From 2090d067c1acf65ff63e46f311f19c9965ac48ca Mon Sep 17 00:00:00 2001
From: Erik Boasson <eb@ilities.com>
Date: Fri, 7 Jun 2019 11:16:37 +0200
Subject: [PATCH] Specialize deserializer for strings (#3)

As std::string is not a basic type, "new" must sometimes be called to
initialze the memory before passing it as a reference.
---
 .../rmw_cyclonedds_cpp/TypeSupport_impl.hpp   | 32 +++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/rmw_cyclonedds_cpp/include/rmw_cyclonedds_cpp/TypeSupport_impl.hpp b/rmw_cyclonedds_cpp/include/rmw_cyclonedds_cpp/TypeSupport_impl.hpp
index 298351a..513ffdb 100644
--- a/rmw_cyclonedds_cpp/include/rmw_cyclonedds_cpp/TypeSupport_impl.hpp
+++ b/rmw_cyclonedds_cpp/include/rmw_cyclonedds_cpp/TypeSupport_impl.hpp
@@ -421,6 +421,38 @@ void deserialize_field(
   }
 }
 
+template<>
+inline void deserialize_field<std::string>(
+  const rosidl_typesupport_introspection_cpp::MessageMember * member,
+  void * field,
+  cycdeser & deser,
+  bool call_new)
+{
+  if (!member->is_array_) {
+    if (call_new) {
+      // Because std::string is a complex datatype, we need to make sure that
+      // the memory is initialized to something reasonable before eventually
+      // passing it as a reference.
+      new(field) std::string();
+    }
+    deser >> *static_cast<std::string *>(field);
+  } else if (member->array_size_ && !member->is_upper_bound_) {
+    std::string * array = static_cast<std::string *>(field);
+    if (call_new) {
+      for (size_t i = 0; i < member->array_size_; ++i) {
+        new(&array[i]) std::string();
+      }
+    }
+    deser.deserializeA(array, member->array_size_);
+  } else {
+    auto & vector = *reinterpret_cast<std::vector<std::string> *>(field);
+    if (call_new) {
+      new(&vector) std::vector<std::string>;
+    }
+    deser >> vector;
+  }
+}
+
 template<typename T>
 void deserialize_field(
   const rosidl_typesupport_introspection_c__MessageMember * member,