ash/wm/video_detector.cc

   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 #include "ash/wm/video_detector.h"
   6
   7 #include "ash/shell.h"
   8 #include "ash/shell_window_ids.h"
   9 #include "ash/wm/window_state.h"
  10 #include "ui/aura/env.h"
  11 #include "ui/aura/window.h"
  12 #include "ui/aura/window_event_dispatcher.h"
  13 #include "ui/gfx/rect.h"
  14 #include "ui/wm/core/window_util.h"
  15
  16 namespace ash {
  17
  18 const int VideoDetector::kMinUpdateWidth = 333;
  19 const int VideoDetector::kMinUpdateHeight = 250;
  20 const int VideoDetector::kMinFramesPerSecond = 15;
  21 const double VideoDetector::kNotifyIntervalSec = 1.0;
  22
  23 // Stores information about updates to a window and determines whether it's
  24 // likely that a video is playing in it.
  25 class VideoDetector::WindowInfo {
  26  public:
  27   WindowInfo() : buffer_start_(0), buffer_size_(0) {}
  28
  29   // Handles an update within a window, returning true if it appears that
  30   // video is currently playing in the window.
  31   bool RecordUpdateAndCheckForVideo(const gfx::Rect& region,
  32                                     base::TimeTicks now) {
  33     if (region.width() < kMinUpdateWidth || region.height() < kMinUpdateHeight)
  34       return false;
  35
  36     // If the buffer is full, drop the first timestamp.
  37     if (buffer_size_ == static_cast<size_t>(kMinFramesPerSecond)) {
  38       buffer_start_ = (buffer_start_ + 1) % kMinFramesPerSecond;
  39       buffer_size_--;
  40     }
  41
  42     update_times_[(buffer_start_ + buffer_size_) % kMinFramesPerSecond] = now;
  43     buffer_size_++;
  44
  45     return buffer_size_ == static_cast<size_t>(kMinFramesPerSecond) &&
  46         (now - update_times_[buffer_start_]).InSecondsF() <= 1.0;
  47   }
  48
  49  private:
  50   // Circular buffer containing update times of the last (up to
  51   // |kMinFramesPerSecond|) video-sized updates to this window.
  52   base::TimeTicks update_times_[kMinFramesPerSecond];
  53
  54   // Index into |update_times_| of the oldest update.
  55   size_t buffer_start_;
  56
  57   // Number of updates stored in |update_times_|.
  58   size_t buffer_size_;
  59
  60   DISALLOW_COPY_AND_ASSIGN(WindowInfo);
  61 };
  62
  63 VideoDetector::VideoDetector()
  64     : observer_manager_(this),
  65       is_shutting_down_(false) {
  66   aura::Env::GetInstance()->AddObserver(this);
  67   Shell::GetInstance()->AddShellObserver(this);
  68 }
  69
  70 VideoDetector::~VideoDetector() {
  71   Shell::GetInstance()->RemoveShellObserver(this);
  72   aura::Env::GetInstance()->RemoveObserver(this);
  73 }
  74
  75 void VideoDetector::AddObserver(VideoDetectorObserver* observer) {
  76   observers_.AddObserver(observer);
  77 }
  78
  79 void VideoDetector::RemoveObserver(VideoDetectorObserver* observer) {
  80   observers_.RemoveObserver(observer);
  81 }
  82
  83 void VideoDetector::OnWindowInitialized(aura::Window* window) {
  84   observer_manager_.Add(window);
  85 }
  86
  87 void VideoDetector::OnWindowPaintScheduled(aura::Window* window,
  88                                            const gfx::Rect& region) {
  89   if (is_shutting_down_)
  90     return;
  91   linked_ptr<WindowInfo>& info = window_infos_[window];
  92   if (!info.get())
  93     info.reset(new WindowInfo);
  94
  95   base::TimeTicks now =
  96       !now_for_test_.is_null() ? now_for_test_ : base::TimeTicks::Now();
  97   if (info->RecordUpdateAndCheckForVideo(region, now))
  98     MaybeNotifyObservers(window, now);
  99 }
 100
 101 void VideoDetector::OnWindowDestroyed(aura::Window* window) {
 102   window_infos_.erase(window);
 103   observer_manager_.Remove(window);
 104 }
 105
 106 void VideoDetector::OnAppTerminating() {
 107   // Stop checking video activity once the shutdown
 108   // process starts. crbug.com/231696.
 109   is_shutting_down_ = true;
 110 }
 111
 112 void VideoDetector::MaybeNotifyObservers(aura::Window* window,
 113                                          base::TimeTicks now) {
 114   if (!last_observer_notification_time_.is_null() &&
 115       (now - last_observer_notification_time_).InSecondsF() <
 116       kNotifyIntervalSec)
 117     return;
 118
 119   if (!window->IsVisible())
 120     return;
 121
 122   gfx::Rect root_bounds = window->GetRootWindow()->bounds();
 123   if (!window->GetBoundsInRootWindow().Intersects(root_bounds))
 124     return;
 125
 126   // As a relatively-cheap way to avoid flipping back and forth between
 127   // fullscreen and non-fullscreen notifications when one video is playing in a
 128   // fullscreen window and a second video is playing in a non-fullscreen window,
 129   // report fullscreen video whenever a fullscreen window exists on any desktop
 130   // regardless of whether the video is actually playing in that window:
 131   // http://crbug.com/340666
 132   bool fullscreen_window_exists = false;
 133   std::vector<aura::Window*> containers =
 134       Shell::GetContainersFromAllRootWindows(kShellWindowId_DefaultContainer,
 135                                              NULL);
 136   for (std::vector<aura::Window*>::const_iterator container =
 137        containers.begin(); container != containers.end(); ++container) {
 138     const aura::Window::Windows& windows = (*container)->children();
 139     for (aura::Window::Windows::const_iterator window = windows.begin();
 140          window != windows.end(); ++window) {
 141       if (wm::GetWindowState(*window)->IsFullscreen()) {
 142         fullscreen_window_exists = true;
 143         break;
 144       }
 145     }
 146   }
 147
 148   FOR_EACH_OBSERVER(VideoDetectorObserver,
 149                     observers_,
 150                     OnVideoDetected(fullscreen_window_exists));
 151   last_observer_notification_time_ = now;
 152 }
 153
 154 }  // namespace ash