Files
scylladb/utils/file_lock.cc
Avi Kivity 88ade3110f treewide: replace calls to engine().some_api() with some_api()
This removes the need to include reactor.hh, a source of compile
time bloat.

In some places, the call is qualified with seastar:: in order
to resolve ambiguities with a local name.

Includes are adjusted to make everything compile. We end up
having 14 translation units including reactor.hh, primarily for
deprecated things like reactor::at_exit().

Ref #1
2020-04-05 12:46:04 +03:00

82 lines
2.3 KiB
C++

/*
* Copyright (C) 2014 ScyllaDB
*/
/*
* This file is part of Scylla.
*
* Scylla is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Scylla is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Scylla. If not, see <http://www.gnu.org/licenses/>.
*/
#include <seastar/core/seastar.hh>
#include <seastar/core/posix.hh>
#include <unistd.h>
#include <fcntl.h>
#include "file_lock.hh"
class utils::file_lock::impl {
public:
impl(fs::path path)
: _path(std::move(path)), _fd(
file_desc::open(_path.native(), O_RDWR | O_CREAT | O_CLOEXEC,
S_IRWXU)) {
if (::lockf(_fd.get(), F_TLOCK, 0) != 0) {
throw std::system_error(errno, std::system_category(),
"Could not acquire lock: " + _path.native());
}
}
impl(impl&&) = default;
~impl() {
if (!_path.empty()) {
::unlink(_path.c_str());
}
assert(_fd.get() != -1);
auto r = ::lockf(_fd.get(), F_ULOCK, 0);
assert(r == 0);
}
fs::path _path;
file_desc _fd;
};
utils::file_lock::file_lock(fs::path path)
: _impl(std::make_unique<impl>(std::move(path)))
{}
utils::file_lock::file_lock(file_lock&& f) noexcept
: _impl(std::move(f._impl))
{}
utils::file_lock::~file_lock()
{}
fs::path utils::file_lock::path() const {
return _impl ? _impl->_path : "";
}
future<utils::file_lock> utils::file_lock::acquire(fs::path path) {
// meh. not really any future stuff here. but pretend, for the
// day when a future version of lock etc is added.
try {
return make_ready_future<file_lock>(file_lock(path));
} catch (...) {
return make_exception_future<utils::file_lock>(std::current_exception());
}
}
std::ostream& utils::operator<<(std::ostream& out, const file_lock& f) {
return out << "file lock '" << f.path() << "'";
}