[pypy-commit] pypy null_byte_after_str: Cancel a fragile dependency with details of space.str_w(), and instead

[arigo]

Author: Armin Rigo <arigo at tunes.org>
Branch: null_byte_after_str
Changeset: r85987:2977ce236abb
Date: 2016-08-02 15:27 +0200
http://bitbucket.org/pypy/pypy/changeset/2977ce236abb/

Log:	Cancel a fragile dependency with details of space.str_w(), and
	instead do it all inside W_CTypeFunc._call

diff --git a/pypy/module/_cffi_backend/ctypefunc.py b/pypy/module/_cffi_backend/ctypefunc.py
--- a/pypy/module/_cffi_backend/ctypefunc.py
+++ b/pypy/module/_cffi_backend/ctypefunc.py
@@ -157,11 +157,13 @@
         mustfree_max_plus_1 = 0
         buffer = lltype.malloc(rffi.CCHARP.TO, size, flavor='raw')
         try:
+            keepalives = [None] * len(args_w)    # None or strings
             for i in range(len(args_w)):
                 data = rffi.ptradd(buffer, cif_descr.exchange_args[i])
                 w_obj = args_w[i]
                 argtype = self.fargs[i]
-                if argtype.convert_argument_from_object(data, w_obj):
+                if argtype.convert_argument_from_object(data, w_obj,
+                                                        keepalives, i):
                     # argtype is a pointer type, and w_obj a list/tuple/str
                     mustfree_max_plus_1 = i + 1
 
@@ -181,7 +183,8 @@
                     if flag == 1:
                         lltype.free(raw_cdata, flavor='raw')
                     elif flag >= 4:
-                        value = args_w[i].str_w(space)
+                        value = keepalives[i]
+                        assert value is not None
                         rffi.free_nonmovingbuffer(value, raw_cdata, chr(flag))
             lltype.free(buffer, flavor='raw')
             keepalive_until_here(args_w)
diff --git a/pypy/module/_cffi_backend/ctypeobj.py b/pypy/module/_cffi_backend/ctypeobj.py
--- a/pypy/module/_cffi_backend/ctypeobj.py
+++ b/pypy/module/_cffi_backend/ctypeobj.py
@@ -83,7 +83,7 @@
         raise oefmt(space.w_TypeError, "cannot initialize cdata '%s'",
                     self.name)
 
-    def convert_argument_from_object(self, cdata, w_ob):
+    def convert_argument_from_object(self, cdata, w_ob, keepalives, i):
         self.convert_from_object(cdata, w_ob)
         return False
 
diff --git a/pypy/module/_cffi_backend/ctypeptr.py b/pypy/module/_cffi_backend/ctypeptr.py
--- a/pypy/module/_cffi_backend/ctypeptr.py
+++ b/pypy/module/_cffi_backend/ctypeptr.py
@@ -261,13 +261,12 @@
         else:
             return lltype.nullptr(rffi.CCHARP.TO)
 
-    def _prepare_pointer_call_argument(self, w_init, cdata):
+    def _prepare_pointer_call_argument(self, w_init, cdata, keepalives, i):
         space = self.space
         if self.accept_str and space.isinstance_w(w_init, space.w_str):
             # special case to optimize strings passed to a "char *" argument
-            # WARNING: this relies on the fact that w_init.str_w() returns
-            # always the same object for the same w_init!
             value = w_init.str_w(space)
+            keepalives[i] = value
             buf, buf_flag = rffi.get_nonmovingbuffer_final_null(value)
             rffi.cast(rffi.CCHARPP, cdata)[0] = buf
             return ord(buf_flag)    # 4, 5 or 6
@@ -307,10 +306,11 @@
         rffi.cast(rffi.CCHARPP, cdata)[0] = result
         return 1
 
-    def convert_argument_from_object(self, cdata, w_ob):
+    def convert_argument_from_object(self, cdata, w_ob, keepalives, i):
         from pypy.module._cffi_backend.ctypefunc import set_mustfree_flag
         result = (not isinstance(w_ob, cdataobj.W_CData) and
-                  self._prepare_pointer_call_argument(w_ob, cdata))
+                  self._prepare_pointer_call_argument(w_ob, cdata,
+                                                      keepalives, i))
         if result == 0:
             self.convert_from_object(cdata, w_ob)
         set_mustfree_flag(cdata, result)
diff --git a/pypy/objspace/std/bytesobject.py b/pypy/objspace/std/bytesobject.py
--- a/pypy/objspace/std/bytesobject.py
+++ b/pypy/objspace/std/bytesobject.py
@@ -451,9 +451,6 @@
         return self._value
 
     def str_w(self, space):
-        # WARNING: _cffi_backend/ctypeptr.py depends on the fact that
-        # w_obj.str_w() called twice on the same object returns the
-        # exact same string object!
         return self._value
 
     def buffer_w(self, space, flags):