chore: initialize standalone UPM package

2026-08-26 02:49:58 +08:00
commit 6eebb8e8e4
50 changed files with 3458 additions and 0 deletions
@@ -0,0 +1,61 @@
+#nullable enable
+using System;
+using Cysharp.Threading.Tasks;
+
+namespace ShrinkContext
+{
+    /// <summary>
+    /// 单个可逆效应的句柄（论文算法 1 的 effect 封装）。
+    /// 前向执行时产出逆操作并累积在句柄内部；DisposeAsync 至多执行一次（armed 语义），
+    /// 若前向仍在进行中则先等待其完成再运行累积的逆操作（dispose = await task; recover()）。
+    /// </summary>
+    public sealed class ShrinkEffectHandle
+    {
+        private static readonly Func<UniTask> Nop = static () => UniTask.CompletedTask;
+
+        private bool _armed = true;
+        private UniTask _forwardTask;
+        private bool _hasForwardTask;
+        private Func<UniTask> _inverseChain = Nop;
+
+        public bool IsArmed => _armed;
+
+        /// <summary>登记一个进行中的异步前向；DisposeAsync 会先等待它完成。</summary>
+        internal void BeginForward(UniTask forwardTask)
+        {
+            _forwardTask = forwardTask;
+            _hasForwardTask = true;
+        }
+
+        /// <summary>前向完成后登记其逆操作；新逆操作在链首执行（LIFO）。</summary>
+        internal void CompleteForward(Func<UniTask> inverse)
+        {
+            if (inverse == null)
+                return;
+
+            var previous = _inverseChain;
+            _inverseChain = async () =>
+            {
+                await inverse();
+                await previous();
+            };
+        }
+
+        /// <summary>直接附加逆操作（等效于前向已同步完成）。</summary>
+        internal void AttachInverse(Func<UniTask> inverse) => CompleteForward(inverse);
+
+        public async UniTask DisposeAsync()
+        {
+            if (!_armed)
+                return;
+
+            _armed = false;
+            if (_hasForwardTask && _forwardTask.Status == UniTaskStatus.Pending)
+                await _forwardTask;
+
+            var chain = _inverseChain;
+            _inverseChain = Nop;
+            await chain();
+        }
+    }
+}