track time independently of reads and connections

main.ha

@@ -102,6 +102,20 @@ fn closefd(fd: *poll::pollfd) void = {
 	fd.revents = 0;
 };
 
+// shouldtick returns a boolean representing if a tick
+// message should be sent and a time::duration indicating
+// when the next tick should be.
+fn shouldtick(next: time::instant) (bool, time::duration) = {
+	let now = time::now(time::clock::MONOTONIC);
+
+	if (time::compare(now, next) >= 0) {
+		return (true, time::SECOND);
+	};
+
+	let diff = time::diff(now, next);
+	return (false, diff);
+};
+
 export fn main() void = {
 
 	let socket = tcp::listen(ip::LOCAL_V4, 8080)!;
@@ -123,17 +137,28 @@ export fn main() void = {
 		revents = 0
 	};
 
+	let start = time::now(time::clock::MONOTONIC);
+	let nexttick = time::add(start, time::SECOND);
+	let wait = time::SECOND;
+
 	for (true) {
-		match(poll::poll(fds, time::SECOND)) {
+		match(poll::poll(fds, wait)) {
 
 		case let n: uint =>
 			if (n > 0) {
 				tryconn(fds);
 				tryread(fds);
-			} else {
+			};
+
+			let (shouldtick, d) = shouldtick(nexttick);
+			if (shouldtick) {
+				let now = time::now(time::clock::MONOTONIC);
+				nexttick = time::add(now, d);
 				write(fds);
 			};
 
+			wait = d;
+
 		case let err: poll::error =>
 			log::fatal("poll failed");
 		};