Allow policy refresh rate to be configured through policy.

chrome/browser/policy/device_management_policy_provider.h

 // Copyright (c) 2011 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_MANAGEMENT_POLICY_PROVIDER_H_
 #define CHROME_BROWSER_POLICY_DEVICE_MANAGEMENT_POLICY_PROVIDER_H_
 #pragma once
 
 #include <string>
 
 #include "base/file_path.h"
 #include "base/observer_list.h"
 #include "base/scoped_ptr.h"
 #include "base/time.h"
-#include "base/weak_ptr.h"
 #include "chrome/browser/policy/configuration_policy_provider.h"
 #include "chrome/browser/policy/device_management_backend.h"
 #include "chrome/browser/policy/device_token_fetcher.h"
 
 class Profile;
 class TokenService;
 
 namespace policy {
 
 class DeviceManagementBackend;
 class DeviceManagementPolicyCache;
 
 // Provides policy fetched from the device management server. With the exception
 // of the Provide method, which can be called on the FILE thread, all public
 // methods must be called on the UI thread.
 class DeviceManagementPolicyProvider
     :  public ConfigurationPolicyProvider,
        public DeviceManagementBackend::DevicePolicyResponseDelegate,
-       public base::SupportsWeakPtr<DeviceManagementPolicyProvider>,
        public DeviceTokenFetcher::Observer {
  public:
   DeviceManagementPolicyProvider(const PolicyDefinitionList* policy_list,
                                  DeviceManagementBackend* backend,
                                  Profile* profile);
 
   virtual ~DeviceManagementPolicyProvider();
 
   // ConfigurationPolicyProvider implementation:
   virtual bool Provide(ConfigurationPolicyStoreInterface* store);
   virtual bool IsInitializationComplete() const;
 
   // DevicePolicyResponseDelegate implementation:
   virtual void HandlePolicyResponse(
       const em::DevicePolicyResponse& response);
   virtual void OnError(DeviceManagementBackend::ErrorCode code);
 
   // DeviceTokenFetcher::Observer implementation:
   virtual void OnTokenSuccess();
   virtual void OnTokenError();
   virtual void OnNotManaged();
 
+  // Sets the refresh rate at which to re-fetch policy information.
+  void SetRefreshRate(int64 refresh_rate_milliseconds);
+
  private:
-  class InitializeAfterIOThreadExistsTask;
+  // Indicates the current state the provider is in.
+  enum ProviderState {
+    // The provider is initializing, policy information not yet available.
+    STATE_INITIALIZING,
+    // This device is not managed through policy.
+    STATE_UNMANAGED,
+    // The token is valid, but policy is yet to be fetched.
+    STATE_TOKEN_VALID,
+    // Policy information is available and valid.
+    STATE_POLICY_VALID,
+    // The token was found to be invalid and needs to be obtained again.
+    STATE_TOKEN_RESET,
+    // There has been an error fetching the token, retry later.
+    STATE_TOKEN_ERROR,
+    // The service returned an error when requesting policy, ask again later.
+    STATE_POLICY_ERROR,
+  };
+
   class RefreshTask;
 
   friend class DeviceManagementPolicyProviderTest;
 
   // More configurable constructor for use by test cases.
   DeviceManagementPolicyProvider(const PolicyDefinitionList* policy_list,
                                  DeviceManagementBackend* backend,
                                  Profile* profile,
                                  int64 policy_refresh_rate_ms,
-                                 int64 policy_refresh_max_earlier_ms,
+                                 int policy_refresh_fuzz_factor_percent,

[danno, 2011/01/06 19:16:26]

how about "deviation" or "random_deviation" instead of "fuzz"? 

[Mattias Nissler (ping if slow), 2011/01/07 11:15:33]

Done.

+                                 int64 policy_refresh_fuzz_max_ms,
                                  int64 policy_refresh_error_delay_ms,
                                  int64 token_fetch_error_delay_ms,
                                  int64 unmanaged_device_refresh_rate_ms);
 
   // Called by constructors to perform shared initialization. Initialization
   // requiring the IOThread must not be performed directly in this method,
   // rather must be deferred until the IOThread is fully initialized. This is
   // the case in InitializeAfterIOThreadExists.
   void Initialize(DeviceManagementBackend* backend,
                   Profile* profile,
                   int64 policy_refresh_rate_ms,
-                  int64 policy_refresh_max_earlier_ms,
+                  int policy_refresh_fuzz_factor_percent,
+                  int64 policy_refresh_fuzz_max_ms,
                   int64 policy_refresh_error_delay_ms,
                   int64 token_fetch_error_delay_ms,
                   int64 unmanaged_device_refresh_rate_ms);
 
-  // Called by a deferred task posted to the UI thread to complete the portion
-  // of initialization that requires the IOThread.
-  void InitializeAfterIOThreadExists();
-
   // ConfigurationPolicyProvider overrides:
   virtual void AddObserver(ConfigurationPolicyProvider::Observer* observer);
   virtual void RemoveObserver(ConfigurationPolicyProvider::Observer* observer);
 
   // Sends a request to the device manager backend to fetch policy if one isn't
   // already outstanding.
   void SendPolicyRequest();
 
   // Triggers policy refresh, re-requesting device token and policy information
   // as necessary.
   void RefreshTaskExecute();
 
-  // Schedules a new RefreshTask.
-  void ScheduleRefreshTask(int64 delay_in_milliseconds);
-
-  // Calculates when the next RefreshTask shall be executed.
-  int64 GetRefreshTaskDelay();
-
-  void StopWaitingForInitialPolicies();
+  // Cancels the refresh task.
+  void CancelRefreshTask();
 
   // Notify observers about a policy update.
   void NotifyCloudPolicyUpdate();
 
   // The path of the device token file.
   FilePath GetTokenPath();
 
   // Used only by tests.
   void SetDeviceTokenFetcher(DeviceTokenFetcher* token_fetcher);
 
+  // Switches to a new state and triggers any appropriate actions.
+  void SetState(ProviderState new_state);
+
+  // Check whether the current state is one in which the token is available.
+  bool TokenAvailable() const;
+
+  // Computes the refresh delay to use.
+  int64 GetRefreshDelay();
+
   // Provides the URL at which requests are sent to from the device management
   // backend.
   static std::string GetDeviceManagementURL();
 
   // Returns the path to the sub-directory in the user data directory
   // in which device management persistent state is stored.
   static FilePath GetOrCreateDeviceManagementDir(
       const FilePath& user_data_dir);
 
   scoped_ptr<DeviceManagementBackend> backend_;
   Profile* profile_;  // weak
   scoped_ptr<DeviceManagementPolicyCache> cache_;
   scoped_refptr<DeviceTokenFetcher> token_fetcher_;
   DeviceTokenFetcher::ObserverRegistrar registrar_;
   ObserverList<ConfigurationPolicyProvider::Observer, true> observer_list_;
   FilePath storage_dir_;
-  bool policy_request_pending_;
-  bool refresh_task_pending_;
-  bool waiting_for_initial_policies_;
+  ProviderState state_;
+  RefreshTask* refresh_task_;
   int64 policy_refresh_rate_ms_;
-  int64 policy_refresh_max_earlier_ms_;
+  int policy_refresh_fuzz_factor_percent_;
+  int64 policy_refresh_fuzz_max_ms_;
   int64 policy_refresh_error_delay_ms_;
+  int64 effective_policy_refresh_error_delay_ms_;
   int64 token_fetch_error_delay_ms_;
+  int64 effective_token_fetch_error_delay_ms_;
   int64 unmanaged_device_refresh_rate_ms_;
 
   DISALLOW_COPY_AND_ASSIGN(DeviceManagementPolicyProvider);
 };
 
 }  // namespace policy
 
 #endif  // CHROME_BROWSER_POLICY_DEVICE_MANAGEMENT_POLICY_PROVIDER_H_