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 #ifndef SYNC_SESSIONS_DATA_TYPE_TRACKER_H_
   6 #define SYNC_SESSIONS_DATA_TYPE_TRACKER_H_
   7
   8 #include <string>
   9
  10 #include "base/basictypes.h"
  11 #include "base/memory/scoped_ptr.h"
  12 #include "base/memory/scoped_vector.h"
  13 #include "base/time/time.h"
  14 #include "sync/internal_api/public/base/invalidation_interface.h"
  15 #include "sync/internal_api/public/base/model_type.h"
  16 #include "sync/protocol/sync.pb.h"
  17
  18 namespace syncer {
  19
  20 class InvalidationInterface;
  21
  22 namespace sessions {
  23
  24 // A class to track the per-type scheduling data.
  25 class DataTypeTracker {
  26  public:
  27   explicit DataTypeTracker();
  28   ~DataTypeTracker();
  29
  30   // For STL compatibility, we do not forbid the creation of a default copy
  31   // constructor and assignment operator.
  32
  33   // Tracks that a local change has been made to this type.
  34   // Returns the current local change nudge delay for this type.
  35   base::TimeDelta RecordLocalChange();
  36
  37   // Tracks that a local refresh request has been made for this type.
  38   void RecordLocalRefreshRequest();
  39
  40   // Tracks that we received invalidation notifications for this type.
  41   void RecordRemoteInvalidation(scoped_ptr<InvalidationInterface> incoming);
  42
  43   // Takes note that initial sync is pending for this type.
  44   void RecordInitialSyncRequired();
  45
  46   // Records that a sync cycle has been performed successfully.
  47   // Generally, this means that all local changes have been committed and all
  48   // remote changes have been downloaded, so we can clear any flags related to
  49   // pending work.
  50   void RecordSuccessfulSyncCycle();
  51
  52   // Updates the size of the invalidations payload buffer.
  53   void UpdatePayloadBufferSize(size_t new_size);
  54
  55   // Returns true if there is a good reason to perform a sync cycle.  This does
  56   // not take into account whether or not now is a good time to perform a sync
  57   // cycle.  That's for the scheduler to decide.
  58   bool IsSyncRequired() const;
  59
  60   // Returns true if there is a good reason to fetch updates for this type as
  61   // part of the next sync cycle.
  62   bool IsGetUpdatesRequired() const;
  63
  64   // Returns true if there is an uncommitted local change.
  65   bool HasLocalChangePending() const;
  66
  67   // Returns true if we've received an invalidation since we last fetched
  68   // updates.
  69   bool HasPendingInvalidation() const;
  70
  71   // Returns true if an explicit refresh request is still outstanding.
  72   bool HasRefreshRequestPending() const;
  73
  74   // Returns true if this type is requesting an initial sync.
  75   bool IsInitialSyncRequired() const;
  76
  77   // Fills in the legacy invalidaiton payload information fields.
  78   void SetLegacyNotificationHint(
  79       sync_pb::DataTypeProgressMarker* progress) const;
  80
  81   // Fills some type-specific contents of a GetUpdates request protobuf.  These
  82   // messages provide the server with the information it needs to decide how to
  83   // handle a request.
  84   void FillGetUpdatesTriggersMessage(sync_pb::GetUpdateTriggers* msg) const;
  85
  86   // Returns true if the type is currently throttled.
  87   bool IsThrottled() const;
  88
  89   // Returns the time until this type's throttling interval expires.  Should not
  90   // be called unless IsThrottled() returns true.  The returned value will be
  91   // increased to zero if it would otherwise have been negative.
  92   base::TimeDelta GetTimeUntilUnthrottle(base::TimeTicks now) const;
  93
  94   // Throttles the type from |now| until |now| + |duration|.
  95   void ThrottleType(base::TimeDelta duration, base::TimeTicks now);
  96
  97   // Unthrottles the type if |now| >= the throttle expiry time.
  98   void UpdateThrottleState(base::TimeTicks now);
  99
 100   // Update the local change nudge delay for this type.
 101   void UpdateLocalNudgeDelay(base::TimeDelta delay);
 102
 103  private:
 104   // Number of local change nudges received for this type since the last
 105   // successful sync cycle.
 106   int local_nudge_count_;
 107
 108   // Number of local refresh requests received for this type since the last
 109   // successful sync cycle.
 110   int local_refresh_request_count_;
 111
 112   // The list of invalidations received since the last successful sync cycle.
 113   // This list may be incomplete.  See also:
 114   // drop_tracker_.IsRecoveringFromDropEvent() and server_payload_overflow_.
 115   //
 116   // This list takes ownership of its contents.
 117   ScopedVector<InvalidationInterface> pending_invalidations_;
 118
 119   size_t payload_buffer_size_;
 120
 121   // Set to true if this type is ready for, but has not yet completed initial
 122   // sync.
 123   bool initial_sync_required_;
 124
 125   // If !unthrottle_time_.is_null(), this type is throttled and may not download
 126   // or commit data until the specified time.
 127   base::TimeTicks unthrottle_time_;
 128
 129   // A helper to keep track invalidations we dropped due to overflow.
 130   scoped_ptr<InvalidationInterface> last_dropped_invalidation_;
 131
 132   // The amount of time to delay a sync cycle by when a local change for this
 133   // type occurs.
 134   base::TimeDelta nudge_delay_;
 135
 136   DISALLOW_COPY_AND_ASSIGN(DataTypeTracker);
 137 };
 138
 139 }  // namespace sessions
 140 }  // namespace syncer
 141
 142 #endif  // SYNC_SESSIONS_DATA_TYPE_TRACKER_H_