chrome/browser/chromeos/settings/device_oauth2_token_service_factory.h

// Copyright 2013 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 CHROME_BROWSER_CHROMEOS_SETTINGS_DEVICE_OAUTH2_TOKEN_SERVICE_FACTORY_H_
#define CHROME_BROWSER_CHROMEOS_SETTINGS_DEVICE_OAUTH2_TOKEN_SERVICE_FACTORY_H_

#include <queue>
#include <string>

#include "base/basictypes.h"
#include "base/callback_forward.h"
#include "base/memory/weak_ptr.h"

namespace chromeos {

class DeviceOAuth2TokenService;

class DeviceOAuth2TokenServiceFactory {
 public:
  // Callback type used for Get() function.
  typedef base::Callback<void(DeviceOAuth2TokenService*)> GetCallback;

  // Returns the instance of the DeviceOAuth2TokenService singleton via the
  // given callback. This function is asynchronous as initializing
  // DeviceOAuth2TokenService involves asynchronous D-Bus method calls.
  //
  // May return NULL during browser startup and shutdown. May also return
  // NULL if Initialize() is not called beforehand, which can happen in unit
  // tests.
  //
  // Do not hold the pointer returned by this method; call this method every
  // time and check for NULL to handle the case where this instance is
  // destroyed during shutdown.
  static void Get(const GetCallback& callback);

  // Called by ChromeBrowserMainPartsChromeOS in order to bootstrap the
  // DeviceOAuth2TokenService instance after the required global data is
  // available (local state and request context getter).
  static void Initialize();

  // Called by ChromeBrowserMainPartsChromeOS in order to shutdown the
  // DeviceOAuth2TokenService instance and cancel all in-flight requests
  // before the required global data is destroyed (local state and request
  // context getter).
  static void Shutdown();

 private:
  DeviceOAuth2TokenServiceFactory();
  ~DeviceOAuth2TokenServiceFactory();

  // Creates the token service asynchronously in the following steps:
  // 1) Get the system salt from cryptohomed asynchronously
  // 2) Create CryptohomeTokenEncryptor using the system salt
  // 3) Create DeviceOAuth2TokenServiceFactory using the token encryptor
  void CreateTokenService();

  // Continuation of CreateTokenService(). Called when GetSystemSalt() is
  // complete.
  void DidGetSystemSalt(const std::string& system_salt);

  // Runs the callback asynchronously. If |token_service_| is ready, the
  // callback will be simply run via MessageLoop. Otherwise, the callback
  // will be queued in |pending_callbacks_| and run when |token_service_| is
  // ready.
  void RunAsync(const GetCallback& callback);

  // True if the factory is initialized (i.e. system salt retrieval is done
  // regardless of whether it succeeded or failed).
  bool initialized_;
  DeviceOAuth2TokenService* token_service_;
  std::queue<GetCallback> pending_callbacks_;
  base::WeakPtrFactory<DeviceOAuth2TokenServiceFactory> weak_ptr_factory_;

  DISALLOW_COPY_AND_ASSIGN(DeviceOAuth2TokenServiceFactory);
};

}  // namespace chromeos

#endif  // CHROME_BROWSER_CHROMEOS_SETTINGS_DEVICE_OAUTH2_TOKEN_SERVICE_FACTORY_H_