update rclcpp::Waitable API to use references and const

rclcpp/include/rclcpp/event_handler.hpp

@@ -117,12 +117,12 @@ class EventHandlerBase : public Waitable
   /// Add the Waitable to a wait set.
   RCLCPP_PUBLIC
   void
-  add_to_wait_set(rcl_wait_set_t * wait_set) override;
+  add_to_wait_set(rcl_wait_set_t & wait_set) override;
 
   /// Check if the Waitable is ready.
   RCLCPP_PUBLIC
   bool
-  is_ready(rcl_wait_set_t * wait_set) override;
+  is_ready(const rcl_wait_set_t & wait_set) override;
 
   /// Set a callback to be called when each new event instance occurs.
   /**
@@ -294,7 +294,7 @@ class EventHandler : public EventHandlerBase
 
   /// Execute any entities of the Waitable that are ready.
   void
-  execute(std::shared_ptr<void> & data) override
+  execute(const std::shared_ptr<void> & data) override
   {
     if (!data) {
       throw std::runtime_error("'data' is empty");

rclcpp/include/rclcpp/executors/executor_notify_waitable.hpp

@@ -60,7 +60,7 @@ class ExecutorNotifyWaitable : public rclcpp::Waitable
    */
   RCLCPP_PUBLIC
   void
-  add_to_wait_set(rcl_wait_set_t * wait_set) override;
+  add_to_wait_set(rcl_wait_set_t & wait_set) override;
 
   /// Check conditions against the wait set
   /**
@@ -69,7 +69,7 @@ class ExecutorNotifyWaitable : public rclcpp::Waitable
    */
   RCLCPP_PUBLIC
   bool
-  is_ready(rcl_wait_set_t * wait_set) override;
+  is_ready(const rcl_wait_set_t & wait_set) override;
 
   /// Perform work associated with the waitable.
   /**
@@ -78,7 +78,7 @@ class ExecutorNotifyWaitable : public rclcpp::Waitable
    */
   RCLCPP_PUBLIC
   void
-  execute(std::shared_ptr<void> & data) override;
+  execute(const std::shared_ptr<void> & data) override;
 
   /// Retrieve data to be used in the next execute call.
   /**

rclcpp/include/rclcpp/experimental/subscription_intra_process.hpp

@@ -132,23 +132,22 @@ class SubscriptionIntraProcess
     );
   }
 
-  void execute(std::shared_ptr<void> & data) override
+  void execute(const std::shared_ptr<void> & data) override
   {
     execute_impl<SubscribedType>(data);
   }
 
 protected:
   template<typename T>
   typename std::enable_if<std::is_same<T, rcl_serialized_message_t>::value, void>::type
-  execute_impl(std::shared_ptr<void> & data)
+  execute_impl(const std::shared_ptr<void> &)
   {
-    (void)data;
     throw std::runtime_error("Subscription intra-process can't handle serialized messages");
   }
 
   template<class T>
   typename std::enable_if<!std::is_same<T, rcl_serialized_message_t>::value, void>::type
-  execute_impl(std::shared_ptr<void> & data)
+  execute_impl(const std::shared_ptr<void> & data)
   {
     if (!data) {
       return;

rclcpp/include/rclcpp/experimental/subscription_intra_process_base.hpp

@@ -60,7 +60,7 @@ class SubscriptionIntraProcessBase : public rclcpp::Waitable
 
   RCLCPP_PUBLIC
   void
-  add_to_wait_set(rcl_wait_set_t * wait_set) override;
+  add_to_wait_set(rcl_wait_set_t & wait_set) override;
 
   RCLCPP_PUBLIC
   virtual
@@ -72,7 +72,7 @@ class SubscriptionIntraProcessBase : public rclcpp::Waitable
   is_durability_transient_local() const;
 
   bool
-  is_ready(rcl_wait_set_t * wait_set) override = 0;
+  is_ready(const rcl_wait_set_t & wait_set) override = 0;
 
   std::shared_ptr<void>
   take_data() override = 0;
@@ -85,7 +85,7 @@ class SubscriptionIntraProcessBase : public rclcpp::Waitable
   }
 
   void
-  execute(std::shared_ptr<void> & data) override = 0;
+  execute(const std::shared_ptr<void> & data) override = 0;
 
   virtual
   bool

rclcpp/include/rclcpp/experimental/subscription_intra_process_buffer.hpp

@@ -101,16 +101,16 @@ class SubscriptionIntraProcessBuffer : public SubscriptionROSMsgIntraProcessBuff
   }
 
   void
-  add_to_wait_set(rcl_wait_set_t * wait_set) override
+  add_to_wait_set(rcl_wait_set_t & wait_set) override
   {
     if (this->buffer_->has_data()) {
       this->trigger_guard_condition();
     }
-    detail::add_guard_condition_to_rcl_wait_set(*wait_set, this->gc_);
+    detail::add_guard_condition_to_rcl_wait_set(wait_set, this->gc_);
   }
 
   bool
-  is_ready(rcl_wait_set_t * wait_set) override
+  is_ready(const rcl_wait_set_t & wait_set) override
   {
     (void) wait_set;
     return buffer_->has_data();

rclcpp/include/rclcpp/guard_condition.hpp

@@ -100,7 +100,7 @@ class GuardCondition
    */
   RCLCPP_PUBLIC
   void
-  add_to_wait_set(rcl_wait_set_t * wait_set);
+  add_to_wait_set(rcl_wait_set_t & wait_set);
 
   /// Set a callback to be called whenever the guard condition is triggered.
   /**
@@ -128,7 +128,9 @@ class GuardCondition
   std::recursive_mutex reentrant_mutex_;
   std::function<void(size_t)> on_trigger_callback_{nullptr};
   size_t unread_count_{0};
-  rcl_wait_set_t * wait_set_{nullptr};
+  // the type of wait_set_ is actually rcl_wait_set_t *, but it's never
+  // dereferenced, only compared to, so make it void * to avoid accidental use
+  void * wait_set_{nullptr};
 };
 
 }  // namespace rclcpp

rclcpp/include/rclcpp/strategies/allocator_memory_strategy.hpp

@@ -121,7 +121,7 @@ class AllocatorMemoryStrategy : public memory_strategy::MemoryStrategy
       }
     }
     for (size_t i = 0; i < waitable_handles_.size(); ++i) {
-      if (waitable_handles_[i]->is_ready(wait_set)) {
+      if (waitable_handles_[i]->is_ready(*wait_set)) {
         waitable_triggered_handles_.emplace_back(std::move(waitable_handles_[i]));
       }
     }
@@ -235,7 +235,7 @@ class AllocatorMemoryStrategy : public memory_strategy::MemoryStrategy
     }
 
     for (const std::shared_ptr<Waitable> & waitable : waitable_handles_) {
-      waitable->add_to_wait_set(wait_set);
+      waitable->add_to_wait_set(*wait_set);
     }
     return true;
   }

rclcpp/include/rclcpp/wait_result.hpp

@@ -277,7 +277,7 @@ class WaitResult final
       auto rcl_wait_set = wait_set.get_rcl_wait_set();
       while (next_waitable_index_ < wait_set.size_of_waitables()) {
         auto cur_waitable = wait_set.waitables(next_waitable_index_++);
-        if (cur_waitable != nullptr && cur_waitable->is_ready(&rcl_wait_set)) {
+        if (cur_waitable != nullptr && cur_waitable->is_ready(rcl_wait_set)) {
           waitable = cur_waitable;
           break;
         }

rclcpp/include/rclcpp/wait_set_policies/detail/storage_policy_common.hpp

@@ -375,7 +375,7 @@ class StoragePolicyCommon
         needs_pruning_ = true;
         continue;
       }
-      waitable_entry.waitable->add_to_wait_set(&rcl_wait_set_);
+      waitable_entry.waitable->add_to_wait_set(rcl_wait_set_);
     }
   }
 

rclcpp/include/rclcpp/waitable.hpp

@@ -101,6 +101,23 @@ class Waitable
   size_t
   get_number_of_ready_guard_conditions();
 
+#ifdef __GNUC__
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Woverloaded-virtual"
+#endif
+  /// Deprecated.
+  /**
+   * \sa add_to_wait_set(rcl_wait_set_t &)
+   */
+  [[deprecated("Use add_to_wait_set(rcl_wait_set_t & wait_set) signature")]]
+  RCLCPP_PUBLIC
+  virtual
+  void
+  add_to_wait_set(rcl_wait_set_t * wait_set);
+#ifdef __GNUC__
+#pragma GCC diagnostic pop
+#endif
+
   /// Add the Waitable to a wait set.
   /**
    * \param[in] wait_set A handle to the wait set to add the Waitable to.
@@ -109,7 +126,24 @@ class Waitable
   RCLCPP_PUBLIC
   virtual
   void
-  add_to_wait_set(rcl_wait_set_t * wait_set) = 0;
+  add_to_wait_set(rcl_wait_set_t & wait_set);
+
+#ifdef __GNUC__
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Woverloaded-virtual"
+#endif
+  /// Deprecated.
+  /**
+   * \sa is_ready(const rcl_wait_set_t &)
+   */
+  [[deprecated("Use is_ready(const rcl_wait_set_t & wait_set) signature")]]
+  RCLCPP_PUBLIC
+  virtual
+  bool
+  is_ready(rcl_wait_set_t * wait_set);
+#ifdef __GNUC__
+#pragma GCC diagnostic pop
+#endif
 
   /// Check if the Waitable is ready.
   /**
@@ -124,7 +158,7 @@ class Waitable
   RCLCPP_PUBLIC
   virtual
   bool
-  is_ready(rcl_wait_set_t * wait_set) = 0;
+  is_ready(const rcl_wait_set_t & wait_set);
 
   /// Take the data so that it can be consumed with `execute`.
   /**
@@ -178,6 +212,23 @@ class Waitable
   std::shared_ptr<void>
   take_data_by_entity_id(size_t id);
 
+#ifdef __GNUC__
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Woverloaded-virtual"
+#endif
+  /// Deprecated.
+  /**
+   * \sa execute(const std::shared_ptr<void> &)
+   */
+  [[deprecated("Use execute(const std::shared_ptr<void> & data) signature")]]
+  RCLCPP_PUBLIC
+  virtual
+  void
+  execute(std::shared_ptr<void> & data);
+#ifdef __GNUC__
+#pragma GCC diagnostic pop
+#endif
+
   /// Execute data that is passed in.
   /**
    * Before calling this method, the Waitable should be added to a wait set,
@@ -203,7 +254,7 @@ class Waitable
   RCLCPP_PUBLIC
   virtual
   void
-  execute(std::shared_ptr<void> & data) = 0;
+  execute(const std::shared_ptr<void> & data);
 
   /// Exchange the "in use by wait set" state for this timer.
   /**

rclcpp/src/rclcpp/event_handler.cpp

@@ -56,19 +56,19 @@ EventHandlerBase::get_number_of_ready_events()
 
 /// Add the Waitable to a wait set.
 void
-EventHandlerBase::add_to_wait_set(rcl_wait_set_t * wait_set)
+EventHandlerBase::add_to_wait_set(rcl_wait_set_t & wait_set)
 {
-  rcl_ret_t ret = rcl_wait_set_add_event(wait_set, &event_handle_, &wait_set_event_index_);
+  rcl_ret_t ret = rcl_wait_set_add_event(&wait_set, &event_handle_, &wait_set_event_index_);
   if (RCL_RET_OK != ret) {
     exceptions::throw_from_rcl_error(ret, "Couldn't add event to wait set");
   }
 }
 
 /// Check if the Waitable is ready.
 bool
-EventHandlerBase::is_ready(rcl_wait_set_t * wait_set)
+EventHandlerBase::is_ready(const rcl_wait_set_t & wait_set)
 {
-  return wait_set->events[wait_set_event_index_] == &event_handle_;
+  return wait_set.events[wait_set_event_index_] == &event_handle_;
 }
 
 void

rclcpp/src/rclcpp/executor.cpp

@@ -398,7 +398,8 @@ Executor::execute_any_executable(AnyExecutable & any_exec)
     execute_client(any_exec.client);
   }
   if (any_exec.waitable) {
-    any_exec.waitable->execute(any_exec.data);
+    const std::shared_ptr<void> & const_data = any_exec.data;
+    any_exec.waitable->execute(const_data);
   }
 
   // Reset the callback_group, regardless of type

rclcpp/src/rclcpp/executors/executor_entities_collection.cpp

@@ -232,7 +232,7 @@ ready_executables(
     if (!waitable) {
       continue;
     }
-    if (!waitable->is_ready(&rcl_wait_set)) {
+    if (!waitable->is_ready(rcl_wait_set)) {
       continue;
     }
     auto group_info = group_cache(entry.callback_group);

rclcpp/src/rclcpp/executors/executor_notify_waitable.cpp

@@ -45,16 +45,15 @@ ExecutorNotifyWaitable & ExecutorNotifyWaitable::operator=(ExecutorNotifyWaitabl
 }
 
 void
-ExecutorNotifyWaitable::add_to_wait_set(rcl_wait_set_t * wait_set)
+ExecutorNotifyWaitable::add_to_wait_set(rcl_wait_set_t & wait_set)
 {
   std::lock_guard<std::mutex> lock(guard_condition_mutex_);
   for (auto weak_guard_condition : this->notify_guard_conditions_) {
     auto guard_condition = weak_guard_condition.lock();
     if (!guard_condition) {continue;}
 
     rcl_guard_condition_t * cond = &guard_condition->get_rcl_guard_condition();
-
-    rcl_ret_t ret = rcl_wait_set_add_guard_condition(wait_set, cond, NULL);
+    rcl_ret_t ret = rcl_wait_set_add_guard_condition(&wait_set, cond, NULL);
 
     if (RCL_RET_OK != ret) {
       rclcpp::exceptions::throw_from_rcl_error(
@@ -64,13 +63,13 @@ ExecutorNotifyWaitable::add_to_wait_set(rcl_wait_set_t * wait_set)
 }
 
 bool
-ExecutorNotifyWaitable::is_ready(rcl_wait_set_t * wait_set)
+ExecutorNotifyWaitable::is_ready(const rcl_wait_set_t & wait_set)
 {
   std::lock_guard<std::mutex> lock(guard_condition_mutex_);
 
   bool any_ready = false;
-  for (size_t ii = 0; ii < wait_set->size_of_guard_conditions; ++ii) {
-    const auto * rcl_guard_condition = wait_set->guard_conditions[ii];
+  for (size_t ii = 0; ii < wait_set.size_of_guard_conditions; ++ii) {
+    const auto * rcl_guard_condition = wait_set.guard_conditions[ii];
 
     if (nullptr == rcl_guard_condition) {
       continue;
@@ -87,7 +86,7 @@ ExecutorNotifyWaitable::is_ready(rcl_wait_set_t * wait_set)
 }
 
 void
-ExecutorNotifyWaitable::execute(std::shared_ptr<void> & data)
+ExecutorNotifyWaitable::execute(const std::shared_ptr<void> & data)
 {
   (void) data;
   this->execute_callback_();

rclcpp/src/rclcpp/executors/static_single_threaded_executor.cpp

@@ -183,7 +183,7 @@ bool StaticSingleThreadedExecutor::execute_ready_executables(
   while (auto waitable = wait_result.next_ready_waitable()) {
     auto entity_iter = collection.waitables.find(waitable.get());
     if (entity_iter != collection.waitables.end()) {
-      auto data = waitable->take_data();
+      const auto data = waitable->take_data();
       waitable->execute(data);
       any_ready_executable = true;
       if (spin_once) {return any_ready_executable;}

rclcpp/src/rclcpp/experimental/executors/events_executor/events_executor.cpp

@@ -339,7 +339,7 @@ EventsExecutor::execute_event(const ExecutorEvent & event)
         }
         if (waitable) {
           for (size_t i = 0; i < event.num_events; i++) {
-            auto data = waitable->take_data_by_entity_id(event.waitable_data);
+            const auto data = waitable->take_data_by_entity_id(event.waitable_data);
             waitable->execute(data);
           }
         }