ios/web/active_state_manager_impl.h

   1 // Copyright 2015 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 IOS_WEB_ACTIVE_STATE_MANAGER_IMPL_H_
   6 #define IOS_WEB_ACTIVE_STATE_MANAGER_IMPL_H_
   7
   8 #include "base/macros.h"
   9 #include "base/observer_list.h"
  10 #include "base/supports_user_data.h"
  11 #include "ios/web/public/active_state_manager.h"
  12
  13 namespace web {
  14
  15 class BrowserState;
  16
  17 // Concrete subclass of web::ActiveStateManager. Informs observers when an
  18 // ActiveStateManager becomes active/inactive.
  19 class ActiveStateManagerImpl : public ActiveStateManager,
  20                                public base::SupportsUserData::Data {
  21  public:
  22   explicit ActiveStateManagerImpl(BrowserState* browser_state);
  23   ~ActiveStateManagerImpl() override;
  24
  25   // ActiveStateManager methods.
  26   void SetActive(bool active) override;
  27   bool IsActive() override;
  28
  29   // Observer that is notified when a ActiveStateManager becomes active,
  30   // inactive or destroyed.
  31   class Observer {
  32    public:
  33     // Called when the ActiveStateManager becomes active.
  34     virtual void OnActive() = 0;
  35     // Called when the ActiveStateManager becomes inactive.
  36     virtual void OnInactive() = 0;
  37     // Called just before the ActiveStateManager is destroyed.
  38     virtual void WillBeDestroyed() = 0;
  39   };
  40   // Adds an observer for this class. An observer should not be added more
  41   // than once. The caller retains the ownership of the observer object.
  42   void AddObserver(Observer* obs);
  43   // Removes an observer.
  44   void RemoveObserver(Observer* obs);
  45
  46  private:
  47   BrowserState* browser_state_;  // weak, owns this object.
  48   // true if the ActiveStateManager is active.
  49   bool active_;
  50   // The list of observers.
  51   base::ObserverList<Observer> observer_list_;
  52
  53   DISALLOW_COPY_AND_ASSIGN(ActiveStateManagerImpl);
  54 };
  55
  56 }  // namespace web
  57
  58 #endif  // IOS_WEB_ACTIVE_STATE_MANAGER_IMPL_H_