File type_support.hpp

File type_support.hpp

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Introspection type-support resolution plus DDS topic-name and DDS type-name derivation. More...

  • #include <cstdint>
  • #include <string>
  • #include <rosidl_runtime_c/message_type_support_struct.h>
  • #include <rosidl_runtime_c/service_type_support_struct.h>
  • #include <rosidl_runtime_c/string.h>
  • #include <rosidl_runtime_c/string_functions.h>
  • #include <rosidl_typesupport_introspection_c/field_types.h>
  • #include <rosidl_typesupport_introspection_c/identifier.h>
  • #include <rosidl_typesupport_introspection_c/message_introspection.h>
  • #include <rosidl_typesupport_introspection_c/service_introspection.h>
  • #include <rosidl_typesupport_introspection_cpp/identifier.hpp>
  • #include <rosidl_typesupport_introspection_cpp/message_introspection.hpp>
  • #include <rosidl_typesupport_introspection_cpp/service_introspection.hpp>

Classes

Type Name
struct TypeSupportHandle

Public Types

Type Name
typedef rosidl_typesupport_introspection_c__MessageMember MemberC
C-backend MessageMember (a single field description).
typedef rosidl_typesupport_introspection_cpp::MessageMember MemberCpp
C++-backend MessageMember .
typedef rosidl_typesupport_introspection_c__MessageMembers MembersC
C-backend MessageMembers (walks C-generated message structs).
typedef rosidl_typesupport_introspection_cpp::MessageMembers MembersCpp
C++-backend MessageMembers (walks C++-generated message classes).
typedef rosidl_typesupport_introspection_c__ServiceMembers ServiceMembersC
C-backend ServiceMembers (request + response pair).
typedef rosidl_typesupport_introspection_cpp::ServiceMembers ServiceMembersCpp
C++-backend ServiceMembers (request + response pair).

Public Functions

Type Name
std::string dds_topic_name (const char * ros_topic)
std::string dds_type_name (const TypeSupportHandle & ts)
std::string demangle_ros_service_name (const std::string & dds_topic)
std::string demangle_ros_topic (const std::string & dds_topic)
std::string demangle_ros_type (const std::string & dds_type_name)
bool get_service_type_support (const rosidl_service_type_support_t * type_support, TypeSupportHandle & request_out, TypeSupportHandle & response_out)
TypeSupportHandle get_type_support (const rosidl_message_type_support_t * type_support)
bool is_regular_ros_topic (const std::string & dds_topic)
bool is_ros_service_reply_topic (const std::string & dds_topic)
bool is_ros_service_request_topic (const std::string & dds_topic)

Detailed Description

This RMW uses introspection type support (rosidl_typesupport_introspection_c and _cpp) rather than a DDS-vendor-specific type support. Any ROS 2 IDL type works without vendor-generated glue: the introspection tables describe the message layout at runtime and the CDR codec (see serialization.hpp) walks those tables. Either the C or C++ backend is accepted, depending on which one the caller pinned into the rosidl_message_type_support_t handed to us.

TypeSupportHandle is the small tagged handle carried inside every RMW publisher / subscription / service / client PIMPL so that serialization and name derivation need not re-resolve the type support on every call.

Public Types Documentation

typedef MemberC

C-backend MessageMember (a single field description). 

using MemberC =  rosidl_typesupport_introspection_c__MessageMember;

typedef MemberCpp

C++-backend MessageMember . 

using MemberCpp =  rosidl_typesupport_introspection_cpp::MessageMember;

typedef MembersC

C-backend MessageMembers (walks C-generated message structs). 

using MembersC =  rosidl_typesupport_introspection_c__MessageMembers;

typedef MembersCpp

C++-backend MessageMembers (walks C++-generated message classes). 

using MembersCpp =  rosidl_typesupport_introspection_cpp::MessageMembers;

typedef ServiceMembersC

C-backend ServiceMembers (request + response pair). 

using ServiceMembersC =  rosidl_typesupport_introspection_c__ServiceMembers;

typedef ServiceMembersCpp

C++-backend ServiceMembers (request + response pair). 

using ServiceMembersCpp =  rosidl_typesupport_introspection_cpp::ServiceMembers;

Public Functions Documentation

function dds_topic_name

std::string dds_topic_name (
    const char * ros_topic
)

Convert a ROS 2 topic name into its on-the-wire DDS topic name.

ROS 2 uses a mandatory rt/ prefix for regular topics and rq//rr/ for service request/reply topics. Names already carrying one of those prefixes are returned unchanged; otherwise leading slashes are stripped and rt/ is prepended.

Parameters:

  • ros_topic ROS 2 topic name (e.g. "/chatter").

Returns:

DDS topic name (e.g. "rt/chatter").

function dds_type_name

std::string dds_type_name (
    const TypeSupportHandle & ts
)

Build the DDS type name for a given message type support.

The DDS type-name format is <namespace>::dds_::<Type>_; the rosidl introspection namespace uses __ as separator, converted to :: here.

Parameters:

Returns:

DDS type name (e.g. "std_msgs::msg::dds_::String_"), or a placeholder when ts.valid() is false.

function demangle_ros_service_name

std::string demangle_ros_service_name (
    const std::string & dds_topic
)

Recover the ROS 2 service name from a service request or reply DDS topic name (e.g. "rq/add_two_intsRequest" → "/add_two_ints"). Names that do not match either convention are returned unchanged.

function demangle_ros_topic

std::string demangle_ros_topic (
    const std::string & dds_topic
)

Recover the ROS 2 topic name from a DDS topic name that carries the rt/ prefix (e.g. "rt/chatter" → "/chatter"). Names without the prefix are returned unchanged.

function demangle_ros_type

std::string demangle_ros_type (
    const std::string & dds_type_name
)

Recover the ROS 2 type name from a DDS type name (e.g. "std_msgs::msg::dds_::String_" → "std_msgs/msg/String"). The mechanical inverse of dds_type_name.

function get_service_type_support

bool get_service_type_support (
    const rosidl_service_type_support_t * type_support,
    TypeSupportHandle & request_out,
    TypeSupportHandle & response_out
)

Resolve a service-type-support pointer into a request/response pair of message handles.

Parameters:

  • type_support Non-null service type support supplied by the caller.
  • request_out On success, the request-type handle.
  • response_out On success, the response-type handle.

Returns:

true on success; false if neither backend recognised the service or a members pointer was null.

function get_type_support

TypeSupportHandle get_type_support (
    const rosidl_message_type_support_t * type_support
)

Resolve a message-type-support pointer into a TypeSupportHandle.

Tries the C++ introspection backend first, then the C backend. On success the returned handle has valid() == true and points at the members table owned by the caller's type-support object (do not free).

Parameters:

  • type_support Non-null message type support supplied by the caller.

Returns:

A handle; valid() is false when neither backend recognised the type.

function is_regular_ros_topic

bool is_regular_ros_topic (
    const std::string & dds_topic
)

Returns:

true iff dds_topic carries the rt/ prefix used for regular (non-service) ROS 2 topics.

function is_ros_service_reply_topic

bool is_ros_service_reply_topic (
    const std::string & dds_topic
)

Returns:

true iff dds_topic is a service reply topic (rr/…Reply).

function is_ros_service_request_topic

bool is_ros_service_request_topic (
    const std::string & dds_topic
)

Returns:

true iff dds_topic is a service request topic (rq/…Request).

The documentation for this class was generated from the following file include/astutedds/rmw/type_support.hpp