Implement Kernel::System to manage system services

src/kernel/system/System.cpp

@@ -1 +1,8 @@
 #include "System.h"
+
+namespace Kernel {
+
+// TODO: This initializer ({nullptr}) isn't implemented yet
+Container::Array<Kernel::Service *, 256> System::systemServices = {nullptr};
+
+}

src/kernel/system/System.h

@@ -1,20 +1,47 @@
-#ifndef CHURLOS_SYSTEM_H
-#define CHURLOS_SYSTEM_H
+#ifndef CHURLOS_KERNEL_SYSTEM_H
+#define CHURLOS_KERNEL_SYSTEM_H
 
 #include "kernel/service/Service.h"
-#include "lib/stream/CGA_Stream.h"
-#include "lib/container/Vector.h"
+#include "lib/container/Array.h"
 
-namespace Util {
+namespace Kernel {
 
 class System {
 public:
-    static CGA_Stream out;
+    template<typename T>
+    static void registerService() {
+        static_assert(std::is_base_of_v<Service, T>, "Tried to register invalid service!");
+
+        if (isServiceRegistered<T>()) {
+            // TODO: Exception
+        }
+
+        systemServices[T::ID] = new T();
+    };
+
+    template<typename T>
+    static bool isServiceRegistered() {
+        static_assert(std::is_base_of_v<Service, T>, "Tried to query invalid service!");
+
+        return systemServices[T::ID] != nullptr;
+    }
+
+    template<typename T>
+    static T &getService() {
+        static_assert(std::is_base_of_v<Service, T>, "Tried to retrieve invalid service!");
+
+        if (!isServiceRegistered<T>()) {
+            // TODO: Exception
+        }
+
+        // Might be dangerous (?), but dynamic_cast needs runtime type information
+        return *reinterpret_cast<T *>(systemServices[T::ID]);
+    }
 
 private:
-    static Container::Vector<Kernel::Service> systemServices;
+    static Container::Array<Kernel::Service *, 256> systemServices; // Service ID determines array position
 };
 
 }
 
-#endif //CHURLOS_SYSTEM_H
+#endif //CHURLOS_KERNEL_SYSTEM_H