content/browser/device_monitor_mac.h

   1 // Copyright (c) 2012 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 CONTENT_BROWSER_DEVICE_MONITOR_MAC_H_
   6 #define CONTENT_BROWSER_DEVICE_MONITOR_MAC_H_
   7
   8 #include "base/basictypes.h"
   9 #include "base/system_monitor/system_monitor.h"
  10 #include "base/threading/thread_checker.h"
  11
  12 namespace {
  13 class DeviceMonitorMacImpl;
  14 }
  15
  16 namespace content {
  17
  18 // Class to track audio/video devices removal or addition via callback to
  19 // base::SystemMonitor ProcessDevicesChanged(). A single object of this class
  20 // is created from the browser main process and lives as long as this one.
  21 class DeviceMonitorMac {
  22  public:
  23   DeviceMonitorMac();
  24   ~DeviceMonitorMac();
  25
  26   // Registers the observers for the audio/video device removal, connection and
  27   // suspension. The AVFoundation library is also loaded and initialised if the
  28   // OS supports it. The |device_task_runner| argument represents the thread on
  29   // which device enumeration will occur.
  30   void StartMonitoring(
  31     const scoped_refptr<base::SingleThreadTaskRunner>& device_task_runner);
  32
  33   // Method called by the internal DeviceMonitorMacImpl object
  34   // |device_monitor_impl_| when a device of type |type| has been added to or
  35   // removed from the system. This code executes in the notification thread
  36   // (QTKit or AVFoundation).
  37   void NotifyDeviceChanged(base::SystemMonitor::DeviceType type);
  38
  39  private:
  40   scoped_ptr<DeviceMonitorMacImpl> device_monitor_impl_;
  41
  42   // |thread_checker_| is used to check that constructor and StartMonitoring()
  43   // are called in the correct thread, the UI thread, that also owns the object.
  44   base::ThreadChecker thread_checker_;
  45
  46   DISALLOW_COPY_AND_ASSIGN(DeviceMonitorMac);
  47 };
  48
  49 }  // namespace content
  50
  51 #endif  // CONTENT_BROWSER_DEVICE_MONITOR_MAC_H_