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/*
* Phusion Passenger - https://www.phusionpassenger.com/
* Copyright (c) 2010-2017 Phusion Holding B.V.
*
* "Passenger", "Phusion Passenger" and "Union Station" are registered
* trademarks of Phusion Holding B.V.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#ifndef _PASSENGER_BLOCKING_QUEUE_H_
#define _PASSENGER_BLOCKING_QUEUE_H_
#include <boost/thread.hpp>
#include <boost/date_time/posix_time/posix_time.hpp>
#include <queue>
namespace Passenger {
using namespace std;
using namespace boost;
template<typename T>
class BlockingQueue {
private:
mutable boost::timed_mutex lock;
boost::condition_variable_any added;
boost::condition_variable_any removed;
unsigned int max;
std::queue<T> queue;
bool atMaxCapacity() const {
return max > 0 && queue.size() >= max;
}
public:
BlockingQueue(unsigned int max = 0) {
this->max = max;
}
unsigned int size() const {
boost::lock_guard<boost::timed_mutex> l(lock);
return queue.size();
}
void add(const T &item) {
boost::unique_lock<boost::timed_mutex> l(lock);
while (atMaxCapacity()) {
removed.wait(l);
}
queue.push(item);
added.notify_one();
if (!atMaxCapacity()) {
removed.notify_one();
}
}
bool tryAdd(const T &item) {
boost::lock_guard<boost::timed_mutex> l(lock);
if (!atMaxCapacity()) {
queue.push(item);
added.notify_one();
if (!atMaxCapacity()) {
removed.notify_one();
}
return true;
} else {
return false;
}
}
T get() {
boost::unique_lock<boost::timed_mutex> l(lock);
while (queue.empty()) {
added.wait(l);
}
T item = queue.front();
queue.pop();
removed.notify_one();
if (!queue.empty()) {
added.notify_one();
}
return item;
}
bool timedGet(T &output, unsigned int timeout) {
boost::unique_lock<boost::timed_mutex> l(lock);
posix_time::ptime deadline = posix_time::microsec_clock::local_time() +
posix_time::milliseconds(timeout);
bool timedOut = false;
while (queue.empty() && !timedOut) {
posix_time::time_duration diff = deadline -
posix_time::microsec_clock::local_time();
if (diff.is_negative()) {
timedOut = true;
} else {
timedOut = !added.timed_wait(l,
posix_time::milliseconds(diff.total_milliseconds()));
}
}
if (!queue.empty()) {
output = queue.front();
queue.pop();
removed.notify_one();
if (!queue.empty()) {
added.notify_one();
}
return true;
} else {
return false;
}
}
bool tryGet(T &output) {
boost::unique_lock<boost::timed_mutex> l(lock);
if (queue.empty()) {
return false;
} else {
output = queue.front();
queue.pop();
removed.notify_one();
if (!queue.empty()) {
added.notify_one();
}
return true;
}
}
T peek() {
boost::unique_lock<boost::timed_mutex> l(lock);
while (queue.empty()) {
added.wait(l);
}
return queue.front();
}
};
} // namespace Passenger
#endif /* _PASSENGER_BLOCKING_QUEUE_H_ */
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