Compute interface implementation attributes on demand

danabr · danabr · commit 33ed60fa3428 · 2020-10-01T21:25:37.000+02:00
diff --git a/src/runtime/interfaceobject.cs b/src/runtime/interfaceobject.cs
@@ -76,16 +76,38 @@ public static IntPtr tp_new(IntPtr tp, IntPtr args, IntPtr kw)
 
         /// <summary>
         /// Wrap the given object in an interface object, so that only methods
-        /// of the interface are available. The wrapped object is available
-        /// through properties in both converted/encoded (__implementation__)
-        /// and raw form (__raw_implementation__).
+        /// of the interface are available.
         /// </summary>
         public IntPtr WrapObject(object impl)
         {
             var objPtr = CLRObject.GetInstHandle(impl, pyHandle);
-            Runtime.PyObject_SetAttrString(objPtr, "__implementation__", Converter.ToPython(impl));
-            Runtime.PyObject_SetAttrString(objPtr, "__raw_implementation__", CLRObject.GetInstHandle(impl));
             return objPtr;
         }
+
+        /// <summary>
+        /// Expose the wrapped implementation through attributes in both
+        /// converted/encoded (__implementation__) and raw (__raw_implementation__) form.
+        /// </summary>
+        public static IntPtr tp_getattro(IntPtr ob, IntPtr key)
+        {
+            var clrObj = (CLRObject)GetManagedObject(ob);
+
+            if (!Runtime.PyString_Check(key))
+            {
+                return Exceptions.RaiseTypeError("string expected");
+            }
+
+            string name = Runtime.GetManagedString(key);
+            if (name == "__implementation__")
+            {
+                return Converter.ToPython(clrObj.inst);
+            }
+            else if (name == "__raw_implementation__")
+            {
+                return CLRObject.GetInstHandle(clrObj.inst);
+            }
+
+            return Runtime.PyObject_GenericGetAttr(ob, key);
+        }
     }
 }
