Split out an ActivityUtils class.

OpenRA.Game/Traits/ActivityUtils.cs

@@ -0,0 +1,59 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2015 The OpenRA Developers (see AUTHORS)
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation. For more information,
+ * see COPYING.
+ */
+#endregion
+
+using System.Diagnostics;
+using System.Linq;
+using OpenRA.Activities;
+using OpenRA.Support;
+
+namespace OpenRA.Traits
+{
+	public static class ActivityUtils
+	{
+		public static Activity RunActivity(Actor self, Activity act)
+		{
+			// PERF: If there are no activities we can bail straight away and save ourselves a call to
+			// Stopwatch.GetTimestamp.
+			if (act == null)
+				return act;
+
+			// PERF: This is a hot path and must run with minimal added overhead.
+			// Calling Stopwatch.GetTimestamp is a bit expensive, so we enumerate manually to allow us to call it only
+			// once per iteration in the normal case.
+			// See also: DoTimed
+			var longTickThresholdInStopwatchTicks = PerfTimer.LongTickThresholdInStopwatchTicks;
+			var start = Stopwatch.GetTimestamp();
+			while (act != null)
+			{
+				var prev = act;
+				act = act.Tick(self);
+				var current = Stopwatch.GetTimestamp();
+				if (current - start > longTickThresholdInStopwatchTicks)
+				{
+					PerfTimer.LogLongTick(start, current, "Activity", prev);
+					start = Stopwatch.GetTimestamp();
+				}
+				else
+					start = current;
+
+				if (prev == act)
+					break;
+			}
+
+			return act;
+		}
+
+		public static Activity SequenceActivities(params Activity[] acts)
+		{
+			return acts.Reverse().Aggregate(
+				(next, a) => { a.Queue(next); return a; });
+		}
+	}
+}