libcruft-util/posix/fd.hpp

129 lines
3.8 KiB
C++

/*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*
* Copyright 2017-2018 Danny Robson <danny@nerdcruft.net>
*/
#ifndef CRUFT_UTIL_POSIX_FD_HPP
#define CRUFT_UTIL_POSIX_FD_HPP
#include "../debug.hpp"
#include "../view.hpp"
#include <experimental/filesystem>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#if !defined(O_BINARY)
#define O_BINARY 0
#endif
namespace cruft::posix {
///------------------------------------------------------------------------
/// A simple RAII wrapper for file descriptors
class fd {
public:
///////////////////////////////////////////////////////////////////////
// If you are using a system which delineates between binary/text mode
// for descriptors the behaviour is undefined if you don't set the
// necessary flags for binary mode.
fd (const std::experimental::filesystem::path &path, int flags);
fd (const std::experimental::filesystem::path &path, int flags, mode_t);
fd (fd &&) noexcept;
fd& operator= (fd &&) noexcept;
fd& operator= (int);
// The int constructor steals the fd. So don't pass in something that
// you don't want closed at destruct time. This should really only be
// used when interfacing with results of syscalls that we don't wrap.
explicit fd (int);
// copy constructors are removed in favour of explicit calls to dup.
// This should reduce unexpected or expensive copies as much as
// possible; one should not be doing this unless it is absolutely
// required.
fd (const fd&) = delete;
fd dup (void) const;
static fd dup (int);
~fd ();
///////////////////////////////////////////////////////////////////////
struct ::stat stat (void) const;
///////////////////////////////////////////////////////////////////////
void close (void);
void reset (int);
void reset (void);
int release (void);
//---------------------------------------------------------------------
[[nodiscard]] ssize_t read (void *buf, size_t count);
[[nodiscard]] ssize_t write (const void *buf, size_t count);
//---------------------------------------------------------------------
template <typename ValueT>
[[nodiscard]]
ValueT*
read (cruft::view<ValueT*> dst)
{
return dst.begin () + read (
&*std::data (dst), std::size (dst) * sizeof (ValueT)
);
}
//---------------------------------------------------------------------
template <typename ValueT>
[[nodiscard]]
auto
write (const cruft::view<ValueT*> &src)
{
return const_cast<ValueT*> (
write (
cruft::view<const ValueT*> (src)
)
);
}
//---------------------------------------------------------------------
template <typename ValueT>
[[nodiscard]]
const ValueT*
write (const cruft::view<const ValueT*> &src)
{
const auto written = write (
&*std::data (src), std::size (src) * sizeof (ValueT)
);
CHECK_MOD (written, sizeof (ValueT));
return src.begin () + written / sizeof (ValueT);
}
//---------------------------------------------------------------------
[[nodiscard]] off_t lseek (off_t offset, int whence);
///////////////////////////////////////////////////////////////////////
operator int (void) const;
int native (void) const { return m_fd; }
private:
int m_fd;
};
}
#endif