kernel/vfs: extract fs type registry

3 files changed, 56 insertions, 5 deletions

diff --git a/kernel/include/kernel/filesystem/type.hpp b/kernel/include/kernel/filesystem/type.hpp
index 87e466b..0948e54 100644
--- a/kernel/include/kernel/filesystem/type.hpp
+++ b/kernel/include/kernel/filesystem/type.hpp
@@ -28,6 +28,15 @@ namespace kernel::filesystem
     [[nodiscard]] virtual auto make_instance() const -> kstd::shared_ptr<filesystem> = 0;
   };
 
+  template<typename Type>
+  struct type_registration
+  {
+    constexpr auto static instance = Type{};
+    [[using gnu: section("fs_types"), used, visibility("hidden")]] constexpr auto static pointer{
+      kstd::make_observer<type const>(&instance),
+    };
+  };
+
 }  // namespace kernel::filesystem
 
 #endif
diff --git a/kernel/include/kernel/filesystem/type_registry.hpp b/kernel/include/kernel/filesystem/type_registry.hpp
new file mode 100644
index 0000000..2f5e708
--- /dev/null
+++ b/kernel/include/kernel/filesystem/type_registry.hpp
@@ -0,0 +1,47 @@
+#ifndef TEACH_OS_KERNEL_TYPE_REGISRY_HPP
+#define TEACH_OS_KERNEL_TYPE_REGISRY_HPP
+
+#include <kernel/filesystem/type.hpp>
+
+#include <kstd/flat_map>
+#include <kstd/memory>
+#include <kstd/string>
+
+#include <span>
+#include <string_view>
+
+namespace kernel::filesystem
+{
+
+  struct type_registry
+  {
+    using value_type = type;
+    using pointer = kstd::observer_ptr<value_type const>;
+
+    auto static init() -> void;
+    auto static get() -> type_registry &;
+
+    constexpr type_registry() noexcept = default;
+
+    //! Add a type descriptor to this registry.
+    //!
+    //! This function will register the given descriptor with this registry, given that no descriptor for a filesystem
+    //! with the same name exists in this registry already.
+    //!
+    //! @param descriptor The filesystem type descriptor to add to the registry.
+    //! @return @p true iff. the descriptor was successfully added, @p false if not.
+    auto add(pointer descriptor) -> bool;
+
+    //! Get all currently registered type descriptors.
+    //!
+    //! @return A span containing all currently registered filesystem type descriptors.
+    [[nodiscard]] auto all() const noexcept -> std::span<pointer>;
+
+  private:
+    //! A map from filesystem names (identifiers) to filesystem type descriptors.
+    kstd::flat_map<std::string_view, pointer> m_descriptors{};
+  };
+
+}  // namespace kernel::filesystem
+
+#endif
diff --git a/kernel/include/kernel/filesystem/vfs.hpp b/kernel/include/kernel/filesystem/vfs.hpp
index c8aae5c..ddc9a9b 100644
--- a/kernel/include/kernel/filesystem/vfs.hpp
+++ b/kernel/include/kernel/filesystem/vfs.hpp
@@ -6,11 +6,8 @@
 #include <kernel/filesystem/filesystem.hpp>
 #include <kernel/filesystem/mount.hpp>
 #include <kernel/filesystem/mount_table.hpp>
-#include <kernel/filesystem/type.hpp>
 
-#include <kstd/flat_map>
 #include <kstd/memory>
-#include <kstd/string>
 
 #include <string_view>
 #include <utility>
@@ -109,8 +106,6 @@ namespace kernel::filesystem
 
     auto graft_persistent_device_fs(kstd::shared_ptr<devfs::filesystem> const & device_fs) -> void;
 
-    //! A map from filesystem names (identifiers) to filesystem type descriptors.
-    kstd::flat_map<kstd::string, kstd::observer_ptr<type const>> m_filesystems{};
     mount_table m_mount_table{};
   };
 }  // namespace kernel::filesystem