From 22a32e2ab9fcb779a7359cec9b0244f262661288 Mon Sep 17 00:00:00 2001
From: Lukas Oesch <lukasoesch20@gmail.com>
Date: Wed, 11 Mar 2026 18:15:54 +0100
Subject: use optional instead of pointer, improve error handling (do not just
 panic, return std::nullopt)

---
 .../include/filesystem/file_descriptor_table.hpp   |  7 +++++--
 kernel/filesystem/src/file_descriptor_table.cpp    | 24 ++++++++--------------
 2 files changed, 14 insertions(+), 17 deletions(-)

diff --git a/kernel/filesystem/include/filesystem/file_descriptor_table.hpp b/kernel/filesystem/include/filesystem/file_descriptor_table.hpp
index a865d32..44fd428 100644
--- a/kernel/filesystem/include/filesystem/file_descriptor_table.hpp
+++ b/kernel/filesystem/include/filesystem/file_descriptor_table.hpp
@@ -4,6 +4,7 @@
 #include "open_file_description.hpp"
 
 #include <array>
+#include <optional>
 
 namespace filesystem
 {
@@ -15,13 +16,15 @@ namespace filesystem
     ~file_descriptor_table() = default;
 
     auto add_file(open_file_description & f) -> int;
-    auto get_file(int fd) -> open_file_description &;
+    auto get_file(int fd) -> std::optional<open_file_description>;
     auto remove_file(int fd) -> void;
 
   private:
     file_descriptor_table() = default;
 
-    std::array<open_file_description *, 32> m_open_files{};  // TODO BA-FS26 use kstd::vector when available
+    // TODO BA-FS26 use kstd::shared_ptr when available
+    // TODO BA-FS26 use kstd::vector when available
+    std::array<std::optional<open_file_description>, 32> m_open_files{};
   };
 }  // namespace filesystem
 
diff --git a/kernel/filesystem/src/file_descriptor_table.cpp b/kernel/filesystem/src/file_descriptor_table.cpp
index 645da9f..286678c 100644
--- a/kernel/filesystem/src/file_descriptor_table.cpp
+++ b/kernel/filesystem/src/file_descriptor_table.cpp
@@ -37,29 +37,27 @@ namespace filesystem
 
   auto file_descriptor_table::add_file(open_file_description & f) -> int
   {
-    auto it = std::ranges::find(m_open_files, nullptr);
+    auto it = std::ranges::find_if(m_open_files, [](auto & open_file) { return !open_file.has_value(); });
     if (it != m_open_files.end())
     {
-      *it = &f;
+      *it = f;
       return static_cast<int>(it - m_open_files.begin());
     }
 
     return -1;
   }
 
-  auto file_descriptor_table::get_file(int fd) -> open_file_description &
+  auto file_descriptor_table::get_file(int fd) -> std::optional<open_file_description>
   {
-    // TODO BA-FS26 do not panic, its an user error
     if (fd < 0)
     {
-      kapi::system::panic("[FILESYSTEM] get_file called with negative descriptor.");
+      return std::nullopt;
     }
 
-    // TODO BA-FS26 do not panic, its an user error
     auto const index = static_cast<size_t>(fd);
-    if (index >= m_open_files.size() || m_open_files[index] == nullptr)
+    if (index >= m_open_files.size() || !m_open_files[index].has_value())
     {
-      kapi::system::panic("[FILESYSTEM] get_file called with invalid descriptor.");
+      return std::nullopt;
     }
 
     return *m_open_files[index];
@@ -67,21 +65,17 @@ namespace filesystem
 
   auto file_descriptor_table::remove_file(int fd) -> void
   {
-    // TODO BA-FS26 do not panic, its an user error
     if (fd < 0)
     {
-      kapi::system::panic("[FILESYSTEM] remove_file called with negative descriptor.");
+      return;
     }
 
-    // TODO BA-FS26 do not panic, its an user error
     auto const index = static_cast<size_t>(fd);
     if (index >= m_open_files.size())
     {
-      kapi::system::panic("[FILESYSTEM] remove_file called with out-of-range descriptor.");
+      return;
     }
 
-    // TODO BA-FS26
-    // delete m_open_files[index];
-    m_open_files[index] = nullptr;
+    m_open_files[index].reset();
   }
 }  // namespace filesystem
\ No newline at end of file
-- 
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