Add function for checking QoS profile compatibility

rmw_dds_common/CMakeLists.txt

@@ -33,6 +33,7 @@ rosidl_generate_interfaces(
 add_library(${PROJECT_NAME}_library SHARED
   src/gid_utils.cpp
   src/graph_cache.cpp
+  src/qos.cpp
   src/time_utils.cpp)
 
 set_target_properties(${PROJECT_NAME}_library
@@ -92,6 +93,11 @@ if(BUILD_TESTING)
     target_link_libraries(test_gid_utils ${PROJECT_NAME}_library)
   endif()
 
+  ament_add_gmock(test_qos test/test_qos.cpp)
+  if(TARGET test_qos)
+    target_link_libraries(test_qos ${PROJECT_NAME}_library)
+  endif()
+
   ament_add_gmock(test_time_utils test/test_time_utils.cpp)
   if(TARGET test_time_utils)
     target_link_libraries(test_time_utils ${PROJECT_NAME}_library)

rmw_dds_common/docs/FEATURES.md

@@ -11,3 +11,4 @@ This package includes:
   - A generic [`Context`](rmw_dds_common/include/rmw_dds_common/context.hpp) type to withhold most state needed to implement [ROS nodes discovery](https://github.com/ros2/design/pull/250)
   - [Comparison utilities and some C++ operator overloads](rmw_dds_common/include/rmw_dds_common/gid_utils.hpp) for `rmw_gid_t` instances
   - [Conversion utilities](rmw_dds_common/include/rmw_dds_common/gid_utils.hpp) between `rmw_dds_common/msg/Gid` messages and `rmw_gid_t` instances
+  - A function for checking the compatibility of two QoS profiles, [`qos_profile_check_compatible`](rmw_dds_common/include/rmw_dds_common/qos.hpp)

rmw_dds_common/include/rmw_dds_common/qos.hpp

@@ -0,0 +1,61 @@
+// Copyright 2021 Open Source Robotics Foundation, Inc.
+//
+// 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.
+
+#ifndef RMW_DDS_COMMON__QOS_HPP_
+#define RMW_DDS_COMMON__QOS_HPP_
+
+#include "rmw/qos_profiles.h"
+#include "rmw/types.h"
+
+#include "rmw_dds_common/visibility_control.h"
+
+namespace rmw_dds_common
+{
+
+/// Check if two QoS profiles are compatible
+/**
+ * Two QoS profiles are compatible if a publisher and subcription
+ * using the QoS policies can communicate with each other.
+ *
+ * This implements the rmw API \ref rmw_qos_profile_check_compatible().
+ * See \ref rmw_qos_profile_check_compatible() for more information.
+ *
+ * \param[in] publisher_profile: The QoS profile used for a publisher.
+ * \param[in] subscription_profile: The QoS profile used for a subscription.
+ * \param[out] compatibility: `RMW_QOS_COMPATIBILITY_OK` if the QoS profiles are compatible, or
+ *   `RMW_QOS_COMPATIBILITY_WARNING` if the QoS profiles might be compatible, or
+ *   `RMW_QOS_COMPATIBILITY_ERROR` if the QoS profiles are not compatible.
+ * \param[out] reason: A detailed reason for a QoS incompatibility or potential incompatibility.
+ *   Must be pre-allocated by the caller.
+ *   This parameter is optional and may be set to `nullptr` if the reason information is not
+ *   desired.
+ * \param[in] reason_size: Size of the string buffer `reason`, if one is provided.
+ *   If `reason` is `nullptr`, then this parameter must be zero.
+ * \return `RMW_RET_OK` if the check was successful, or
+ * \return `RMW_RET_INVALID_ARGUMENT` if `compatiblity` is `nullptr`, or
+ * \return `RMW_RET_INVALID_ARGUMENT` if `reason` is `nullptr` and  `reason_size` is not zero, or
+ * \return `RMW_RET_ERROR` if there is an unexpected error.
+ */
+RMW_DDS_COMMON_PUBLIC
+rmw_ret_t
+qos_profile_check_compatible(
+  const rmw_qos_profile_t publisher_qos,
+  const rmw_qos_profile_t subscription_qos,
+  rmw_qos_compatibility_type_t * compatibility,
+  char * reason,
+  size_t reason_size);
+
+}  // namespace rmw_dds_common
+
+#endif  // RMW_DDS_COMMON__QOS_HPP_