chrome/browser/sync_file_system/sync_process_runner.h

   1 // Copyright 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 CHROME_BROWSER_SYNC_FILE_SYSTEM_SYNC_PROCESS_RUNNER_H_
   6 #define CHROME_BROWSER_SYNC_FILE_SYSTEM_SYNC_PROCESS_RUNNER_H_
   7
   8 #include <string>
   9
  10 #include "base/basictypes.h"
  11 #include "base/memory/weak_ptr.h"
  12 #include "base/timer/timer.h"
  13 #include "chrome/browser/sync_file_system/sync_callbacks.h"
  14 #include "chrome/browser/sync_file_system/sync_service_state.h"
  15
  16 namespace sync_file_system {
  17
  18 class SyncFileSystemService;
  19
  20 // A base class to schedule a sync.
  21 // Each subclass must implement StartSync().
  22 // An instance of this class is supposed to be owned by SyncFileSystemService.
  23 //
  24 // Note that multiple SyncProcessRunner doesn't coordinate its sync schedule
  25 // with each other.
  26 class SyncProcessRunner {
  27  public:
  28   // Default delay when more changes are available.
  29   static const int64 kSyncDelayInMilliseconds;
  30
  31   // Default delay when the previous change has had an error (but remote service
  32   // is running).
  33   static const int64 kSyncDelayWithSyncError;
  34
  35   // Default delay when there're more than 10 pending changes.
  36   static const int64 kSyncDelayFastInMilliseconds;
  37   static const int kPendingChangeThresholdForFastSync;
  38
  39   // Default delay when remote service is temporarily unavailable.
  40   // The delay backs off exponentially from initial value on repeated failure.
  41   static const int64 kSyncDelaySlowInMilliseconds;
  42
  43   // Default delay when there're no changes.
  44   static const int64 kSyncDelayMaxInMilliseconds;
  45
  46   class Client {
  47    public:
  48     virtual ~Client() {}
  49     virtual void OnSyncIdle() {}
  50     virtual SyncServiceState GetSyncServiceState() = 0;
  51     virtual SyncFileSystemService* GetSyncService() = 0;
  52   };
  53
  54   class TimerHelper {
  55    public:
  56     virtual ~TimerHelper() {}
  57     virtual bool IsRunning() = 0;
  58     virtual void Start(const tracked_objects::Location& from_here,
  59                        const base::TimeDelta& delay,
  60                        const base::Closure& closure) = 0;
  61     virtual base::TimeTicks Now() const = 0;
  62
  63    protected:
  64     TimerHelper() {}
  65   };
  66
  67   SyncProcessRunner(const std::string& name,
  68                     Client* client,
  69                     scoped_ptr<TimerHelper> timer_helper,
  70                     size_t max_parallel_task);
  71   virtual ~SyncProcessRunner();
  72
  73   // Subclass must implement this.
  74   virtual void StartSync(const SyncStatusCallback& callback) = 0;
  75
  76   // Schedules a new sync.
  77   void Schedule();
  78
  79   int64 pending_changes() const { return pending_changes_; }
  80
  81   // Returns the current service state.  Default implementation returns
  82   // sync_service()->GetSyncServiceState().
  83   virtual SyncServiceState GetServiceState();
  84
  85  protected:
  86   void OnChangesUpdated(int64 pending_changes);
  87   SyncFileSystemService* GetSyncService();
  88
  89  private:
  90   void Finished(const base::TimeTicks& start_time, SyncStatusCode status);
  91   void Run();
  92   void ScheduleInternal(int64 delay);
  93
  94   // Throttles new sync for |base_delay| milliseconds for an error case.
  95   // If new sync is already throttled, back off the duration.
  96   void ThrottleSync(int64 base_delay);
  97
  98   // Clears old throttling setting that is already over.
  99   void ResetOldThrottling();
 100   void ResetThrottling();
 101
 102   void CheckIfIdle();
 103
 104   std::string name_;
 105   Client* client_;
 106   size_t max_parallel_task_;
 107   size_t running_tasks_;
 108   scoped_ptr<TimerHelper> timer_helper_;
 109   base::TimeTicks last_run_;
 110   base::TimeTicks last_scheduled_;
 111   SyncServiceState service_state_;
 112
 113   base::TimeTicks throttle_from_;
 114   base::TimeTicks throttle_until_;
 115
 116   int64 pending_changes_;
 117   base::WeakPtrFactory<SyncProcessRunner> factory_;
 118
 119   DISALLOW_COPY_AND_ASSIGN(SyncProcessRunner);
 120 };
 121
 122 }  // namespace sync_file_system
 123
 124 #endif  // CHROME_BROWSER_SYNC_FILE_SYSTEM_SYNC_PROCESS_RUNNER_H_