Move FindOrNull to common/utils.h. (#1305)

cartographer/common/utils.h

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2018 The Cartographer Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+namespace cartographer {
+namespace common {
+
+template <typename MapType, typename KeyType = typename MapType::key_type,
+          typename ValueType = typename MapType::mapped_type>
+ValueType* FindOrNull(MapType& map, const KeyType& key) {
+  auto it = map.find(key);
+  if (it == map.end()) return nullptr;
+  return &(it->second);
+}
+
+}  // namespace common
+}  // namespace cartographer

cartographer/pose_graph/constraint/relative_pose_constraint_2d.cc

@@ -17,21 +17,10 @@
 #include "cartographer/pose_graph/constraint/relative_pose_constraint_2d.h"
 
 #include "cartographer/common/make_unique.h"
+#include "cartographer/common/utils.h"
 
 namespace cartographer {
 namespace pose_graph {
-namespace {
-
-// TODO(pifon): Move to common/utils.h.
-template <typename MapType, typename KeyType = typename MapType::key_type,
-          typename ValueType = typename MapType::mapped_type>
-ValueType* FindOrNull(MapType& map, const KeyType& key) {
-  auto it = map.find(key);
-  if (it == map.end()) return nullptr;
-  return &(it->second);
-}
-
-}  // namespace
 
 RelativePoseConstraint2D::RelativePoseConstraint2D(
     const ConstraintId& id, const proto::RelativePose2D& proto)
@@ -43,13 +32,13 @@ RelativePoseConstraint2D::RelativePoseConstraint2D(
 
 void RelativePoseConstraint2D::AddToOptimizer(Nodes* nodes,
                                               ceres::Problem* problem) const {
-  auto first_node = FindOrNull(nodes->pose_2d_nodes, first_);
+  auto first_node = common::FindOrNull(nodes->pose_2d_nodes, first_);
   if (first_node == nullptr) {
     LOG(INFO) << "First node was not found in pose_2d_nodes.";
     return;
   }
 
-  auto second_node = FindOrNull(nodes->pose_2d_nodes, second_);
+  auto second_node = common::FindOrNull(nodes->pose_2d_nodes, second_);
   if (second_node == nullptr) {
     LOG(INFO) << "Second node was not found in pose_2d_nodes.";
     return;