checkpoint

Alpm/EnumerableWrapper`3.cs

@@ -0,0 +1,44 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+namespace Foodsoft.Alpm
+{
+    internal struct EnumerableWrapper<TImpl, TElement, THandle> : IEnumerable<TElement> where TImpl : struct,
+        IItemsReader<TElement, THandle>
+        where THandle : SafeHandle
+    {
+        private TImpl _impl;
+
+        public EnumerableWrapper(TImpl impl)
+        {
+            _impl = impl;
+        }
+
+        public IEnumerator<TElement> GetEnumerator()
+        {
+            var handle = _impl.Handle;
+            var release = false;
+
+            RuntimeHelpers.PrepareConstrainedRegions();
+            try
+            {
+                handle.DangerousAddRef(ref release);
+                if (!release) throw new ObjectDisposedException(_impl.GetType().FullName);
+                for (var list = _impl.GetItems(); list != IntPtr.Zero; list = Wrapper.ListNext(list))
+                {
+                    yield return _impl.PtrToItem(Wrapper.ListData(list));
+                }
+            }
+            finally
+            {
+                if (release)
+                    handle.DangerousRelease();
+            }
+        }
+
+        IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
+    }
+}