* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at https://mozilla.org/MPL/2.0/.
*
* (c) ZeroTier, Inc.
* https://www.zerotier.com/
*/
#ifndef ZT_BLOCKINGQUEUE_HPP
#define ZT_BLOCKINGQUEUE_HPP
#include <atomic>
#include <chrono>
#include <condition_variable>
#include <mutex>
#include <queue>
#include <vector>
namespace ZeroTier {
* Simple C++11 thread-safe queue
*
* Do not use in node/ since we have not gone C++11 there yet.
*/
template <class T> class BlockingQueue {
public:
BlockingQueue(void) : r(true)
{
}
inline void post(T t)
{
std::lock_guard<std::mutex> lock(m);
q.push(t);
c.notify_one();
}
inline void postLimit(T t, const unsigned long limit)
{
std::unique_lock<std::mutex> lock(m);
for (;;) {
if (q.size() < limit) {
q.push(t);
c.notify_one();
break;
}
if (! r)
break;
gc.wait(lock);
}
}
inline void stop(void)
{
std::lock_guard<std::mutex> lock(m);
r = false;
c.notify_all();
gc.notify_all();
}
inline bool get(T& value)
{
std::unique_lock<std::mutex> lock(m);
if (! r)
return false;
while (q.empty()) {
c.wait(lock);
if (! r) {
gc.notify_all();
return false;
}
}
value = q.front();
q.pop();
gc.notify_all();
return true;
}
inline std::vector<T> drain()
{
std::vector<T> v;
while (! q.empty()) {
v.push_back(q.front());
q.pop();
}
return v;
}
enum TimedWaitResult { OK, TIMED_OUT, STOP };
inline TimedWaitResult get(T& value, const unsigned long ms)
{
const std::chrono::milliseconds ms2 { ms };
std::unique_lock<std::mutex> lock(m);
if (! r)
return STOP;
while (q.empty()) {
if (c.wait_for(lock, ms2) == std::cv_status::timeout)
return ((r) ? TIMED_OUT : STOP);
else if (! r)
return STOP;
}
value = q.front();
q.pop();
return OK;
}
inline size_t size() const
{
return q.size();
}
private:
std::queue<T> q;
mutable std::mutex m;
mutable std::condition_variable c, gc;
std::atomic_bool r;
};
}
#endif