sync/sessions/nudge_tracker.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 // A class to track the outstanding work required to bring the client back into
   6 // sync with the server.
   7 #ifndef SYNC_SESSIONS_NUDGE_TRACKER_H_
   8 #define SYNC_SESSIONS_NUDGE_TRACKER_H_
   9
  10 #include <list>
  11 #include <map>
  12
  13 #include "base/compiler_specific.h"
  14 #include "base/memory/scoped_ptr.h"
  15 #include "sync/base/sync_export.h"
  16 #include "sync/internal_api/public/base/invalidation_interface.h"
  17 #include "sync/internal_api/public/base/model_type.h"
  18 #include "sync/protocol/sync.pb.h"
  19 #include "sync/sessions/data_type_tracker.h"
  20
  21 namespace syncer {
  22
  23 class ObjectIdInvalidationMap;
  24
  25 namespace sessions {
  26
  27 class SYNC_EXPORT_PRIVATE NudgeTracker {
  28  public:
  29   static size_t kDefaultMaxPayloadsPerType;
  30
  31   NudgeTracker();
  32   ~NudgeTracker();
  33
  34   // Returns true if there is a good reason for performing a sync cycle.
  35   // This does not take into account whether or not this is a good *time* to
  36   // perform a sync cycle; that's the scheduler's job.
  37   bool IsSyncRequired() const;
  38
  39   // Returns true if there is a good reason for performing a get updates
  40   // request as part of the next sync cycle.
  41   bool IsGetUpdatesRequired() const;
  42
  43   // Return true if should perform a sync cycle for GU retry.
  44   //
  45   // This is sensitive to changes in 'current time'.  Its value can be affected
  46   // by SetSyncCycleStartTime(), SetNextRetryTime(), and
  47   // RecordSuccessfulSyncCycle().  Please refer to those functions for more
  48   // information on how this flag is maintained.
  49   bool IsRetryRequired() const;
  50
  51   // Tells this class that all required update fetching or committing has
  52   // completed successfully.
  53   void RecordSuccessfulSyncCycle();
  54
  55   // Takes note of a local change.
  56   void RecordLocalChange(ModelTypeSet types);
  57
  58   // Takes note of a locally issued request to refresh a data type.
  59   void RecordLocalRefreshRequest(ModelTypeSet types);
  60
  61   // Takes note of the receipt of an invalidation notice from the server.
  62   void RecordRemoteInvalidation(syncer::ModelType type,
  63                                 scoped_ptr<InvalidationInterface> invalidation);
  64
  65   // These functions should be called to keep this class informed of the status
  66   // of the connection to the invalidations server.
  67   void OnInvalidationsEnabled();
  68   void OnInvalidationsDisabled();
  69
  70   // Marks |types| as being throttled from |now| until |now| + |length|.
  71   void SetTypesThrottledUntil(ModelTypeSet types,
  72                               base::TimeDelta length,
  73                               base::TimeTicks now);
  74
  75   // Removes any throttling that have expired by time |now|.
  76   void UpdateTypeThrottlingState(base::TimeTicks now);
  77
  78   // Returns the time of the next type unthrottling, relative to
  79   // the input |now| value.
  80   base::TimeDelta GetTimeUntilNextUnthrottle(base::TimeTicks now) const;
  81
  82   // Returns true if any type is currenlty throttled.
  83   bool IsAnyTypeThrottled() const;
  84
  85   // Returns true if |type| is currently throttled.
  86   bool IsTypeThrottled(ModelType type) const;
  87
  88   // Returns the set of currently throttled types.
  89   ModelTypeSet GetThrottledTypes() const;
  90
  91   // Returns the set of types with local changes pending.
  92   ModelTypeSet GetNudgedTypes() const;
  93
  94   // Returns the set of types that have pending invalidations.
  95   ModelTypeSet GetNotifiedTypes() const;
  96
  97   // Returns the set of types that have pending refresh requests.
  98   ModelTypeSet GetRefreshRequestedTypes() const;
  99
 100   // Returns the 'source' of the GetUpdate request.
 101   //
 102   // This flag is deprecated, but still used by the server.  There can be more
 103   // than one reason to perform a particular sync cycle.  The GetUpdatesTrigger
 104   // message will contain more reliable information about the reasons for
 105   // performing a sync.
 106   //
 107   // See the implementation for important information about the coalesce logic.
 108   sync_pb::GetUpdatesCallerInfo::GetUpdatesSource GetLegacySource() const;
 109
 110   // Fills a GetUpdatesTrigger message for the next GetUpdates request.  This is
 111   // used by the DownloadUpdatesCommand to dump lots of useful per-type state
 112   // information into the GetUpdate request before sending it off to the server.
 113   void FillProtoMessage(
 114       ModelType type,
 115       sync_pb::GetUpdateTriggers* msg) const;
 116
 117   // Fills a ProgressMarker with single legacy notification hint expected by the
 118   // sync server.  Newer servers will rely on the data set by FillProtoMessage()
 119   // instead of this.
 120   void SetLegacyNotificationHint(
 121       ModelType type,
 122       sync_pb::DataTypeProgressMarker* progress) const;
 123
 124   // Flips the flag if we're due for a retry.
 125   void SetSyncCycleStartTime(base::TimeTicks now);
 126
 127   // Adjusts the number of hints that can be stored locally.
 128   void SetHintBufferSize(size_t size);
 129
 130   // Schedules a retry GetUpdate request for some time in the future.
 131   //
 132   // This is a request sent to us as part of a server response requesting
 133   // that the client perform a GetUpdate request at |next_retry_time| to
 134   // fetch any updates it may have missed in the first attempt.
 135   //
 136   // To avoid strange results from IsRetryRequired() during a sync cycle, the
 137   // effects of this change are not guaranteed to take effect until
 138   // SetSyncCycleStartTime() is called at the start of the *next* sync cycle.
 139   void SetNextRetryTime(base::TimeTicks next_retry_time);
 140
 141  private:
 142   typedef std::map<ModelType, DataTypeTracker*> TypeTrackerMap;
 143
 144   TypeTrackerMap type_trackers_;
 145   STLValueDeleter<TypeTrackerMap> type_tracker_deleter_;
 146
 147   // Merged updates source.  This should be obsolete, but the server still
 148   // relies on it for some heuristics.
 149   sync_pb::GetUpdatesCallerInfo::GetUpdatesSource updates_source_;
 150
 151   // Tracks whether or not invalidations are currently enabled.
 152   bool invalidations_enabled_;
 153
 154   // This flag is set if suspect that some technical malfunction or known bug
 155   // may have left us with some unserviced invalidations.
 156   //
 157   // Keeps track of whether or not we're fully in sync with the invalidation
 158   // server.  This can be false even if invalidations are enabled and working
 159   // correctly.  For example, until we get ack-tracking working properly, we
 160   // won't persist invalidations between restarts, so we may be out of sync when
 161   // we restart.  The only way to get back into sync is to have invalidations
 162   // enabled, then complete a sync cycle to make sure we're fully up to date.
 163   bool invalidations_out_of_sync_;
 164
 165   size_t num_payloads_per_type_;
 166
 167   base::TimeTicks last_successful_sync_time_;
 168
 169   // A pending update to the current_retry_time_.
 170   //
 171   // The GU retry time is specified by a call to SetNextRetryTime, but we don't
 172   // want that change to take effect right away, since it could happen in the
 173   // middle of a sync cycle.  We delay the update until the start of the next
 174   // sync cycle, which is indicated by a call to SetSyncCycleStartTime().
 175   base::TimeTicks next_retry_time_;
 176
 177   // The currently active retry GU time.  Will be null if there is no retry GU
 178   // pending at this time.
 179   base::TimeTicks current_retry_time_;
 180
 181   // The time when the sync cycle started.  This value is maintained by
 182   // SetSyncCycleStartTime().  This may contain a stale value if we're not
 183   // currently in a sync cycle.
 184   base::TimeTicks sync_cycle_start_time_;
 185
 186   DISALLOW_COPY_AND_ASSIGN(NudgeTracker);
 187 };
 188
 189 }  // namespace sessions
 190 }  // namespace syncer
 191
 192 #endif  // SYNC_SESSIONS_NUDGE_TRACKER_H_