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      1 // Copyright 2013 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_MEDIA_DESKTOP_MEDIA_PICKER_MODEL_H_
      6 #define CHROME_BROWSER_MEDIA_DESKTOP_MEDIA_PICKER_MODEL_H_
      7 
      8 #include "base/basictypes.h"
      9 #include "base/memory/scoped_ptr.h"
     10 #include "base/memory/weak_ptr.h"
     11 #include "base/sequenced_task_runner.h"
     12 #include "content/public/common/desktop_media_id.h"
     13 #include "ui/gfx/image/image_skia.h"
     14 
     15 namespace webrtc {
     16 class ScreenCapturer;
     17 class WindowCapturer;
     18 }
     19 
     20 // DesktopMediaPickerModel provides the list of desktop media source (screens,
     21 // windows, tabs), and their thumbnails, to the desktop media picker dialog. It
     22 // transparently updates the list in the background, and notifies the desktop
     23 // media picker when something changes.
     24 class DesktopMediaPickerModel {
     25  public:
     26   // Interface implemented by the picker dialog to receive notifications when
     27   // the model's contents change.
     28   class Observer {
     29    public:
     30     virtual ~Observer() {}
     31 
     32     virtual void OnSourceAdded(int index) = 0;
     33     virtual void OnSourceRemoved(int index) = 0;
     34     virtual void OnSourceNameChanged(int index) = 0;
     35     virtual void OnSourceThumbnailChanged(int index) = 0;
     36   };
     37 
     38   // Struct used to represent each entry in the model.
     39   struct Source {
     40     Source(content::DesktopMediaID id, const string16& name);
     41 
     42     // Id of the source.
     43     content::DesktopMediaID id;
     44 
     45     // Name of the source that should be shown to the user.
     46     string16 name;
     47 
     48     // The thumbnail for the source.
     49     gfx::ImageSkia thumbnail;
     50   };
     51 
     52   DesktopMediaPickerModel();
     53   virtual ~DesktopMediaPickerModel();
     54 
     55   // Sets screen/window capturer implementations to use (e.g. for tests). Caller
     56   // may pass NULL for either of the arguments in case when only some types of
     57   // sources the model should be populated with (e.g. it will only contain
     58   // windows, if |screen_capturer| is NULL). Must be called before
     59   // StartUpdating().
     60   void SetCapturers(scoped_ptr<webrtc::ScreenCapturer> screen_capturer,
     61                     scoped_ptr<webrtc::WindowCapturer> window_capturer);
     62 
     63   // Sets time interval between updates. By default list of sources and their
     64   // thumbnail are updated once per second. If called after StartUpdating() then
     65   // it will take effect only after the next update.
     66   void SetUpdatePeriod(base::TimeDelta period);
     67 
     68   // Sets size to which the thumbnails should be scaled. If called after
     69   // StartUpdating() then some thumbnails may be still scaled to the old size
     70   // until they are updated.
     71   void SetThumbnailSize(const gfx::Size& thumbnail_size);
     72 
     73   // Starts updating the model. The model is initially empty, so OnSourceAdded()
     74   // notifications will be generated for each existing source as it is
     75   // enumerated. After the initial enumeration the model will be refreshed based
     76   // on the update period, and notifications generated only for changes in the
     77   // model.
     78   void StartUpdating(Observer* observer);
     79 
     80   int source_count() const { return sources_.size(); }
     81   const Source& source(int index) const { return sources_.at(index); }
     82 
     83  private:
     84   class Worker;
     85   friend class Worker;
     86 
     87   // Struct used to represent sources list the model gets from the Worker.
     88   struct SourceDescription {
     89     SourceDescription(content::DesktopMediaID id, const string16& name);
     90 
     91     content::DesktopMediaID id;
     92     string16 name;
     93   };
     94 
     95   // Order comparator for sources. Used to sort list of sources.
     96   static bool CompareSources(const SourceDescription& a,
     97                              const SourceDescription& b);
     98 
     99   // Post a task for the |worker_| to update list of windows and get thumbnails.
    100   void Refresh();
    101 
    102   // Called by |worker_| to refresh the model. First it posts tasks for
    103   // OnSourcesList() with the fresh list of sources, then follows with
    104   // OnSourceThumbnail() for each changed thumbnail and then calls
    105   // OnRefreshFinished() at the end.
    106   void OnSourcesList(const std::vector<SourceDescription>& sources);
    107   void OnSourceThumbnail(int index, const gfx::ImageSkia& thumbnail);
    108   void OnRefreshFinished();
    109 
    110   // Flags passed to the constructor.
    111   int flags_;
    112 
    113   // Capturers specified in SetCapturers() and passed to the |worker_| later.
    114   scoped_ptr<webrtc::ScreenCapturer> screen_capturer_;
    115   scoped_ptr<webrtc::WindowCapturer> window_capturer_;
    116 
    117   // Time interval between mode updates.
    118   base::TimeDelta update_period_;
    119 
    120   // Size of thumbnails generated by the model.
    121   gfx::Size thumbnail_size_;
    122 
    123   // The observer passed to StartUpdating().
    124   Observer* observer_;
    125 
    126   // Task runner used for the |worker_|.
    127   scoped_refptr<base::SequencedTaskRunner> capture_task_runner_;
    128 
    129   // An object that does all the work of getting list of sources on a background
    130   // thread (see |capture_task_runner_|). Destroyed on |capture_task_runner_|
    131   // after the model is destroyed.
    132   scoped_ptr<Worker> worker_;
    133 
    134   // Current list of sources.
    135   std::vector<Source> sources_;
    136 
    137   base::WeakPtrFactory<DesktopMediaPickerModel> weak_factory_;
    138 
    139   DISALLOW_COPY_AND_ASSIGN(DesktopMediaPickerModel);
    140 };
    141 
    142 #endif  // CHROME_BROWSER_MEDIA_DESKTOP_MEDIA_PICKER_MODEL_H_
    143