components/variations/variations_request_scheduler.h

   1 // Copyright (c) 2013 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 COMPONENTS_VARIATIONS_VARIATIONS_REQUEST_SCHEDULER_H_
   6 #define COMPONENTS_VARIATIONS_VARIATIONS_REQUEST_SCHEDULER_H_
   7
   8 #include "base/bind.h"
   9 #include "base/gtest_prod_util.h"
  10 #include "base/time/time.h"
  11 #include "base/timer/timer.h"
  12
  13 class PrefService;
  14
  15 namespace variations {
  16
  17 // A helper class that makes VariationsService requests at the correct times.
  18 class VariationsRequestScheduler {
  19  public:
  20   virtual ~VariationsRequestScheduler();
  21
  22   // Starts the task. This can be a repeated event or a one-off.
  23   virtual void Start();
  24
  25   // Resets the scheduler if it is currently on a timer.
  26   virtual void Reset();
  27
  28   // Schedules a fetch shortly, for example to re-try the initial request which
  29   // may have failed.
  30   void ScheduleFetchShortly();
  31
  32   // Called when the application has been foregrounded. This may fetch a new
  33   // seed.
  34   virtual void OnAppEnterForeground();
  35
  36   // Factory method for this class.
  37   static VariationsRequestScheduler* Create(const base::Closure& task,
  38                                             PrefService* local_state);
  39
  40  protected:
  41   // |task| is the closure to call when the scheduler deems ready.
  42   explicit VariationsRequestScheduler(const base::Closure& task);
  43
  44   // Returns the time interval between variations seed fetches.
  45   base::TimeDelta GetFetchPeriod() const;
  46
  47   // Getter for derived classes.
  48   base::Closure task() const;
  49
  50  private:
  51   FRIEND_TEST_ALL_PREFIXES(VariationsRequestSchedulerTest,
  52                            ScheduleFetchShortly);
  53
  54   // The task scheduled by this class.
  55   base::Closure task_;
  56
  57   // The timer used to repeatedly ping the server. Keep this as an instance
  58   // member so if VariationsRequestScheduler goes out of scope, the timer is
  59   // automatically canceled.
  60   base::RepeatingTimer<VariationsRequestScheduler> timer_;
  61
  62   // A one-shot timer used for scheduling out-of-band fetches.
  63   base::OneShotTimer<VariationsRequestScheduler> one_shot_timer_;
  64
  65   DISALLOW_COPY_AND_ASSIGN(VariationsRequestScheduler);
  66 };
  67
  68 }  // namespace variations
  69
  70 #endif  // COMPONENTS_VARIATIONS_VARIATIONS_REQUEST_SCHEDULER_H_