[#490] Translate from Slice<T> in CXX to [u8] in Rust

iceoryx2-ffi/cxx/include/iox/slice.hpp

@@ -26,22 +26,21 @@ class Slice {
     using ConstIterator = const T*;
     using ValueType = T;
 
-    template <typename U>
-    Slice(U* data, uint64_t len)
-        : m_data { const_cast<T*>(static_cast<const std::remove_pointer_t<U>*>(data)) }
-        , m_len { len } {
+    Slice(const void* data, uint64_t number_of_elements)
+        : m_data { static_cast<T*>(const_cast<void*>(data)) }
+        , m_number_of_elements { number_of_elements } {
     }
 
-    auto len() const -> uint64_t {
-        return m_len;
+    auto number_of_elements() const -> uint64_t {
+        return m_number_of_elements;
     }
     auto operator[](const uint64_t n) const -> const T& {
-        IOX_ASSERT(n < m_len, "Index out of bounds");
+        IOX_ASSERT(n < m_number_of_elements, "Index out of bounds");
         return *(m_data + n);
     }
 
     auto operator[](const uint64_t n) -> T& {
-        IOX_ASSERT(n < m_len, "Index out of bounds");
+        IOX_ASSERT(n < m_number_of_elements, "Index out of bounds");
         return *(m_data + n);
     }
 
@@ -55,17 +54,17 @@ class Slice {
 
     auto end() -> Iterator {
         if constexpr (std::is_same_v<T, void>) {
-            return reinterpret_cast<T*>(reinterpret_cast<char*>(m_data) + m_len);
+            return reinterpret_cast<T*>(reinterpret_cast<uint8_t*>(m_data) + m_number_of_elements);
         } else {
-            return m_data + m_len;
+            return m_data + m_number_of_elements;
         }
     }
 
     auto end() const -> ConstIterator {
         if constexpr (std::is_same_v<T, void>) {
-            return reinterpret_cast<const T*>(reinterpret_cast<const char*>(m_data) + m_len);
+            return reinterpret_cast<const T*>(reinterpret_cast<const uint8_t*>(m_data) + m_number_of_elements);
         } else {
-            return m_data + m_len;
+            return m_data + m_number_of_elements;
         }
     }
 
@@ -79,7 +78,7 @@ class Slice {
 
   private:
     T* m_data;
-    uint64_t m_len;
+    uint64_t m_number_of_elements;
 };
 
 template <typename>

iceoryx2-ffi/cxx/include/iox2/port_factory_publisher.hpp

@@ -71,8 +71,26 @@ PortFactoryPublisher<S, Payload, UserHeader>::create() && -> iox::expected<Publi
         iox2_port_factory_publisher_builder_unable_to_deliver_strategy(
             &m_handle, static_cast<iox2_unable_to_deliver_strategy_e>(iox::into<int>(value)));
     });
-    m_max_slice_len.and_then(
-        [&](auto value) { iox2_port_factory_publisher_builder_set_max_slice_len(&m_handle, value); });
+    m_max_slice_len
+        .and_then([&](auto value) {
+            // The payload type used by the C API is always a [u8].
+            // Thus need to convert from N to N * sizeof(payload).
+            // TODO: Consider alignment... not aligning each element properly will impact performance
+            if constexpr (iox::IsSlice<Payload>::VALUE) {
+                iox2_port_factory_publisher_builder_set_max_slice_len(&m_handle,
+                                                                      value * sizeof(typename Payload::ValueType));
+            } else {
+                iox2_port_factory_publisher_builder_set_max_slice_len(&m_handle, value * sizeof(Payload));
+            }
+        })
+        .or_else([&]() {
+            // Assume only one element if not otherwise specified
+            if constexpr (iox::IsSlice<Payload>::VALUE) {
+                iox2_port_factory_publisher_builder_set_max_slice_len(&m_handle, sizeof(typename Payload::ValueType));
+            } else {
+                iox2_port_factory_publisher_builder_set_max_slice_len(&m_handle, sizeof(Payload));
+            }
+        });
     m_max_loaned_samples.and_then(
         [&](auto value) { iox2_port_factory_publisher_builder_set_max_loaned_samples(&m_handle, value); });
 

iceoryx2-ffi/cxx/include/iox2/publisher.hpp

@@ -147,7 +147,15 @@ inline auto Publisher<S, Payload, UserHeader>::unable_to_deliver_strategy() cons
 
 template <ServiceType S, typename Payload, typename UserHeader>
 inline auto Publisher<S, Payload, UserHeader>::max_slice_len() const -> uint64_t {
-    return iox2_publisher_max_slice_len(&m_handle);
+    // NOTE: The C API always uses a [u8] payload, therefore the max length returned is the number of bytes.
+    //       Dividing by the size gives the number of slice elements available to the C++ API.
+    //
+    // NOTE: For non-slice types, the number of slice elements is always 1.
+    if constexpr (iox::IsSlice<Payload>::VALUE) {
+        return iox2_publisher_max_slice_len(&m_handle) / sizeof(typename Payload::ValueType);
+    } else {
+        return iox2_publisher_max_slice_len(&m_handle) / sizeof(Payload);
+    }
 }
 
 template <ServiceType S, typename Payload, typename UserHeader>
@@ -180,7 +188,7 @@ inline auto Publisher<S, Payload, UserHeader>::loan_uninit()
     -> iox::expected<SampleMutUninit<S, Payload, UserHeader>, PublisherLoanError> {
     SampleMutUninit<S, Payload, UserHeader> sample;
 
-    auto result = iox2_publisher_loan(&m_handle, &sample.m_sample.m_sample, &sample.m_sample.m_handle);
+    auto result = iox2_publisher_loan_slice_uninit(&m_handle, &sample.m_sample.m_sample, &sample.m_sample.m_handle, 1);
 
     if (result == IOX2_OK) {
         return iox::ok(std::move(sample));
@@ -208,19 +216,18 @@ template <ServiceType S, typename Payload, typename UserHeader>
 template <typename T, typename>
 inline auto Publisher<S, Payload, UserHeader>::loan_slice(const uint64_t number_of_elements)
     -> iox::expected<SampleMut<S, T, UserHeader>, PublisherLoanError> {
-    SampleMutUninit<S, Payload, UserHeader> sample;
+    auto sample_uninit = loan_slice_uninit(number_of_elements);
 
-    auto result = iox2_publisher_loan_slice_uninit(
-        number_of_elements, &m_handle, &sample.m_sample.m_sample, &sample.m_sample.m_handle);
+    if (sample_uninit.has_error()) {
+        return iox::err(sample_uninit.error());
+    }
+    auto sample_init = std::move(sample_uninit.value());
 
-    if (result == IOX2_OK) {
-        for (auto it = sample.payload_slice().begin(); it != sample.payload_slice().end(); ++it) {
-            new (it) typename T::ValueType();
-        }
-        return iox::ok(assume_init(std::move(sample)));
+    for (auto it = sample_init.payload_slice().begin(); it != sample_init.payload_slice().end(); ++it) {
+        new (it) typename T::ValueType();
     }
 
-    return iox::err(iox::into<PublisherLoanError>(result));
+    return iox::ok(assume_init(std::move(sample_init)));
 }
 
 template <ServiceType S, typename Payload, typename UserHeader>
@@ -230,7 +237,7 @@ inline auto Publisher<S, Payload, UserHeader>::loan_slice_uninit(const uint64_t
     SampleMutUninit<S, Payload, UserHeader> sample;
 
     auto result = iox2_publisher_loan_slice_uninit(
-        number_of_elements, &m_handle, &sample.m_sample.m_sample, &sample.m_sample.m_handle);
+        &m_handle, &sample.m_sample.m_sample, &sample.m_sample.m_handle, number_of_elements);
 
     if (result == IOX2_OK) {
         return iox::ok(std::move(sample));

iceoryx2-ffi/cxx/include/iox2/sample.hpp

@@ -130,23 +130,24 @@ template <ServiceType S, typename Payload, typename UserHeader>
 template <typename T, typename>
 inline auto Sample<S, Payload, UserHeader>::payload() const -> const Payload& {
     const void* ptr = nullptr;
-    size_t number_of_elements = 0;
+    size_t number_of_bytes = 0;
 
-    iox2_sample_payload(&m_handle, &ptr, &number_of_elements);
+    iox2_sample_payload(&m_handle, &ptr, &number_of_bytes);
 
     return *static_cast<const Payload*>(ptr);
 }
 
-
 template <ServiceType S, typename Payload, typename UserHeader>
 template <typename T, typename>
 inline auto Sample<S, Payload, UserHeader>::payload_slice() const -> Payload {
     const void* ptr = nullptr;
-    size_t number_of_elements = 0;
+    size_t number_of_bytes = 0;
+
+    iox2_sample_payload(&m_handle, &ptr, &number_of_bytes);
 
-    iox2_sample_payload(&m_handle, &ptr, &number_of_elements);
+    size_t number_of_elements = number_of_bytes / sizeof(typename Payload::ValueType);
 
-    return Payload(static_cast<const typename Payload::ValueType*>(ptr), number_of_elements);
+    return Payload(ptr, number_of_elements);
 }
 
 template <ServiceType S, typename Payload, typename UserHeader>

iceoryx2-ffi/cxx/include/iox2/sample_mut.hpp

@@ -197,10 +197,10 @@ template <ServiceType S, typename Payload, typename UserHeader>
 template <typename T, typename>
 inline auto SampleMut<S, Payload, UserHeader>::payload() const -> const Payload& {
     const void* ptr = nullptr;
-    size_t number_of_elements = 0;
+    size_t number_of_bytes = 0;
 
-    iox2_sample_mut_payload(&m_handle, &ptr, &number_of_elements);
-    IOX_ASSERT(sizeof(Payload) <= number_of_elements, "");
+    iox2_sample_mut_payload(&m_handle, &ptr, &number_of_bytes);
+    IOX_ASSERT(sizeof(Payload) <= number_of_bytes, "");
 
     return *static_cast<const Payload*>(ptr);
 }
@@ -209,10 +209,10 @@ template <ServiceType S, typename Payload, typename UserHeader>
 template <typename T, typename>
 inline auto SampleMut<S, Payload, UserHeader>::payload_mut() -> Payload& {
     void* ptr = nullptr;
-    size_t number_of_elements = 0;
+    size_t number_of_bytes = 0;
 
-    iox2_sample_mut_payload_mut(&m_handle, &ptr, &number_of_elements);
-    IOX_ASSERT(sizeof(Payload) <= number_of_elements, "");
+    iox2_sample_mut_payload_mut(&m_handle, &ptr, &number_of_bytes);
+    IOX_ASSERT(sizeof(Payload) <= number_of_bytes, "");
 
     return *static_cast<Payload*>(ptr);
 }
@@ -221,22 +221,26 @@ template <ServiceType S, typename Payload, typename UserHeader>
 template <typename T, typename>
 inline auto SampleMut<S, Payload, UserHeader>::payload_slice() const -> const Payload {
     const void* ptr = nullptr;
-    size_t number_of_elements = 0;
+    size_t number_of_bytes = 0;
 
-    iox2_sample_mut_payload(&m_handle, &ptr, &number_of_elements);
+    iox2_sample_mut_payload(&m_handle, &ptr, &number_of_bytes);
 
-    return Payload(static_cast<const typename Payload::ValueType*>(ptr), number_of_elements);
+    size_t number_of_elements = number_of_bytes / sizeof(typename Payload::ValueType);
+
+    return Payload(ptr, number_of_elements);
 }
 
 template <ServiceType S, typename Payload, typename UserHeader>
 template <typename T, typename>
 inline auto SampleMut<S, Payload, UserHeader>::payload_slice_mut() -> Payload {
     void* ptr = nullptr;
-    size_t number_of_elements = 0;
+    size_t number_of_bytes = 0;
+
+    iox2_sample_mut_payload_mut(&m_handle, &ptr, &number_of_bytes);
 
-    iox2_sample_mut_payload_mut(&m_handle, &ptr, &number_of_elements);
+    size_t number_of_elements = number_of_bytes / sizeof(typename Payload::ValueType);
 
-    return Payload(static_cast<typename Payload::ValueType*>(ptr), number_of_elements);
+    return Payload(ptr, number_of_elements);
 }
 
 template <ServiceType S, typename Payload, typename UserHeader>

iceoryx2-ffi/cxx/include/iox2/service_builder_publish_subscribe.hpp

@@ -26,6 +26,17 @@
 #include <typeinfo>
 
 namespace iox2 {
+
+template <typename T>
+struct PayloadValueType {
+    using TYPE = T;
+};
+
+template <typename T>
+struct PayloadValueType<iox::Slice<T>> {
+    using TYPE = typename iox::Slice<T>::ValueType;
+};
+
 /// Builder to create new [`MessagingPattern::PublishSubscribe`] based [`Service`]s
 template <typename Payload, typename UserHeader, ServiceType S>
 class ServiceBuilderPublishSubscribe {
@@ -138,18 +149,17 @@ inline void ServiceBuilderPublishSubscribe<Payload, UserHeader, S>::set_paramete
         [&](auto value) { iox2_service_builder_pub_sub_set_payload_alignment(&m_handle, value); });
     m_max_nodes.and_then([&](auto value) { iox2_service_builder_pub_sub_set_max_nodes(&m_handle, value); });
 
+    using ValueType = typename PayloadValueType<Payload>::TYPE;
+    auto type_variant = iox::IsSlice<Payload>::VALUE ? iox2_type_variant_e_DYNAMIC : iox2_type_variant_e_FIXED_SIZE;
+
     // payload type details
-    const auto* payload_type_name = typeid(Payload).name();
+    const auto* payload_type_name = typeid(ValueType).name();
     const auto payload_type_name_len = strlen(payload_type_name);
-    const auto payload_type_size = sizeof(Payload);
-    const auto payload_type_align = alignof(Payload);
+    const auto payload_type_size = sizeof(ValueType);
+    const auto payload_type_align = alignof(ValueType);
 
-    const auto payload_result = iox2_service_builder_pub_sub_set_payload_type_details(&m_handle,
-                                                                                      iox2_type_variant_e_FIXED_SIZE,
-                                                                                      payload_type_name,
-                                                                                      payload_type_name_len,
-                                                                                      payload_type_size,
-                                                                                      payload_type_align);
+    const auto payload_result = iox2_service_builder_pub_sub_set_payload_type_details(
+        &m_handle, type_variant, payload_type_name, payload_type_name_len, payload_type_size, payload_type_align);
 
     if (payload_result != IOX2_OK) {
         IOX_PANIC("This should never happen! Implementation failure while setting the Payload-Type.");
@@ -162,13 +172,12 @@ inline void ServiceBuilderPublishSubscribe<Payload, UserHeader, S>::set_paramete
     const auto user_header_type_size = header_layout.size();
     const auto user_header_type_align = header_layout.alignment();
 
-    const auto user_header_result =
-        iox2_service_builder_pub_sub_set_user_header_type_details(&m_handle,
-                                                                  iox2_type_variant_e_FIXED_SIZE,
-                                                                  user_header_type_name,
-                                                                  user_header_type_name_len,
-                                                                  user_header_type_size,
-                                                                  user_header_type_align);
+    const auto user_header_result = iox2_service_builder_pub_sub_set_user_header_type_details(&m_handle,
+                                                                                              type_variant,
+                                                                                              user_header_type_name,
+                                                                                              user_header_type_name_len,
+                                                                                              user_header_type_size,
+                                                                                              user_header_type_align);
 
     if (user_header_result != IOX2_OK) {
         IOX_PANIC("This should never happen! Implementation failure while setting the User-Header-Type.");