Implementing get_qos_for_publishers/subscribers

- Implemented the functions defined in ros2#511
  - rcl_get_qos_for_publishers
  - rcl_get_qos_for_subscribers
- Wrote tests for the same

Note: colcon build --packages-up-to rcl && colcon test --packages-select rcl && colcon test-result --verbose --test-result-base build/rcl
runs successfully without any errors or failures.

Signed-off-by: Jaison Titus <[email protected]>

Author: jaisontj

rcl/src/rcl/graph.c

@@ -375,6 +375,67 @@ rcl_count_subscribers(
   return rcl_convert_rmw_ret_to_rcl_ret(rmw_ret);
 }
 
+
+typedef rmw_ret_t (* get_qos_func)(
+  const rmw_node_t * node, const char * topic_name,
+  rmw_participants_t * participants);
+
+rcl_ret_t
+__rcl_get_qos_for_participants(
+  const rcl_node_t * node,
+  const char * topic_name,
+  rmw_participants_t * participants,
+  get_qos_func get_qos_for_participants)
+{
+  if (!rcl_node_is_valid(node)) {
+    RCL_SET_ERROR_MSG("Invalid node provided.");
+    return RCL_RET_NODE_INVALID;  // error already set
+  }
+  const rcl_node_options_t * node_options = rcl_node_get_options(node);
+  if (!node_options) {
+    RCL_SET_ERROR_MSG("Node options are invalid.");
+    return RCL_RET_NODE_INVALID;  // shouldn't happen, but error is already set if so
+  }
+  RCL_CHECK_ARGUMENT_FOR_NULL(topic_name, RCL_RET_INVALID_ARGUMENT);
+  RCL_CHECK_ARGUMENT_FOR_NULL(participants, RCL_RET_INVALID_ARGUMENT);
+  if (participants->participants != NULL) {
+    RCL_SET_ERROR_MSG("The variable participants inside rmw_participants_t should be set to null. "
+      "It will be malloc'd where it gets populated.");
+    return RCL_RET_INVALID_ARGUMENT;
+  }
+  rmw_ret_t rmw_ret = get_qos_for_participants(
+    rcl_node_get_rmw_handle(node),
+    topic_name,
+    participants);
+  return rcl_convert_rmw_ret_to_rcl_ret(rmw_ret);
+}
+
+rcl_ret_t
+rcl_get_qos_for_publishers(
+  const rcl_node_t * node,
+  const char * topic_name,
+  rmw_participants_t * publishers)
+{
+  return __rcl_get_qos_for_participants(
+    node,
+    topic_name,
+    publishers,
+    rmw_get_qos_for_publishers);
+}
+
+rcl_ret_t
+rcl_get_qos_for_subscribers(
+  const rcl_node_t * node,
+  const char * topic_name,
+  rmw_participants_t * subscribers)
+{
+  return __rcl_get_qos_for_participants(
+    node,
+    topic_name,
+    subscribers,
+    rmw_get_qos_for_subscribers);
+}
+
 rcl_ret_t
 rcl_service_server_is_available(
   const rcl_node_t * node,

rcl/test/rcl/test_graph.cpp

@@ -63,6 +63,9 @@ class CLASSNAME (TestGraphFixture, RMW_IMPLEMENTATION) : public ::testing::Test
   rcl_wait_set_t * wait_set_ptr;
   const char * test_graph_node_name = "test_graph_node";
 
+  rmw_participants_t * participants;
+  const char * topic_name = "valid_topic_name";
+
   void SetUp()
   {
     rcl_ret_t ret;
@@ -101,6 +104,12 @@ class CLASSNAME (TestGraphFixture, RMW_IMPLEMENTATION) : public ::testing::Test
     ret = rcl_wait_set_init(
       this->wait_set_ptr, 0, 1, 0, 0, 0, 0, this->context_ptr, rcl_get_default_allocator());
     ASSERT_EQ(RCL_RET_OK, ret) << rcl_get_error_string().str;
+
+    rmw_participants_t valid_participants = {
+      0,     /*count*/
+      nullptr     /*participants*/
+    };
+    this->participants = &valid_participants;
   }
 
   void TearDown()
@@ -1321,3 +1330,126 @@ TEST_F(CLASSNAME(TestGraphFixture, RMW_IMPLEMENTATION), test_rcl_service_server_
   wait_for_service_state_to_change(false, is_available);
   ASSERT_FALSE(is_available);
 }
+
+
+/*
+ * This does not test content of the response.
+ * It only tests if the return code is the one expected.
+ */
+TEST_F(CLASSNAME(TestGraphFixture, RMW_IMPLEMENTATION),
+  test_rcl_get_qos_for_publishers_null_node)
+{
+  auto ret = rcl_get_qos_for_publishers(nullptr, this->topic_name, this->participants);
+  EXPECT_EQ(RCL_RET_NODE_INVALID, ret);
+}
+
+/*
+ * This does not test content of the response.
+ * It only tests if the return code is the one expected.
+ */
+TEST_F(CLASSNAME(TestGraphFixture, RMW_IMPLEMENTATION),
+  test_rcl_get_qos_for_subscribers_null_node)
+{
+  auto ret = rcl_get_qos_for_subscribers(nullptr, this->topic_name, this->participants);
+  EXPECT_EQ(RCL_RET_NODE_INVALID, ret);
+}
+
+/*
+ * This does not test content of the response.
+ * It only tests if the return code is the one expected.
+ */
+TEST_F(CLASSNAME(TestGraphFixture, RMW_IMPLEMENTATION),
+  test_rcl_get_qos_for_publishers_invalid_node)
+{
+  // this->old_node_ptr is a pointer to an invalid node.
+  auto ret =
+    rcl_get_qos_for_publishers(this->old_node_ptr, this->topic_name, this->participants);
+  EXPECT_EQ(RCL_RET_NODE_INVALID, ret);
+}
+
+/*
+ * This does not test content of the response.
+ * It only tests if the return code is the one expected.
+ */
+TEST_F(CLASSNAME(TestGraphFixture, RMW_IMPLEMENTATION),
+  test_rcl_get_qos_for_subscribers_invalid_node)
+{
+  // this->old_node_ptr is a pointer to an invalid node.
+  auto ret = rcl_get_qos_for_subscribers(this->old_node_ptr, this->topic_name,
+      this->participants);
+  EXPECT_EQ(RCL_RET_NODE_INVALID, ret);
+}
+
+/*
+ * This does not test content of the response.
+ * It only tests if the return code is the one expected.
+ */
+TEST_F(CLASSNAME(TestGraphFixture, RMW_IMPLEMENTATION),
+  test_rcl_get_qos_for_publishers_null_topic)
+{
+  auto ret = rcl_get_qos_for_publishers(this->node_ptr, nullptr, this->participants);
+  EXPECT_EQ(RCL_RET_INVALID_ARGUMENT, ret);
+}
+
+/*
+ * This does not test content of the response.
+ * It only tests if the return code is the one expected.
+ */
+TEST_F(CLASSNAME(TestGraphFixture, RMW_IMPLEMENTATION),
+  test_rcl_get_qos_for_subscribers_null_topic)
+{
+  auto ret = rcl_get_qos_for_subscribers(this->node_ptr, nullptr, this->participants);
+  EXPECT_EQ(RCL_RET_INVALID_ARGUMENT, ret);
+}
+
+/*
+ * This does not test content of the response.
+ * It only tests if the return code is the one expected.
+ */
+TEST_F(CLASSNAME(TestGraphFixture, RMW_IMPLEMENTATION),
+  test_rcl_get_qos_for_publishers_null_participants)
+{
+  auto ret = rcl_get_qos_for_publishers(this->node_ptr, this->topic_name, nullptr);
+  EXPECT_EQ(RCL_RET_INVALID_ARGUMENT, ret);
+}
+
+/*
+ * This does not test content of the response.
+ * It only tests if the return code is the one expected.
+ */
+TEST_F(CLASSNAME(TestGraphFixture, RMW_IMPLEMENTATION),
+  test_rcl_get_qos_for_subscribers_null_participants)
+{
+  auto ret = rcl_get_qos_for_subscribers(this->node_ptr, this->topic_name, nullptr);
+  EXPECT_EQ(RCL_RET_INVALID_ARGUMENT, ret);
+}
+
+/*
+ * This does not test content of the response.
+ * It only tests if the return code is the one expected.
+ */
+TEST_F(CLASSNAME(TestGraphFixture, RMW_IMPLEMENTATION),
+  test_rcl_get_qos_for_publishers_invalid_participants)
+{
+  // this participant is invalid as the pointer "participants" inside is expected to be null.
+  this->participants->participants =
+    reinterpret_cast<rmw_participant_qos_profile_t *>(malloc(
+      sizeof(rmw_participant_qos_profile_t *)));
+  auto ret = rcl_get_qos_for_publishers(this->node_ptr, this->topic_name, this->participants);
+  EXPECT_EQ(RCL_RET_INVALID_ARGUMENT, ret);
+}
+
+/*
+ * This does not test content of the response.
+ * It only tests if the return code is the one expected.
+ */
+TEST_F(CLASSNAME(TestGraphFixture, RMW_IMPLEMENTATION),
+  test_rcl_get_qos_for_subscribers_invalid_participants)
+{
+  // this participant is invalid as the pointer "participants" inside is expected to be null.
+  this->participants->participants =
+    reinterpret_cast<rmw_participant_qos_profile_t *>(malloc(
+      sizeof(rmw_participant_qos_profile_t *)));
+  auto ret = rcl_get_qos_for_subscribers(this->node_ptr, this->topic_name, this->participants);
+  EXPECT_EQ(RCL_RET_INVALID_ARGUMENT, ret);
+}