Refresh policies from DM server periodically

chrome/browser/policy/device_token_fetcher.h

 // Copyright (c) 2010 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_POLICY_DEVICE_TOKEN_FETCHER_H_
 #define CHROME_BROWSER_POLICY_DEVICE_TOKEN_FETCHER_H_
 #pragma once
 
 #include <string>
 
 #include "base/file_path.h"
+#include "base/observer_list.h"
 #include "base/ref_counted.h"
 #include "base/waitable_event.h"
 #include "chrome/browser/policy/device_management_backend.h"
 #include "chrome/common/notification_observer.h"
 #include "chrome/common/notification_registrar.h"
 
 class TokenService;
 
 namespace policy {
 
 namespace em = enterprise_management;
 
 // Fetches the device token that can be used for policy requests with the device
 // management server, either from disk if it already has been successfully
 // requested, otherwise from the device management server. An instance of the
 // fetcher is shared as a singleton by all users of the device management token
 // to ensure they all get the same token.
 class DeviceTokenFetcher
     : public NotificationObserver,
       public DeviceManagementBackend::DeviceRegisterResponseDelegate,
       public base::RefCountedThreadSafe<DeviceTokenFetcher> {
  public:
+  class Observer {
+   public:
+    virtual void OnTokenSuccess() = 0;
+    virtual void OnTokenError() = 0;
+    virtual ~Observer() {}
+  };
+
   // Requests to the device management server are sent through |backend|. It
   // obtains the authentication token from |token_service|. The fetcher stores
   // the device token to |token_path| once it's retrieved from the server.
   DeviceTokenFetcher(DeviceManagementBackend* backend,
                      TokenService* token_service,
                      const FilePath& token_path);
   virtual ~DeviceTokenFetcher() {}
 
   // NotificationObserver method overrides:
   virtual void Observe(NotificationType type,
                        const NotificationSource& source,
                        const NotificationDetails& details);
 
   // DeviceManagementBackend::DeviceRegisterResponseDelegate method overrides:
   virtual void HandleRegisterResponse(
       const em::DeviceRegisterResponse& response);
   virtual void OnError(DeviceManagementBackend::ErrorCode code);
 
+  // Re-initializes this DeviceTokenFetcher
+  void Restart();
+
   // Called by subscribers of the device management token to indicate that they
   // will need the token in the future. Must be called on the UI thread.
   void StartFetching();
 
   // Instructs the fetcher to shut down, before the backend and token service
   // references become stale.
   void Shutdown();
 
   // Returns true if there is a pending token request to the device management
   // server.
   bool IsTokenPending();
 
   // Returns the device management token for this device, blocking until
   // outstanding requests to the device management server are satisfied.  In the
   // case that the token could not be fetched, an empty string is returned.
   std::string GetDeviceToken();
 
   // Returns the device ID for this device. If no such ID has been set yet, a
   // new ID is generated and returned.
   std::string GetDeviceID();
 
   // True if the fetcher has a valid AuthToken for the device management server.
   bool HasAuthToken() const { return !auth_token_.empty(); }
 
   // True if the device token has been fetched and is valid.
   bool IsTokenValid() const;
 
+  void AddObserver(Observer* obs) {
+    observer_list_.AddObserver(obs);
+  }
+
+  void RemoveObserver(Observer* obs) {
+    observer_list_.RemoveObserver(obs);
+  }
+
  private:
   friend class DeviceTokenFetcherTest;
 
   // The different states that the fetcher can be in during the process of
   // getting the device token.
   enum FetcherState {
     kStateNotStarted,
     kStateLoadDeviceTokenFromDisk,
     kStateReadyToRequestDeviceTokenFromServer,
     kStateRequestingDeviceTokenFromServer,
@@ skipping 18 matching lines @@
   // management server and receive the device token in return. If the AuthToken
   // for the device management server is available, initiate the server
   // request.
   void MakeReadyToRequestDeviceToken();
 
   // Issues a registration request to the server if both the fetcher is in the
   // ready-to-request state and the device management server AuthToken is
   // available.
   void SendServerRequestIfPossible();
 
+  void NotifyTokenSuccess() {
+    FOR_EACH_OBSERVER(Observer, observer_list_, OnTokenSuccess());
+  }
+
+  void NotifyTokenError() {
+    FOR_EACH_OBSERVER(Observer, observer_list_, OnTokenError());
+  }
+
   // Saves the device management token to disk once it has been retrieved from
   // the server. Must be called on the FILE thread.
   static void WriteDeviceTokenToDisk(const FilePath& path,
                                      const std::string& token,
                                      const std::string& device_id);
 
   // Generates a new device ID used to register the device with the device
   // management server and generate the device token.
   static std::string GenerateNewDeviceID();
 
+  ObserverList<Observer> observer_list_;
   FilePath token_path_;
   DeviceManagementBackend* backend_;  // weak
   TokenService* token_service_;
   FetcherState state_;
   std::string device_token_;
   std::string device_id_;
 
   // Contains the AuthToken for the device management server. Empty if the
   // AuthToken hasn't been issued yet or that was an error getting the
   // AuthToken.
   std::string auth_token_;
 
   // An event that is signaled only once the device token has been fetched
   // or it has been determined that there was an error during fetching.
   base::WaitableEvent device_token_load_complete_event_;
 
   // Registers the fetcher for notification of successful Gaia logins.
   NotificationRegistrar registrar_;
 };
 
 }  // namespace policy
 
 #endif  // CHROME_BROWSER_POLICY_DEVICE_TOKEN_FETCHER_H_