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/*
* This source code is released into the public domain.
*/
module;
#include <algorithm>
#include <coroutine>
#include <expected>
#include <filesystem>
#include <random>
#include <string>
#include <fcntl.h>
#include <unistd.h>
module nihil.posix;
import nihil.flagset;
import :getenv;
import :open;
namespace nihil {
temporary_file::temporary_file(nihil::fd &&fd,
std::filesystem::path path) noexcept
: m_fd(std::move(fd))
, m_path(std::move(path))
{
}
temporary_file::temporary_file(nihil::fd &&fd) noexcept
: m_fd(std::move(fd))
{
}
temporary_file::temporary_file(temporary_file &&other) noexcept
: m_fd(std::move(other.m_fd))
, m_path(std::move(other.m_path))
{
}
temporary_file::~temporary_file() //NOLINT(bugprone-exception-escape)
{
if (m_fd)
release();
}
auto temporary_file::release(this temporary_file &self) -> void
{
if (!self.m_fd)
throw std::logic_error(
"release() called on already-released tempfile");
if (!self.m_path.empty()) {
auto ec = std::error_code(); // ignore errors
remove(self.path(), ec);
self.m_path.clear();
}
std::ignore = self.m_fd.close();
}
auto temporary_file::path(this temporary_file const &self)
-> std::filesystem::path const &
{
if (self.m_path.empty())
throw std::logic_error(
"path() called on unlinked temporary_file");
return self.m_path;
}
auto temporary_file::fd(this temporary_file &self) -> nihil::fd &
{
if (!self.m_fd)
throw std::logic_error("fd() called on empty temporary_file");
return self.m_fd;
}
auto tempfile(tempfile_flags_t flags) -> std::expected<temporary_file, error>
{
auto rng = std::default_random_engine(std::random_device{}());
auto random_name = [&] -> std::string {
auto constexpr length = std::size_t{12};
auto constexpr randchars = std::string_view(
"abcdefghijklmnopqrstuvwxyz"
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"0123456789");
auto dist = std::uniform_int_distribution<>(
0, randchars.size() - 1);
auto ret = std::string(length, 0);
std::ranges::generate_n(ret.begin(), length,
[&] -> char {
return randchars[dist(rng)];
});
return ret;
};
auto dir = std::filesystem::path(getenv("TMPDIR").value_or("/tmp"));
// Keep trying until we don't get EEXIST.
for (;;) {
auto filename = dir / (random_name() + ".tmp");
auto fd = nihil::open(filename, O_RDWR | O_CREAT | O_EXCL,
0600);
if (!fd) {
if (fd.error() == std::errc::file_exists)
continue;
return std::unexpected(fd.error());
}
if (flags & tempfile_unlink) {
auto ec = std::error_code();
remove(filename, ec);
return temporary_file(std::move(*fd));
} else {
return temporary_file(std::move(*fd),
std::move(filename));
}
}
}
} // namespace nihil
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