| // 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. |
| |
| #ifndef SYNC_SYNCABLE_SYNCABLE_CHANGES_VERSION_H_ |
| #define SYNC_SYNCABLE_SYNCABLE_CHANGES_VERSION_H_ |
| |
| namespace syncer { |
| namespace syncable { |
| |
| // For the most part, the sync engine treats version numbers as opaque values. |
| // However, there are parts of our code base that break this abstraction, and |
| // depend on the following two invariants: |
| // |
| // 1. CHANGES_VERSION is less than 0. |
| // 2. The server only issues positive version numbers. |
| // |
| // Breaking these abstractions makes some operations 10 times |
| // faster. If either of these invariants change, then those queries |
| // must be revisited. |
| |
| enum { |
| CHANGES_VERSION = -1 |
| }; |
| |
| #define CHANGES_VERSION_STRING "-1" |
| |
| } // namespace syncable |
| } // namespace syncer |
| |
| #endif // SYNC_SYNCABLE_SYNCABLE_CHANGES_VERSION_H_ |
