sketch of reservation support

OpenRa.DataStructures/DisposableAction.cs

@@ -0,0 +1,28 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace OpenRa
+{
+	public class DisposableAction : IDisposable
+	{
+		public DisposableAction(Action a) { this.a = a; }
+
+		Action a;
+		bool disposed;
+
+		public void Dispose()
+		{
+			if (disposed) return;
+			disposed = true;
+			a();
+			GC.SuppressFinalize(this);
+		}
+
+		~DisposableAction()
+		{
+			Dispose();
+		}
+	}
+}

OpenRa.DataStructures/OpenRa.DataStructures.csproj

@@ -43,6 +43,7 @@
   </ItemGroup>
   <ItemGroup>
     <Compile Include="AssetInfo.cs" />
+    <Compile Include="DisposableAction.cs" />
     <Compile Include="float2.cs" />
     <Compile Include="int2.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />

OpenRa.Game/OpenRa.Game.csproj

@@ -196,6 +196,7 @@
     <Compile Include="Traits\MineImmune.cs" />
     <Compile Include="Traits\Minelayer.cs" />
     <Compile Include="Traits\LimitedAmmo.cs" />
+    <Compile Include="Traits\Reservable.cs" />
     <Compile Include="Traits\SquishByTank.cs" />
     <Compile Include="Traits\Plane.cs" />
     <Compile Include="Traits\ProductionQueue.cs" />

OpenRa.Game/Traits/Activities/ReturnToBase.cs

@@ -16,13 +16,18 @@ namespace OpenRa.Game.Traits.Activities
 		float2 w1, w2, w3;	/* tangent points to turn circles */
 		float2 landPoint;
 
+		static bool IsReserved(Actor a)
+		{
+			var res = a.traits.GetOrDefault<Reservable>();
+			return res != null && res.IsReserved;
+		}
+
 		Actor ChooseAirfield(Actor self)
 		{
-			// todo: handle reservations
-
 			var airfield = Game.world.Actors
 				.Where(a => a.Info == Rules.UnitInfo["AFLD"]
-					&& a.Owner == self.Owner)
+					&& a.Owner == self.Owner
+					&& !IsReserved(a))
 				.FirstOrDefault();
 
 			if (airfield == null)
@@ -34,6 +39,9 @@ namespace OpenRa.Game.Traits.Activities
 		void Calculate(Actor self)
 		{
 			if (dest == null) dest = ChooseAirfield(self);
+			var res = dest.traits.GetOrDefault<Reservable>();
+			if (res != null)
+				self.traits.Get<Plane>().reservation = res.Reserve(self);
 
 			var landPos = dest.CenterLocation;
 			var unit = self.traits.Get<Unit>();

OpenRa.Game/Traits/Plane.cs

@@ -8,6 +8,8 @@ namespace OpenRa.Game.Traits
 {
 	class Plane : IOrder, IMovement
 	{
+		public IDisposable reservation;
+
 		public Plane(Actor self) {}
 
 		public Order IssueOrder(Actor self, int2 xy, MouseInput mi, Actor underCursor)
@@ -18,13 +20,25 @@ namespace OpenRa.Game.Traits
 
 			if (underCursor.Info == Rules.UnitInfo["AFLD"]
 				&& underCursor.Owner == self.Owner)
+			{
+				var res = underCursor.traits.GetOrDefault<Reservable>();
+				if (res != null && res.IsReserved)
+					return null;
+
 				return new Order("Enter", self, underCursor, int2.Zero, null);
+			}
 
 			return null;
 		}
 
 		public void ResolveOrder(Actor self, Order order)
 		{
+			if (reservation != null)
+			{
+				reservation.Dispose();
+				reservation = null;
+			}
+
 			if (order.OrderString == "Move")
 			{
 				self.CancelActivity();
@@ -34,6 +48,13 @@ namespace OpenRa.Game.Traits
 
 			if (order.OrderString == "Enter")
 			{
+				var res = order.TargetActor.traits.GetOrDefault<Reservable>();
+				if (res != null)
+				{
+					if (res.IsReserved) return;
+					reservation = res.Reserve(self);
+				}
+
 				self.CancelActivity();
 				self.QueueActivity(new ReturnToBase(self, order.TargetActor));
 			}

OpenRa.Game/Traits/Reservable.cs

@@ -0,0 +1,26 @@
+using System;
+
+namespace OpenRa.Game.Traits
+{
+	class Reservable : ITick
+	{
+		public Reservable(Actor self) { }
+		Actor reservedFor;
+
+		public bool IsReserved { get { return reservedFor != null; } }
+
+		public void Tick(Actor self)
+		{
+			if (reservedFor == null) 
+				return;		/* nothing to do */
+
+			if (reservedFor.IsDead) reservedFor = null;		/* not likely to arrive now. */
+		}
+
+		public IDisposable Reserve(Actor forActor)
+		{
+			reservedFor = forActor;
+			return new DisposableAction(() => reservedFor = null);
+		}
+	}
+}

units.ini

@@ -394,7 +394,7 @@ LongDesc=Stores excess harvested Ore
 
 [HPAD]
 Description=Helipad
-Traits=Building, RenderBuilding, Production, BelowUnits
+Traits=Building, RenderBuilding, Production, BelowUnits, Reservable
 Dimensions=2,2
 Footprint=xx xx
 Produces=Plane
@@ -410,7 +410,7 @@ SelectionPriority=3
 LongDesc=Provides an overview of the battlefield.\n  Requires power to operate.
 [AFLD]
 Description=Airstrip
-Traits=Building, RenderBuilding, Production, BelowUnits
+Traits=Building, RenderBuilding, Production, BelowUnits, Reservable
 Dimensions=3,2
 Footprint=xxx xxx
 Produces=Plane
@@ -465,7 +465,7 @@ SelectionPriority=3
 LongDesc=Produces attack dogs
 [FIX]
 Description=Service Depot
-Traits=Building, RenderBuilding, BelowUnits
+Traits=Building, RenderBuilding, BelowUnits, Reservable
 Dimensions=3,3
 Footprint=_x_ xxx _x_
 SelectionPriority=3