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

sync/internal_api/change_reorder_buffer.h

-// Copyright (c) 2012 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.
-//
-// Defines ChangeReorderBuffer, which can be used to sort a list of item
-// actions to achieve the ordering constraint required by the SyncObserver
-// interface of the SyncAPI.
-
-#ifndef SYNC_INTERNAL_API_CHANGE_REORDER_BUFFER_H_
-#define SYNC_INTERNAL_API_CHANGE_REORDER_BUFFER_H_
-
-#include <stdint.h>
-
-#include <map>
-#include <vector>
-
-#include "base/compiler_specific.h"
-#include "base/macros.h"
-#include "base/memory/linked_ptr.h"
-#include "sync/internal_api/public/change_record.h"
-#include "sync/protocol/sync.pb.h"
-
-namespace syncer {
-
-class BaseTransaction;
-
-// ChangeReorderBuffer is a utility type which accepts an unordered set
-// of changes (via its Push methods), and yields an ImmutableChangeRecordList
-// (via the GetAllChangesInTreeOrder method) that are in the order that
-// the SyncObserver expects them to be. A buffer is initially empty.
-//
-// The ordering produced by ChangeReorderBuffer is as follows:
-//  (a) All Deleted items appear first.
-//  (b) For Updated and/or Added items, parents appear before their children.
-//
-// The sibling order is not necessarily preserved.
-class ChangeReorderBuffer {
- public:
-  ChangeReorderBuffer();
-  ~ChangeReorderBuffer();
-
-  // Insert an item, identified by the metahandle |id|, into the reorder buffer.
-  // This item will appear in the output list as an ACTION_ADD ChangeRecord.
-  void PushAddedItem(int64_t id);
-
-  // Insert an item, identified by the metahandle |id|, into the reorder buffer.
-  // This item will appear in the output list as an ACTION_DELETE ChangeRecord.
-  void PushDeletedItem(int64_t id);
-
-  // Insert an item, identified by the metahandle |id|, into the reorder buffer.
-  // This item will appear in the output list as an ACTION_UPDATE ChangeRecord.
-  void PushUpdatedItem(int64_t id);
-
-  void SetExtraDataForId(int64_t id, ExtraPasswordChangeRecordData* extra);
-
-  void SetSpecificsForId(int64_t id, const sync_pb::EntitySpecifics& specifics);
-
-  // Reset the buffer, forgetting any pushed items, so that it can be used again
-  // to reorder a new set of changes.
-  void Clear();
-
-  bool IsEmpty() const;
-
-  // Output a reordered list of changes to |changes| using the items
-  // that were pushed into the reorder buffer. |sync_trans| is used to
-  // determine the ordering.  Returns true if successful, or false if
-  // an error was encountered.
-  bool GetAllChangesInTreeOrder(
-      const BaseTransaction* sync_trans,
-      ImmutableChangeRecordList* changes) WARN_UNUSED_RESULT;
-
- private:
-  class Traversal;
-  typedef std::map<int64_t, ChangeRecord::Action> OperationMap;
-  typedef std::map<int64_t, sync_pb::EntitySpecifics> SpecificsMap;
-  typedef std::map<int64_t, linked_ptr<ExtraPasswordChangeRecordData>>
-      ExtraDataMap;
-
-  // Stores the items that have been pushed into the buffer, and the type of
-  // operation that was associated with them.
-  OperationMap operations_;
-
-  // Stores entity-specific ChangeRecord data per-ID.
-  SpecificsMap specifics_;
-
-  // Stores type-specific extra data per-ID.
-  ExtraDataMap extra_data_;
-
-  DISALLOW_COPY_AND_ASSIGN(ChangeReorderBuffer);
-};
-
-}  // namespace syncer
-
-#endif  // SYNC_INTERNAL_API_CHANGE_REORDER_BUFFER_H_