Add Runtime.PyObject_IsIterable and fix PyIter_Check for Python 2

Rickard Holmberg · Rickard Holmberg · commit 6bfef31fc176 · 2017-06-15T09:44:27.000+02:00
diff --git a/src/runtime/pyobject.cs b/src/runtime/pyobject.cs
@@ -802,7 +802,7 @@ public bool IsCallable()
         /// </remarks>
         public bool IsIterable()
         {
-            return Runtime.PyIter_Check(obj);
+            return Runtime.PyObject_IsIterable(obj);
         }
 
 
diff --git a/src/runtime/runtime.cs b/src/runtime/runtime.cs
@@ -1,4 +1,4 @@
-using System;
+﻿using System;
 using System.Runtime.InteropServices;
 using System.Security;
 using System.Text;
@@ -274,19 +274,17 @@ internal static void Initialize()
 
             Error = new IntPtr(-1);
 
-#if PYTHON3
             IntPtr dllLocal = IntPtr.Zero;
             if (PythonDll != "__Internal")
             {
-                NativeMethods.LoadLibrary(PythonDll);
+                dllLocal = NativeMethods.LoadLibrary(PythonDll);
             }
             _PyObject_NextNotImplemented = NativeMethods.GetProcAddress(dllLocal, "_PyObject_NextNotImplemented");
 #if !(MONO_LINUX || MONO_OSX)
             if (dllLocal != IntPtr.Zero)
             {
                 NativeMethods.FreeLibrary(dllLocal);
             }
-#endif
 #endif
 
             // Initialize modules that depend on the runtime class.
@@ -349,8 +347,8 @@ internal static int AtExit()
 
 #if PYTHON3
         internal static IntPtr PyBytesType;
-        internal static IntPtr _PyObject_NextNotImplemented;
 #endif
+        internal static IntPtr _PyObject_NextNotImplemented;
 
         internal static IntPtr PyNotImplemented;
         internal const int Py_LT = 0;
@@ -780,6 +778,22 @@ internal static string PyObject_GetTypeName(IntPtr op)
             return Marshal.PtrToStringAnsi(ppName);
         }
 
+        /// <summary>
+        /// Test whether the Python object is an iterable.
+        /// </summary>
+        internal static bool PyObject_IsIterable(IntPtr pointer)
+        {
+            var ob_type = Marshal.ReadIntPtr(pointer, ObjectOffset.ob_type);
+#if PYTHON2
+            int Py_TPFLAGS_HAVE_ITER = 1 << 7;
+            long tp_flags = Marshal.ReadInt64(ob_type, TypeOffset.tp_flags);
+            if ((tp_flags & Py_TPFLAGS_HAVE_ITER) == 0)
+                return false;
+#endif
+            IntPtr tp_iter = Marshal.ReadIntPtr(ob_type, TypeOffset.tp_iter);
+            return tp_iter != null;
+        }
+
         [DllImport(PythonDll, CallingConvention = CallingConvention.Cdecl)]
         internal static extern int PyObject_HasAttrString(IntPtr pointer, string name);
 
@@ -1425,17 +1439,18 @@ internal static bool PyTuple_Check(IntPtr ob)
         // Python iterator API
         //====================================================================
 
-#if PYTHON2
-        [DllImport(PythonDll, CallingConvention = CallingConvention.Cdecl)]
-        internal static extern bool PyIter_Check(IntPtr pointer);
-#elif PYTHON3
         internal static bool PyIter_Check(IntPtr pointer)
         {
-            var ob_type = (IntPtr)Marshal.PtrToStructure(pointer + ObjectOffset.ob_type, typeof(IntPtr));
-            IntPtr tp_iternext = ob_type + TypeOffset.tp_iternext;
+            var ob_type = Marshal.ReadIntPtr(pointer, ObjectOffset.ob_type);
+#if PYTHON2
+            int Py_TPFLAGS_HAVE_ITER = 1 << 7;
+            long tp_flags = Marshal.ReadInt64(ob_type, TypeOffset.tp_flags);
+            if ((tp_flags & Py_TPFLAGS_HAVE_ITER) == 0)
+                return false;
+#endif
+            IntPtr tp_iternext = Marshal.ReadIntPtr(ob_type, TypeOffset.tp_iternext);
             return tp_iternext != null && tp_iternext != _PyObject_NextNotImplemented;
         }
-#endif
 
         [DllImport(PythonDll, CallingConvention = CallingConvention.Cdecl)]
         internal static extern IntPtr PyIter_Next(IntPtr pointer);

Original file line number	Diff line number	Diff line change
`@@ -802,7 +802,7 @@ public bool IsCallable()`
`802`	`802`	`/// </remarks>`
`803`	`803`	`public bool IsIterable()`
`804`	`804`	`{`
`805`		`- return Runtime.PyIter_Check(obj);`
	`805`	`+ return Runtime.PyObject_IsIterable(obj);`
`806`	`806`	`}`
`807`	`807`
`808`	`808`