libcruft-util/posix/fd.hpp

127 lines
3.9 KiB
C++

/*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* 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 <sys/types.h>
#include <sys/stat.h>
#include <experimental/filesystem>
namespace util::posix {
///------------------------------------------------------------------------
/// A simple RAII wrapper for file descriptors
class fd {
public:
///////////////////////////////////////////////////////////////////////
fd (const std::experimental::filesystem::path &path, int flags);
fd (const std::experimental::filesystem::path &path, int flags, mode_t);
fd (fd &&);
fd& operator= (fd &&);
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);
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 (util::view<ValueT*> dst)
{
return dst.begin () + read (
&*std::data (dst), std::size (dst) * sizeof (ValueT)
);
}
//---------------------------------------------------------------------
template <typename ValueT>
[[nodiscard]]
auto
write (const util::view<ValueT*> &src)
{
return const_cast<ValueT*> (
write (
util::view<const ValueT*> (src)
)
);
}
//---------------------------------------------------------------------
template <typename ValueT>
[[nodiscard]]
const ValueT*
write (const util::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