Home | History | Annotate | Download | only in wm 
      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
    155