sync/sessions/data_type_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 per-type scheduling data.
   6 #ifndef SYNC_SESSIONS_DATA_TYPE_TRACKER_H_
   7 #define SYNC_SESSIONS_DATA_TYPE_TRACKER_H_
   8
   9 #include <deque>
  10 #include <string>
  11
  12 #include "base/basictypes.h"
  13 #include "base/time/time.h"
  14 #include "sync/notifier/dropped_invalidation_tracker.h"
  15 #include "sync/notifier/single_object_invalidation_set.h"
  16 #include "sync/protocol/sync.pb.h"
  17
  18 namespace syncer {
  19
  20 class Invalidation;
  21 class SingleObjectInvalidationSet;
  22
  23 namespace sessions {
  24
  25 typedef std::deque<std::string> PayloadList;
  26
  27 class DataTypeTracker {
  28  public:
  29   explicit DataTypeTracker(const invalidation::ObjectId& object_id);
  30   ~DataTypeTracker();
  31
  32   // For STL compatibility, we do not forbid the creation of a default copy
  33   // constructor and assignment operator.
  34
  35   // Tracks that a local change has been made to this type.
  36   void RecordLocalChange();
  37
  38   // Tracks that a local refresh request has been made for this type.
  39   void RecordLocalRefreshRequest();
  40
  41   // Tracks that we received invalidation notifications for this type.
  42   void RecordRemoteInvalidations(
  43       const SingleObjectInvalidationSet& invalidations);
  44
  45   // Records that a sync cycle has been performed successfully.
  46   // Generally, this means that all local changes have been committed and all
  47   // remote changes have been downloaded, so we can clear any flags related to
  48   // pending work.
  49   void RecordSuccessfulSyncCycle();
  50
  51   // Updates the size of the invalidations payload buffer.
  52   void UpdatePayloadBufferSize(size_t new_size);
  53
  54   // Returns true if there is a good reason to perform a sync cycle.  This does
  55   // not take into account whether or not now is a good time to perform a sync
  56   // cycle.  That's for the scheduler to decide.
  57   bool IsSyncRequired() const;
  58
  59   // Returns true if there is a good reason to fetch updates for this type as
  60   // part of the next sync cycle.
  61   bool IsGetUpdatesRequired() const;
  62
  63   // Returns true if there is an uncommitted local change.
  64   bool HasLocalChangePending() const;
  65
  66   // Returns true if we've received an invalidation since we last fetched
  67   // updates.
  68   bool HasPendingInvalidation() const;
  69
  70   // Fills in the legacy invalidaiton payload information fields.
  71   void SetLegacyNotificationHint(
  72       sync_pb::DataTypeProgressMarker* progress) const;
  73
  74   // Fills some type-specific contents of a GetUpdates request protobuf.  These
  75   // messages provide the server with the information it needs to decide how to
  76   // handle a request.
  77   void FillGetUpdatesTriggersMessage(sync_pb::GetUpdateTriggers* msg) const;
  78
  79   // Returns true if the type is currently throttled.
  80   bool IsThrottled() const;
  81
  82   // Returns the time until this type's throttling interval expires.  Should not
  83   // be called unless IsThrottled() returns true.  The returned value will be
  84   // increased to zero if it would otherwise have been negative.
  85   base::TimeDelta GetTimeUntilUnthrottle(base::TimeTicks now) const;
  86
  87   // Throttles the type from |now| until |now| + |duration|.
  88   void ThrottleType(base::TimeDelta duration, base::TimeTicks now);
  89
  90   // Unthrottles the type if |now| >= the throttle expiry time.
  91   void UpdateThrottleState(base::TimeTicks now);
  92
  93  private:
  94   // Number of local change nudges received for this type since the last
  95   // successful sync cycle.
  96   int local_nudge_count_;
  97
  98   // Number of local refresh requests received for this type since the last
  99   // successful sync cycle.
 100   int local_refresh_request_count_;
 101
 102   // The list of invalidations received since the last successful sync cycle.
 103   // This list may be incomplete.  See also:
 104   // drop_tracker_.IsRecoveringFromDropEvent() and server_payload_overflow_.
 105   SingleObjectInvalidationSet pending_invalidations_;
 106
 107   size_t payload_buffer_size_;
 108
 109   // If !unthrottle_time_.is_null(), this type is throttled and may not download
 110   // or commit data until the specified time.
 111   base::TimeTicks unthrottle_time_;
 112
 113   // A helper to keep track invalidations we dropped due to overflow.
 114   DroppedInvalidationTracker drop_tracker_;
 115 };
 116
 117 }  // namespace syncer
 118 }  // namespace sessions
 119
 120 #endif  // SYNC_SESSIONS_DATA_TYPE_TRACKER_H_