StimProd,DevReattacher: use CDaemon nonviral nursery coro

We ported these two daemons over to the new nursery mechanism and
they work nicely.

smocore/deviceManager/deviceReattacher.cpp

@@ -1,5 +1,6 @@
 #include <config.h>
 #include <iostream>
+#include <chrono>
 #include <functional>
 #include <componentThread.h>
 #include <adapters/boostAsio/deadlineTimerAReq.h>
@@ -10,6 +11,28 @@
 namespace smo {
 namespace device {
 
+namespace {
+
+long computeTimesliceResidueMs(
+	long workDurationMs, long periodMs)
+{
+	if (workDurationMs >= periodMs) {
+		return 0;
+	}
+	return periodMs - workDurationMs;
+}
+
+long durationMsSince(
+	const std::chrono::high_resolution_clock::time_point &startStamp,
+	const std::chrono::high_resolution_clock::time_point &endStamp)
+{
+	const auto duration = endStamp - startStamp;
+	return std::chrono::duration_cast<std::chrono::milliseconds>(
+		duration).count();
+}
+
+} // namespace
+
 DeviceReattacher::DeviceReattacher(
 	DeviceManager& parent, std::shared_ptr<sscl::ComponentThread> ioThread)
 :	parent(parent),
@@ -19,6 +42,8 @@ ioThread(ioThread), daemonTimer(ioThread->getIoContext())
 	 * deviceReattacherCDaemon is a dynamic posting non-viral coroutine: start()
 	 * passes ExplicitPostTarget{ioThread->getIoContext()} so the daemon body
 	 * always runs on ioThread. daemonTimer is reused each loop iteration.
+	 * Each timeslice runs attach work first, then sleeps only the period
+	 * residue so reattach polls stay on a wall-clock cadence.
 	 */
 }
 
@@ -31,20 +56,31 @@ DeviceReattacher::deviceReattacherCDaemon(
 {
 	boost::asio::io_context &timerIoContext =
 		sscl::ComponentThread::getSelf()->getIoContext();
-	const auto periodMs = boost::posix_time::milliseconds(
-		CONFIG_MRNTT_DEVMGR_REATTACHER_PERIOD_MS);
+	const long reattacherPeriodMs = CONFIG_MRNTT_DEVMGR_REATTACHER_PERIOD_MS;
 
 	while (!canceler.isCancellationRequested())
 	{
+		const auto workStartStamp =
+			std::chrono::high_resolution_clock::now();
+
+		co_await parent.attachAllUnattachedDevicesFromKnownListCReq();
+
+		const auto workEndStamp =
+			std::chrono::high_resolution_clock::now();
+		const long workDurationMs = durationMsSince(
+			workStartStamp, workEndStamp);
+
+		const long residueMs = computeTimesliceResidueMs(
+			workDurationMs, reattacherPeriodMs);
+
 		const bool expiredNormally = co_await
 			adapters::boostAsio::getDeadlineTimerAReqAwaiter(
-				timerIoContext, daemonTimer, periodMs);
+				timerIoContext, daemonTimer,
+				boost::posix_time::milliseconds(residueMs));
 
 		if (!expiredNormally) {
 			break;
 		}
-
-		co_await parent.attachAllUnattachedDevicesFromKnownListCReq();
 	}
 
 	co_return;