Make sure that the UI window created by base::MessagePumpForUI is destoyed on the same thread (Wind…

base/message_loop/message_pump_win.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef BASE_MESSAGE_LOOP_MESSAGE_PUMP_WIN_H_
 #define BASE_MESSAGE_LOOP_MESSAGE_PUMP_WIN_H_
 
 #include <windows.h>
 
 #include <list>
 
 #include "base/base_export.h"
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_pump.h"
 #include "base/message_loop/message_pump_dispatcher.h"
 #include "base/message_loop/message_pump_observer.h"
 #include "base/observer_list.h"
+#include "base/synchronization/lock.h"
 #include "base/time.h"
 #include "base/win/scoped_handle.h"
 
 namespace base {
 
 // MessagePumpWin serves as the base for specialized versions of the MessagePump
 // for Windows. It provides basic functionality like handling of observers and
 // controlling the lifetime of the message pump.
 class BASE_EXPORT MessagePumpWin : public MessagePump {
  public:
   MessagePumpWin() : have_work_(0), state_(NULL) {}
   virtual ~MessagePumpWin() {}
 
   // Add an Observer, which will start receiving notifications immediately.
   void AddObserver(MessagePumpObserver* observer);
 
   // Remove an Observer.  It is safe to call this method while an Observer is
   // receiving a notification callback.
   void RemoveObserver(MessagePumpObserver* observer);
 
   // Give a chance to code processing additional messages to notify the
   // message loop observers that another message has been processed.
   void WillProcessMessage(const MSG& msg);
   void DidProcessMessage(const MSG& msg);
 
   // Like MessagePump::Run, but MSG objects are routed through dispatcher.
   void RunWithDispatcher(Delegate* delegate, MessagePumpDispatcher* dispatcher);
 
   // MessagePump methods:
-  virtual void Run(Delegate* delegate) { RunWithDispatcher(delegate, NULL); }
-  virtual void Quit();
+  virtual void Run(Delegate* delegate) OVERRIDE;
+  virtual void Quit() OVERRIDE;
 
  protected:
   struct RunState {
     Delegate* delegate;
     MessagePumpDispatcher* dispatcher;
 
     // Used to flag that the current Run() invocation should return ASAP.
     bool should_quit;
 
     // Used to count how many Run() invocations are on the stack.
@@ skipping 99 matching lines @@
 
   MessagePumpForUI();
   virtual ~MessagePumpForUI();
 
   // Sets a new MessageFilter. MessagePumpForUI takes ownership of
   // |message_filter|. When SetMessageFilter is called, old MessageFilter is
   // deleted.
   void SetMessageFilter(scoped_ptr<MessageFilter> message_filter);
 
   // MessagePump methods:
-  virtual void ScheduleWork();
-  virtual void ScheduleDelayedWork(const TimeTicks& delayed_work_time);
+  virtual void ScheduleWork() OVERRIDE;
+  virtual void ScheduleDelayedWork(const TimeTicks& delayed_work_time) OVERRIDE;
+  virtual void Shutdown() OVERRIDE;
 
   // Applications can call this to encourage us to process all pending WM_PAINT
   // messages.  This method will process all paint messages the Windows Message
   // queue can provide, up to some fixed number (to avoid any infinite loops).
   void PumpOutPendingPaintMessages();
 
  private:
   static LRESULT CALLBACK WndProcThunk(HWND window_handle,
                                        UINT message,
                                        WPARAM wparam,
                                        LPARAM lparam);
   virtual void DoRunLoop();
   void InitMessageWnd();
   void WaitForWork();
   void HandleWorkMessage();
   void HandleTimerMessage();
   bool ProcessNextWindowsMessage();
   bool ProcessMessageHelper(const MSG& msg);
   bool ProcessPumpReplacementMessage();
 
   // Atom representing the registered window class.
   ATOM atom_;
 
   // A hidden message-only window.
   HWND message_hwnd_;
 
+  // Protectes access to |message_hwnd_|.
+  base::Lock message_hwnd_lock_;
+
   scoped_ptr<MessageFilter> message_filter_;
 };
 
 //-----------------------------------------------------------------------------
 // MessagePumpForIO extends MessagePumpWin with methods that are particular to a
 // MessageLoop instantiated with TYPE_IO. This version of MessagePump does not
 // deal with Windows mesagges, and instead has a Run loop based on Completion
 // Ports so it is better suited for IO operations.
 //
 class BASE_EXPORT MessagePumpForIO : public MessagePumpWin {
@@ skipping 113 matching lines @@
     OVERLAPPED overlapped;
     IOHandler* handler;
   };
 
   MessagePumpForIO();
   virtual ~MessagePumpForIO() {}
 
   // MessagePump methods:
   virtual void ScheduleWork();
   virtual void ScheduleDelayedWork(const TimeTicks& delayed_work_time);
+  virtual void Shutdown() OVERRIDE;
 
   // Register the handler to be used when asynchronous IO for the given file
   // completes. The registration persists as long as |file_handle| is valid, so
   // |handler| must be valid as long as there is pending IO for the given file.
   void RegisterIOHandler(HANDLE file_handle, IOHandler* handler);
 
   // Register the handler to be used to process job events. The registration
   // persists as long as the job object is live, so |handler| must be valid
   // until the job object is destroyed. Returns true if the registration
   // succeeded, and false otherwise.
@@ skipping 47 matching lines @@
   // This list will be empty almost always. It stores IO completions that have
   // not been delivered yet because somebody was doing cleanup.
   std::list<IOItem> completed_io_;
 
   ObserverList<IOObserver> io_observers_;
 };
 
 }  // namespace base
 
 #endif  // BASE_MESSAGE_LOOP_MESSAGE_PUMP_WIN_H_