athena/activity/public/activity.h

   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 #ifndef ATHENA_ACTIVITY_PUBLIC_ACTIVITY_H_
   6 #define ATHENA_ACTIVITY_PUBLIC_ACTIVITY_H_
   7
   8 #include <string>
   9
  10 #include "athena/athena_export.h"
  11
  12 namespace aura {
  13 class Window;
  14 }
  15
  16 namespace content {
  17 class WebContents;
  18 }
  19
  20 namespace athena {
  21
  22 class ActivityViewModel;
  23
  24 // This class is a high level abstraction of an activity (which could be either
  25 // a web page or a V1/V2 app/extension). Through this class the activity can
  26 // be controlled (e.g. loaded / unloaded).
  27 // An Activity gets created with state |ACTIVITY_UNLOADED|.
  28 // Requesting |ACTIVITY_VISIBLE| or |ACTIVITY_INVISIBLE| will load it.
  29 // Once an activity was |ACTIVITY_INVISIBLE| for a while it can be transitioned
  30 // into |ACTIVITY_BACKGROUND_LOW_PRIORITY| to surrender more resources. After
  31 // more time it can be transitions to |ACTIVITY_PERSISTENT| in which it only
  32 // has it's runtime state left. At any time it can be transitioned back to one
  33 // of the higher levels or unloaded via |ACTIVITY_UNLOADED|.
  34 // Note that the resource manager will also query the media state before
  35 // deciding if an activity can put into a lower state then |ACTIVITY_INVISIBLE|.
  36 class ATHENA_EXPORT Activity {
  37  public:
  38   // The state of an activity which could either be set or requested by e.g. the
  39   // resource management system.
  40   enum ActivityState {
  41     // The activity is allowed to have gpu compositor layers and can be visible.
  42     ACTIVITY_VISIBLE,
  43     // The activity does not have gpu compositing layers, will not be visible
  44     // and will be treated as a background priority task.
  45     // By transitioning from VISIBLE to INVISIBLE, a screen shot of the current
  46     // web content will be taken and replaces the "active content".
  47     ACTIVITY_INVISIBLE,
  48     // The activity should surrender additional resources. This has only an
  49     // effect when the activity is in a loaded state (Visible, Active, Hidden).
  50     ACTIVITY_BACKGROUND_LOW_PRIORITY,
  51     // The activity will only keep a minimum set of resources to get back to the
  52     // running state. It will get stalled however. Note that it is not possible
  53     // to get into this state from the |ACTIVITY_UNLOADED| state.
  54     ACTIVITY_PERSISTENT,
  55     // Unloads the activity and can be called in any state - but unloaded.
  56     ACTIVITY_UNLOADED
  57   };
  58
  59   // This enum declares the media state the activity is in.
  60   // TODO(skuhne): Move the |TabMediaState| out of chrome and combine it in a
  61   // media library within content and then use that enum instead.
  62   enum ActivityMediaState {
  63     ACTIVITY_MEDIA_STATE_NONE,
  64     ACTIVITY_MEDIA_STATE_RECORDING,  // Audio/Video being recorded by activity.
  65     ACTIVITY_MEDIA_STATE_CAPTURING,  // Activity is being captured.
  66     ACTIVITY_MEDIA_STATE_AUDIO_PLAYING  // Audible audio is playing in activity.
  67   };
  68
  69   // Shows and activates an activity.
  70   static void Show(Activity* activity);
  71
  72   // Deletes an activity.
  73   static void Delete(Activity* activity);
  74
  75   // The Activity retains ownership of the returned view-model.
  76   virtual ActivityViewModel* GetActivityViewModel() = 0;
  77
  78   // Transition the activity into a new state.
  79   virtual void SetCurrentState(ActivityState state) = 0;
  80
  81   // Returns the current state of the activity.
  82   virtual ActivityState GetCurrentState() = 0;
  83
  84   // Returns if the activity is visible or not.
  85   virtual bool IsVisible() = 0;
  86
  87   // Returns the current media state.
  88   virtual ActivityMediaState GetMediaState() = 0;
  89
  90   // Returns the window for the activity. This can be used to determine the
  91   // stacking order of this activity against others.
  92   // TODO(oshima): Consider returning base::Window window instead,
  93   // which has Show/ShowInactive and other control methods.
  94   virtual aura::Window* GetWindow() = 0;
  95
  96   // Returns the web contents used to draw the content of the activity.
  97   // This may return nullptr if the web content is not available.
  98   virtual content::WebContents* GetWebContents() = 0;
  99
 100  protected:
 101   virtual ~Activity() {}
 102 };
 103
 104 }  // namespace athena
 105
 106 #endif  // ATHENA_ACTIVITY_PUBLIC_ACTIVITY_H_