abandon rank and use three codecs

pythonnet · lostmsu · Feb 18, 2021 · Mar 10, 2020 · Mar 10, 2020 · Mar 11, 2020
commit 224df0ea94e8c081052159106051797e487bef32
diff --git a/src/embed_tests/Codecs.cs b/src/embed_tests/Codecs.cs
diff --git a/src/runtime/Codecs/IterableDecoder.cs b/src/runtime/Codecs/IterableDecoder.cs
@@ -0,0 +1,57 @@
+using System;
+using System.Collections.Generic;
+
+namespace Python.Runtime.Codecs
+{
+    class IterableDecoder : IPyObjectDecoder
+    {
+        internal static bool IsIterable(Type targetType)
+        {
+            //if it is a plain IEnumerable, we can decode it using sequence protocol.
+            if (targetType == typeof(System.Collections.IEnumerable))
+                return true;
+
+            if (!targetType.IsGenericType)
+                return false;
+
+            return targetType.GetGenericTypeDefinition() == typeof(IEnumerable<>);
+        }
+
+        internal static bool IsIterable(PyObject objectType)
+        {
+            //TODO - do I need to decref iterObject?
+            IntPtr iterObject = Runtime.PyObject_GetIter(objectType.Handle);
+            return iterObject != IntPtr.Zero;
+        }
+
+        public bool CanDecode(PyObject objectType, Type targetType)
+        {
+            return IsIterable(objectType) && IsIterable(targetType);
+        }
+
+        public bool TryDecode<T>(PyObject pyObj, out T value)
+        {
+            //first see if T is a plan IEnumerable
+            if (typeof(T) == typeof(System.Collections.IEnumerable))
+            {
+                object enumerable = new CollectionWrappers.IterableWrapper<object>(pyObj);
+                value = (T)enumerable;
+                return true;
+            }
+
+            var elementType = typeof(T).GetGenericArguments()[0];
+            var collectionType = typeof(CollectionWrappers.IterableWrapper<>).MakeGenericType(elementType);
+
+            var instance = Activator.CreateInstance(collectionType, new[] { pyObj });
+            value = (T)instance;
+            return true;
+        }
+
+        public static IterableDecoder Instance { get; } = new IterableDecoder();
+
+        public static void Register()
+        {
+            PyObjectConversions.RegisterDecoder(Instance);
+        }
+    }
+}