Allow InitByTagLookup for WriteNodes.

BUG=none
TEST=Modified the Nigori permanent node.

Review URL: http://codereview.chromium.org/2844004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@50176 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 28 insertions, 3 deletions

diff --git a/chrome/browser/sync/engine/syncapi.cc b/chrome/browser/sync/engine/syncapi.cc
index 76be27a..20d6a2c 100644
--- a/chrome/browser/sync/engine/syncapi.cc
+++ b/chrome/browser/sync/engine/syncapi.cc
@@ -469,6 +469,21 @@ bool WriteNode::InitByClientTagLookup(syncable::ModelType model_type,
   return (entry_->good() && !entry_->Get(syncable::IS_DEL));
 }
 
+bool WriteNode::InitByTagLookup(const std::string& tag) {
+  DCHECK(!entry_) << "Init called twice";
+  if (tag.empty())
+    return false;
+  entry_ = new syncable::MutableEntry(transaction_->GetWrappedWriteTrans(),
+                                      syncable::GET_BY_SERVER_TAG, tag);
+  if (!entry_->good())
+    return false;
+  if (entry_->Get(syncable::IS_DEL))
+    return false;
+  syncable::ModelType model_type = GetModelType();
+  DCHECK(model_type == syncable::NIGORI);
+  return true;
+}
+
 void WriteNode::PutModelType(syncable::ModelType model_type) {
   // Set an empty specifics of the appropriate datatype.  The presence
   // of the specific extension will identify the model type.
diff --git a/chrome/browser/sync/engine/syncapi.h b/chrome/browser/sync/engine/syncapi.h
index 56d0834..d7b984f 100644
--- a/chrome/browser/sync/engine/syncapi.h
+++ b/chrome/browser/sync/engine/syncapi.h
@@ -278,6 +278,11 @@ class WriteNode : public BaseNode {
                             const BaseNode& parent,
                             const std::string& client_tag);
 
+  // Each server-created permanent node is tagged with a unique string.
+  // Look up the node with the particular tag.  If it does not exist,
+  // return false.
+  bool InitByTagLookup(const std::string& tag);
+
   // These Set() functions correspond to the Get() functions of BaseNode.
   void SetIsFolder(bool folder);
   void SetTitle(const std::wstring& title);
@@ -406,9 +411,7 @@ class ReadNode : public BaseNode {
 
   // Each server-created permanent node is tagged with a unique string.
   // Look up the node with the particular tag.  If it does not exist,
-  // return false.  Since these nodes are special, lookup is only
-  // provided through ReadNode.
-  // TODO(chron): Rename this function.
+  // return false.
   bool InitByTagLookup(const std::string& tag);
 
   // Implementation of BaseNode's abstract virtual accessors.
diff --git a/chrome/browser/sync/syncable/syncable.cc b/chrome/browser/sync/syncable/syncable.cc
index 42e4867..e694ebe 100644
--- a/chrome/browser/sync/syncable/syncable.cc
+++ b/chrome/browser/sync/syncable/syncable.cc
@@ -1168,6 +1168,12 @@ MutableEntry::MutableEntry(WriteTransaction* trans, GetByClientTag,
   trans->SaveOriginal(kernel_);
 }
 
+MutableEntry::MutableEntry(WriteTransaction* trans, GetByServerTag,
+                           const string& tag)
+    : Entry(trans, GET_BY_SERVER_TAG, tag), write_transaction_(trans) {
+  trans->SaveOriginal(kernel_);
+}
+
 bool MutableEntry::PutIsDel(bool is_del) {
   DCHECK(kernel_);
   if (is_del == kernel_->ref(IS_DEL)) {
diff --git a/chrome/browser/sync/syncable/syncable.h b/chrome/browser/sync/syncable/syncable.h
index 270d2bf..ff58f1f 100644
--- a/chrome/browser/sync/syncable/syncable.h
+++ b/chrome/browser/sync/syncable/syncable.h
@@ -460,6 +460,7 @@ class MutableEntry : public Entry {
   MutableEntry(WriteTransaction* trans, GetByHandle, int64);
   MutableEntry(WriteTransaction* trans, GetById, const Id&);
   MutableEntry(WriteTransaction* trans, GetByClientTag, const std::string& tag);
+  MutableEntry(WriteTransaction* trans, GetByServerTag, const std::string& tag);
 
   inline WriteTransaction* write_transaction() const {
     return write_transaction_;