[Sync] Add support for loading, updating and querying delete journals in

sync/syncable/mutable_entry.cc

 // 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.
 
 #include "sync/syncable/mutable_entry.h"
 
 #include "base/memory/scoped_ptr.h"
 #include "sync/internal_api/public/base/node_ordinal.h"
 #include "sync/syncable/directory.h"
 #include "sync/syncable/scoped_index_updater.h"
@@ skipping 255 matching lines @@
       dir()->kernel_->unapplied_update_metahandles[new_server_type]
           .insert(metahandle);
     }
   }
   return true;
 }
 
 bool MutableEntry::Put(BitField field, bool value) {
   DCHECK(kernel_);
   write_transaction_->SaveOriginal(kernel_);
-  if (kernel_->ref(field) != value) {
+  bool old_value = kernel_->ref(field);
+  if (old_value != value) {
     kernel_->put(field, value);
     kernel_->mark_dirty(GetDirtyIndexHelper());
+
+    if (field == SERVER_IS_DEL)

[tim (not reviewing), 2012/12/13 02:48:10]

This can't be IS_DEL (and hence live in PutIsDel) I presume... can you explain /
comment why?

[haitaol1, 2012/12/13 21:34:21]

I think it's more accurate to use SERVER_IS_DEL to decide the status of an
entry. There are several early returns on the path from where SERVER_IS_DEL's
updated to where IS_DEL's updated. I'm concerned that we may not get update of
IS_DEL and leave or miss entries in delete journal accidentally.

On 2012/12/13 02:48:10, timsteele wrote:

+      dir()->UpdateDeleteJournals(write_transaction(), old_value, kernel_);
   }
   return true;
 }
 
 MetahandleSet* MutableEntry::GetDirtyIndexHelper() {
   return dir()->kernel_->dirty_metahandles;
 }
 
 bool MutableEntry::PutUniqueClientTag(const string& new_tag) {
   write_transaction_->SaveOriginal(kernel_);
@@ skipping 137 matching lines @@
   DCHECK_NE(static_cast<MutableEntry*>(NULL), e);
   DCHECK(!e->IsRoot()) << "We shouldn't mark a permanent object for syncing.";
   if (!(e->Put(IS_UNSYNCED, true)))
     return false;
   e->Put(SYNCING, false);
   return true;
 }
 
 }  // namespace syncable
 }  // namespace syncer