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| 1 | +using System; |
| 2 | +using System.Collections.Generic; |
| 3 | + |
| 4 | +namespace Python.Runtime.Codecs |
| 5 | +{ |
| 6 | + class IterableDecoder : IPyObjectDecoder |
| 7 | + { |
| 8 | + internal static bool IsIterable(Type targetType) |
| 9 | + { |
| 10 | + //if it is a plain IEnumerable, we can decode it using sequence protocol. |
| 11 | + if (targetType == typeof(System.Collections.IEnumerable)) |
| 12 | + return true; |
| 13 | + |
| 14 | + if (!targetType.IsGenericType) |
| 15 | + return false; |
| 16 | + |
| 17 | + return targetType.GetGenericTypeDefinition() == typeof(IEnumerable<>); |
| 18 | + } |
| 19 | + |
| 20 | + internal static bool IsIterable(PyObject objectType) |
| 21 | + { |
| 22 | + //TODO - do I need to decref iterObject? |
| 23 | + IntPtr iterObject = Runtime.PyObject_GetIter(objectType.Handle); |
| 24 | + return iterObject != IntPtr.Zero; |
| 25 | + } |
| 26 | + |
| 27 | + public bool CanDecode(PyObject objectType, Type targetType) |
| 28 | + { |
| 29 | + return IsIterable(objectType) && IsIterable(targetType); |
| 30 | + } |
| 31 | + |
| 32 | + public bool TryDecode<T>(PyObject pyObj, out T value) |
| 33 | + { |
| 34 | + //first see if T is a plan IEnumerable |
| 35 | + if (typeof(T) == typeof(System.Collections.IEnumerable)) |
| 36 | + { |
| 37 | + object enumerable = new CollectionWrappers.IterableWrapper<object>(pyObj); |
| 38 | + value = (T)enumerable; |
| 39 | + return true; |
| 40 | + } |
| 41 | + |
| 42 | + var elementType = typeof(T).GetGenericArguments()[0]; |
| 43 | + var collectionType = typeof(CollectionWrappers.IterableWrapper<>).MakeGenericType(elementType); |
| 44 | + |
| 45 | + var instance = Activator.CreateInstance(collectionType, new[] { pyObj }); |
| 46 | + value = (T)instance; |
| 47 | + return true; |
| 48 | + } |
| 49 | + |
| 50 | + public static IterableDecoder Instance { get; } = new IterableDecoder(); |
| 51 | + |
| 52 | + public static void Register() |
| 53 | + { |
| 54 | + PyObjectConversions.RegisterDecoder(Instance); |
| 55 | + } |
| 56 | + } |
| 57 | +} |
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