Replace const char * with a std::array<char, TOPIC_NAME_LENGTH> as the key of IPM IDTopicMap

rclcpp/include/rclcpp/intra_process_manager_impl.hpp

@@ -15,6 +15,8 @@
 #ifndef RCLCPP__INTRA_PROCESS_MANAGER_IMPL_HPP_
 #define RCLCPP__INTRA_PROCESS_MANAGER_IMPL_HPP_
 
+#include <rmw/validate_full_topic_name.h>
+
 #include <algorithm>
 #include <atomic>
 #include <cstring>
@@ -87,6 +89,20 @@ class IntraProcessManagerImplBase
   RCLCPP_DISABLE_COPY(IntraProcessManagerImplBase)
 };
 
+class FixedSizeString
+{
+public:
+  explicit FixedSizeString(const char * str);
+  const char * c_str() const;
+
+private:
+  char str_[RMW_TOPIC_MAX_NAME_LENGTH + 1];
+};
+
+RCLCPP_PUBLIC
+bool
+operator<(const FixedSizeString & lhs, const FixedSizeString & rhs);
+
 template<typename Allocator = std::allocator<void>>
 class IntraProcessManagerImpl : public IntraProcessManagerImplBase
 {
@@ -98,9 +114,7 @@ class IntraProcessManagerImpl : public IntraProcessManagerImplBase
   add_subscription(uint64_t id, SubscriptionBase::SharedPtr subscription)
   {
     subscriptions_[id] = subscription;
-    // subscription->get_topic_name() -> const char * can be used as the key,
-    // since subscriptions_ shares the ownership of subscription
-    subscription_ids_by_topic_[subscription->get_topic_name()].insert(id);
+    subscription_ids_by_topic_[FixedSizeString(subscription->get_topic_name())].insert(id);
   }
 
   void
@@ -175,7 +189,8 @@ class IntraProcessManagerImpl : public IntraProcessManagerImplBase
     }
 
     // Figure out what subscriptions should receive the message.
-    auto & destined_subscriptions = subscription_ids_by_topic_[publisher->get_topic_name()];
+    auto & destined_subscriptions =
+      subscription_ids_by_topic_[FixedSizeString(publisher->get_topic_name())];
     // Store the list for later comparison.
     if (info.target_subscriptions_by_message_sequence.count(message_seq) == 0) {
       info.target_subscriptions_by_message_sequence.emplace(
@@ -263,7 +278,7 @@ class IntraProcessManagerImpl : public IntraProcessManagerImplBase
     if (!publisher) {
       throw std::runtime_error("publisher has unexpectedly gone out of scope");
     }
-    auto sub_map_it = subscription_ids_by_topic_.find(publisher->get_topic_name());
+    auto sub_map_it = subscription_ids_by_topic_.find(FixedSizeString(publisher->get_topic_name()));
     if (sub_map_it == subscription_ids_by_topic_.end()) {
       // No intraprocess subscribers
       return 0;
@@ -285,19 +300,11 @@ class IntraProcessManagerImpl : public IntraProcessManagerImplBase
     std::hash<uint64_t>, std::equal_to<uint64_t>,
     RebindAlloc<std::pair<const uint64_t, SubscriptionBase::WeakPtr>>>;
 
-  struct strcmp_wrapper
-  {
-    bool
-    operator()(const char * lhs, const char * rhs) const
-    {
-      return std::strcmp(lhs, rhs) < 0;
-    }
-  };
   using IDTopicMap = std::map<
-    const char *,
+    FixedSizeString,
     AllocSet,
-    strcmp_wrapper,
-    RebindAlloc<std::pair<const char * const, AllocSet>>>;
+    std::less<FixedSizeString>,
+    RebindAlloc<std::pair<const FixedSizeString, AllocSet>>>;
 
   SubscriptionMap subscriptions_;
 

rclcpp/src/rclcpp/intra_process_manager_impl.cpp

@@ -16,8 +16,28 @@
 
 #include <memory>
 
-rclcpp::intra_process_manager::IntraProcessManagerImplBase::SharedPtr
+using rclcpp::intra_process_manager::FixedSizeString;
+using rclcpp::intra_process_manager::IntraProcessManagerImplBase;
+
+IntraProcessManagerImplBase::SharedPtr
 rclcpp::intra_process_manager::create_default_impl()
 {
   return std::make_shared<IntraProcessManagerImpl<>>();
 }
+
+FixedSizeString::FixedSizeString(const char * str)
+{
+  std::strncpy(str_, str, RMW_TOPIC_MAX_NAME_LENGTH + 1);
+}
+
+const char * FixedSizeString::c_str() const
+{
+  return str_;
+}
+
+bool rclcpp::intra_process_manager::operator<(
+  const FixedSizeString & lhs,
+  const FixedSizeString & rhs)
+{
+  return std::strcmp(lhs.c_str(), rhs.c_str());
+}