text: // Copyright 2014 The Chromium Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  #ifndef GOOGLE_APIS_GAIA_IDENTITY_PROVIDER_H_
  #define GOOGLE_APIS_GAIA_IDENTITY_PROVIDER_H_
  
  #include <string>
  
  #include "base/compiler_specific.h"
  #include "base/macros.h"
  #include "base/observer_list.h"
  #include "google_apis/gaia/oauth2_token_service.h"
  
  // Helper class that provides access to information about logged-in GAIA
  // accounts. Each instance of this class references an entity who may be logged
  // in to zero, one or multiple GAIA accounts. The class provides access to the
  // OAuth tokens for all logged-in accounts and indicates which of these is
  // currently active.
  // The main purpose of this abstraction layer is to isolate consumers of GAIA
  // information from the different sources and various token service
  // implementations. Whenever possible, consumers of GAIA information should be
  // provided with an instance of this class instead of accessing other GAIA APIs
  // directly.
  class IdentityProvider : public OAuth2TokenService::Observer {
   public:
    class Observer {
     public:
      // Called when a GAIA account logs in and becomes the active account. All
      // account information is available when this method is called and all
      // |IdentityProvider| methods will return valid data.
      virtual void OnActiveAccountLogin() {}
  
      // Called when the active GAIA account logs out. The account information may
      // have been cleared already when this method is called. The
      // |IdentityProvider| methods may return inconsistent or outdated
      // information if called from within OnLogout().
      virtual void OnActiveAccountLogout() {}
  
     protected:
      virtual ~Observer();
    };
  
    ~IdentityProvider() override;
  
    // Adds and removes observers that will be notified of changes to the refresh
    // token availability for the active account.
    void AddActiveAccountRefreshTokenObserver(
        OAuth2TokenService::Observer* observer);
    void RemoveActiveAccountRefreshTokenObserver(
        OAuth2TokenService::Observer* observer);
  
    // Gets the active account's user name.
    virtual std::string GetActiveUsername() = 0;
  
    // Gets the active account's account ID.
    virtual std::string GetActiveAccountId() = 0;
  
    // Gets the token service vending OAuth tokens for all logged-in accounts.
    virtual OAuth2TokenService* GetTokenService() = 0;
  
    void AddObserver(Observer* observer);
    void RemoveObserver(Observer* observer);
  
    // OAuth2TokenService::Observer:
    void OnRefreshTokenAvailable(const std::string& account_id) override;
    void OnRefreshTokenRevoked(const std::string& account_id) override;
    void OnRefreshTokensLoaded() override;
  
   protected:
    IdentityProvider();
  
    // Fires an OnActiveAccountLogin notification.
    void FireOnActiveAccountLogin();
  
    // Fires an OnActiveAccountLogout notification.
    void FireOnActiveAccountLogout();
  
   private:
    base::ObserverList<Observer, true> observers_;
    base::ObserverList<OAuth2TokenService::Observer, true>
        token_service_observers_;
    int token_service_observer_count_;
  
    DISALLOW_COPY_AND_ASSIGN(IdentityProvider);
  };
  
  #endif  // GOOGLE_APIS_GAIA_IDENTITY_PROVIDER_H_
  