Get network flows of publishers and subscriptions

Signed-off-by: Ananya Muddukrishna <ananya.x.muddukrishna@ericsson.com>

rcl/CMakeLists.txt

@@ -49,6 +49,7 @@ set(${PROJECT_NAME}_sources
   src/rcl/logging_rosout.c
   src/rcl/logging.c
   src/rcl/log_level.c
+  src/rcl/network_flow.c
   src/rcl/node.c
   src/rcl/node_options.c
   src/rcl/publisher.c

rcl/include/rcl/network_flow.h

@@ -0,0 +1,142 @@
+// Copyright 2020 Ericsson AB
+//
+// 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 RCL__NETWORK_FLOW_H_
+#define RCL__NETWORK_FLOW_H_
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+#include <rmw/network_flow.h>
+#include <rmw/network_flow_array.h>
+
+#include "rcl/allocator.h"
+#include "rcl/arguments.h"
+#include "rcl/context.h"
+#include "rcl/macros.h"
+#include "rcl/publisher.h"
+#include "rcl/subscription.h"
+#include "rcl/types.h"
+#include "rcl/visibility_control.h"
+
+typedef rmw_network_flow_t rcl_network_flow_t;
+typedef rmw_network_flow_array_t rcl_network_flow_array_t;
+typedef rmw_transport_protocol_t rcl_transport_protocol_t;
+typedef rmw_internet_protocol_t rcl_internet_protocol_t;
+
+#define rcl_get_zero_initialized_network_flow_array \
+  rmw_get_zero_initialized_network_flow_array
+#define rcl_network_flow_array_fini rmw_network_flow_array_fini
+
+#define rcl_network_flow_get_transport_protocol_string \
+  rmw_network_flow_get_transport_protocol_string
+#define rcl_network_flow_get_internet_protocol_string \
+  rmw_network_flow_get_internet_protocol_string
+
+/// Get network flows of a publisher
+/**
+ * Query the underlying middleware for a given publisher's network flows
+ *
+ * The `publisher` argument must point to a valid publisher.
+ *
+ * The `allocator` argument must be a valid allocator.
+ *
+ * The `network_flow_array` argument must be allocated and zero-initialized.
+ * The function returns network flows in the `network_flow_array` argument,
+ * using the allocator to allocate memory for the `network_flow_array`
+ * argument's internal data structures whenever required. The caller is
+ * reponsible for memory deallocation by passing the `network_flow_array`
+ * argument to `rcl_network_flow_array_fini` function.
+ *
+ * \todo TODO(anamud): Are the same network flows returned by successive calls
+ * to this function?
+ *
+ * <hr>
+ * Attribute          | Adherence
+ * ------------------ | -------------
+ * Allocates Memory   | Yes
+ * Thread-Safe        | No
+ * Uses Atomics       | No
+ * Lock-Free          | Maybe [1]
+ * <i>[1] implementation may need to protect the data structure with a lock</i>
+ *
+ * \param[in] publisher the publisher instance to inspect
+ * \param[in] allocator allocator to be used when allocating space for network_flow_array_t
+ * \param[out] network_flow_array the network flows
+ * \return `RCL_RET_OK` if successful, or
+ * \return `RCL_RET_INVALID_ARGUMENT` if any argument is null, or
+ * \return `RCL_RET_BAD_ALLOC` if memory allocation fails, or
+ * \return `RCL_RET_UNSUPPORTED` if not supported, or
+ * \return `RCL_RET_ERROR` if an unexpected error occurs.
+ */
+RCL_PUBLIC
+RCL_WARN_UNUSED
+rcl_ret_t
+rcl_publisher_get_network_flow(
+  const rcl_publisher_t * publisher,
+  rcutils_allocator_t * allocator,
+  rcl_network_flow_array_t * network_flow_array);
+
+/// Get network flows of a subscription
+/**
+ * Query the underlying middleware for a given subscription's network flows
+ *
+ * The `subscription` argument must point to a valid subscription.
+ *
+ * The `allocator` argument must be a valid allocator.
+ *
+ * The `network_flow_array` argument must be allocated and zero-initialized.
+ * The function returns network flows in the `network_flow_array` argument,
+ * using the allocator to allocate memory for the `network_flow_array`
+ * argument's internal data structures whenever required. The caller is
+ * reponsible for memory deallocation by passing the `network_flow_array`
+ * argument to `rcl_network_flow_array_fini` function.
+ *
+ * \todo TODO(anamud): Are the same network flows returned by successive calls
+ * to this function?
+ *
+ * <hr>
+ * Attribute          | Adherence
+ * ------------------ | -------------
+ * Allocates Memory   | Yes
+ * Thread-Safe        | No
+ * Uses Atomics       | No
+ * Lock-Free          | Maybe [1]
+ * <i>[1] implementation may need to protect the data structure with a lock</i>
+ *
+ * \param[in] subscription the subscription instance to inspect
+ * \param[in] allocator allocator to be used when allocating space for network_flow_array_t
+ * \param[out] network_flow_array the network flows
+ * \return `RCL_RET_OK` if successful, or
+ * \return `RCL_RET_INVALID_ARGUMENT` if any argument is null, or
+ * \return `RCL_RET_BAD_ALLOC` if memory allocation fails, or
+ * \return `RCL_RET_UNSUPPORTED` if not supported, or
+ * \return `RCL_RET_ERROR` if an unexpected error occurs.
+ */
+RCL_PUBLIC
+RCL_WARN_UNUSED
+rcl_ret_t
+rcl_subscription_get_network_flow(
+  const rcl_subscription_t * subscription,
+  rcutils_allocator_t * allocator,
+  rcl_network_flow_array_t * network_flow_array);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif  // RCL__NETWORK_FLOW_H_

rcl/src/rcl/network_flow.c

@@ -0,0 +1,118 @@
+// Copyright 2020 Ericsson AB
+//
+// 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.
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+#include "rcl/error_handling.h"
+#include "rcl/graph.h"
+#include "rcl/network_flow.h"
+#include "rcl/publisher.h"
+#include "rcl/subscription.h"
+
+#include "rcutils/allocator.h"
+#include "rcutils/macros.h"
+#include "rcutils/types.h"
+
+#include "rmw/error_handling.h"
+#include "rmw/get_network_flow.h"
+#include "rmw/network_flow_array.h"
+#include "rmw/types.h"
+
+#include "./common.h"
+
+rcl_ret_t
+__validate_allocator_and_network_flow_array(
+  rcutils_allocator_t * allocator,
+  rcl_network_flow_array_t * network_flow_array)
+{
+  RCL_CHECK_ALLOCATOR_WITH_MSG(allocator, "invalid allocator", return RCL_RET_INVALID_ARGUMENT);
+
+  RCL_CHECK_ARGUMENT_FOR_NULL(network_flow_array, RCL_RET_INVALID_ARGUMENT);
+
+  rmw_error_string_t error_string;
+  rmw_ret_t rmw_ret = rmw_network_flow_array_check_zero(network_flow_array);
+  if (rmw_ret != RMW_RET_OK) {
+    error_string = rmw_get_error_string();
+    rmw_reset_error();
+    RCL_SET_ERROR_MSG_WITH_FORMAT_STRING(
+      "rcl_network_flow_array_t must be zero initialized: %s,\n"
+      "Use rcl_get_zero_initialized_network_flow_array",
+      error_string.str);
+  }
+
+  return rcl_convert_rmw_ret_to_rcl_ret(rmw_ret);
+}
+
+rcl_ret_t
+rcl_publisher_get_network_flow(
+  const rcl_publisher_t * publisher,
+  rcutils_allocator_t * allocator,
+  rcl_network_flow_array_t * network_flow_array)
+{
+  if (!rcl_publisher_is_valid(publisher)) {
+    return RCL_RET_INVALID_ARGUMENT;
+  }
+
+  rcl_ret_t rcl_ret = __validate_allocator_and_network_flow_array(allocator, network_flow_array);
+  if (rcl_ret != RCL_RET_OK) {
+    return rcl_ret;
+  }
+
+  rmw_error_string_t error_string;
+  rmw_ret_t rmw_ret = rmw_publisher_get_network_flow(
+    rcl_publisher_get_rmw_handle(publisher),
+    allocator,
+    network_flow_array);
+  if (rmw_ret != RMW_RET_OK) {
+    error_string = rmw_get_error_string();
+    rmw_reset_error();
+    RCL_SET_ERROR_MSG(error_string.str);
+  }
+  return rcl_convert_rmw_ret_to_rcl_ret(rmw_ret);
+}
+
+rcl_ret_t
+rcl_subscription_get_network_flow(
+  const rcl_subscription_t * subscription,
+  rcutils_allocator_t * allocator,
+  rcl_network_flow_array_t * network_flow_array)
+{
+  if (!rcl_subscription_is_valid(subscription)) {
+    return RCL_RET_INVALID_ARGUMENT;
+  }
+
+  rcl_ret_t rcl_ret = __validate_allocator_and_network_flow_array(allocator, network_flow_array);
+  if (rcl_ret != RCL_RET_OK) {
+    return rcl_ret;
+  }
+
+  rmw_error_string_t error_string;
+  rmw_ret_t rmw_ret = rmw_subscription_get_network_flow(
+    rcl_subscription_get_rmw_handle(subscription),
+    allocator,
+    network_flow_array);
+  if (rmw_ret != RMW_RET_OK) {
+    error_string = rmw_get_error_string();
+    rmw_reset_error();
+    RCL_SET_ERROR_MSG(error_string.str);
+  }
+  return rcl_convert_rmw_ret_to_rcl_ret(rmw_ret);
+}
+
+#ifdef __cplusplus
+}
+#endif

rcl/test/CMakeLists.txt

@@ -318,6 +318,15 @@ function(test_target_function)
     AMENT_DEPENDENCIES ${rmw_implementation}
   )
 
+  rcl_add_custom_gtest(test_network_flow${target_suffix}
+    SRCS rcl/test_network_flow.cpp
+    ENV ${rmw_implementation_env_var}
+    APPEND_LIBRARY_DIRS ${extra_lib_dirs}
+    INCLUDE_DIRS ${CMAKE_CURRENT_SOURCE_DIR}/../src/rcl/
+    LIBRARIES ${PROJECT_NAME} mimick
+    AMENT_DEPENDENCIES ${rmw_implementation} "osrf_testing_tools_cpp" "test_msgs"
+  )
+
   # Launch tests
 
   rcl_add_custom_executable(service_fixture${target_suffix}