[Sync] Move //sync to //components/sync.

sync/engine/worker_entity_tracker.h

-// 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 <memory>
-#include <string>
-
-#include "base/macros.h"
-#include "base/time/time.h"
-#include "sync/base/sync_export.h"
-#include "sync/protocol/sync.pb.h"
-
-namespace syncer_v2 {
-struct CommitRequestData;
-struct CommitResponseData;
-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.
-  void PopulateCommitProto(sync_pb::SyncEntity* commit_entity) 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);
-
-  // Tracks the receipt of a commit response and fills in some local-only data
-  // on it to be passed back to the processor.
-  void ReceiveCommitResponse(CommitResponseData* ack);
-
-  // Handles receipt of an update from the server.
-  void ReceiveUpdate(int64_t version);
-
-  // Handles the receipt of an encrypted 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-  // is out of date.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 ReceiveEncryptedUpdate(const UpdateResponseData& data);
-
-  // Functions to fetch the latest encrypted update.
-  bool HasEncryptedUpdate() const;
-  UpdateResponseData GetEncryptedUpdate() const;
-
-  // Clears the encrypted update. Allows us to resume regular commit behavior.
-  void ClearEncryptedUpdate();
-
- 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.
-  std::unique_ptr<CommitRequestData> pending_commit_;
-
-  // The specifics hash for the pending commit if there is one, "" otherwise.
-  std::string pending_commit_specifics_hash_;
-
-  // 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.
-  std::unique_ptr<UpdateResponseData> encrypted_update_;
-
-  DISALLOW_COPY_AND_ASSIGN(WorkerEntityTracker);
-};
-
-}  // namespace syncer_v2
-
-#endif  // SYNC_ENGINE_WORKER_ENTITY_TRACKER_H_