chrome/browser/chromeos/camera_presence_notifier.cc

   1 // Copyright 2014 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 #include "chrome/browser/chromeos/camera_presence_notifier.h"
   6
   7 #include "base/bind.h"
   8 #include "base/memory/singleton.h"
   9 #include "base/time/time.h"
  10 #include "chrome/browser/chromeos/camera_detector.h"
  11
  12 namespace chromeos {
  13
  14 namespace {
  15
  16 // Interval between checks for camera presence.
  17 const int kCameraCheckIntervalSeconds = 3;
  18
  19 }  // namespace
  20
  21 CameraPresenceNotifier::CameraPresenceNotifier() :
  22     camera_present_on_last_check_(false),
  23     weak_factory_(this) {}
  24
  25 CameraPresenceNotifier::~CameraPresenceNotifier() {}
  26
  27 // static
  28 CameraPresenceNotifier* CameraPresenceNotifier::GetInstance() {
  29   return base::Singleton<CameraPresenceNotifier>::get();
  30 }
  31
  32 void CameraPresenceNotifier::AddObserver(
  33     CameraPresenceNotifier::Observer* observer) {
  34   bool had_no_observers = !observers_.might_have_observers();
  35   observers_.AddObserver(observer);
  36   observer->OnCameraPresenceCheckDone(camera_present_on_last_check_);
  37   if (had_no_observers) {
  38     CheckCameraPresence();
  39     camera_check_timer_.Start(
  40         FROM_HERE,
  41         base::TimeDelta::FromSeconds(kCameraCheckIntervalSeconds),
  42         this,
  43         &CameraPresenceNotifier::CheckCameraPresence);
  44   }
  45 }
  46
  47 void CameraPresenceNotifier::RemoveObserver(
  48     CameraPresenceNotifier::Observer* observer) {
  49   observers_.RemoveObserver(observer);
  50   if (!observers_.might_have_observers()) {
  51     camera_check_timer_.Stop();
  52     camera_present_on_last_check_ = false;
  53   }
  54 }
  55
  56 void CameraPresenceNotifier::CheckCameraPresence() {
  57   CameraDetector::StartPresenceCheck(
  58       base::Bind(&CameraPresenceNotifier::OnCameraPresenceCheckDone,
  59                  weak_factory_.GetWeakPtr()));
  60 }
  61
  62 void CameraPresenceNotifier::OnCameraPresenceCheckDone() {
  63   bool is_camera_present =
  64       CameraDetector::camera_presence() == CameraDetector::kCameraPresent;
  65   if (is_camera_present != camera_present_on_last_check_) {
  66     camera_present_on_last_check_ = is_camera_present;
  67     FOR_EACH_OBSERVER(Observer,
  68                       observers_,
  69                       OnCameraPresenceCheckDone(camera_present_on_last_check_));
  70   }
  71 }
  72
  73 }  // namespace chromeos