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Add check_argument_types #130

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merged 1 commit into from
Oct 15, 2015
Merged

Add check_argument_types #130

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66 changes: 22 additions & 44 deletions rclcpp/include/rclcpp/any_subscription_callback.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -59,80 +59,58 @@ struct AnySubscriptionCallback

template<
typename CallbackT,
std::size_t Arity = 1
>
typename std::enable_if<rclcpp::arity_comparator<Arity, CallbackT>::value, void>::type
set(
CallbackT callback,
typename std::enable_if<
std::is_same<
typename function_traits<CallbackT>::template argument_type<0>,
rclcpp::check_argument_types<
CallbackT,
typename std::shared_ptr<MessageT>
>::value
>::type * = nullptr)
>::type * = nullptr
>
void set(CallbackT callback)
{
shared_ptr_callback = callback;
}

template<
typename CallbackT,
std::size_t Arity = 2
>
typename std::enable_if<rclcpp::arity_comparator<Arity, CallbackT>::value, void>::type
set(
CallbackT callback,
typename std::enable_if<
std::is_same<
typename function_traits<CallbackT>::template argument_type<0>,
typename std::shared_ptr<MessageT>
>::value
>::type * = nullptr,
typename std::enable_if<
std::is_same<
typename function_traits<CallbackT>::template argument_type<1>,
rclcpp::check_argument_types<
CallbackT,
typename std::shared_ptr<MessageT>,
const rmw_message_info_t &
>::value
>::type * = nullptr)
>::type * = nullptr
>
void set(CallbackT callback)
{
shared_ptr_with_info_callback = callback;
}

template<
typename CallbackT,
std::size_t Arity = 1
>
typename std::enable_if<rclcpp::arity_comparator<Arity, CallbackT>::value, void>::type
set(
CallbackT callback,
typename std::enable_if<
std::is_same<
typename function_traits<CallbackT>::template argument_type<0>,
rclcpp::check_argument_types<
CallbackT,
typename std::shared_ptr<const MessageT>
>::value
>::type * = nullptr)
>::type * = nullptr
>
void set(CallbackT callback)
{
const_shared_ptr_callback = callback;
}

template<
typename CallbackT,
std::size_t Arity = 2
>
typename std::enable_if<rclcpp::arity_comparator<Arity, CallbackT>::value, void>::type
set(
CallbackT callback,
typename std::enable_if<
std::is_same<
typename function_traits<CallbackT>::template argument_type<0>,
typename std::shared_ptr<const MessageT>
>::value
>::type * = nullptr,
typename std::enable_if<
std::is_same<
typename function_traits<CallbackT>::template argument_type<1>,
rclcpp::check_argument_types<
CallbackT,
typename std::shared_ptr<const MessageT>,
const rmw_message_info_t &
>::value
>::type * = nullptr)
>::type * = nullptr
>
void set(CallbackT callback)
{
const_shared_ptr_with_info_callback = callback;
}
Expand Down
34 changes: 30 additions & 4 deletions rclcpp/include/rclcpp/function_traits.hpp
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Expand Up @@ -64,10 +64,36 @@ struct function_traits<ReturnTypeT (ClassT::*)(Args ...) const>
* the arity of a function.
*/
template<std::size_t Arity, typename FunctorT>
struct arity_comparator
{
static constexpr bool value = (Arity == function_traits<FunctorT>::arity);
};
struct arity_comparator : std::integral_constant<
bool, (Arity == function_traits<FunctorT>::arity)>{};

template<typename FunctorT, typename First, typename ... Last>
struct check_argument_types_recursive : std::conditional<
std::is_same<
typename function_traits<FunctorT>::template argument_type<
function_traits<FunctorT>::arity - sizeof ... (Last) -1
>,
First
>::value,
check_argument_types_recursive<FunctorT, Last ...>,
std::false_type>::type
{};

template<typename FunctorT, typename Arg>
struct check_argument_types_recursive<FunctorT, Arg>: std::is_same<
typename function_traits<FunctorT>::template argument_type<
function_traits<FunctorT>::arity - 1
>,
Arg
>
{};

template<typename FunctorT, typename ... Args>
struct check_argument_types : std::conditional<
arity_comparator<sizeof ... (Args), FunctorT>::value,
check_argument_types_recursive<FunctorT, Args ...>,
std::false_type>::type
{};

} /* namespace rclcpp */

Expand Down
71 changes: 19 additions & 52 deletions rclcpp/include/rclcpp/node.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -283,42 +283,23 @@ class Node
bool ignore_local_publications,
typename message_memory_strategy::MessageMemoryStrategy<MessageT>::SharedPtr msg_mem_strat);

/* NOTE(esteve):
* The following template machinery works around VS2015's lack of support for expression SFINAE:
* - We first declare the arity we want to match, i.e. 2 or 3.
* - Then we use the arity_comparator template to SFINAE on the arity of the passed functor.
* - Lastly, we SFINAE on the types of the arguments of the functor.
* These steps happen in different parts of the function signature because we want to stagger
* instantation of the templates because VS2015 can't conditionally enable templates that depend
* on another template.
* See test_function_traits.cpp for streamlined examples of how to use this pattern.
*/
template<
typename ServiceT,
typename FunctorT,
std::size_t Arity = 2
typename std::enable_if<
rclcpp::check_argument_types<
FunctorT,
typename std::shared_ptr<typename ServiceT::Request>,
typename std::shared_ptr<typename ServiceT::Response>
>::value
>::type * = nullptr
>
typename std::enable_if<
rclcpp::arity_comparator<Arity, FunctorT>::value,
typename rclcpp::service::Service<ServiceT>::SharedPtr
>::type
typename rclcpp::service::Service<ServiceT>::SharedPtr
create_service_internal(
std::shared_ptr<rmw_node_t> node_handle,
rmw_service_t * service_handle,
const std::string & service_name,
FunctorT callback,
typename std::enable_if<
std::is_same<
typename function_traits<FunctorT>::template argument_type<0>,
typename std::shared_ptr<typename ServiceT::Request>
>::value
>::type * = nullptr,
typename std::enable_if<
std::is_same<
typename function_traits<FunctorT>::template argument_type<1>,
typename std::shared_ptr<typename ServiceT::Response>
>::value
>::type * = nullptr)
FunctorT callback)
{
typename rclcpp::service::Service<ServiceT>::CallbackType callback_without_header =
callback;
Expand All @@ -329,35 +310,21 @@ class Node
template<
typename ServiceT,
typename FunctorT,
std::size_t Arity = 3
typename std::enable_if<
rclcpp::check_argument_types<
FunctorT,
std::shared_ptr<rmw_request_id_t>,
typename std::shared_ptr<typename ServiceT::Request>,
typename std::shared_ptr<typename ServiceT::Response>
>::value
>::type * = nullptr
>
typename std::enable_if<
arity_comparator<Arity, FunctorT>::value,
typename rclcpp::service::Service<ServiceT>::SharedPtr
>::type
typename rclcpp::service::Service<ServiceT>::SharedPtr
create_service_internal(
std::shared_ptr<rmw_node_t> node_handle,
rmw_service_t * service_handle,
const std::string & service_name,
FunctorT callback,
typename std::enable_if<
std::is_same<
typename function_traits<FunctorT>::template argument_type<0>,
std::shared_ptr<rmw_request_id_t>
>::value
>::type * = nullptr,
typename std::enable_if<
std::is_same<
typename function_traits<FunctorT>::template argument_type<1>,
typename std::shared_ptr<typename ServiceT::Request>
>::value
>::type * = nullptr,
typename std::enable_if<
std::is_same<
typename function_traits<FunctorT>::template argument_type<2>,
typename std::shared_ptr<typename ServiceT::Response>
>::value
>::type * = nullptr)
FunctorT callback)
{
typename rclcpp::service::Service<ServiceT>::CallbackWithHeaderType callback_with_header =
callback;
Expand Down
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