Merge ConditionManager trait directly into Actor

OpenRA.Game/Actor.cs

@@ -74,6 +74,31 @@ namespace OpenRA
 			}
 		}
 
+		/// <summary>Value used to represent an invalid token.</summary>
+		public static readonly int InvalidConditionToken = -1;
+
+		class ConditionState
+		{
+			/// <summary>Delegates that have registered to be notified when this condition changes.</summary>
+			public readonly List<VariableObserverNotifier> Notifiers = new List<VariableObserverNotifier>();
+
+			/// <summary>Unique integers identifying granted instances of the condition.</summary>
+			public readonly HashSet<int> Tokens = new HashSet<int>();
+		}
+
+		readonly Dictionary<string, ConditionState> conditionStates = new Dictionary<string, ConditionState>();
+
+		/// <summary>Each granted condition receives a unique token that is used when revoking.</summary>
+		readonly Dictionary<int, string> conditionTokens = new Dictionary<int, string>();
+
+		int nextConditionToken = 1;
+
+		/// <summary>Cache of condition -> enabled state for quick evaluation of token counter conditions.</summary>
+		readonly Dictionary<string, int> conditionCache = new Dictionary<string, int>();
+
+		/// <summary>Read-only version of conditionCache that is passed to IConditionConsumers.</summary>
+		readonly IReadOnlyDictionary<string, int> readOnlyConditionCache;
+
 		internal SyncHash[] SyncHashes { get; private set; }
 
 		readonly IFacing facing;
@@ -93,6 +118,8 @@ namespace OpenRA
 		{
 			var init = new ActorInitializer(this, initDict);
 
+			readOnlyConditionCache = new ReadOnlyDictionary<string, int>(conditionCache);
+
 			World = world;
 			ActorID = world.NextAID();
 			if (initDict.Contains<OwnerInit>())
@@ -148,9 +175,36 @@ namespace OpenRA
 		{
 			created = true;
 
+			// Make sure traits are usable for condition notifiers
 			foreach (var t in TraitsImplementing<INotifyCreated>())
 				t.Created(this);
 
+			var allObserverNotifiers = new HashSet<VariableObserverNotifier>();
+			foreach (var provider in TraitsImplementing<IObservesVariables>())
+			{
+				foreach (var variableUser in provider.GetVariableObservers())
+				{
+					allObserverNotifiers.Add(variableUser.Notifier);
+					foreach (var variable in variableUser.Variables)
+					{
+						var cs = conditionStates.GetOrAdd(variable);
+						cs.Notifiers.Add(variableUser.Notifier);
+
+						// Initialize conditions that have not yet been granted to 0
+						// NOTE: Some conditions may have already been granted by INotifyCreated calling GrantCondition,
+						// and we choose to assign the token count to safely cover both cases instead of adding an if branch.
+						conditionCache[variable] = cs.Tokens.Count;
+					}
+				}
+			}
+
+			// Update all traits with their initial condition state
+			foreach (var notify in allObserverNotifiers)
+				notify(this, readOnlyConditionCache);
+
+			// TODO: Some traits may need initialization after being notified of initial condition state.
+
+			// TODO: A post condition initialization notification phase may allow queueing activities instead.
 			// The initial activity should run before any activities queued by INotifyCreated.Created
 			// However, we need to know which traits are enabled (via conditions), so wait for after the calls and insert the activity as the first
 			ICreationActivity creationActivity = null;
@@ -454,6 +508,60 @@ namespace OpenRA
 			return new[] { CenterPosition };
 		}
 
+		#region Conditions
+
+		void UpdateConditionState(string condition, int token, bool isRevoke)
+		{
+			ConditionState conditionState = conditionStates.GetOrAdd(condition);
+
+			if (isRevoke)
+				conditionState.Tokens.Remove(token);
+			else
+				conditionState.Tokens.Add(token);
+
+			conditionCache[condition] = conditionState.Tokens.Count;
+
+			// Conditions may be granted or revoked before the state is initialized.
+			// These notifications will be processed after INotifyCreated.Created.
+			if (created)
+				foreach (var notify in conditionState.Notifiers)
+					notify(this, readOnlyConditionCache);
+		}
+
+		/// <summary>Grants a specified condition.</summary>
+		/// <returns>The token that is used to revoke this condition.</returns>
+		public int GrantCondition(string condition)
+		{
+			var token = nextConditionToken++;
+			conditionTokens.Add(token, condition);
+			UpdateConditionState(condition, token, false);
+			return token;
+		}
+
+		/// <summary>
+		/// Revokes a previously granted condition.
+		/// </summary>
+		/// <param name="token">The token ID returned by GrantCondition.</param>
+		/// <returns>The invalid token ID.</returns>
+		public int RevokeCondition(int token)
+		{
+			string condition;
+			if (!conditionTokens.TryGetValue(token, out condition))
+				throw new InvalidOperationException("Attempting to revoke condition with invalid token {0} for {1}.".F(token, this));
+
+			conditionTokens.Remove(token);
+			UpdateConditionState(condition, token, true);
+			return InvalidConditionToken;
+		}
+
+		/// <summary>Returns whether the specified token is valid for RevokeCondition</summary>
+		public bool TokenValid(int token)
+		{
+			return conditionTokens.ContainsKey(token);
+		}
+
+		#endregion
+
 		#region Scripting interface
 
 		Lazy<ScriptActorInterface> luaInterface;

OpenRA.Game/Traits/TraitsInterfaces.cs

@@ -539,4 +539,24 @@ namespace OpenRA.Traits
 
 	[RequireExplicitImplementation]
 	public interface ICreationActivity { Activity GetCreationActivity(); }
+
+	[RequireExplicitImplementation]
+	public interface IObservesVariablesInfo : ITraitInfo { }
+
+	public delegate void VariableObserverNotifier(Actor self, IReadOnlyDictionary<string, int> variables);
+	public struct VariableObserver
+	{
+		public VariableObserverNotifier Notifier;
+		public IEnumerable<string> Variables;
+		public VariableObserver(VariableObserverNotifier notifier, IEnumerable<string> variables)
+		{
+			Notifier = notifier;
+			Variables = variables;
+		}
+	}
+
+	public interface IObservesVariables
+	{
+		IEnumerable<VariableObserver> GetVariableObservers();
+	}
 }