Added GrantConditionOnMinelaying trait

Uses INotifyMineLaying callbacks

OpenRA.Mods.Common/Traits/Conditions/GrantConditionOnMinelaying.cs

@@ -0,0 +1,44 @@
+using OpenRA.Traits;
+
+namespace OpenRA.Mods.Common.Traits
+{
+	public class GrantConditionOnMinelayingInfo : ConditionalTraitInfo, Requires<MinelayerInfo>
+	{
+		[FieldLoader.Require]
+		[GrantedConditionReference]
+		[Desc("Condition to grant.")]
+		public readonly string Condition = null;
+
+		public override object Create(ActorInitializer init)
+		{
+			return new GrantConditionOnMinelaying(this);
+		}
+	}
+
+	public class GrantConditionOnMinelaying : ConditionalTrait<GrantConditionOnMinelayingInfo>, INotifyMineLaying
+	{
+		int conditionToken = Actor.InvalidConditionToken;
+
+		public GrantConditionOnMinelaying(GrantConditionOnMinelayingInfo info)
+			: base(info)
+		{
+		}
+
+		void INotifyMineLaying.MineLaid(Actor self, Actor mine)
+		{
+			if (conditionToken != Actor.InvalidConditionToken)
+				conditionToken = self.RevokeCondition(conditionToken);
+		}
+
+		void INotifyMineLaying.MineLaying(Actor self, CPos location)
+		{
+			conditionToken = self.GrantCondition(Info.Condition);
+		}
+
+		void INotifyMineLaying.MineLayingCanceled(Actor self, CPos location)
+		{
+			if (conditionToken != Actor.InvalidConditionToken)
+				conditionToken = self.RevokeCondition(conditionToken);
+		}
+	}
+}