fixes

src/concurrency/PeriodicScheduler.cpp

@@ -0,0 +1,35 @@
+#include "PeriodicScheduler.h"
+#include "PeriodicTask.h"
+#include "LockGuard.h"
+#include "../time.h"
+
+namespace concurrency {
+
+/// call this from loop
+void PeriodicScheduler::loop()
+{
+    LockGuard lg(&lock);
+
+    uint32_t now = time::millis();
+    for (auto t : tasks) {
+        if (t->period && (now - t->lastMsec) >= t->period) {
+
+            t->doTask();
+            t->lastMsec = now;
+        }
+    }
+}
+
+void PeriodicScheduler::schedule(PeriodicTask *t)
+{
+    LockGuard lg(&lock);
+    tasks.insert(t);
+}
+
+void PeriodicScheduler::unschedule(PeriodicTask *t)
+{
+    LockGuard lg(&lock);
+    tasks.erase(t);
+}
+
+} // namespace concurrency