| // Copyright 2014 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef SYNC_ENGINE_WORKER_ENTITY_TRACKER_H_ |
| #define SYNC_ENGINE_WORKER_ENTITY_TRACKER_H_ |
| |
| #include <stdint.h> |
| |
| #include <string> |
| |
| #include "base/macros.h" |
| #include "base/memory/scoped_ptr.h" |
| #include "base/time/time.h" |
| #include "sync/base/sync_export.h" |
| #include "sync/protocol/sync.pb.h" |
| |
| namespace syncer_v2 { |
| struct CommitRequestData; |
| struct UpdateResponseData; |
| |
| // Manages the pending commit and update state for an entity on the sync |
| // thread. |
| // |
| // It should be considered a helper class internal to the |
| // ModelTypeWorker. |
| // |
| // Maintains the state associated with a particular sync entity which is |
| // necessary for decision-making on the sync thread. It can track pending |
| // commit state, received update state, and can detect conflicts. |
| // |
| // This object may contain state associated with a pending commit, pending |
| // update, or both. |
| class SYNC_EXPORT WorkerEntityTracker { |
| public: |
| // Initializes the entity tracker's main fields. Does not initialize state |
| // related to a pending commit. |
| WorkerEntityTracker(const std::string& id, |
| const std::string& client_tag_hash); |
| |
| ~WorkerEntityTracker(); |
| |
| // Returns true if this entity should be commited to the server. |
| bool HasPendingCommit() const; |
| |
| // Populates a sync_pb::SyncEntity for a commit. Also sets the |
| // |sequence_number|, so we can track it throughout the commit process. |
| void PrepareCommitProto(sync_pb::SyncEntity* commit_entity, |
| int64_t* sequence_number) const; |
| |
| // Updates this entity with data from the latest version that the |
| // model asked us to commit. May clobber state related to the |
| // model's previous commit attempt(s). |
| void RequestCommit(const CommitRequestData& data); |
| |
| // Handles the receipt of a commit response. |
| // |
| // Since commits happen entirely on the sync thread, we can safely assume |
| // that our item's state at the end of the commit is the same as it was at |
| // the start. |
| void ReceiveCommitResponse(const std::string& response_id, |
| int64_t response_version, |
| int64_t sequence_number); |
| |
| // Handles receipt of an update from the server. |
| void ReceiveUpdate(int64_t version); |
| |
| // Handles the receipt of an pending update from the server. |
| // |
| // Returns true if the tracker decides this item is worth keeping. Returns |
| // false if the item is discarded, which could happen if the version number |
| // is out of date. |
| bool ReceivePendingUpdate(const UpdateResponseData& data); |
| |
| // Functions to fetch the latest pending update. |
| bool HasPendingUpdate() const; |
| UpdateResponseData GetPendingUpdate() const; |
| |
| // Clears the pending update. Allows us to resume regular commit behavior. |
| void ClearPendingUpdate(); |
| |
| private: |
| // Checks if the current state indicates a conflict. |
| // |
| // This can be true only while a call to this object is in progress. |
| // Conflicts are always cleared before the method call ends. |
| bool IsInConflict() const; |
| |
| // Checks if the server knows about this item. |
| bool IsServerKnown() const; |
| |
| // Clears flag and optionally clears state associated with a pending commit. |
| void ClearPendingCommit(); |
| |
| // The ID for this entry. May be empty if the entry has never been committed. |
| std::string id_; |
| |
| // The hashed client tag for this entry. |
| std::string client_tag_hash_; |
| |
| // The highest version seen in a commit response for this entry. |
| int64_t highest_commit_response_version_; |
| |
| // The highest version seen in a GU response for this entry. |
| int64_t highest_gu_response_version_; |
| |
| // Used to track in-flight commit requests on the model thread. All we need |
| // to do here is return it back to the model thread when the pending commit |
| // is completed and confirmed. Not valid if no commit is pending. |
| int64_t sequence_number_; |
| |
| // The server version on which this item is based. |
| int64_t base_version_; |
| |
| // A commit for this entity waiting for a sync cycle to be committed. |
| scoped_ptr<CommitRequestData> pending_commit_; |
| |
| // An update for this entity which can't be applied right now. The presence |
| // of an pending update prevents commits. As of this writing, the only |
| // source of pending updates is updates that can't currently be decrypted. |
| scoped_ptr<UpdateResponseData> pending_update_; |
| |
| DISALLOW_COPY_AND_ASSIGN(WorkerEntityTracker); |
| }; |
| |
| } // namespace syncer_v2 |
| |
| #endif // SYNC_ENGINE_WORKER_ENTITY_TRACKER_H_ |