components/proximity_auth/cryptauth/sync_scheduler_impl.h

   1 // Copyright 2015 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_PROXIMITY_AUTH_CRYPTAUTH_CRYPTAUTH_SYNC_SCHEDULER_IMPL_H
   6 #define COMPONENTS_PROXIMITY_AUTH_CRYPTAUTH_CRYPTAUTH_SYNC_SCHEDULER_IMPL_H
   7
   8 #include "base/timer/timer.h"
   9 #include "components/proximity_auth/cryptauth/sync_scheduler.h"
  10
  11 namespace proximity_auth {
  12
  13 // Implementation of SyncScheduler.
  14 class SyncSchedulerImpl : public SyncScheduler {
  15  public:
  16   // Creates the scheduler:
  17   // |delegate|: Handles sync requests and must outlive the scheduler.
  18   // |refresh_period|: The time to wait for the PERIODIC_REFRESH strategy.
  19   // |base_recovery_period|: The initial time to wait for the
  20   //    AGGRESSIVE_RECOVERY strategy. The time delta is increased for each
  21   //    subsequent failure.
  22   // |max_jitter_ratio|: The maximum ratio that the time to next sync can be
  23   //    jittered (both positively and negatively).
  24   // |scheduler_name|: The name of the scheduler for debugging purposes.
  25   SyncSchedulerImpl(Delegate* delegate,
  26                     base::TimeDelta refresh_period,
  27                     base::TimeDelta base_recovery_period,
  28                     double max_jitter_ratio,
  29                     const std::string& scheduler_name);
  30
  31   ~SyncSchedulerImpl() override;
  32
  33   // SyncScheduler:
  34   void Start(const base::TimeDelta& elapsed_time_since_last_sync,
  35              Strategy strategy) override;
  36   void ForceSync() override;
  37   base::TimeDelta GetTimeToNextSync() const override;
  38   Strategy GetStrategy() const override;
  39   SyncState GetSyncState() const override;
  40
  41  protected:
  42   // Creates and returns a base::Timer object. Exposed for testing.
  43   virtual scoped_ptr<base::Timer> CreateTimer();
  44
  45  private:
  46   // SyncScheduler:
  47   void OnSyncCompleted(bool success) override;
  48
  49   // Called when |timer_| is fired.
  50   void OnTimerFired();
  51
  52   // Schedules |timer_| for the next sync request.
  53   void ScheduleNextSync(const base::TimeDelta& sync_delta);
  54
  55   // Adds a random jitter to the value of GetPeriod(). The returned
  56   // TimeDelta will be clamped to be non-negative.
  57   base::TimeDelta GetJitteredPeriod();
  58
  59   // Returns the time to wait for the current strategy.
  60   base::TimeDelta GetPeriod();
  61
  62   // The delegate handling sync requests when they are fired.
  63   Delegate* const delegate_;
  64
  65   // The time to wait until the next refresh when the last sync attempt was
  66   // successful.
  67   const base::TimeDelta refresh_period_;
  68
  69   // The base recovery period for the AGGRESSIVE_RECOVERY strategy before
  70   // backoffs are applied.
  71   const base::TimeDelta base_recovery_period_;
  72
  73   // The maximum percentage (both positively and negatively) that the time to
  74   // wait between each sync request is jittered. The jitter is randomly applied
  75   // to each period so we can avoid synchronous calls to the server.
  76   const double max_jitter_ratio_;
  77
  78   // The name of the scheduler, used for debugging purposes.
  79   const std::string scheduler_name_;
  80
  81   // The current strategy of the scheduler.
  82   Strategy strategy_;
  83
  84   // The current state of the scheduler.
  85   SyncState sync_state_;
  86
  87   // The number of failed syncs made in a row. Once a sync request succeeds,
  88   // this counter is reset.
  89   size_t failure_count_;
  90
  91   // Timer firing for the next sync request.
  92   scoped_ptr<base::Timer> timer_;
  93
  94   base::WeakPtrFactory<SyncSchedulerImpl> weak_ptr_factory_;
  95
  96   DISALLOW_COPY_AND_ASSIGN(SyncSchedulerImpl);
  97 };
  98
  99 }  // namespace proximity_auth
 100
 101 #endif  // COMPONENTS_PROXIMITY_CRYPTAUTH_CRYPTAUTH_SYNC_SCHEDULER_IMPL_H