Fix use-after-free bugs in components

src/SampSharp.OpenMp.Entities/SAMP/Components/Actor.cs

@@ -8,7 +8,6 @@ namespace SampSharp.Entities.SAMP;
 /// </summary>
 public class Actor : WorldEntity
 {
-    private readonly IActor _actor;
     private readonly IActorsComponent _actors;
 
     /// <summary>
@@ -17,20 +16,24 @@ public class Actor : WorldEntity
     protected Actor(IActorsComponent actors, IActor actor) : base((IEntity)actor)
     {
         _actors = actors;
-        _actor = actor;
+        Resource = actor;
     }
 
-    /// <summary>
-    /// Gets a value indicating whether the open.mp entity counterpart has been destroyed.
-    /// </summary>
-    protected bool IsOmpEntityDestroyed => _actor.TryGetExtension<ComponentExtension>()?.IsOmpEntityDestroyed ?? true;
+    private IActor Resource
+    {
+        get
+        {
+            ObjectDisposedException.ThrowIf(!IsComponentAlive, typeof(Actor));
+            return field;
+        }
+    }
 
     /// <summary>
     /// Gets or sets the facing angle of this actor.
     /// </summary>
     public virtual float Angle
     {
-        get => float.RadiansToDegrees(MathHelper.GetZAngleFromRotationMatrix(Matrix4x4.CreateFromQuaternion(_actor.GetRotation())));
+        get => float.RadiansToDegrees(MathHelper.GetZAngleFromRotationMatrix(Matrix4x4.CreateFromQuaternion(Resource.GetRotation())));
         set => Rotation = Quaternion.CreateFromAxisAngle(GtaVector.Up, float.DegreesToRadians(value));
     }
 
@@ -39,26 +42,26 @@ public virtual float Angle
     /// </summary>
     public virtual int Skin
     {
-        get => _actor.GetSkin();
-        set => _actor.SetSkin(value);
+        get => Resource.GetSkin();
+        set => Resource.SetSkin(value);
     }
 
     /// <summary>
     /// Gets or sets the health of this actor.
     /// </summary>
     public virtual float Health
     {
-        get => _actor.GetHealth();
-        set => _actor.SetHealth(value);
+        get => Resource.GetHealth();
+        set => Resource.SetHealth(value);
     }
 
     /// <summary>
     /// Gets or sets a value indicating whether this actor is invulnerable.
     /// </summary>
     public virtual bool IsInvulnerable
     {
-        get => _actor.IsInvulnerable();
-        set => _actor.SetInvulnerable(value);
+        get => Resource.IsInvulnerable();
+        set => Resource.SetInvulnerable(value);
     }
 
     /// <summary>
@@ -70,7 +73,7 @@ public virtual bool IsStreamedIn(Player player)
     {
         ArgumentNullException.ThrowIfNull(player);
 
-        return _actor.IsStreamedInForPlayer(player);
+        return Resource.IsStreamedInForPlayer(player);
     }
 
     /// <summary>
@@ -89,7 +92,7 @@ public virtual void ApplyAnimation(string library, string name, float fDelta, bo
     {
         ArgumentNullException.ThrowIfNull(library);
         ArgumentNullException.ThrowIfNull(name);
-        _actor.ApplyAnimation(new AnimationData(fDelta, loop, lockX, lockY, freeze, (uint)time.TotalMilliseconds, library, name));
+        Resource.ApplyAnimation(new AnimationData(fDelta, loop, lockX, lockY, freeze, (uint)time.TotalMilliseconds, library, name));
     }
 
     /// <inheritdoc cref="ApplyAnimation(string, string, float, bool, bool, bool, bool, TimeSpan)" />
@@ -102,29 +105,33 @@ public virtual void ApplyAnimation(string library, string name, float fDelta, bo
     /// </summary>
     public virtual void ClearAnimations()
     {
-        _actor.ClearAnimations();
+        Resource.ClearAnimations();
     }
 
     /// <inheritdoc />
     protected override void OnDestroyComponent()
     {
-        if (!IsOmpEntityDestroyed)
+        if (!Resource.GetExtension<ComponentExtension>().IsOmpEntityDestroyed)
         {
-            _actors.AsPool().Release(Id);
+            _actors.AsPool().Release(Resource.GetID());
         }
     }
 
     /// <inheritdoc />
     public override string ToString()
     {
-        return $"(Id: {Id})";
+        if (!IsComponentAlive)
+        {
+            return "(Destroyed)";
+        }
+        return $"(Id: {Id}, Health: {Health}, Position: {Position})";
     }
 
     /// <summary>
     /// Performs an implicit conversion from <see cref="Actor" /> to <see cref="IActor" />.
     /// </summary>
     public static implicit operator IActor(Actor? actor)
     {
-        return actor?._actor ?? default;
+        return actor?.Resource ?? default;
     }
 }

src/SampSharp.OpenMp.Entities/SAMP/Components/BaseGangZone.cs

@@ -10,7 +10,6 @@ namespace SampSharp.Entities.SAMP;
 public abstract class BaseGangZone : IdProvider
 {
     private readonly IOmpEntityProvider _entityProvider;
-    private readonly IGangZone _gangZone;
     private readonly IGangZonesComponent _gangZones;
 
     /// <summary>
@@ -19,24 +18,28 @@ public abstract class BaseGangZone : IdProvider
     protected BaseGangZone(IOmpEntityProvider entityProvider, IGangZonesComponent gangZones, IGangZone gangZone) : base((IIDProvider)gangZone)
     {
         _entityProvider = entityProvider;
-        _gangZone = gangZone;
+        Resource = gangZone;
         _gangZones = gangZones;
     }
 
-    /// <summary>
-    /// Gets a value indicating whether the open.mp entity counterpart has been destroyed.
-    /// </summary>
-    protected bool IsOmpEntityDestroyed => _gangZone.TryGetExtension<ComponentExtension>()?.IsOmpEntityDestroyed ?? true;
+    private IGangZone Resource
+    {
+        get
+        {
+            ObjectDisposedException.ThrowIf(!IsComponentAlive, typeof(BaseGangZone));
+            return field;
+        }
+    }
 
     /// <summary>
     /// Gets the minimum position of this gang zone as a <see cref="Vector2" />.
     /// </summary>
-    public virtual Vector2 Min => _gangZone.GetPosition().Min;
+    public virtual Vector2 Min => Resource.GetPosition().Min;
 
     /// <summary>
     /// Gets the maximum position of this gang zone as a <see cref="Vector2" />.
     /// </summary>
-    public virtual Vector2 Max => _gangZone.GetPosition().Max;
+    public virtual Vector2 Max => Resource.GetPosition().Max;
 
     /// <summary>
     /// Gets the minimum x coordinate of this gang zone.
@@ -69,7 +72,7 @@ protected BaseGangZone(IOmpEntityProvider entityProvider, IGangZonesComponent ga
     /// <returns>A lazy sequence of <see cref="Player" /> components.</returns>
     public virtual IEnumerable<Player> GetShownFor()
     {
-        foreach (var raw in _gangZone.GetShownFor())
+        foreach (var raw in Resource.GetShownFor())
         {
             var component = _entityProvider.GetComponent(raw);
             if (component != null)
@@ -87,13 +90,13 @@ public virtual IEnumerable<Player> GetShownFor()
     public virtual void SetPosition(Vector2 min, Vector2 max)
     {
         var pos = new GangZonePos(min, max);
-        _gangZone.SetPosition(ref pos);
+        Resource.SetPosition(ref pos);
     }
 
     /// <inheritdoc />
     protected override void OnDestroyComponent()
     {
-        if (!IsOmpEntityDestroyed)
+        if (!Resource.GetExtension<ComponentExtension>().IsOmpEntityDestroyed)
         {
             _gangZones.AsPool().Release(Id);
         }
@@ -102,14 +105,18 @@ protected override void OnDestroyComponent()
     /// <inheritdoc />
     public override string ToString()
     {
-        return $"(Id: {Id}, Color: {Color})";
+        if (!IsComponentAlive)
+        {
+            return "(Destroyed)";
+        }
+        return $"(Id: {Id}, Color: {Color}, Min: {Min}, Max: {Max})";
     }
 
     /// <summary>
     /// Performs an implicit conversion from <see cref="BaseGangZone" /> to <see cref="IGangZone" />.
     /// </summary>
     public static implicit operator IGangZone(BaseGangZone? gangZone)
     {
-        return gangZone?._gangZone ?? default;
+        return gangZone?.Resource ?? default;
     }
 }

src/SampSharp.OpenMp.Entities/SAMP/Components/BasePickup.cs

@@ -9,7 +9,6 @@ namespace SampSharp.Entities.SAMP;
 /// </summary>
 public abstract class BasePickup : WorldEntity
 {
-    private readonly IPickup _pickup;
     private readonly IPickupsComponent _pickups;
 
     /// <summary>
@@ -18,51 +17,55 @@ public abstract class BasePickup : WorldEntity
     protected BasePickup(IPickupsComponent pickups, IPickup pickup) : base((IEntity)pickup)
     {
         _pickups = pickups;
-        _pickup = pickup;
+        Resource = pickup;
     }
 
-    /// <summary>
-    /// Gets a value indicating whether the open.mp entity counterpart has been destroyed.
-    /// </summary>
-    protected bool IsOmpEntityDestroyed => _pickup.TryGetExtension<ComponentExtension>()?.IsOmpEntityDestroyed ?? true;
+    private IPickup Resource
+    {
+        get
+        {
+            ObjectDisposedException.ThrowIf(!IsComponentAlive, typeof(BasePickup));
+            return field;
+        }
+    }
 
     /// <summary>
     /// Gets the model of this pickup.
     /// </summary>
-    public virtual int Model => _pickup.GetModel();
+    public virtual int Model => Resource.GetModel();
 
     /// <summary>
     /// Gets the type of this pickup.
     /// </summary>
-    public virtual PickupType SpawnType => (PickupType)_pickup.GetPickupType();
+    public virtual PickupType SpawnType => (PickupType)Resource.GetPickupType();
 
     /// <summary>Changes the type of this pickup.</summary>
     /// <param name="type">The new <see cref="PickupType" />.</param>
     /// <param name="update">Whether to update the pickup visually for streamed-in players.</param>
     public virtual void SetType(PickupType type, bool update = true)
     {
-        _pickup.SetType((byte)type, update);
+        Resource.SetType((byte)type, update);
     }
 
     /// <summary>Changes the model of this pickup.</summary>
     /// <param name="model">The new model ID.</param>
     /// <param name="update">Whether to update the pickup visually for streamed-in players.</param>
     public virtual void SetModel(int model, bool update = true)
     {
-        _pickup.SetModel(model, update);
+        Resource.SetModel(model, update);
     }
 
     /// <summary>Sets the position of this pickup without sending a visual update.</summary>
     /// <param name="position">The new position.</param>
     public virtual void SetPositionNoUpdate(Vector3 position)
     {
-        _pickup.SetPositionNoUpdate(position);
+        Resource.SetPositionNoUpdate(position);
     }
 
     /// <inheritdoc />
     protected override void OnDestroyComponent()
     {
-        if (!IsOmpEntityDestroyed)
+        if (!Resource.GetExtension<ComponentExtension>().IsOmpEntityDestroyed)
         {
             _pickups.AsPool().Release(Id);
         }
@@ -71,6 +74,10 @@ protected override void OnDestroyComponent()
     /// <inheritdoc />
     public override string ToString()
     {
+        if (!IsComponentAlive)
+        {
+            return "(Destroyed)";
+        }
         return $"(Id: {Id}, Model: {Model})";
     }
 
@@ -79,6 +86,6 @@ public override string ToString()
     /// </summary>
     public static implicit operator IPickup(BasePickup? pickup)
     {
-        return pickup?._pickup ?? default;
+        return pickup?.Resource ?? default;
     }
 }

src/SampSharp.OpenMp.Entities/SAMP/Components/Class.cs

@@ -8,7 +8,6 @@ namespace SampSharp.Entities.SAMP;
 /// </summary>
 public class Class : IdProvider
 {
-    private readonly IClass _class;
     private readonly IClassesComponent _classes;
 
     /// <summary>
@@ -17,13 +16,17 @@ public class Class : IdProvider
     protected Class(IClassesComponent classes, IClass playerClass) : base((IIDProvider)playerClass)
     {
         _classes = classes;
-        _class = playerClass;
+        Resource = playerClass;
     }
 
-    /// <summary>
-    /// Gets a value indicating whether the open.mp entity counterpart has been destroyed.
-    /// </summary>
-    protected bool IsOmpEntityDestroyed => _class.TryGetExtension<ComponentExtension>()?.IsOmpEntityDestroyed ?? true;
+    private IClass Resource
+    {
+        get
+        {
+            ObjectDisposedException.ThrowIf(!IsComponentAlive, typeof(Class));
+            return field;
+        }
+    }
 
     /// <summary>
     /// Gets or sets the team ID for this player class.
@@ -59,7 +62,7 @@ public virtual void SetSpawnData(PlayerSpawnData data)
         ArgumentNullException.ThrowIfNull(data);
 
         var omp = data.ToOmpData();
-        _class.SetClass(ref omp);
+        Resource.SetClass(ref omp);
     }
 
     /// <summary>
@@ -68,22 +71,26 @@ public virtual void SetSpawnData(PlayerSpawnData data)
     /// <returns>A <see cref="PlayerSpawnData"/> instance containing the player's spawn information.</returns>
     public virtual PlayerSpawnData GetSpawnData()
     {
-        ref var dat = ref _class.GetClass();
+        ref var dat = ref Resource.GetClass();
         return PlayerSpawnData.FromOmpData(ref dat);
     }
 
     /// <inheritdoc />
     protected override void OnDestroyComponent()
     {
-        if (!IsOmpEntityDestroyed)
+        if (!Resource.GetExtension<ComponentExtension>().IsOmpEntityDestroyed)
         {
-            _classes.AsPool().Release(Id);
+            _classes.AsPool().Release(Resource.GetID());
         }
     }
 
     /// <inheritdoc />
     public override string ToString()
     {
+        if (!IsComponentAlive)
+        {
+            return "(Destroyed)";
+        }
         return $"(Id: {Id})";
     }
 
@@ -92,6 +99,6 @@ public override string ToString()
     /// </summary>
     public static implicit operator IClass(Class? playerClass)
     {
-        return playerClass?._class ?? default;
+        return playerClass?.Resource ?? default;
     }
 }