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construct/include/ircd/fs/fd.h

121 lines
2.9 KiB
C++

// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2018 Jason Volk <jason@zemos.net>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice is present in all copies. The
// full license for this software is available in the LICENSE file.
#pragma once
#define HAVE_IRCD_FS_FD_H
namespace ircd::fs
{
struct fd;
size_t size(const fd &);
size_t block_size(const fd &);
ulong fstype(const fd &);
ulong device(const fd &);
uint64_t write_life(const fd &) noexcept;
void write_life(const fd &, const uint64_t &);
size_t advise(const fd &, const int &, const size_t & = 0, const opts & = opts_default);
size_t evict(const fd &, const size_t &size = 0, const opts & = opts_default);
}
/// File Desc++ptor. This is simply a native fd (i.e. integer) with c++ object
/// semantics.
struct ircd::fs::fd
{
struct opts;
int fdno {-1};
public:
operator const int &() const;
operator bool() const;
bool operator!() const;
opts options() const;
int release() noexcept;
explicit fd(const int &);
fd(const int &dirfd, const string_view &path, const opts &);
fd(const string_view &path, const opts &);
fd(const string_view &path);
fd() = default;
fd(fd &&) noexcept;
fd(const fd &) = delete;
fd &operator=(fd &&) noexcept;
fd &operator=(const fd &) = delete;
~fd() noexcept;
};
/// Descriptor options (open options)
struct ircd::fs::fd::opts
:fs::opts
{
static conf::item<bool> direct_io_enable;
/// std openmode passed from ctor.
std::ios::openmode mode {std::ios::openmode(0)};
/// open(2) flags. Usually generated from ios::open_mode ctor.
ulong flags {0};
/// open(2) mode_t mode used for file creation.
ulong mask {0};
/// Seek to end after open. This exists to convey the flag for open_mode.
bool ate {false};
/// (O_DIRECT) Direct IO bypassing the operating system caches.
bool direct {false};
/// (O_CLOEXEC) Close this descriptor on an exec().
bool cloexec {true};
/// Allows file to be created if it doesn't exist. Set this to false to
/// prevent file from being created when opened with a write-mode.
bool create {true};
/// Allows file to opened if and only if it doesn't exist and will be
/// created by this open().
bool exclusive {false};
/// Advise for random access (ignored when direct=true)
bool random {false};
/// Advise for sequential access (ignored when direct=true)
bool sequential {false};
/// Advise for dontneed access (ignored when direct=true)
bool dontneed {false};
/// Construct options from an std::ios::open_mode bitmask.
opts(const std::ios::openmode &);
opts() = default;
};
inline bool
ircd::fs::fd::operator!()
const
{
return !bool(*this);
}
inline ircd::fs::fd::operator
bool()
const
{
return int(*this) >= 0;
}
inline ircd::fs::fd::operator
const int &()
const
{
return fdno;
}