chrome/browser/chromeos/camera_detector.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_BROWSER_CHROMEOS_CAMERA_DETECTOR_H_
   6 #define CHROME_BROWSER_CHROMEOS_CAMERA_DETECTOR_H_
   7
   8 #include "base/callback.h"
   9
  10 namespace chromeos {
  11
  12 // Class used to check for camera presence.
  13 class CameraDetector {
  14  public:
  15   enum CameraPresence {
  16     kCameraPresenceUnknown = 0,
  17     kCameraAbsent,
  18     kCameraPresent
  19   };
  20
  21   // Returns result of the last presence check. If no check has been performed
  22   // yet, returns |kCameraPresenceUnknown|.
  23   static CameraPresence camera_presence() {
  24     return camera_presence_;
  25   }
  26
  27   // Checks asynchronously for camera device presence. Only one
  28   // presence check can be running at a time. Calls |check_done|
  29   // on current thread when the check has been completed.
  30   static void StartPresenceCheck(const base::Closure& check_done);
  31
  32  private:
  33   // Called back on UI thread after check has been performed.
  34   static void OnPresenceCheckDone(const base::Closure& callback, bool present);
  35
  36   // Checks for camera presence. Runs on a thread that allows I/O.
  37   static bool CheckPresence();
  38
  39   // Result of the last presence check.
  40   static CameraPresence camera_presence_;
  41
  42   static bool presence_check_in_progress_;
  43
  44   DISALLOW_COPY_AND_ASSIGN(CameraDetector);
  45 };
  46
  47 }  // namespace chromeos
  48
  49 #endif  // CHROME_BROWSER_CHROMEOS_CAMERA_DETECTOR_H_