realm-js/src/concurrent_deque.hpp

77 lines
2.1 KiB
C++

////////////////////////////////////////////////////////////////////////////
//
// Copyright 2016 Realm Inc.
//
// 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.
//
////////////////////////////////////////////////////////////////////////////
#pragma once
#include <condition_variable>
#include <deque>
#include <mutex>
#include <realm/util/optional.hpp>
namespace realm {
template <typename T>
class ConcurrentDeque {
public:
T pop_back() {
std::unique_lock<std::mutex> lock(m_mutex);
m_condition.wait(lock, [this] { return !m_deque.empty(); });
return do_pop_back();
}
util::Optional<T> try_pop_back(size_t timeout) {
std::unique_lock<std::mutex> lock(m_mutex);
m_condition.wait_for(lock, std::chrono::milliseconds(timeout),
[this] { return !m_deque.empty(); });
return m_deque.empty() ? util::none : util::make_optional(do_pop_back());
}
void push_front(T&& item) {
std::unique_lock<std::mutex> lock(m_mutex);
m_deque.push_front(std::move(item));
lock.unlock();
m_condition.notify_one();
}
void push_back(T&& item) {
std::unique_lock<std::mutex> lock(m_mutex);
m_deque.push_back(std::move(item));
lock.unlock();
m_condition.notify_one();
}
bool empty() {
std::lock_guard<std::mutex> lock(m_mutex);
return m_deque.empty();
}
private:
std::condition_variable m_condition;
std::mutex m_mutex;
std::deque<T> m_deque;
T do_pop_back() {
T item = std::move(m_deque.back());
m_deque.pop_back();
return item;
}
};
} // realm