From 14ec8e92b45a2eae5bdb3d459cee9633ea129359 Mon Sep 17 00:00:00 2001
From: Felix Morgner <felix.morgner@ost.ch>
Date: Thu, 10 Sep 2026 14:33:19 +0200
Subject: kstd/memory: introduce observer_ptr casts

---
 kapi/kapi/acpi.hpp                   |  2 +-
 kapi/kapi/devices/device.hpp         |  4 ++--
 kapi/kapi/devices/driver.hpp         | 12 +++++++++---
 kapi/kapi/devices/facet_registry.hpp |  8 ++++----
 4 files changed, 16 insertions(+), 10 deletions(-)

(limited to 'kapi')

diff --git a/kapi/kapi/acpi.hpp b/kapi/kapi/acpi.hpp
index eb82c781..49806433 100644
--- a/kapi/kapi/acpi.hpp
+++ b/kapi/kapi/acpi.hpp
@@ -32,7 +32,7 @@ namespace kapi::acpi
   template<char const * Signature>
   auto get_table() -> kstd::observer_ptr<::acpi::table_type_t<Signature> const>
   {
-    return kstd::make_observer(static_cast<::acpi::table_type_t<Signature> const *>(get_table(Signature).get()));
+    return static_pointer_cast<::acpi::table_type_t<Signature> const>(get_table(Signature));
   }
 
 }  // namespace kapi::acpi
diff --git a/kapi/kapi/devices/device.hpp b/kapi/kapi/devices/device.hpp
index c3a33daf..6b2288e5 100644
--- a/kapi/kapi/devices/device.hpp
+++ b/kapi/kapi/devices/device.hpp
@@ -71,7 +71,7 @@ namespace kapi::devices
     template<typename FacetType>
     [[nodiscard]] auto facet() -> kstd::observer_ptr<FacetType>
     {
-      return kstd::observer_ptr{static_cast<FacetType *>(facet(FacetType::id).get())};
+      return static_pointer_cast<FacetType>(facet(FacetType::id));
     }
 
     //! Get a specific facet of this device, if it supports it.
@@ -81,7 +81,7 @@ namespace kapi::devices
     template<typename FacetType>
     [[nodiscard]] auto facet() const noexcept -> kstd::observer_ptr<FacetType const>
     {
-      return kstd::observer_ptr{static_cast<FacetType const *>(facet(FacetType::id).get())};
+      return static_pointer_cast<FacetType const>(facet(FacetType::id));
     }
 
     //! Check if this device has a specific facet.
diff --git a/kapi/kapi/devices/driver.hpp b/kapi/kapi/devices/driver.hpp
index 8c4d5e97..e789b19a 100644
--- a/kapi/kapi/devices/driver.hpp
+++ b/kapi/kapi/devices/driver.hpp
@@ -69,7 +69,7 @@ namespace kapi::devices
     template<typename FacetType>
     [[nodiscard]] auto facet() -> kstd::observer_ptr<FacetType>
     {
-      return kstd::observer_ptr{static_cast<FacetType *>(query_facet(FacetType::id))};
+      return static_pointer_cast<FacetType>(query_facet(FacetType::id));
     }
 
     //! Retrieve this drivers implementation of a given capability facet.
@@ -79,8 +79,7 @@ namespace kapi::devices
     template<typename FacetType>
     [[nodiscard]] auto facet() const -> kstd::observer_ptr<FacetType const>
     {
-      return kstd::observer_ptr{
-        static_cast<FacetType const *>(const_cast<driver *>(this)->query_facet(FacetType::id).get())};
+      return static_pointer_cast<FacetType const>(query_facet(FacetType::id));
     }
 
     //! Check if this driver implements a given capability facet.
@@ -110,6 +109,13 @@ namespace kapi::devices
   protected:
     //! Return a pointer to the implementation of the given facet if this driver supports it.
     virtual auto query_facet(kapi::capabilities::facet_id facet) -> kstd::observer_ptr<void>;
+
+  private:
+    //! Return a pointer to the implementation of the given facet if this driver supports it.
+    [[nodiscard]] auto query_facet(kapi::capabilities::facet_id facet) const -> kstd::observer_ptr<void const>
+    {
+      return const_cast<driver *>(this)->query_facet(facet);
+    }
   };
 
   //! @}
diff --git a/kapi/kapi/devices/facet_registry.hpp b/kapi/kapi/devices/facet_registry.hpp
index 5e0367c1..4fa6186a 100644
--- a/kapi/kapi/devices/facet_registry.hpp
+++ b/kapi/kapi/devices/facet_registry.hpp
@@ -99,7 +99,7 @@ namespace kapi::devices
       {
         if (m_id == FacetType::id)
         {
-          return kstd::observer_ptr{static_cast<FacetType *>(untyped_facet().get())};
+          return static_pointer_cast<FacetType>(untyped_facet());
         }
         return nullptr;
       }
@@ -112,7 +112,7 @@ namespace kapi::devices
       {
         if (m_id == FacetType::id)
         {
-          return kstd::observer_ptr{static_cast<FacetType const *>(untyped_facet().get())};
+          return static_pointer_cast<FacetType const>(untyped_facet());
         }
         return nullptr;
       }
@@ -213,7 +213,7 @@ namespace kapi::devices
     template<typename FacetType>
     [[nodiscard]] auto resolve(std::string_view name) -> kstd::observer_ptr<FacetType>
     {
-      return kstd::observer_ptr{static_cast<FacetType *>(resolve(FacetType::id, name).get())};
+      return static_pointer_cast<FacetType>(resolve(FacetType::id, name));
     }
 
     //! Attempt to resolve a facet for a device.
@@ -223,7 +223,7 @@ namespace kapi::devices
     template<typename FacetType>
     [[nodiscard]] auto resolve(device & device) -> kstd::observer_ptr<FacetType>
     {
-      return kstd::observer_ptr{static_cast<FacetType *>(resolve(FacetType::id, device).get())};
+      return static_pointer_cast<FacetType>(resolve(FacetType::id, device));
     }
 
     //! Subscribe to facet publish/withdraw notifications.
-- 
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