Files
serenity/Kernel/FileSystem/RAMFS/FileSystem.h
Liav A. cb10f70394 Kernel: Change internal handling of filesystem-specific options
Instead of using a raw `KBuffer` and letting each implementation to
populating the specific flags on its own, we change things so we only
let each FileSystem implementation to validate the flag and its value
but then store it in a HashMap which its key is the flag name and
the value is a special new class called `FileSystemSpecificOption`
which wraps around `AK::Variant<...>`.

This approach has multiple advantages over the previous:
- It allows runtime inspection of what the user has set on a `MountFile`
  description for a specific filesystem.
- It ensures accidental overriding of filesystem specific option that
  was already set is not possible
- It removes ugly casting of a `KBuffer` contents to a strongly-typed
  values. Instead, a strongly-typed `AK::Variant` is used which ensures
  we always get a value without doing any casting.

Please note that we have removed support for ASCII string-oriented flags
as there were no actual use cases, and supporting such type would make
`FileSystemSpecificOption` more complicated unnecessarily for now.
2024-08-03 20:35:06 +02:00

46 lines
1.2 KiB
C++

/*
* Copyright (c) 2019-2020, Sergey Bugaev <bugaevc@serenityos.org>
* Copyright (c) 2022-2024, Liav A. <liavalb@hotmail.co.il>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <Kernel/FileSystem/FileSystem.h>
#include <Kernel/FileSystem/FileSystemSpecificOption.h>
#include <Kernel/FileSystem/Inode.h>
#include <Kernel/Forward.h>
namespace Kernel {
class RAMFS final : public FileSystem {
friend class RAMFSInode;
public:
virtual ~RAMFS() override;
static ErrorOr<NonnullRefPtr<FileSystem>> try_create(FileSystemSpecificOptions const&);
virtual ErrorOr<void> initialize() override;
virtual StringView class_name() const override { return "RAMFS"sv; }
virtual bool supports_watchers() const override { return true; }
virtual bool supports_backing_loop_devices() const override { return true; }
virtual Inode& root_inode() override;
virtual u8 internal_file_type_to_directory_entry_type(DirectoryEntryView const& entry) const override;
private:
RAMFS();
RefPtr<RAMFSInode> m_root_inode;
// NOTE: We start by assigning InodeIndex of 2, because 0 is invalid and 1
// is reserved for the root directory inode.
unsigned m_next_inode_index { 2 };
unsigned next_inode_index();
};
}