Implement method to get endpoints info

rmw_zenoh_cpp/src/detail/graph_cache.cpp

@@ -683,3 +683,111 @@ rmw_ret_t GraphCache::get_entity_names_and_types_by_node(
 
   return RMW_RET_OK;
 }
+
+
+///=============================================================================
+rmw_ret_t GraphCache::get_entities_info_by_topic(
+  liveliness::EntityType entity_type,
+  rcutils_allocator_t * allocator,
+  const char * topic_name,
+  bool no_demangle,
+  rmw_topic_endpoint_info_array_t * endpoints_info) const
+{
+  static_cast<void>(no_demangle);
+  RMW_CHECK_ARGUMENT_FOR_NULL(topic_name, RMW_RET_INVALID_ARGUMENT);
+  RCUTILS_CHECK_ALLOCATOR_WITH_MSG(
+    allocator, "allocator argument is invalid", return RMW_RET_INVALID_ARGUMENT);
+
+  if (entity_type != EntityType::Publisher && entity_type != EntityType::Subscription) {
+    return RMW_RET_INVALID_ARGUMENT;
+  }
+
+  std::lock_guard<std::mutex> lock(graph_mutex_);
+
+  // Minor optimization to exit early if the topic does not exist in the graph.
+  if (graph_topics_.find(topic_name) == graph_topics_.end()) {
+    return RMW_RET_OK;
+  }
+  // TODO(Yadunund): Refactor graph_topics_ to map to a list of GraphNodePtr to
+  // avoid this expensive iteration.
+  std::size_t size = 0;
+  std::vector<GraphNodePtr> nodes = {};
+  for (NamespaceMap::const_iterator ns_it = graph_.begin(); ns_it != graph_.end(); ++ns_it) {
+    for (NodeMap::const_iterator node_it = ns_it->second.begin(); node_it != ns_it->second.end();
+      ++node_it)
+    {
+      const GraphNode::TopicMap & entity_map =
+        entity_type == EntityType::Publisher ? node_it->second->pubs_ :
+        node_it->second->subs_;
+      GraphNode::TopicMap::const_iterator topic_it = entity_map.find(topic_name);
+      if (topic_it != entity_map.end()) {
+        nodes.push_back(node_it->second);
+        size += topic_it->second.size();
+      }
+    }
+  }
+
+
+  rmw_ret_t ret = rmw_topic_endpoint_info_array_init_with_size(
+    endpoints_info,
+    nodes.size(),
+    allocator);
+  if (RMW_RET_OK != ret) {
+    return ret;
+  }
+
+  auto cleanup_endpoints_info = rcpputils::make_scope_exit(
+    [endpoints_info, allocator] {
+      rmw_ret_t fail_ret = rmw_topic_endpoint_info_array_fini(
+        endpoints_info, allocator);
+      if (fail_ret != RMW_RET_OK) {
+        RMW_SAFE_FWRITE_TO_STDERR("failed to cleanup endpoints info during error handling");
+      }
+    });
+
+  for (std::size_t i = 0; i < nodes.size(); ++i) {
+    const GraphNode::TopicMap & entity_map =
+      entity_type == EntityType::Publisher ? nodes[i]->pubs_ :
+      nodes[i]->subs_;
+    const GraphNode::TopicDataMap & topic_data_map = entity_map.find(topic_name)->second;
+    for (const auto & [topic_data, _] : topic_data_map) {
+      rmw_topic_endpoint_info_t & endpoint_info = endpoints_info->info_array[i];
+      endpoint_info = rmw_get_zero_initialized_topic_endpoint_info();
+
+      ret = rmw_topic_endpoint_info_set_node_name(
+        &endpoint_info,
+        nodes[i]->name_.c_str(),
+        allocator);
+      if (RMW_RET_OK != ret) {
+        return ret;
+      }
+
+      ret = rmw_topic_endpoint_info_set_node_namespace(
+        &endpoint_info,
+        nodes[i]->ns_.c_str(),
+        allocator);
+      if (RMW_RET_OK != ret) {
+        return ret;
+      }
+
+      ret = rmw_topic_endpoint_info_set_topic_type(
+        &endpoint_info,
+        _demangle_if_ros_type(topic_data).c_str(),
+        allocator);
+      if (RMW_RET_OK != ret) {
+        return ret;
+      }
+
+      ret = rmw_topic_endpoint_info_set_endpoint_type(
+        &endpoint_info,
+        entity_type == EntityType::Publisher ? RMW_ENDPOINT_PUBLISHER : RMW_ENDPOINT_SUBSCRIPTION);
+      if (RMW_RET_OK != ret) {
+        return ret;
+      }
+      // TODO(Yadunund): Set type_hash, qos_profile, gid.
+    }
+  }
+
+  cleanup_endpoints_info.cancel();
+  return RMW_RET_OK;
+}

rmw_zenoh_cpp/src/detail/graph_cache.hpp

@@ -29,6 +29,7 @@
 #include "rcutils/types.h"
 
 #include "rmw/rmw.h"
+#include "rmw/get_topic_endpoint_info.h"
 #include "rmw/names_and_types.h"
 
 
@@ -108,6 +109,13 @@ class GraphCache final
     bool no_demangle,
     rmw_names_and_types_t * names_and_types) const;
 
+  rmw_ret_t get_entities_info_by_topic(
+    liveliness::EntityType entity_type,
+    rcutils_allocator_t * allocator,
+    const char * topic_name,
+    bool no_demangle,
+    rmw_topic_endpoint_info_array_t * endpoints_info) const;
+
 private:
   /*
   namespace_1:

rmw_zenoh_cpp/src/rmw_get_topic_endpoint_info.cpp

@@ -13,7 +13,12 @@
 // limitations under the License.
 
 
+#include "detail/identifier.hpp"
+#include "detail/liveliness_utils.hpp"
+#include "detail/rmw_data_types.hpp"
+
 #include "rmw/get_topic_endpoint_info.h"
+#include "rmw/impl/cpp/macros.hpp"
 
 extern "C"
 {
@@ -27,12 +32,20 @@ rmw_get_publishers_info_by_topic(
   bool no_mangle,
   rmw_topic_endpoint_info_array_t * publishers_info)
 {
-  static_cast<void>(node);
-  static_cast<void>(allocator);
-  static_cast<void>(topic_name);
-  static_cast<void>(no_mangle);
-  static_cast<void>(publishers_info);
-  return RMW_RET_OK;
+  RMW_CHECK_ARGUMENT_FOR_NULL(node, RMW_RET_INVALID_ARGUMENT);
+  RMW_CHECK_TYPE_IDENTIFIERS_MATCH(
+    node,
+    node->implementation_identifier,
+    rmw_zenoh_identifier,
+    return RMW_RET_INCORRECT_RMW_IMPLEMENTATION);
+  RMW_CHECK_ARGUMENT_FOR_NULL(node->context, RMW_RET_INVALID_ARGUMENT);
+  RMW_CHECK_ARGUMENT_FOR_NULL(node->context->impl, RMW_RET_INVALID_ARGUMENT);
+  return node->context->impl->graph_cache.get_entities_info_by_topic(
+    liveliness::EntityType::Publisher,
+    allocator,
+    topic_name,
+    no_mangle,
+    publishers_info);
 }
 
 ///==============================================================================
@@ -45,11 +58,19 @@ rmw_get_subscriptions_info_by_topic(
   bool no_mangle,
   rmw_topic_endpoint_info_array_t * subscriptions_info)
 {
-  static_cast<void>(node);
-  static_cast<void>(allocator);
-  static_cast<void>(topic_name);
-  static_cast<void>(no_mangle);
-  static_cast<void>(subscriptions_info);
-  return RMW_RET_OK;
+  RMW_CHECK_ARGUMENT_FOR_NULL(node, RMW_RET_INVALID_ARGUMENT);
+  RMW_CHECK_TYPE_IDENTIFIERS_MATCH(
+    node,
+    node->implementation_identifier,
+    rmw_zenoh_identifier,
+    return RMW_RET_INCORRECT_RMW_IMPLEMENTATION);
+  RMW_CHECK_ARGUMENT_FOR_NULL(node->context, RMW_RET_INVALID_ARGUMENT);
+  RMW_CHECK_ARGUMENT_FOR_NULL(node->context->impl, RMW_RET_INVALID_ARGUMENT);
+  return node->context->impl->graph_cache.get_entities_info_by_topic(
+    liveliness::EntityType::Subscription,
+    allocator,
+    topic_name,
+    no_mangle,
+    subscriptions_info);
 }
 }  // extern "C"