Mailing List Archive

Update of /cvsroot/python/python/dist/src/Objects
In directory usw-pr-cvs1:/tmp/cvs-serv17165/python/Objects

Modified Files:
fileobject.c
Log Message:
Change Windows file.truncate() to (a) restore the original file position,
and (b) stop trying to prevent file growth.

Beef up the file.truncate() docs.

Change test_largefile.py to stop assuming that f.truncate() moves the
file pointer to the truncation point, and to verify instead that it leaves
the file position alone. Remove the test for what happens when a
specified size exceeds the original file size (it's ill-defined, according
to the Single Unix Spec).


Index: fileobject.c
===================================================================
RCS file: /cvsroot/python/python/dist/src/Objects/fileobject.c,v
retrieving revision 2.145
retrieving revision 2.146
diff -C2 -d -r2.145 -r2.146
*** fileobject.c 11 Mar 2002 00:24:00 -0000 2.145
--- fileobject.c 12 Mar 2002 03:04:44 -0000 2.146
***************
*** 416,454 ****
#ifdef MS_WIN32
/* MS _chsize doesn't work if newsize doesn't fit in 32 bits,
! so don't even try using it. truncate() should never grow the
! file, but MS SetEndOfFile will grow a file, so we need to
! compare the specified newsize to the actual size. Some
! optimization could be done here when newsizeobj is NULL. */
{
! Py_off_t currentEOF; /* actual size */
HANDLE hFile;
int error;

! /* First move to EOF, and set currentEOF to the size. */
! errno = 0;
! if (_portable_fseek(f->f_fp, 0, SEEK_END) != 0)
! goto onioerror;
! errno = 0;
! currentEOF = _portable_ftell(f->f_fp);
! if (currentEOF == -1)
! goto onioerror;
!
! if (newsize > currentEOF)
! newsize = currentEOF; /* never grow the file */
!
! /* Move to newsize, and truncate the file there. */
! if (newsize != currentEOF) {
errno = 0;
! if (_portable_fseek(f->f_fp, newsize, SEEK_SET) != 0)
goto onioerror;
Py_BEGIN_ALLOW_THREADS
errno = 0;
! hFile = (HANDLE)_get_osfhandle(fileno(f->f_fp));
! error = hFile == (HANDLE)-1;
! if (!error) {
! error = SetEndOfFile(hFile) == 0;
! if (error)
! errno = EACCES;
! }
Py_END_ALLOW_THREADS
if (error)
--- 416,443 ----
#ifdef MS_WIN32
/* MS _chsize doesn't work if newsize doesn't fit in 32 bits,
! so don't even try using it. */
{
! Py_off_t current; /* current file position */
HANDLE hFile;
int error;

! /* current <- current file postion. */
! if (newsizeobj == NULL)
! current = newsize;
! else {
! Py_BEGIN_ALLOW_THREADS
errno = 0;
! current = _portable_ftell(f->f_fp);
! Py_END_ALLOW_THREADS
! if (current == -1)
goto onioerror;
+ }
+
+ /* Move to newsize. */
+ if (current != newsize) {
Py_BEGIN_ALLOW_THREADS
errno = 0;
! error = _portable_fseek(f->f_fp, newsize, SEEK_SET)
! != 0;
Py_END_ALLOW_THREADS
if (error)
***************
*** 456,459 ****
--- 445,472 ----
}

+ /* Truncate. Note that this may grow the file! */
+ Py_BEGIN_ALLOW_THREADS
+ errno = 0;
+ hFile = (HANDLE)_get_osfhandle(fileno(f->f_fp));
+ error = hFile == (HANDLE)-1;
+ if (!error) {
+ error = SetEndOfFile(hFile) == 0;
+ if (error)
+ errno = EACCES;
+ }
+ Py_END_ALLOW_THREADS
+ if (error)
+ goto onioerror;
+
+ /* Restore original file position. */
+ if (current != newsize) {
+ Py_BEGIN_ALLOW_THREADS
+ errno = 0;
+ error = _portable_fseek(f->f_fp, current, SEEK_SET)
+ != 0;
+ Py_END_ALLOW_THREADS
+ if (error)
+ goto onioerror;
+ }
}
#else