ladybird/Kernel/FileSystem/FileSystem.h
Lenny Maiorani 5751327195 Kernel: static vs non-static constexpr variables
Problem:
- `static` variables consume memory and sometimes are less
  optimizable.
- `static const` variables can be `constexpr`, usually.
- `static` function-local variables require an initialization check
  every time the function is run.

Solution:
- If a global `static` variable is only used in a single function then
  move it into the function and make it non-`static` and `constexpr`.
- Make all global `static` variables `constexpr` instead of `const`.
- Change function-local `static const[expr]` variables to be just
  `constexpr`.
2021-05-19 21:21:47 +01:00

106 lines
2.6 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/RefCounted.h>
#include <AK/RefPtr.h>
#include <AK/String.h>
#include <AK/StringView.h>
#include <Kernel/FileSystem/InodeIdentifier.h>
#include <Kernel/KResult.h>
#include <Kernel/Lock.h>
#include <Kernel/UnixTypes.h>
#include <Kernel/UserOrKernelBuffer.h>
namespace Kernel {
static constexpr u32 mepoch = 476763780;
class Inode;
class FileDescription;
class LocalSocket;
class VMObject;
class FS : public RefCounted<FS> {
friend class Inode;
public:
virtual ~FS();
unsigned fsid() const { return m_fsid; }
static FS* from_fsid(u32);
static void sync();
static void lock_all();
virtual bool initialize() = 0;
virtual const char* class_name() const = 0;
virtual NonnullRefPtr<Inode> root_inode() const = 0;
virtual bool supports_watchers() const { return false; }
bool is_readonly() const { return m_readonly; }
virtual unsigned total_block_count() const { return 0; }
virtual unsigned free_block_count() const { return 0; }
virtual unsigned total_inode_count() const { return 0; }
virtual unsigned free_inode_count() const { return 0; }
virtual KResult prepare_to_unmount() const { return KSuccess; }
struct DirectoryEntryView {
DirectoryEntryView(const StringView& name, InodeIdentifier, u8 file_type);
StringView name;
InodeIdentifier inode;
u8 file_type { 0 };
};
virtual void flush_writes() { }
size_t block_size() const { return m_block_size; }
size_t fragment_size() const { return m_fragment_size; }
virtual bool is_file_backed() const { return false; }
// Converts file types that are used internally by the filesystem to DT_* types
virtual u8 internal_file_type_to_directory_entry_type(const DirectoryEntryView& entry) const { return entry.file_type; }
protected:
FS();
void set_block_size(size_t);
void set_fragment_size(size_t);
mutable Lock m_lock { "FS" };
private:
unsigned m_fsid { 0 };
size_t m_block_size { 0 };
size_t m_fragment_size { 0 };
bool m_readonly { false };
};
inline FS* InodeIdentifier::fs()
{
return FS::from_fsid(m_fsid);
}
inline const FS* InodeIdentifier::fs() const
{
return FS::from_fsid(m_fsid);
}
}
namespace AK {
template<>
struct Traits<Kernel::InodeIdentifier> : public GenericTraits<Kernel::InodeIdentifier> {
static unsigned hash(const Kernel::InodeIdentifier& inode) { return pair_int_hash(inode.fsid(), inode.index().value()); }
};
}