Martin v. Löwis wrote:
>> So, the question is what we should do?:
>
> Before this question can be answered, I think we need to fully
> understand what precisely is happening in 2.4, and what precisely
> is happening in 2.5.
>
Seeing this thread drag on was enough to get me to find out what
changed. The implementation of "os.stat" has been changed. In 2.4.4,
_stati64/_wstati64 were called directly, but in 2.5.1, a new pair of
functions were wrote win32_stat/win32_wstat.
_stati64/_wstati64 (as others have noted) fallback onto the use of
FindFirstFile. win32_stat/win32_wstat use some functions called
Py_GetFileAttributesExA/Py_GetFileAttributesExW which ultimately use
GetFileAttributesA/GetFileAttributesW.
The change to this implementation is r42230 with the Misc/NEWS comment
saying:
- Use Win32 API to implement os.stat/fstat. As a result, subsecond
timestamps are reported, the limit on path name lengths is
removed, and stat reports WindowsError now (instead of OSError).
As to the specifics of what FindFirstFile* does with the values, I
tested this quickly with ctypes on 'nul' (or any of the other special
files):
cAlternameFileName:
cFileName: nul
dwFileAttributes: 32
dwReserved0: 0
dwReserved1: 0
ftCreationTime: (dwLowDateTime: 0, dwHighDateTime: 0)
ftLastAccessTime: (dwLowDateTime: 0, dwHighDateTime: 0)
ftLastWriteTime: (dwLowDateTime: 0, dwHighDateTime: 0)
nFileSizeHigh: 0
nFileSizeLow: 0
In order to keep the higher accuracy timestamps for normal files and to
maintain the old behavior, my recommendation would be that the existing
implementation of win32_stat/win32_wstat be extended to use
FindFileFirst if GetFileAttributes* fails. I would be willing to do the
legwork for such a patch if everyone agrees this is the appropriate
solution.
* As an aside, Martin, I find the argument that "hard-wiring is bad" to
be against what is actually occurring in the posixmodule. For that
matter, the S_IFEXEC flag is hardwired to path in (*.bat, *.cmd, *.exe,
*.com) despite the fact that the platform says it is really anything in
the list of os.getenv('PATHEXT'), but I suppose that is a bug for
another day.
-Scott
--
Scott Dial
[EMAIL PROTECTED]
[EMAIL PROTECTED]
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