add content-filtered-topic interfaces

rclcpp/CMakeLists.txt

@@ -2,6 +2,11 @@ cmake_minimum_required(VERSION 3.12)
 
 project(rclcpp)
 
+option(DEFINE_CONTENT_FILTER "Content filter feature support" ON)
+if(DEFINE_CONTENT_FILTER)
+  add_definitions(-DCONTENT_FILTER_ENABLE)
+endif()
+
 find_package(Threads REQUIRED)
 
 find_package(ament_cmake_ros REQUIRED)

rclcpp/include/rclcpp/subscription_base.hpp

@@ -491,6 +491,38 @@ class SubscriptionBase : public std::enable_shared_from_this<SubscriptionBase>
     event_handlers_[event_type]->clear_on_ready_callback();
   }
 
+#ifdef CONTENT_FILTER_ENABLE
+  /// Set the filter expression and expression parameters for the subscription.
+  /**
+   * \param[in] filter_expression An filter expression to set.
+   *   \sa SubscriptionOptionsBase::ContentFilterOptions::filter_expression
+   * \param[in] expression_parameters Array of expression parameters to set.
+   *   \sa SubscriptionOptionsBase::ContentFilterOptions::expression_parameters
+   * \throws RCLBadAlloc if memory cannot be allocated
+   * \throws RCLError if an unexpect error occurs
+   */
+  RCLCPP_PUBLIC
+  virtual
+  void
+  set_content_filter(
+    const std::string & filter_expression,
+    const std::vector<std::string> & expression_parameters = {});
+
+  /// Get the filter expression and expression parameters for the subscription.
+  /**
+   * \param[out] filter_expression An filter expression to get.
+   * \param[out] expression_parameters Array of expression parameters to get.
+   * \throws RCLBadAlloc if memory cannot be allocated
+   * \throws RCLError if an unexpect error occurs
+   */
+  RCLCPP_PUBLIC
+  virtual
+  void
+  get_content_filter(
+    std::string & filter_expression,
+    std::vector<std::string> & expression_parameters) const;
+#endif  // CONTENT_FILTER_ENABLE
+
 protected:
   template<typename EventCallbackT>
   void

rclcpp/include/rclcpp/subscription_options.hpp

@@ -81,6 +81,22 @@ struct SubscriptionOptionsBase
   TopicStatisticsOptions topic_stats_options;
 
   QosOverridingOptions qos_overriding_options;
+
+#ifdef CONTENT_FILTER_ENABLE
+  /// Options to configure content filtered topic in the subscription.
+  struct ContentFilterOptions
+  {
+    /// Filter expression is similar to the WHERE part of an SQL clause
+    std::string filter_expression;
+    /**
+     * Expression parameters is the tokens placeholder ‘parameters’ (i.e., "%n" tokens begin from 0)
+     * in the filter_expression
+     */
+    std::vector<std::string> expression_parameters;
+  };
+
+  ContentFilterOptions content_filter_options;
+#endif  // CONTENT_FILTER_ENABLE
 };
 
 /// Structure containing optional configuration for Subscriptions.

rclcpp/src/rclcpp/subscription_base.cpp

@@ -354,3 +354,27 @@ SubscriptionBase::set_on_new_message_callback(
     throw_from_rcl_error(ret, "failed to set the on new message callback for subscription");
   }
 }
+
+#ifdef CONTENT_FILTER_ENABLE
+void
+SubscriptionBase::set_content_filter(
+  const std::string & filter_expression,
+  const std::vector<std::string> & expression_parameters)
+{
+  static_cast<void>(filter_expression);
+  static_cast<void>(expression_parameters);
+
+  rclcpp::exceptions::throw_from_rcl_error(RMW_RET_UNSUPPORTED, "content filter unsupported");
+}
+
+void
+SubscriptionBase::get_content_filter(
+  std::string & filter_expression,
+  std::vector<std::string> & expression_parameters) const
+{
+  static_cast<void>(filter_expression);
+  static_cast<void>(expression_parameters);
+
+  rclcpp::exceptions::throw_from_rcl_error(RMW_RET_UNSUPPORTED, "content filter unsupported");
+}
+#endif  // CONTENT_FILTER_ENABLE

rclcpp/test/rclcpp/CMakeLists.txt

@@ -733,3 +733,20 @@ ament_add_gtest(test_graph_listener test_graph_listener.cpp)
 if(TARGET test_graph_listener)
   target_link_libraries(test_graph_listener ${PROJECT_NAME} mimick)
 endif()
+
+function(test_subscription_content_filter_for_rmw_implementation)
+  set(rmw_implementation_env_var RMW_IMPLEMENTATION=${rmw_implementation})
+  ament_add_gmock(test_subscription_content_filter${target_suffix}
+    test_subscription_content_filter.cpp
+    ENV ${rmw_implementation_env_var}
+  )
+  if(TARGET test_subscription_content_filter${target_suffix})
+    target_link_libraries(test_subscription_content_filter${target_suffix} ${PROJECT_NAME} mimick)
+    ament_target_dependencies(test_subscription_content_filter${target_suffix}
+      "rcpputils"
+      "rosidl_typesupport_cpp"
+      "test_msgs"
+    )
+  endif()
+endfunction()
+call_for_each_rmw_implementation(test_subscription_content_filter_for_rmw_implementation)

rclcpp/test/rclcpp/test_subscription_content_filter.cpp

@@ -0,0 +1,82 @@
+// 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.
+
+#include <gtest/gtest.h>
+
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "rclcpp/exceptions.hpp"
+#include "rclcpp/rclcpp.hpp"
+
+#include "test_msgs/msg/basic_types.hpp"
+
+#ifdef RMW_IMPLEMENTATION
+# define CLASSNAME_(NAME, SUFFIX) NAME ## __ ## SUFFIX
+# define CLASSNAME(NAME, SUFFIX) CLASSNAME_(NAME, SUFFIX)
+#else
+# define CLASSNAME(NAME, SUFFIX) NAME
+#endif
+
+class CLASSNAME (TestContentFilterSubscription, RMW_IMPLEMENTATION) : public ::testing::Test
+{
+public:
+  static void SetUpTestCase()
+  {
+    rclcpp::init(0, nullptr);
+  }
+
+  static void TearDownTestCase()
+  {
+    rclcpp::shutdown();
+  }
+
+  void SetUp()
+  {
+    node = std::make_shared<rclcpp::Node>("test_content_filter_node", "/ns");
+
+    auto options = rclcpp::SubscriptionOptions();
+    auto callback = [](std::shared_ptr<const test_msgs::msg::BasicTypes>) {};
+    sub = node->create_subscription<test_msgs::msg::BasicTypes>(
+      "content_filter_topic", qos.reliable().transient_local(), callback, options);
+  }
+
+  void TearDown()
+  {
+    sub.reset();
+    node.reset();
+  }
+
+protected:
+  rclcpp::Node::SharedPtr node;
+  rclcpp::QoS qos{rclcpp::KeepLast{10}};
+  rclcpp::Subscription<test_msgs::msg::BasicTypes>::SharedPtr sub;
+};
+
+TEST_F(CLASSNAME(TestContentFilterSubscription, RMW_IMPLEMENTATION), get_content_filter_error) {
+  std::string filter_expression;
+  std::vector<std::string> expression_parameters;
+  EXPECT_THROW(
+    sub->get_content_filter(filter_expression, expression_parameters),
+    rclcpp::exceptions::RCLError);
+}
+
+TEST_F(CLASSNAME(TestContentFilterSubscription, RMW_IMPLEMENTATION), set_content_filter_error) {
+  std::string filter_expression = "int32_value = %0";
+  std::string expression_parameter = "100";
+  EXPECT_THROW(
+    sub->set_content_filter(filter_expression, {expression_parameter}),
+    rclcpp::exceptions::RCLError);
+}