feat: Added new CBGExecutor

Signed-off-by: Janosch Machowinski <[email protected]>

Author: Janosch Machowinski

rclcpp/CMakeLists.txt

@@ -63,6 +63,7 @@ set(${PROJECT_NAME}_SRCS
   src/rclcpp/executable_list.cpp
   src/rclcpp/executor.cpp
   src/rclcpp/executors.cpp
+  src/rclcpp/executors/cbg_executor.cpp
   src/rclcpp/executors/executor_entities_collection.cpp
   src/rclcpp/executors/executor_entities_collector.cpp
   src/rclcpp/executors/executor_notify_waitable.cpp

rclcpp/include/rclcpp/executors/callback_group_state.hpp

@@ -0,0 +1,37 @@
+#pragma once
+#include <rclcpp/callback_group.hpp>
+#include <rclcpp/guard_condition.hpp>
+#include <vector>
+
+namespace rclcpp::executors
+{
+
+/**
+ * Snapshot of the state of a callback group.
+ *
+ * Contains all registered entities from the point in timer
+ * when the snapshot was taken, as weak ptrs.
+ */
+struct CallbackGroupState
+{
+  CallbackGroupState(rclcpp::CallbackGroup & cbg)
+  {
+    update(cbg);
+  }
+
+  /// Update the state from the callback group
+  void update(rclcpp::CallbackGroup & cbg)
+  {
+    cbg.collect_all_ptrs(subscription_ptrs, timer_ptrs, service_ptrs, client_ptrs, waitable_ptrs);
+    trigger_ptr = cbg.get_notify_guard_condition();
+  }
+
+  std::vector<rclcpp::SubscriptionBase::WeakPtr> subscription_ptrs;
+  std::vector<rclcpp::TimerBase::WeakPtr> timer_ptrs;
+  std::vector<rclcpp::ServiceBase::WeakPtr> service_ptrs;
+  std::vector<rclcpp::ClientBase::WeakPtr> client_ptrs;
+  std::vector<rclcpp::Waitable::WeakPtr> waitable_ptrs;
+
+  rclcpp::GuardCondition::WeakPtr trigger_ptr;
+};
+}