From 526709a1e86d55dd88e2dbdbc471795efce9046b Mon Sep 17 00:00:00 2001
From: Felix Morgner <felix.morgner@ost.ch>
Date: Thu, 23 Jul 2026 01:38:56 +0200
Subject: kapi: bootstrap owning device tree

---
 kernel/kapi/devices.cpp | 56 +++++++++++++++++++++++++++++++------------------
 1 file changed, 36 insertions(+), 20 deletions(-)

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

diff --git a/kernel/kapi/devices.cpp b/kernel/kapi/devices.cpp
index 6da503d9..8f3011fe 100644
--- a/kernel/kapi/devices.cpp
+++ b/kernel/kapi/devices.cpp
@@ -10,7 +10,6 @@
 #include <kstd/print.hpp>
 #include <kstd/string.hpp>
 
-#include <optional>
 #include <string_view>
 #include <utility>
 
@@ -18,37 +17,55 @@ namespace kapi::devices
 {
   namespace
   {
-    auto constinit root_bus = std::optional<kernel::devices::root_bus>{};
-    auto constinit device_tree = kstd::flat_map<kstd::string, kstd::observer_ptr<device>>{};
+    auto constinit root_bus = kstd::shared_ptr<kernel::devices::root_bus>{};
+    auto constinit device_tree = kstd::flat_map<kstd::string, kstd::weak_ptr<device>>{};
   }  // namespace
 
   auto init() -> void
   {
-    if (root_bus.has_value())
+    if (root_bus)
     {
       kapi::system::panic("[OS:DEV] The device subsystem has already been initialized");
     }
 
     interface_registry::init();
 
-    auto & bus = root_bus.emplace();
-    register_device(bus);
-    bus.init();
+    root_bus = kstd::make_shared<kernel::devices::root_bus>();
+    register_device(root_bus);
+    root_bus->init();
   }
 
-  auto get_root_bus() -> bus &
+  auto get_root_bus() -> kstd::shared_ptr<bus>
   {
-    if (!root_bus.has_value())
+    if (!root_bus)
     {
       kapi::system::panic("[OS:DEV] Root bus not initialized!");
     }
-    return *root_bus;
+    return root_bus;
   }
 
-  auto register_device(device & device) -> bool
+  auto register_device(kstd::shared_ptr<device> device) -> bool
   {
-    kstd::println("[OS:DEV] Registering device {}", device.name());
-    return device_tree.emplace(device.name(), &device).second;
+    if (!device)
+    {
+      return false;
+    }
+
+    kstd::println("[OS:DEV] Registering device {}", device->name());
+
+    auto found = device_tree.find(device->name());
+    if (found != device_tree.end())
+    {
+      if (!found->second.expired())
+      {
+        return false;
+      }
+
+      found->second = device;
+      return true;
+    }
+
+    return device_tree.emplace(device->name(), device).second;
   }
 
   auto unregister_device(device &) -> bool
@@ -57,16 +74,15 @@ namespace kapi::devices
     return false;
   }
 
-  auto find_device(std::string_view name) -> kstd::observer_ptr<device>
+  auto find_device(std::string_view name) -> kstd::shared_ptr<device>
   {
-    for (auto const & [key, value] : device_tree)
+    auto found = device_tree.find(kstd::string{name});
+    if (found == device_tree.end())
     {
-      if (value->name() == name)
-      {
-        return value;
-      }
+      return nullptr;
     }
-    return nullptr;
+
+    return found->second.lock();
   }
 
 }  // namespace kapi::devices
-- 
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