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/include/rcl/graph.h

@@ -525,22 +525,22 @@ rcl_count_subscribers(
   size_t * count);
 
 /// Returns a list of all publishers to a topic.
-/// Each element in the list will contain the publisher's name and its respective qos profile.
+/// Each element in the list will contain the node name, node namespace, topic type,
+/// gid and the qos profile of the publisher.
 /**
  * The `node` parameter must point to a valid node.
  *
  * The `topic_name` parameter must not be `NULL`.
  *
- * The `publishers` parameter must point to a valid struct of type rmw_participants_t.
- * The `count` field inside the struct must be set to 0
- * The `participants` field inside the struct must be set to null.
- * The `publishers` parameter is the output for this function and will be set.
+ * The `no_mangle` parameter determines if the provided topic_name should be
+ * expanded to its fully qualified name.
  *
- * The topic name is not automatically remapped by this function.
- * If there is a publisher created with topic name `foo` and remap rule `foo:=bar` then calling
- * this with `topic_name` set to `bar` will return a list with 1 publisher, and with `topic_name` set to `foo`
- * will return a list with 0 publishers.
- * /sa rcl_remap_topic_name()
+ * It is the responsibility of the caller to ensure that `publishers_info` parameter points
+ * to a valid struct of type rmw_topic_info_array_t. The `count` field inside the struct
+ * must be set to 0 and the `info_array` field inside the struct must be set to null.
+ *
+ * The `allocator` will be used to allocate memory to the `info_array` member
+ * inside of `publishers_info`.
  *
  * <hr>
  * Attribute          | Adherence
@@ -552,8 +552,11 @@ rcl_count_subscribers(
  * <i>[1] implementation may need to protect the data structure with a lock</i>
  *
  * \param[in] node the handle to the node being used to query the ROS graph
+ * \param[in] allocator allocator to be used when allocating space for
+ *            the array inside publishers_info
  * \param[in] topic_name the name of the topic in question
- * \param[out] publishers a struct representing a list of publishers with their qos profile.
+ * \param[in] no_mangle if true, the topic_name will be expanded to its fully qualified name.
+ * \param[out] publishers_info a struct representing a list of publisher information.
  * \return `RCL_RET_OK` if the query was successful, or
  * \return `RCL_RET_NODE_INVALID` if the node is invalid, or
  * \return `RCL_RET_INVALID_ARGUMENT` if any arguments are invalid, or
@@ -562,29 +565,32 @@ rcl_count_subscribers(
 RCL_PUBLIC
 RCL_WARN_UNUSED
 rcl_ret_t
-rcl_get_qos_for_publishers(
+rcl_get_publishers_info_by_topic(
   const rcl_node_t * node,
+  rcutils_allocator_t * allocator,
   const char * topic_name,
-  rmw_participants_t * publishers);
+  bool no_mangle,
+  rmw_topic_info_array_t * publishers_info);
+
 
-/// Returns a list of all subscribers to a topic.
-/// Each element in the list will contain the subscriber's name and its respective qos profile.
+/// Returns a list of all subscriptions to a topic.
+/// Each element in the list will contain the node name, node namespace, topic type,
+/// gid and the qos profile of the subscription.
 /**
  * The `node` parameter must point to a valid node.
  *
  * The `topic_name` parameter must not be `NULL`.
  *
- * The `subscriber` parameter must point to a valid struct of type rmw_participants_t.
- * The `count` field inside the struct must be set to 0
- * The `participants` field inside the struct must be set to null.
- * The `subscribers` parameter is the output for this function and will be set.
+ * The `no_mangle` parameter determines if the provided topic_name should be
+ * expanded to its fully qualified name.
  *
- * The topic name is not automatically remapped by this function.
- * If there is a subscriber created with topic name `foo` and remap rule `foo:=bar` then calling
- * this with `topic_name` set to `bar` will return a list with 1 subscriber , and with `topic_name` set to `foo`
- * will return a list with 0 subscribers.
- * /sa rcl_remap_topic_name()
+ * It is the responsibility of the caller to ensure that `subscriptions_info` parameter points
+ * to a valid struct of type rmw_topic_info_array_t. The `count` field inside the struct
+ * must be set to 0 and the `info_array` field inside the struct must be set to null.
  *
+ * The `allocator` will be used to allocate memory to the `info_array` member
+ * inside of `subscriptions_info`.
+
  * <hr>
  * Attribute          | Adherence
  * ------------------ | -------------
@@ -595,8 +601,11 @@ rcl_get_qos_for_publishers(
  * <i>[1] implementation may need to protect the data structure with a lock</i>
  *
  * \param[in] node the handle to the node being used to query the ROS graph
+ * \param[in] allocator allocator to be used when allocating space for
+ *            the array inside publishers_info
  * \param[in] topic_name the name of the topic in question
- * \param[out] subscribers a struct representing a list of subscribers with their qos profile.
+ * \param[in] no_mangle if true, the topic_name will be expanded to its fully qualified name.
+ * \param[out] subscriptions_info a struct representing a list of subscriptions information.
  * \return `RCL_RET_OK` if the query was successful, or
  * \return `RCL_RET_NODE_INVALID` if the node is invalid, or
  * \return `RCL_RET_INVALID_ARGUMENT` if any arguments are invalid, or
@@ -605,10 +614,12 @@ rcl_get_qos_for_publishers(
 RCL_PUBLIC
 RCL_WARN_UNUSED
 rcl_ret_t
-rcl_get_qos_for_subscribers(
+rcl_get_subscriptions_info_by_topic(
   const rcl_node_t * node,
+  rcutils_allocator_t * allocator,
   const char * topic_name,
-  rmw_participants_t * subscribers);
+  bool no_mangle,
+  rmw_topic_info_array_t * subscriptions_info);
 
 
 /// Check if a service server is available for the given service client.

rcl/src/rcl/graph.c

@@ -375,6 +375,73 @@ rcl_count_subscribers(
   return rcl_convert_rmw_ret_to_rcl_ret(rmw_ret);
 }
 
+
+typedef rmw_ret_t (* get_topic_info_func)(
+  const rcl_node_t * node,
+  rcutils_allocator_t * allocator,
+  const char * topic_name,
+  bool no_mangle,
+  rmw_topic_info_array_t * info_array);
+
+rcl_ret_t
+__rcl_get_info_by_topic(
+  const rmw_node_t * node,
+  rcutils_allocator_t * allocator,
+  const char * topic_name,
+  bool no_mangle,
+  rmw_topic_info_array_t * info_array,
+  get_topic_info_func get_topic_info)
+{
+  if (!rcl_node_is_valid(node)) {
+    RCL_SET_ERROR_MSG("Invalid node provided.");
+    return RCL_RET_NODE_INVALID;
+  }
+  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_ALLOCATOR_WITH_MSG(allocator, "invalid allocator", return RCL_RET_INVALID_ARGUMENT);
+  RCL_CHECK_ARGUMENT_FOR_NULL(topic_name, RCL_RET_INVALID_ARGUMENT);
+  RCL_CHECK_ARGUMENT_FOR_NULL(info_array, RCL_RET_INVALID_ARGUMENT);
+  if (info_array->info_array != 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_topic_info(
+    rcl_node_get_rmw_handle(node),
+    allocator,
+    topic_name,
+    no_mangle,
+    info_array);
+  return rcl_convert_rmw_ret_to_rcl_ret(rmw_ret);
+}
+
+rcl_ret_t
+rcl_get_publishers_info_by_topic(
+  const rcl_node_t * node,
+  rcutils_allocator_t * allocator,
+  const char * topic_name,
+  bool no_mangle,
+  rmw_topic_info_array_t * publishers_info)
+{
+  return __rcl_get_info_by_topic(node, allocator, topic_name, no_mangle, publishers_info,
+           rmw_get_publishers_info_by_topic);
+}
+
+rcl_ret_t
+rcl_get_subscriptions_info_by_topic(
+  const rcl_node_t * node,
+  rcutils_allocator_t * allocator,
+  const char * topic_name,
+  bool no_mangle,
+  rmw_topic_info_array_t * subscriptions_info)
+{
+  return __rcl_get_info_by_topic(node, allocator, topic_name, no_mangle, subscriptions_info,
+           rmw_get_subscriptions_info_by_topic);
+}
+
 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_topic_info_array_t * topic_info_array;
+  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_topic_info_array_t valid_topic_info_array = {
+      0,     /*count*/
+      nullptr     /*info_array*/
+    };
+    this->topic_info_array = &valid_topic_info_array;
   }
 
   void TearDown()
@@ -1321,3 +1330,172 @@ 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_publishers_info_by_topic_null_node)
+{
+  rcl_allocator_t allocator = rcl_get_default_allocator();
+  auto ret = rcl_get_publishers_info_by_topic(nullptr,
+      &allocator, this->topic_name, false, this->topic_info_array);
+  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_subscriptions_info_by_topic_null_node)
+{
+  rcl_allocator_t allocator = rcl_get_default_allocator();
+  auto ret = rcl_get_subscriptions_info_by_topic(nullptr,
+      &allocator, this->topic_name, false, this->topic_info_array);
+  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_publishers_info_by_topic_invalid_node)
+{
+  // this->old_node_ptr is a pointer to an invalid node.
+  rcl_allocator_t allocator = rcl_get_default_allocator();
+  auto ret = rcl_get_publishers_info_by_topic(this->old_node_ptr,
+      &allocator, this->topic_name, false, this->topic_info_array);
+  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_subscriptions_info_by_topic_invalid_node)
+{
+  // this->old_node_ptr is a pointer to an invalid node.
+  rcl_allocator_t allocator = rcl_get_default_allocator();
+  auto ret = rcl_get_subscriptions_info_by_topic(this->old_node_ptr,
+      &allocator, this->topic_name, false, this->topic_info_array);
+  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_publishers_info_by_topic_null_allocator)
+{
+  auto ret = rcl_get_publishers_info_by_topic(this->node_ptr, nullptr, this->topic_name, false,
+      this->topic_info_array);
+  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_subscriptions_info_by_topic_null_allocator)
+{
+  auto ret = rcl_get_subscriptions_info_by_topic(this->node_ptr, nullptr, this->topic_name, false,
+      this->topic_info_array);
+  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_publishers_info_by_topic_null_topic)
+{
+  rcl_allocator_t allocator = rcl_get_default_allocator();
+  auto ret = rcl_get_publishers_info_by_topic(this->node_ptr,
+      &allocator, nullptr, false, this->topic_info_array);
+  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_subscriptions_info_by_topic_null_topic)
+{
+  rcl_allocator_t allocator = rcl_get_default_allocator();
+  auto ret = rcl_get_subscriptions_info_by_topic(this->node_ptr,
+      &allocator, nullptr, false, this->topic_info_array);
+  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_publishers_info_by_topic_null_participants)
+{
+  rcl_allocator_t allocator = rcl_get_default_allocator();
+  auto ret = rcl_get_publishers_info_by_topic(this->node_ptr,
+      &allocator, this->topic_name, false, 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_subscriptions_info_by_topic_null_participants)
+{
+  rcl_allocator_t allocator = rcl_get_default_allocator();
+  auto ret = rcl_get_subscriptions_info_by_topic(this->node_ptr,
+      &allocator, this->topic_name, false, 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_publishers_info_by_topic_invalid_participants)
+{
+  // this participant is invalid as the pointer "participants" inside is expected to be null.
+  this->topic_info_array->info_array =
+    reinterpret_cast<rmw_topic_info_t *>(malloc(sizeof(rmw_topic_info_t *)));
+  OSRF_TESTING_TOOLS_CPP_SCOPE_EXIT({
+    free(this->topic_info_array->info_array);
+  });
+  rcl_allocator_t allocator = rcl_get_default_allocator();
+  auto ret = rcl_get_publishers_info_by_topic(this->node_ptr,
+      &allocator, this->topic_name, false, this->topic_info_array);
+  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_subscriptions_info_by_topic_invalid_participants)
+{
+  // this participant is invalid as the pointer "participants" inside is expected to be null.
+  this->topic_info_array->info_array =
+    reinterpret_cast<rmw_topic_info_t *>(malloc(sizeof(rmw_topic_info_t *)));
+  OSRF_TESTING_TOOLS_CPP_SCOPE_EXIT({
+    free(this->topic_info_array->info_array);
+  });
+  rcl_allocator_t allocator = rcl_get_default_allocator();
+  auto ret = rcl_get_subscriptions_info_by_topic(this->node_ptr,
+      &allocator, this->topic_name, false, this->topic_info_array);
+  EXPECT_EQ(RCL_RET_INVALID_ARGUMENT, ret);
+}