Merge branch 'develop-BA-FS26' into 'develop'HEADdevelop

Merge of BA-FS26 branch into develop

See merge request teachos/kernel!49

1 files changed, 87 insertions, 0 deletions

diff --git a/kernel/src/filesystem/open_file_table.cpp b/kernel/src/filesystem/open_file_table.cpp
new file mode 100644
index 0000000..2afe3aa
--- /dev/null
+++ b/kernel/src/filesystem/open_file_table.cpp
@@ -0,0 +1,87 @@
+#include <kernel/filesystem/open_file_table.hpp>
+
+#include <kernel/filesystem/open_file_descriptor.hpp>
+
+#include <kapi/system.hpp>
+
+#include <kstd/memory>
+#include <kstd/unikstd.h>
+
+#include <algorithm>
+#include <cstddef>
+#include <optional>
+
+namespace
+{
+  constinit auto static global_open_file_table = std::optional<kernel::filesystem::open_file_table>{};
+}  // namespace
+
+namespace kernel::filesystem
+{
+  auto open_file_table::init() -> void
+  {
+    if (global_open_file_table)
+    {
+      kapi::system::panic("[FILESYSTEM] Open file table has already been initialized.");
+    }
+
+    global_open_file_table.emplace(open_file_table{});
+  }
+
+  auto open_file_table::get() -> open_file_table &
+  {
+    if (!global_open_file_table)
+    {
+      kapi::system::panic("[FILESYSTEM] Open file table has not been initialized.");
+    }
+
+    return *global_open_file_table;
+  }
+
+  auto open_file_table::add_file(kstd::shared_ptr<open_file_descriptor> const & file_descriptor) -> kstd::ssize_t
+  {
+    if (!file_descriptor)
+    {
+      return -1;
+    }
+
+    auto it = std::ranges::find_if(m_open_files, [](auto const & open_file) { return open_file == nullptr; });
+    if (it != m_open_files.end())
+    {
+      *it = file_descriptor;
+      return it - m_open_files.begin();
+    }
+
+    m_open_files.push_back(file_descriptor);
+    return m_open_files.size() - 1;
+  }
+
+  auto open_file_table::file(size_t fd) const -> kstd::shared_ptr<open_file_descriptor>
+  {
+    if (fd >= m_open_files.size())
+    {
+      return nullptr;
+    }
+
+    return m_open_files.at(fd);
+  }
+
+  auto open_file_table::remove_file(size_t fd) -> kstd::ssize_t
+  {
+    if (fd >= m_open_files.size())
+    {
+      return -1;
+    }
+
+    m_open_files.at(fd) = nullptr;
+    return 0;
+  }
+}  // namespace kernel::filesystem
+
+namespace kernel::tests::filesystem::open_file_table
+{
+  auto deinit() -> void
+  {
+    global_open_file_table.reset();
+  }
+}  // namespace kernel::tests::filesystem::open_file_table