From c2194fe4ef9a94c7cb2793ebccc23cafbe39eb27 Mon Sep 17 00:00:00 2001
From: Christian Eltzschig <me@elchris.org>
Date: Tue, 30 Jul 2024 23:54:43 +0200
Subject: [PATCH] [#264] Enable slice methods only for slice Payload; remove
 reinterpret cast

---
 iceoryx2-ffi/cxx/include/iox2/publisher.hpp | 5 +++++
 iceoryx2-ffi/cxx/include/iox2/sample.hpp    | 8 +++-----
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/iceoryx2-ffi/cxx/include/iox2/publisher.hpp b/iceoryx2-ffi/cxx/include/iox2/publisher.hpp
index be87ed01a..efe79fbb9 100644
--- a/iceoryx2-ffi/cxx/include/iox2/publisher.hpp
+++ b/iceoryx2-ffi/cxx/include/iox2/publisher.hpp
@@ -24,6 +24,7 @@
 #include "iox2/unique_port_id.hpp"
 
 #include <cstdint>
+#include <type_traits>
 
 namespace iox2 {
 /// Sending endpoint of a publish-subscriber based communication.
@@ -64,6 +65,7 @@ class Publisher {
     /// [`Payload`].
     ///
     /// On failure it returns [`PublisherLoanError`] describing the failure.
+    template <typename T = Payload, typename = std::enable_if<iox::IsSlice<T>::VALUE, T>>
     auto
     loan_slice(uint64_t number_of_elements) -> iox::expected<SampleMut<S, Payload, UserHeader>, PublisherLoanError>;
 
@@ -71,6 +73,7 @@ class Publisher {
     /// The user has to initialize the payload before it can be sent.
     ///
     /// On failure it returns [`PublisherLoanError`] describing the failure.
+    template <typename T = Payload, typename = std::enable_if_t<iox::IsSlice<T>::VALUE, T>>
     auto loan_slice_uninit(uint64_t number_of_elements)
         -> iox::expected<SampleMut<S, Payload, UserHeader>, PublisherLoanError>;
 
@@ -171,12 +174,14 @@ Publisher<S, Payload, UserHeader>::loan() -> iox::expected<SampleMut<S, Payload,
 }
 
 template <ServiceType S, typename Payload, typename UserHeader>
+template <typename, typename>
 inline auto Publisher<S, Payload, UserHeader>::loan_slice(const uint64_t number_of_elements)
     -> iox::expected<SampleMut<S, Payload, UserHeader>, PublisherLoanError> {
     IOX_TODO();
 }
 
 template <ServiceType S, typename Payload, typename UserHeader>
+template <typename, typename>
 inline auto Publisher<S, Payload, UserHeader>::loan_slice_uninit(const uint64_t number_of_elements)
     -> iox::expected<SampleMut<S, Payload, UserHeader>, PublisherLoanError> {
     IOX_TODO();
diff --git a/iceoryx2-ffi/cxx/include/iox2/sample.hpp b/iceoryx2-ffi/cxx/include/iox2/sample.hpp
index bf07fba12..013a3e685 100644
--- a/iceoryx2-ffi/cxx/include/iox2/sample.hpp
+++ b/iceoryx2-ffi/cxx/include/iox2/sample.hpp
@@ -117,15 +117,13 @@ inline auto Sample<S, Payload, UserHeader>::operator->() const -> const Payload*
 template <ServiceType S, typename Payload, typename UserHeader>
 inline auto Sample<S, Payload, UserHeader>::payload() const -> const Payload& {
     auto* ref_handle = iox2_cast_sample_ref_h(m_handle);
-    const Payload* payload_ptr = nullptr;
+    const void* payload_ptr = nullptr;
     size_t payload_len = 0;
 
-    // NOLINTBEGIN(cppcoreguidelines-pro-type-reinterpret-cast), no other way for type erasure
-    iox2_sample_payload(ref_handle, reinterpret_cast<const void**>(&payload_ptr), &payload_len);
-    // NOLINTEND(cppcoreguidelines-pro-type-reinterpret-cast)
+    iox2_sample_payload(ref_handle, &payload_ptr, &payload_len);
     IOX_ASSERT(sizeof(Payload) <= payload_len, "");
 
-    return *payload_ptr;
+    return *static_cast<const Payload*>(payload_ptr);
 }
 
 template <ServiceType S, typename Payload, typename UserHeader>