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Copy pathblocking_queue.hpp
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163 lines (140 loc) · 5 KB
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// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements. See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership. The ASF licenses this file
// to you 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.
// This file is copied from
// https://github.com/apache/impala/blob/branch-2.9.0/be/src/util/blocking-queue.hpp
// and modified by Doris
#pragma once
#include <unistd.h>
#include <atomic>
#include <condition_variable>
#include <list>
#include <mutex>
#include "common/logging.h"
#include "util/stopwatch.hpp"
namespace doris {
// Fixed capacity FIFO queue, where both BlockingGet and BlockingPut operations block
// if the queue is empty or full, respectively.
template <typename T>
class BlockingQueue {
public:
BlockingQueue(size_t max_elements)
: _shutdown(false),
_max_elements(max_elements),
_total_get_wait_time(0),
_total_put_wait_time(0),
_get_waiting(0),
_put_waiting(0) {}
// Get an element from the queue, waiting indefinitely for one to become available.
// Returns false if we were shut down prior to getting the element, and there
// are no more elements available.
bool blocking_get(T* out) {
MonotonicStopWatch timer;
timer.start();
std::unique_lock<std::mutex> unique_lock(_lock);
while (!(_shutdown || !_list.empty())) {
++_get_waiting;
_get_cv.wait(unique_lock);
}
_total_get_wait_time += timer.elapsed_time();
if (!_list.empty()) {
*out = _list.front();
_list.pop_front();
if (_put_waiting > 0) {
--_put_waiting;
unique_lock.unlock();
_put_cv.notify_one();
}
return true;
} else {
assert(_shutdown);
return false;
}
}
// Puts an element into the queue, waiting indefinitely until there is space.
// If the queue is shut down, returns false.
bool blocking_put(const T& val) {
MonotonicStopWatch timer;
timer.start();
std::unique_lock<std::mutex> unique_lock(_lock);
while (!(_shutdown || _list.size() < _max_elements)) {
++_put_waiting;
_put_cv.wait(unique_lock);
}
_total_put_wait_time += timer.elapsed_time();
if (_shutdown) {
return false;
}
_list.push_back(val);
if (_get_waiting > 0) {
--_get_waiting;
unique_lock.unlock();
_get_cv.notify_one();
}
return true;
}
// Return false if queue full or has been shutdown.
bool try_put(const T& val) {
if (_shutdown || _list.size() >= _max_elements) {
return false;
}
MonotonicStopWatch timer;
timer.start();
std::unique_lock<std::mutex> unique_lock(_lock);
_total_put_wait_time += timer.elapsed_time();
if (_shutdown || _list.size() >= _max_elements) {
return false;
}
_list.push_back(val);
if (_get_waiting > 0) {
--_get_waiting;
unique_lock.unlock();
_get_cv.notify_one();
}
return true;
}
// Shut down the queue. Wakes up all threads waiting on BlockingGet or BlockingPut.
void shutdown() {
{
std::lock_guard<std::mutex> guard(_lock);
_shutdown = true;
}
_get_cv.notify_all();
_put_cv.notify_all();
}
uint32_t get_size() const {
std::lock_guard<std::mutex> l(_lock);
return _list.size();
}
uint32_t get_capacity() const { return _max_elements; }
// Returns the total amount of time threads have blocked in BlockingGet.
uint64_t total_get_wait_time() const { return _total_get_wait_time; }
// Returns the total amount of time threads have blocked in BlockingPut.
uint64_t total_put_wait_time() const { return _total_put_wait_time; }
private:
bool _shutdown;
const int _max_elements;
std::condition_variable _get_cv; // 'get' callers wait on this
std::condition_variable _put_cv; // 'put' callers wait on this
// _lock guards access to _list, total_get_wait_time, and total_put_wait_time
mutable std::mutex _lock;
std::list<T> _list;
std::atomic<uint64_t> _total_get_wait_time;
std::atomic<uint64_t> _total_put_wait_time;
size_t _get_waiting;
size_t _put_waiting;
};
} // namespace doris