refactor(app): compose live presentation startup

src/AcDream.App/World/DeferredLiveEntityLandblockLoadedSink.cs

@@ -0,0 +1,66 @@
+namespace AcDream.App.World;
+
+internal interface ILiveEntityLandblockLoadedSink
+{
+    void OnLandblockLoaded(uint landblockId);
+}
+
+/// <summary>
+/// Phase-6 bridge for the Phase-7 hydration owner. The presentation pipeline
+/// can publish a loaded landblock without capturing a future nullable owner.
+/// </summary>
+internal sealed class DeferredLiveEntityLandblockLoadedSink
+    : ILiveEntityLandblockLoadedSink
+{
+    private ILiveEntityLandblockLoadedSink? _target;
+    private bool _deactivated;
+
+    public void OnLandblockLoaded(uint landblockId)
+    {
+        if (!_deactivated)
+            _target?.OnLandblockLoaded(landblockId);
+    }
+
+    public IDisposable Bind(ILiveEntityLandblockLoadedSink target)
+    {
+        ArgumentNullException.ThrowIfNull(target);
+        ObjectDisposedException.ThrowIf(_deactivated, this);
+        if (_target is not null)
+        {
+            throw new InvalidOperationException(
+                "Live-entity landblock hydration is already bound.");
+        }
+
+        _target = target;
+        return new Binding(this, target);
+    }
+
+    public void Deactivate()
+    {
+        _deactivated = true;
+        _target = null;
+    }
+
+    private void Unbind(ILiveEntityLandblockLoadedSink expected)
+    {
+        if (ReferenceEquals(_target, expected))
+            _target = null;
+    }
+
+    private sealed class Binding : IDisposable
+    {
+        private DeferredLiveEntityLandblockLoadedSink? _owner;
+        private readonly ILiveEntityLandblockLoadedSink _expected;
+
+        public Binding(
+            DeferredLiveEntityLandblockLoadedSink owner,
+            ILiveEntityLandblockLoadedSink expected)
+        {
+            _owner = owner;
+            _expected = expected;
+        }
+
+        public void Dispose() =>
+            Interlocked.Exchange(ref _owner, null)?.Unbind(_expected);
+    }
+}

src/AcDream.App/World/LiveEntityHydrationController.cs

@@ -137,7 +137,7 @@ internal interface ILiveEntityWorldOriginCoordinator
 /// Retail anchors: <c>SmartBox::HandleCreateObject @ 0x00454C80</c> and
 /// <c>ACCObjectMaint::CreateObject @ 0x00558870</c>.
 /// </summary>
-internal sealed class LiveEntityHydrationController
+internal sealed class LiveEntityHydrationController : ILiveEntityLandblockLoadedSink
 {
     private readonly LiveEntityRuntime _runtime;
     private readonly ClientObjectTable _objects;

src/AcDream.App/World/LiveEntityRuntimeSlot.cs

@@ -21,4 +21,31 @@ internal sealed class LiveEntityRuntimeSlot : ILiveEntityRuntimeSource
             throw new InvalidOperationException("The live entity runtime is already bound.");
         Current = runtime;
     }
+
+    public IDisposable BindOwned(LiveEntityRuntime runtime)
+    {
+        Bind(runtime);
+        return new Binding(this, runtime);
+    }
+
+    private void Unbind(LiveEntityRuntime expected)
+    {
+        if (ReferenceEquals(Current, expected))
+            Current = null;
+    }
+
+    private sealed class Binding : IDisposable
+    {
+        private LiveEntityRuntimeSlot? _owner;
+        private readonly LiveEntityRuntime _expected;
+
+        public Binding(LiveEntityRuntimeSlot owner, LiveEntityRuntime expected)
+        {
+            _owner = owner;
+            _expected = expected;
+        }
+
+        public void Dispose() =>
+            Interlocked.Exchange(ref _owner, null)?.Unbind(_expected);
+    }
 }