From a6166befa7421be233ece97e184139870bbc0af7 Mon Sep 17 00:00:00 2001
From: Felix Morgner <felix.morgner@ost.ch>
Date: Thu, 16 Jul 2026 14:16:33 +0200
Subject: kapi: introduce device interfaces

---
 kernel/kapi/devices/interface_registry.cpp | 108 +++++++++++++++++++++++++++++
 1 file changed, 108 insertions(+)
 create mode 100644 kernel/kapi/devices/interface_registry.cpp

(limited to 'kernel/kapi/devices/interface_registry.cpp')

diff --git a/kernel/kapi/devices/interface_registry.cpp b/kernel/kapi/devices/interface_registry.cpp
new file mode 100644
index 00000000..8882e8db
--- /dev/null
+++ b/kernel/kapi/devices/interface_registry.cpp
@@ -0,0 +1,108 @@
+#include <kapi/devices/interface_registry.hpp>
+
+#include <kapi/devices.hpp>
+#include <kapi/system.hpp>
+#include <kapi/test_support/devices.hpp>
+
+#include <kstd/memory.hpp>
+#include <kstd/result.hpp>
+#include <kstd/string.hpp>
+#include <kstd/system_error.hpp>
+#include <kstd/vector.hpp>
+
+#include <algorithm>
+#include <optional>
+#include <string_view>
+#include <utility>
+
+namespace kapi::devices
+{
+
+  namespace
+  {
+    constinit auto static registry = std::optional<interface_registry>{};
+  }
+
+  auto interface_registry::init() -> void
+  {
+    if (registry.has_value())
+    {
+      system::panic("[kernel] Device interface registry has already been initialized.");
+    }
+
+    registry.emplace();
+  }
+
+  auto interface_registry::get() -> interface_registry &
+  {
+    if (!registry)
+    {
+      system::panic("[kernel] Device interface registry has not been initialized.");
+    }
+
+    return *registry;
+  }
+
+  auto interface_registry::do_publish(kstd::shared_ptr<device> device, kstd::string name, interface interface,
+                                      void * implementation) -> kstd::result<void>
+  {
+    erase_if(m_entries, [interface](auto e) { return e.interface() == interface && e.device().expired(); });
+
+    if (!device || !implementation || name.empty())
+    {
+      return kstd::failure(make_error_code(kstd::errc::invalid_argument));
+    }
+
+    auto published = std::ranges::any_of(m_entries, [&](auto const & entry) {
+      return entry.interface() == interface && entry.device().lock().get() == device.get();
+    });
+
+    if (published)
+    {
+      return kstd::failure(make_error_code(kstd::errc::file_exists));
+    }
+
+    m_entries.emplace_back(device, std::move(name), interface, implementation);
+
+    return kstd::success();
+  }
+
+  auto interface_registry::unpublish(device const & device, interface interface) -> void
+  {
+    erase_if(m_entries, [&](auto e) {
+      auto locked_device = e.device().lock();
+      return e.interface() == interface && locked_device && locked_device.get() == &device;
+    });
+  }
+
+  auto interface_registry::all(interface interface) const -> kstd::vector<entry>
+  {
+    auto filtered = m_entries;
+    erase_if(filtered, [&](auto e) {
+      auto locked_device = e.device().lock();
+      return !(e.interface() == interface && locked_device);
+    });
+    return filtered;
+  }
+
+  auto interface_registry::find(interface interface, std::string_view name) const -> kstd::result<entry>
+  {
+    auto found = std::ranges::find_if(
+        m_entries, [&](auto e) { return e.interface() == interface && e.name() == name && e.device().lock(); });
+    if (found == m_entries.cend())
+    {
+      return kstd::failure(make_error_code(kstd::errc::no_such_device));
+    }
+
+    return *found;
+  }
+
+}  // namespace kapi::devices
+
+namespace kapi::test_support::devices
+{
+  auto deinit_interface_registry() -> void
+  {
+    kapi::devices::registry.reset();
+  }
+}  // namespace kapi::test_support::devices
-- 
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