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_NOTIFIER_DROPPED_INVALIDATION_TRACKER_H_ 6 #define SYNC_NOTIFIER_DROPPED_INVALIDATION_TRACKER_H_ 7 8 #include "google/cacheinvalidation/include/types.h" 9 #include "sync/base/sync_export.h" 10 #include "sync/internal_api/public/base/ack_handle.h" 11 #include "sync/internal_api/public/util/weak_handle.h" 12 #include "sync/notifier/ack_handler.h" 13 14 namespace syncer { 15 16 class Invalidation; 17 18 // Helps InvalidationHandlers keep track of dropped invalidations for a given 19 // ObjectId. 20 // 21 // The intent of this class is to hide some of the implementation details around 22 // how the invalidations system manages dropping and drop recovery. Any 23 // invalidation handler that intends to buffer and occasionally drop 24 // invalidations should keep one instance of it per registered ObjectId. 25 // 26 // When an invalidation handler wishes to drop an invalidation, it must provide 27 // an instance of this class to that Invalidation's Drop() method. In order to 28 // indicate recovery from a drop, the handler can call this class' 29 // RecordRecoveryFromDropEvent(). 30 // 31 // Copy and assign are allowed for this class so we can use it in STL 32 // containers. 33 class SYNC_EXPORT DroppedInvalidationTracker { 34 public: 35 explicit DroppedInvalidationTracker(const invalidation::ObjectId& id); 36 ~DroppedInvalidationTracker(); 37 38 const invalidation::ObjectId& object_id() const; 39 40 // Called by Invalidation::Drop() to keep track of a drop event. 41 // 42 // Takes ownership of the internals belonging to a soon to be discarded 43 // dropped invalidation. See also the comment for this class' 44 // |drop_ack_handler_| member. 45 void RecordDropEvent(WeakHandle<AckHandler> handler, AckHandle handle); 46 47 // Returns true if we're still recovering from a drop event. 48 bool IsRecoveringFromDropEvent() const; 49 50 // Called by the InvalidationHandler when it recovers from the drop event. 51 void RecordRecoveryFromDropEvent(); 52 53 private: 54 invalidation::ObjectId id_; 55 AckHandle drop_ack_handle_; 56 57 // This flag is set to true when we have dropped an invalidation and have not 58 // yet recovered from this drop event. Note that this may not always coincide 59 // with drop_ack_handler_ being initialized because a null AckHandler could be 60 // passed in to RecordDropEvent(). 61 bool recovering_from_drop_; 62 63 // A WeakHandle to the enitity responsible for persisting invalidation 64 // acknowledgement state on disk. We can get away with using a WeakHandle 65 // because we don't care if our drop recovery message doesn't gets delivered 66 // in some shutdown cases. If that happens, we'll have to process the 67 // invalidation state again on the next restart. It would be a waste of time 68 // and resources, but otherwise not particularly harmful. 69 WeakHandle<AckHandler> drop_ack_handler_; 70 }; 71 72 } // namespace syncer 73 74 #endif // SYNC_NOTIFIER_DROPPED_INVALIDATION_TRACKER_H_ 75
