新增 FlowScope Git 包雏形

Packages/com.flowscope.gamecore/Runtime/Save/SaveMigrationRegistry.cs

@@ -0,0 +1,74 @@
+using System;
+using System.Collections.Generic;
+
+namespace FlowScope.Save
+{
+    public sealed class SaveMigrationRegistry
+    {
+        private readonly Dictionary<MigrationKey, ISaveMigration> _migrations = new();
+
+        public void Register(ISaveMigration migration)
+        {
+            if (migration == null)
+            {
+                throw new ArgumentNullException(nameof(migration));
+            }
+
+            _migrations[new MigrationKey(migration.Key, migration.FromVersion)] = migration;
+        }
+
+        public string Migrate(
+            string key,
+            int fromVersion,
+            int currentVersion,
+            string json)
+        {
+            var current = fromVersion;
+            var payload = json;
+            while (current < currentVersion)
+            {
+                if (!_migrations.TryGetValue(new MigrationKey(key, current), out var migration) ||
+                    migration.ToVersion != current + 1)
+                {
+                    throw new InvalidOperationException(
+                        $"Missing save migration for key '{key}' from version {current}.");
+                }
+
+                payload = migration.Migrate(payload);
+                current = migration.ToVersion;
+            }
+
+            return payload;
+        }
+
+        private readonly struct MigrationKey : IEquatable<MigrationKey>
+        {
+            private readonly string _key;
+            private readonly int _fromVersion;
+
+            public MigrationKey(string key, int fromVersion)
+            {
+                _key = key ?? string.Empty;
+                _fromVersion = fromVersion;
+            }
+
+            public bool Equals(MigrationKey other)
+            {
+                return _key == other._key && _fromVersion == other._fromVersion;
+            }
+
+            public override bool Equals(object obj)
+            {
+                return obj is MigrationKey other && Equals(other);
+            }
+
+            public override int GetHashCode()
+            {
+                unchecked
+                {
+                    return ((_key != null ? _key.GetHashCode() : 0) * 397) ^ _fromVersion;
+                }
+            }
+        }
+    }
+}