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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
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#ifndef SHARE_JFR_PERIODIC_SAMPLING_JFRSAMPLEMONITOR_HPP
#define SHARE_JFR_PERIODIC_SAMPLING_JFRSAMPLEMONITOR_HPP

#include "jfr/periodic/sampling/jfrSampleRequest.hpp"
#include "jfr/utilities/jfrTime.hpp"
#include "memory/allocation.hpp"
#include "runtime/javaThread.hpp"
#include "runtime/mutex.hpp"

class JfrSampleMonitor : public StackObj {
 private:
  JfrThreadLocal* const _tl;
  Monitor* const _sample_monitor;
  mutable bool _waiting;
 public:
  JfrSampleMonitor(JfrThreadLocal* tl) :
    _tl(tl), _sample_monitor(tl->sample_monitor()), _waiting(false) {
    assert(tl != nullptr, "invariant");
    assert(_sample_monitor != nullptr, "invariant");
    _sample_monitor->lock_without_safepoint_check();
  }

  bool is_waiting() const {
    assert_lock_strong(_sample_monitor);
    _waiting = _tl->sample_state() == WAITING_FOR_NATIVE_SAMPLE;
    return _waiting;
  }

  void install_java_sample_request() {
    assert_lock_strong(_sample_monitor);
    assert(_waiting, "invariant");
    assert(_tl->sample_state() == WAITING_FOR_NATIVE_SAMPLE, "invariant");
    JfrSampleRequest request;
    request._sample_ticks = JfrTicks::now();
    _tl->set_sample_request(request);
    _tl->set_sample_state(JAVA_SAMPLE);
    _sample_monitor->notify_all();
  }

  ~JfrSampleMonitor() {
    assert_lock_strong(_sample_monitor);
    if (!_waiting) {
      _tl->set_sample_state(NO_SAMPLE);
      _sample_monitor->notify_all();
    }
    _sample_monitor->unlock();
  }
};

#endif // SHARE_JFR_PERIODIC_SAMPLING_JFRSAMPLEMONITOR_HPP