New submission from Christian Heimes:
The patch fixes for real what "Patch # 1323 by Amaury Forgeot d'Arc"
claims to have fixed. I reverted his patch to io.py and implemented the
fix in the Windows specific part of truncate in _fileio.c. It fixes two
tests for raw io on Windows.
----------
components: Library (Lib)
files: py3k_win_io.patch
messages: 56769
nosy: tiran
severity: normal
status: open
title: Fix truncate on Windows, this time for real
type: behavior
versions: Python 3.0
Added file: http://bugs.python.org/file8613/py3k_win_io.patch
__________________________________
Tracker <[EMAIL PROTECTED]>
<http://bugs.python.org/issue1330>
__________________________________
Index: Lib/io.py
===================================================================
--- Lib/io.py (revision 58660)
+++ Lib/io.py (working copy)
@@ -597,25 +597,10 @@
return self.raw.tell()
def truncate(self, pos=None):
- # On Windows, the truncate operation changes the current position
- # to the end of the file, which may leave us with desynchronized
- # buffers.
- # Since we promise that truncate() won't change the current position,
- # the easiest thing is to capture current pos now and seek back to
- # it at the end.
-
- initialpos = self.tell()
if pos is None:
- pos = initialpos
+ pos = self.tell()
+ return self.raw.truncate(pos)
- # Flush the stream. We're mixing buffered I/O with lower-level I/O,
- # and a flush may be necessary to synch both views of the current
- # file state.
- self.flush()
- newpos = self.raw.truncate(pos)
- self.seek(initialpos)
- return newpos
-
### Flush and close ###
def flush(self):
Index: Modules/_fileio.c
===================================================================
--- Modules/_fileio.c (revision 58660)
+++ Modules/_fileio.c (working copy)
@@ -628,14 +628,22 @@
so don't even try using it. */
{
HANDLE hFile;
- PyObject *pos2;
+ PyObject *pos2, *oldposobj;
+ /* store the current position */
+ oldposobj = portable_lseek(self->fd, NULL, 1);
+ if (oldposobj == NULL) {
+ Py_DECREF(posobj);
+ return NULL;
+ }
+
/* Have to move current pos to desired endpoint on Windows. */
errno = 0;
pos2 = portable_lseek(fd, posobj, SEEK_SET);
if (pos2 == NULL)
{
Py_DECREF(posobj);
+ Py_DECREF(oldposobj);
return NULL;
}
Py_DECREF(pos2);
@@ -651,6 +659,16 @@
errno = EACCES;
}
Py_END_ALLOW_THREADS
+
+ /* Move to the previous position in the file */
+ pos2 = portable_lseek(fd, oldposobj, SEEK_SET);
+ if (pos2 == NULL) {
+ Py_DECREF(posobj);
+ Py_DECREF(oldposobj);
+ return NULL;
+ }
+ Py_DECREF(pos2);
+ Py_DECREF(oldposobj);
}
#else
Py_BEGIN_ALLOW_THREADS
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