Original patch by rlarocque@chromium.org at http://codereview.chromium.org/7633077/

chrome/browser/sync/internal_api/read_node.cc

+// Copyright (c) 2011 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 "chrome/browser/sync/internal_api/read_node.h"
+
+#include "base/logging.h"
+#include "chrome/browser/sync/internal_api/base_transaction.h"
+#include "chrome/browser/sync/syncable/syncable.h"
+
+namespace sync_api {
+
+//////////////////////////////////////////////////////////////////////////
+// ReadNode member definitions
+ReadNode::ReadNode(const BaseTransaction* transaction)
+    : entry_(NULL), transaction_(transaction) {
+  DCHECK(transaction);
+}
+
+ReadNode::ReadNode() {
+  entry_ = NULL;
+  transaction_ = NULL;
+}
+
+ReadNode::~ReadNode() {
+  delete entry_;
+}
+
+void ReadNode::InitByRootLookup() {
+  DCHECK(!entry_) << "Init called twice";
+  syncable::BaseTransaction* trans = transaction_->GetWrappedTrans();
+  entry_ = new syncable::Entry(trans, syncable::GET_BY_ID, trans->root_id());
+  if (!entry_->good())
+    DCHECK(false) << "Could not lookup root node for reading.";
+}
+
+bool ReadNode::InitByIdLookup(int64 id) {
+  DCHECK(!entry_) << "Init called twice";
+  DCHECK_NE(id, kInvalidId);
+  syncable::BaseTransaction* trans = transaction_->GetWrappedTrans();
+  entry_ = new syncable::Entry(trans, syncable::GET_BY_HANDLE, id);
+  if (!entry_->good())
+    return false;
+  if (entry_->Get(syncable::IS_DEL))
+    return false;
+  syncable::ModelType model_type = GetModelType();
+  LOG_IF(WARNING, model_type == syncable::UNSPECIFIED ||
+                  model_type == syncable::TOP_LEVEL_FOLDER)
+      << "SyncAPI InitByIdLookup referencing unusual object.";
+  return DecryptIfNecessary();
+}
+
+bool ReadNode::InitByClientTagLookup(syncable::ModelType model_type,
+                                     const std::string& tag) {
+  DCHECK(!entry_) << "Init called twice";
+  if (tag.empty())
+    return false;
+
+  const std::string hash = GenerateSyncableHash(model_type, tag);
+
+  entry_ = new syncable::Entry(transaction_->GetWrappedTrans(),
+                               syncable::GET_BY_CLIENT_TAG, hash);
+  return (entry_->good() && !entry_->Get(syncable::IS_DEL) &&
+          DecryptIfNecessary());
+}
+
+const syncable::Entry* ReadNode::GetEntry() const {
+  return entry_;
+}
+
+const BaseTransaction* ReadNode::GetTransaction() const {
+  return transaction_;
+}
+
+bool ReadNode::InitByTagLookup(const std::string& tag) {
+  DCHECK(!entry_) << "Init called twice";
+  if (tag.empty())
+    return false;
+  syncable::BaseTransaction* trans = transaction_->GetWrappedTrans();
+  entry_ = new syncable::Entry(trans, syncable::GET_BY_SERVER_TAG, tag);
+  if (!entry_->good())
+    return false;
+  if (entry_->Get(syncable::IS_DEL))
+    return false;
+  syncable::ModelType model_type = GetModelType();
+  LOG_IF(WARNING, model_type == syncable::UNSPECIFIED ||
+                  model_type == syncable::TOP_LEVEL_FOLDER)
+      << "SyncAPI InitByTagLookup referencing unusually typed object.";
+  return DecryptIfNecessary();
+}
+
+}  // namespace sync_api