Files
scylladb/utils/atomic_vector.hh
Rafael Ávila de Espíndola d9a71a7cff service: Refactor code into a atomic_vector class
This templates the code for listener_vector, renames it to
atomic_vector and moves it to the utils directory.

Signed-off-by: Rafael Ávila de Espíndola <espindola@scylladb.com>
2020-01-22 08:16:03 -08:00

62 lines
1.9 KiB
C++

/*
* Copyright (C) 2020 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/>.
*/
#pragma once
#include <seastar/core/rwlock.hh>
#include <seastar/util/defer.hh>
#include <seastar/util/noncopyable_function.hh>
#include <vector>
// This class supports atomic removes (by using a lock and returning a
// future) and non atomic insert and iteration (by using indexes).
template <typename T>
class atomic_vector {
std::vector<T> _vec;
seastar::rwlock _vec_lock;
public:
void add(const T& value) {
_vec.push_back(value);
}
seastar::future<> remove(const T& value) {
return with_lock(_vec_lock.for_write(), [this, value] {
_vec.erase(std::remove(_vec.begin(), _vec.end(), value), _vec.end());
});
}
// This must be called on a thread. The callback function must not
// call remove.
void for_each(seastar::noncopyable_function<void(T&)> func) {
_vec_lock.for_read().lock().get();
auto unlock = seastar::defer([this] {
_vec_lock.for_read().unlock();
});
// We grab a lock in remove(), but not in add(), so we
// iterate using indexes to guard against the vector being
// reallocated.
for (size_t i = 0, n = _vec.size(); i < n; ++i) {
func(_vec[i]);
}
}
};