Added PausableConditionalTrait abstract trait

OpenRA.Mods.Common/OpenRA.Mods.Common.csproj

@@ -495,6 +495,7 @@
     <Compile Include="Traits\Conditions\GrantConditionOnDeploy.cs" />
     <Compile Include="Traits\Conditions\DisableOnCondition.cs" />
     <Compile Include="Traits\Conditions\ConditionalTrait.cs" />
+    <Compile Include="Traits\Conditions\PausableConditionalTrait.cs" />
     <Compile Include="Traits\Conditions\ProximityExternalCondition.cs" />
     <Compile Include="Traits\Conditions\GrantConditionOnDamageState.cs" />
     <Compile Include="Traits\Conditions\GrantConditionOnTerrain.cs" />

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

@@ -15,10 +15,10 @@ using OpenRA.Traits;
 
 namespace OpenRA.Mods.Common.Traits
 {
-	/// <summary>Use as base class for *Info to subclass of UpgradableTrait. (See UpgradableTrait.)</summary>
+	/// <summary>Use as base class for *Info to subclass of ConditionalTrait. (See ConditionalTrait.)</summary>
 	public abstract class ConditionalTraitInfo : IObservesVariablesInfo, IRulesetLoaded
 	{
-		static readonly IReadOnlyDictionary<string, int> NoConditions = new ReadOnlyDictionary<string, int>(new Dictionary<string, int>());
+		protected static readonly IReadOnlyDictionary<string, int> NoConditions = new ReadOnlyDictionary<string, int>(new Dictionary<string, int>());
 
 		[ConsumedConditionReference]
 		[Desc("Boolean expression defining the condition to enable this trait.")]
@@ -39,7 +39,7 @@ namespace OpenRA.Mods.Common.Traits
 
 	/// <summary>
 	/// Abstract base for enabling and disabling trait using conditions.
-	/// Requires basing *Info on UpgradableTraitInfo and using base(info) constructor.
+	/// Requires basing *Info on ConditionalTraitInfo and using base(info) constructor.
 	/// TraitEnabled will be called at creation if the trait starts enabled or does not use conditions.
 	/// </summary>
 	public abstract class ConditionalTrait<InfoType> : IObservesVariables, IDisabledTrait, INotifyCreated, ISync where InfoType : ConditionalTraitInfo

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

@@ -0,0 +1,81 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2017 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, either version 3 of
+ * the License, or (at your option) any later version. For more
+ * information, see COPYING.
+ */
+#endregion
+
+using System.Collections.Generic;
+using OpenRA.Primitives;
+using OpenRA.Support;
+using OpenRA.Traits;
+
+namespace OpenRA.Mods.Common.Traits
+{
+	/// <summary>Use as base class for *Info to subclass of PausableConditionalTrait. (See PausableConditionalTrait.)</summary>
+	public abstract class PausableConditionalTraitInfo : ConditionalTraitInfo
+	{
+		[ConsumedConditionReference]
+		[Desc("Boolean expression defining the condition to pause this trait.")]
+		public readonly BooleanExpression PauseOnCondition = null;
+
+		public bool PausedByDefault { get; private set; }
+
+		public override void RulesetLoaded(Ruleset rules, ActorInfo ai)
+		{
+			base.RulesetLoaded(rules, ai);
+			PausedByDefault = PauseOnCondition != null && PauseOnCondition.Evaluate(NoConditions);
+		}
+	}
+
+	/// <summary>
+	/// Abstract base for enabling and disabling trait using conditions.
+	/// Requires basing *Info on PausableConditionalTraitInfo and using base(info) constructor.
+	/// TraitResumed will be called at creation if the trait starts not paused or does not have a pause condition.
+	/// </summary>
+	public abstract class PausableConditionalTrait<InfoType> : ConditionalTrait<InfoType> where InfoType : PausableConditionalTraitInfo
+	{
+		[Sync] public bool IsTraitPaused { get; private set; }
+
+		protected PausableConditionalTrait(InfoType info) : base(info) { IsTraitPaused = info.PausedByDefault; }
+
+		protected override void Created(Actor self)
+		{
+			base.Created(self);
+			if (Info.PauseOnCondition == null)
+				TraitResumed(self);
+		}
+
+		// Overrides must call `base.GetVariableObservers()` to avoid breaking RequiresCondition or PauseOnCondition.
+		public override IEnumerable<VariableObserver> GetVariableObservers()
+		{
+			foreach (var observer in base.GetVariableObservers())
+				yield return observer;
+
+			if (Info.PauseOnCondition != null)
+				yield return new VariableObserver(PauseConditionsChanged, Info.PauseOnCondition.Variables);
+		}
+
+		void PauseConditionsChanged(Actor self, IReadOnlyDictionary<string, int> conditions)
+		{
+			var wasPaused = IsTraitPaused;
+			IsTraitPaused = Info.PauseOnCondition.Evaluate(conditions);
+
+			if (IsTraitPaused != wasPaused)
+			{
+				if (wasPaused)
+					TraitResumed(self);
+				else
+					TraitPaused(self);
+			}
+		}
+
+		// Subclasses can add pause support by querying IsTraitPaused and/or overriding these methods.
+		protected virtual void TraitResumed(Actor self) { }
+		protected virtual void TraitPaused(Actor self) { }
+	}
+}