chrome_frame/task_marshaller.h

   1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CHROME_FRAME_TASK_MARSHALLER_H_
   6 #define CHROME_FRAME_TASK_MARSHALLER_H_
   7
   8 #include <windows.h>
   9 #include <deque>
  10 #include <queue>
  11
  12 #include "base/callback.h"
  13 #include "base/pending_task.h"
  14 #include "base/synchronization/lock.h"
  15 #include "base/threading/non_thread_safe.h"
  16 #include "base/time/time.h"
  17
  18 class Task;
  19
  20 namespace tracked_objects {
  21 class Location;
  22 }
  23
  24 // TaskMarshallerThroughMessageQueue is similar to base::MessageLoopForUI
  25 // in cases where we do not control the thread lifetime and message retrieval
  26 // and dispatching. It uses a HWND to ::PostMessage to it as a signal that
  27 // the task queue is not empty.
  28 class TaskMarshallerThroughMessageQueue : public base::NonThreadSafe {
  29  public:
  30   TaskMarshallerThroughMessageQueue();
  31   virtual ~TaskMarshallerThroughMessageQueue();
  32
  33   void SetWindow(HWND wnd, UINT msg) {
  34     wnd_ = wnd;
  35     msg_ = msg;
  36   }
  37
  38   virtual void PostTask(const tracked_objects::Location& from_here,
  39                         const base::Closure& task);
  40   virtual void PostDelayedTask(const tracked_objects::Location& source,
  41                                const base::Closure& task,
  42                                base::TimeDelta& delay);
  43
  44   // Called by the owner of the HWND.
  45   BOOL ProcessWindowMessage(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam,
  46                             LRESULT& lResult, DWORD dwMsgMapID = 0);
  47  private:
  48   void ClearTasks();
  49   inline base::Closure PopTask();
  50   inline void ExecuteQueuedTasks();
  51   void ExecuteDelayedTasks();
  52
  53   // Shortest delays ordered at the top of the queue.
  54   base::DelayedTaskQueue delayed_tasks_;
  55
  56   // A list of tasks that need to be processed by this instance.
  57   std::queue<base::Closure> pending_tasks_;
  58
  59   // Lock accesses to |pending_tasks_|.
  60   base::Lock lock_;
  61
  62   // ::PostMessage parameters.
  63   HWND wnd_;
  64   UINT msg_;
  65 };
  66
  67 #endif  // CHROME_FRAME_TASK_MARSHALLER_H_