PeriodicTrigger.h

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// SPDX-FileCopyrightText: Deutsches Elektronen-Synchrotron DESY, MSK, ChimeraTK Project <chimeratk-support@desy.de>
// SPDX-License-Identifier: LGPL-3.0-or-later
#pragma once
 
#include "ApplicationModule.h"
#include "ScalarAccessor.h"
 
#include <chrono>
 
namespace ChimeraTK {
 
  struct PeriodicTrigger : public ApplicationModule {
    PeriodicTrigger(ModuleGroup* owner, const std::string& name, const std::string& description,
        const uint32_t defaultPeriod = 1000, const std::unordered_set<std::string>& tags = {},
        const std::string& periodName = "period", const std::string& tickName = "tick")
    : ApplicationModule(owner, name, description, tags),
      period(this, periodName, "ms", "period in milliseconds. The trigger is sent once per the specified duration."),
      tick(this, tickName, "", "Timer tick. Counts the trigger number starting from 0."),
      _defaultPeriod(defaultPeriod) {}
 
    PeriodicTrigger() = default;
 
    ScalarPollInput<uint32_t> period;
    ScalarOutput<uint64_t> tick;
 
    void prepare() override {
      setCurrentVersionNumber({});
      tick.write(); // send initial value
    }
 
    void sendTrigger() {
      setCurrentVersionNumber({});
      ++tick;
      tick.write();
    }
 
    void mainLoop() override {
      if(Application::getInstance().getTestableMode().isEnabled()) {
        return;
      }
      tick = 0;
      std::chrono::time_point<std::chrono::steady_clock> t = std::chrono::steady_clock::now();
 
      while(true) {
        period.read();
        if(period == 0) {
          // set receiving end of timeout. Will only be overwritten if there is
          // new data.
          period = _defaultPeriod;
        }
        t += std::chrono::milliseconds(static_cast<uint32_t>(period));
        boost::this_thread::interruption_point();
        std::this_thread::sleep_until(t);
 
        sendTrigger();
      }
    }
 
   private:
    uint32_t _defaultPeriod{};
  };
} // namespace ChimeraTK