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1 #pragma once
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2
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3 // Alternate lightweight implementation of pfc::event, with similar method sigantures but no support for multi-event-wait-for-any.
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4 // It's a safe drop-in replacement for the regular event - code trying to use unsupported methods will fail to compile rather than behave incorrectly.
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5
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6 // Rationale:
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7 // Mac/Linux multi-wait-capable pipe-backed event is relatively expensive, in terms of CPU, memory and file descriptors opened.
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8 // On Windows, event_std still outperforms regular win32 event but the difference is mostly insignificant in real life use cases.
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9
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10 #include <mutex>
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11 #include <condition_variable>
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12 namespace pfc {
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13 class event_std {
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14 public:
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15 void set_state(bool v = true) {
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16 std::scoped_lock lock(m_mutex);
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17 if (m_state != v) {
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18 m_state = v;
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19 if (v) m_condition.notify_all();
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20 }
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21 }
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22 bool is_set() const { return m_state; }
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23 void wait() {
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24 std::unique_lock lock(m_mutex);
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25 m_condition.wait(lock, [this] { return this->m_state; });
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26 }
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27 bool wait_for(double timeout) {
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28 if (timeout < 0) { wait(); return true; }
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29 std::unique_lock lock(m_mutex);
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30 return m_condition.wait_for(lock, std::chrono::duration<double>(timeout), [this] { return this->m_state; });
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31 }
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32 void wait_and_clear() {
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33 std::unique_lock lock(m_mutex);
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34 m_condition.wait(lock, [this] { return this->m_state; });
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35 m_state = false;
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36 }
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37 bool wait_for_and_clear(double timeout) {
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38 if ( timeout < 0 ) {wait_and_clear(); return true;}
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39 std::unique_lock lock(m_mutex);
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40 bool rv = m_condition.wait_for(lock, std::chrono::duration<double>(timeout), [this] { return this->m_state; });
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41 if ( rv ) m_state = false;
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42 return rv;
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43 }
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44 private:
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45 volatile bool m_state = false;
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46 std::condition_variable m_condition;
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47 std::mutex m_mutex;
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48 };
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49 }
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