[pypy-commit] pypy default: A ll2ctypes bug that depends on the order of the fields in the structure.

[amauryfa]

Author: Amaury Forgeot d'Arc <amauryfa at gmail.com>
Branch: 
Changeset: r47177:d5b0b000a97e
Date: 2011-09-09 01:11 +0200
http://bitbucket.org/pypy/pypy/changeset/d5b0b000a97e/

Log:	A ll2ctypes bug that depends on the order of the fields in the
	structure. Found while trying to implement PyHeapTypeObject in
	cpyext, the equivalent of CPython:: PyHeapTypeObject *type =
	malloc(); type->ht_type.tp_as_number = &type->as_number;

diff --git a/pypy/rpython/lltypesystem/test/test_ll2ctypes.py b/pypy/rpython/lltypesystem/test/test_ll2ctypes.py
--- a/pypy/rpython/lltypesystem/test/test_ll2ctypes.py
+++ b/pypy/rpython/lltypesystem/test/test_ll2ctypes.py
@@ -81,6 +81,26 @@
         lltype.free(s, flavor='raw')
         assert not ALLOCATED     # detects memory leaks in the test
 
+    def test_get_pointer(self):
+        py.test.skip("FIXME")
+        # Equivalent of the C code::
+        #     struct S1 { struct S2 *ptr; struct S2 buf; };
+        #     struct S1 s1;
+        #     s1.ptr = & s1.buf;
+        S2 = lltype.Struct('S2', ('y', lltype.Signed))
+        S1 = lltype.Struct('S',
+                           ('sub', lltype.Struct('SUB', 
+                                                 ('ptr', lltype.Ptr(S2)))),
+                           ('ptr', lltype.Ptr(S2)),
+                           ('buf', S2), # Works when this field is first!
+                           )
+        s1 = lltype.malloc(S1, flavor='raw')
+        s1.ptr = s1.buf
+        s1.sub.ptr = s1.buf
+
+        x = rffi.cast(rffi.CCHARP, s1)
+        lltype.free(s1, flavor='raw')
+
     def test_struct_ptrs(self):
         S2 = lltype.Struct('S2', ('y', lltype.Signed))
         S1 = lltype.Struct('S', ('x', lltype.Signed), ('p', lltype.Ptr(S2)))