLoopBase::Run calls DoRun directly.
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// This arrangement is used because MessagePumpCFRunLoopBase needs to set
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// up and tear down things before and after the "meat" of DoRun.
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virtual void Run(Delegate* delegate) OVERRIDE;
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virtual void DoRun(Delegate* delegate) = 0;
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virtual void ScheduleWork() OVERRIDE;
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virtual void ScheduleDelayedWork(const TimeTicks& delayed_work_time) OVERRIDE;
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// Accessors for private data members to be used by subclasses.
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CFRunLoopRef run_loop() const { return run_loop_; }
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int nesting_level() const { return nesting_level_; }
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int run_nesting_level() const { return run_nesting_level_; }
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// Sets this pump's delegate. Signals the appropriate sources if
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// |delegateless_work_| is true. |delegate| can be NULL.
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void SetDelegate(Delegate* delegate);
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// Return an autorelease pool to wrap around any work being performed.
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// In some cases, CreateAutoreleasePool may return nil intentionally to
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// preventing an autorelease pool from being created, allowing any
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// objects autoreleased by work to fall into the current autorelease pool.
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virtual NSAutoreleasePool* CreateAutoreleasePool();
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// Enables instrumentation of the MessagePump. See MessagePumpInstrumentation
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// in the implementation for details.
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void EnableInstrumentation();
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WeakPtr<MessagePumpInstrumentation> instrumentation_;
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// Timer callback scheduled by ScheduleDelayedWork. This does not do any
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// work, but it signals work_source_ so that delayed work can be performed
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// within the appropriate priority constraints.
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static void RunDelayedWorkTimer(CFRunLoopTimerRef timer, void* info);
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// Perform highest-priority work. This is associated with work_source_
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// signalled by ScheduleWork or RunDelayedWorkTimer. The static method calls
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// the instance method; the instance method returns true if it resignalled
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// work_source_ to be called again from the loop.
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static void RunWorkSource(void* info);
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// Perform idle-priority work. This is normally called by
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// StartOrEndWaitObserver, but is also associated with idle_work_source_. When
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// this function actually does perform idle work, it will resignal that
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// source. The static method calls the instance method; the instance method
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// returns true if idle work was done.
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static void RunIdleWorkSource(void* info);
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// Perform work that may have been deferred because it was not runnable
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// within a nested run loop. This is associated with
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// nesting_deferred_work_source_ and is signalled by
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// MaybeScheduleNestingDeferredWork when returning from a nested loop,
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// so that an outer loop will be able to perform the necessary tasks if it
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// permits nestable tasks.
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static void RunNestingDeferredWorkSource(void* info);
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bool RunNestingDeferredWork();
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// Schedules possible nesting-deferred work to be processed before the run
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// loop goes to sleep, exits, or begins processing sources at the top of its
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// loop. If this function detects that a nested loop had run since the
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// previous attempt to schedule nesting-deferred work, it will schedule a
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// call to RunNestingDeferredWorkSource.
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void MaybeScheduleNestingDeferredWork();
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// Observer callback responsible for performing idle-priority work, before
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// the run loop goes to sleep. Associated with idle_work_observer_.
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static void StartOrEndWaitObserver(CFRunLoopObserverRef observer,
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CFRunLoopActivity activity, void* info);
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// Observer callback called before the run loop processes any sources.
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// Associated with pre_source_observer_.
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static void PreSourceObserver(CFRunLoopObserverRef observer,
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CFRunLoopActivity activity, void* info);
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// Observer callback called when the run loop starts and stops, at the
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// beginning and end of calls to CFRunLoopRun. This is used to maintain
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// nesting_level_. Associated with enter_exit_observer_.
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static void EnterExitObserver(CFRunLoopObserverRef observer,
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CFRunLoopActivity activity, void* info);
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// Called by EnterExitObserver after performing maintenance on nesting_level_.
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// This allows subclasses an opportunity to perform additional processing on
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// the basis of run loops starting and stopping.
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virtual void EnterExitRunLoop(CFRunLoopActivity activity);
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// The thread's run loop.
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CFRunLoopRef run_loop_;
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// The timer, sources, and observers are described above alongside their
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CFRunLoopTimerRef delayed_work_timer_;
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CFRunLoopSourceRef work_source_;
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CFRunLoopSourceRef idle_work_source_;
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CFRunLoopSourceRef nesting_deferred_work_source_;
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CFRunLoopObserverRef pre_wait_observer_;
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CFRunLoopObserverRef pre_source_observer_;
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CFRunLoopObserverRef enter_exit_observer_;
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// (weak) Delegate passed as an argument to the innermost Run call.
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// The time that delayed_work_timer_ is scheduled to fire. This is tracked
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// independently of CFRunLoopTimerGetNextFireDate(delayed_work_timer_)
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// to be able to reset the timer properly after waking from system sleep.
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// See PowerStateNotification.
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CFAbsoluteTime delayed_work_fire_time_;
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// The recursion depth of the currently-executing CFRunLoopRun loop on the
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// run loop's thread. 0 if no run loops are running inside of whatever scope
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// the object was created in.
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// The recursion depth (calculated in the same way as nesting_level_) of the
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// innermost executing CFRunLoopRun loop started by a call to Run.
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int run_nesting_level_;
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// The deepest (numerically highest) recursion depth encountered since the
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// most recent attempt to run nesting-deferred work.
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int deepest_nesting_level_;
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// "Delegateless" work flags are set when work is ready to be performed but
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// must wait until a delegate is available to process it. This can happen
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// when a MessagePumpCFRunLoopBase is instantiated and work arrives without
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// any call to Run on the stack. The Run method will check for delegateless
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// work on entry and redispatch it as needed once a delegate is available.
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bool delegateless_work_;
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bool delegateless_idle_work_;
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DISALLOW_COPY_AND_ASSIGN(MessagePumpCFRunLoopBase);
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class MessagePumpCFRunLoop : public MessagePumpCFRunLoopBase {
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MessagePumpCFRunLoop();
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virtual ~MessagePumpCFRunLoop();
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virtual void DoRun(Delegate* delegate) OVERRIDE;
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virtual void Quit() OVERRIDE;
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virtual void EnterExitRunLoop(CFRunLoopActivity activity) OVERRIDE;
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// True if Quit is called to stop the innermost MessagePump
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// (innermost_quittable_) but some other CFRunLoopRun loop (nesting_level_)
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// is running inside the MessagePump's innermost Run call.
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DISALLOW_COPY_AND_ASSIGN(MessagePumpCFRunLoop);
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class MessagePumpNSRunLoop : public MessagePumpCFRunLoopBase {
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BASE_EXPORT MessagePumpNSRunLoop();
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virtual ~MessagePumpNSRunLoop();
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virtual void DoRun(Delegate* delegate) OVERRIDE;
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virtual void Quit() OVERRIDE;
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// A source that doesn't do anything but provide something signalable
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// attached to the run loop. This source will be signalled when Quit
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// is called, to cause the loop to wake up so that it can stop.
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CFRunLoopSourceRef quit_source_;
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// False after Quit is called.
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DISALLOW_COPY_AND_ASSIGN(MessagePumpNSRunLoop);
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// This is a fake message pump. It attaches sources to the main thread's
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// CFRunLoop, so PostTask() will work, but it is unable to drive the loop
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// directly, so calling Run() or Quit() are errors.
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class MessagePumpUIApplication : public MessagePumpCFRunLoopBase {
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MessagePumpUIApplication();
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virtual ~MessagePumpUIApplication();
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virtual void DoRun(Delegate* delegate) OVERRIDE;
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virtual void Quit() OVERRIDE;
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// This message pump can not spin the main message loop directly. Instead,
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// call |Attach()| to set up a delegate. It is an error to call |Run()|.
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virtual void Attach(Delegate* delegate);
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DISALLOW_COPY_AND_ASSIGN(MessagePumpUIApplication);
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class MessagePumpNSApplication : public MessagePumpCFRunLoopBase {
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MessagePumpNSApplication();
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virtual ~MessagePumpNSApplication();
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virtual void DoRun(Delegate* delegate) OVERRIDE;
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virtual void Quit() OVERRIDE;
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// False after Quit is called.
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// True if DoRun is managing its own run loop as opposed to letting
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// -[NSApplication run] handle it. The outermost run loop in the application
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// is managed by -[NSApplication run], inner run loops are handled by a loop
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bool running_own_loop_;
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DISALLOW_COPY_AND_ASSIGN(MessagePumpNSApplication);
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class MessagePumpCrApplication : public MessagePumpNSApplication {
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MessagePumpCrApplication();
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virtual ~MessagePumpCrApplication();
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// Returns nil if NSApp is currently in the middle of calling
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// -sendEvent. Requires NSApp implementing CrAppProtocol.
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virtual NSAutoreleasePool* CreateAutoreleasePool() OVERRIDE;
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DISALLOW_COPY_AND_ASSIGN(MessagePumpCrApplication);
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#endif // !defined(OS_IOS)
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class MessagePumpMac {
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// If not on the main thread, returns a new instance of
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// MessagePumpNSRunLoop.
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// On the main thread, if NSApp exists and conforms to
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// CrAppProtocol, creates an instances of MessagePumpCrApplication.
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// Otherwise creates an instance of MessagePumpNSApplication using a
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// default NSApplication.
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static MessagePump* Create();
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// If a pump is created before the required CrAppProtocol is
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// created, the wrong MessagePump subclass could be used.
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// UsingCrApp() returns false if the message pump was created before
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// NSApp was initialized, or if NSApp does not implement
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// CrAppProtocol. NSApp must be initialized before calling.
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BASE_EXPORT static bool UsingCrApp();
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// Wrapper to query -[NSApp isHandlingSendEvent] from C++ code.
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// Requires NSApp to implement CrAppProtocol.
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BASE_EXPORT static bool IsHandlingSendEvent();
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#endif // !defined(OS_IOS)
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DISALLOW_IMPLICIT_CONSTRUCTORS(MessagePumpMac);
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#endif // BASE_MESSAGE_LOOP_MESSAGE_PUMP_MAC_H_