Files
scylladb/utils/updateable_value.cc

123 lines
3.1 KiB
C++

/*
* Copyright (C) 2019-present 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 "updateable_value.hh"
#include <seastar/core/seastar.hh>
namespace utils {
updateable_value_base::updateable_value_base(const updateable_value_source_base& source) {
source.add_ref(this);
_source = &source;
}
updateable_value_base::~updateable_value_base() {
if (_source) {
_source->del_ref(this);
}
}
updateable_value_base::updateable_value_base(const updateable_value_base& v) {
if (v._source) {
v._source->add_ref(this);
_source = v._source;
}
}
updateable_value_base&
updateable_value_base::updateable_value_base::operator=(const updateable_value_base& v) {
if (this != &v) {
// If both sources are null, or non-null and equal, nothing needs to be done
if (_source != v._source) {
if (v._source) {
v._source->add_ref(this);
}
if (_source) {
_source->del_ref(this);
}
_source = v._source;
}
}
return *this;
}
updateable_value_base::updateable_value_base(updateable_value_base&& v) noexcept
: _source(std::exchange(v._source, nullptr)) {
if (_source) {
_source->update_ref(&v, this);
}
}
updateable_value_base&
updateable_value_base::operator=(updateable_value_base&& v) noexcept {
if (this != &v) {
if (_source) {
_source->del_ref(this);
}
_source = std::exchange(v._source, nullptr);
if (_source) {
_source->update_ref(&v, this);
}
}
return *this;
}
updateable_value_base&
updateable_value_base::updateable_value_base::operator=(std::nullptr_t) {
if (_source) {
_source->del_ref(this);
_source = nullptr;
}
return *this;
}
void
updateable_value_source_base::for_each_ref(std::function<void (updateable_value_base* ref)> func) {
for (auto ref : _refs) {
func(ref);
}
}
updateable_value_source_base::~updateable_value_source_base() {
for (auto ref : _refs) {
ref->_source = nullptr;
}
}
void
updateable_value_source_base::add_ref(updateable_value_base* ref) const {
_refs.push_back(ref);
}
void
updateable_value_source_base::del_ref(updateable_value_base* ref) const {
_refs.erase(std::remove(_refs.begin(), _refs.end(), ref), _refs.end());
}
void
updateable_value_source_base::update_ref(updateable_value_base* old_ref, updateable_value_base* new_ref) const {
std::replace(_refs.begin(), _refs.end(), old_ref, new_ref);
}
}