sync/engine/conflict_util.cc

   1 // Copyright (c) 2012 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 #include "sync/engine/conflict_util.h"
   6
   7 #include "sync/syncable/mutable_entry.h"
   8
   9 namespace syncer {
  10
  11 using syncable::BASE_VERSION;
  12 using syncable::IS_UNAPPLIED_UPDATE;
  13 using syncable::IS_UNSYNCED;
  14 using syncable::SERVER_VERSION;
  15
  16 using syncable::MutableEntry;
  17
  18 namespace conflict_util {
  19
  20 // Allow the server's changes to take precedence.
  21 // This will take effect during the next ApplyUpdates step.
  22 void IgnoreLocalChanges(MutableEntry* entry) {
  23   DCHECK(entry->Get(IS_UNSYNCED));
  24   DCHECK(entry->Get(IS_UNAPPLIED_UPDATE));
  25   entry->Put(IS_UNSYNCED, false);
  26 }
  27
  28 // Overwrite the server with our own value.
  29 // We will commit our local data, overwriting the server, at the next
  30 // opportunity.
  31 void OverwriteServerChanges(MutableEntry* entry) {
  32   DCHECK(entry->Get(IS_UNSYNCED));
  33   DCHECK(entry->Get(IS_UNAPPLIED_UPDATE));
  34   entry->Put(BASE_VERSION, entry->Get(SERVER_VERSION));
  35   entry->Put(IS_UNAPPLIED_UPDATE, false);
  36 }
  37
  38 // Having determined that everything matches, we ignore the non-conflict.
  39 void IgnoreConflict(MutableEntry* entry) {
  40   // If we didn't also unset IS_UNAPPLIED_UPDATE, then we would lose unsynced
  41   // positional data from adjacent entries when the server update gets applied
  42   // and the item is re-inserted into the PREV_ID/NEXT_ID linked list. This is
  43   // primarily an issue because we commit after applying updates, and is most
  44   // commonly seen when positional changes are made while a passphrase is
  45   // required (and hence there will be many encryption conflicts).
  46   DCHECK(entry->Get(IS_UNSYNCED));
  47   DCHECK(entry->Get(IS_UNAPPLIED_UPDATE));
  48   entry->Put(BASE_VERSION, entry->Get(SERVER_VERSION));
  49   entry->Put(IS_UNAPPLIED_UPDATE, false);
  50   entry->Put(IS_UNSYNCED, false);
  51 }
  52
  53 }  // namespace conflict_util
  54 }  // namespace syncer