>> But the underlying system calls -- ``FindFirstFile`` / >> ``FindNextFile`` on Windows and ``readdir`` on Linux and OS X -- > > What about FreeBSD, OpenBSD, NetBSD, Solaris, etc. They don't provide readdir?
I guess it'd be better to say "Windows" and "Unix-based OSs" throughout the PEP? Because all of these (including Mac OS X) are Unix-based. > It looks like the WIN32_FIND_DATA has a dwFileAttributes field. So we > should mimic stat_result recent addition: the new > stat_result.file_attributes field. Add DirEntry.file_attributes which > would only be available on Windows. > > The Windows structure also contains > > FILETIME ftCreationTime; > FILETIME ftLastAccessTime; > FILETIME ftLastWriteTime; > DWORD nFileSizeHigh; > DWORD nFileSizeLow; > > It would be nice to expose them as well. I'm no more surprised that > the exact API is different depending on the OS for functions of the os > module. I think you've misunderstood how DirEntry.lstat() works on Windows -- it's basically a no-op, as Windows returns the full stat information with the original FindFirst/FindNext OS calls. This is fairly explict in the PEP, but I'm sure I could make it clearer: DirEntry.lstat(): "like os.lstat(), but requires no system calls on Windows So you can already get the dwFileAttributes for free by saying entry.lstat().st_file_attributes. You can also get all the other fields you mentioned for free via .lstat() with no additional OS calls on Windows, for example: entry.lstat().st_size. Feel free to suggest changes to the PEP or scandir docs if this isn't clear. Note that is_dir()/is_file()/is_symlink() are free on all systems, but .lstat() is only free on Windows. > Does your implementation uses a free list to avoid the cost of memory > allocation? A short free list of 10 or maybe just 1 may help. The free > list may be stored directly in the generator object. No, it doesn't. I might add this to the PEP under "possible improvements". However, I think the speed increase by removing the extra OS call and/or disk seek is going to be way more than memory allocation improvements, so I'm not sure this would be worth it. > Does it support also bytes filenames on UNIX? > Python now supports undecodable filenames thanks to the PEP 383 > (surrogateescape). I prefer to use the same type for filenames on > Linux and Windows, so Unicode is better. But some users might prefer > bytes for other reasons. I forget exactly now what my scandir module does, but for os.scandir() I think this should behave exactly like os.listdir() does for Unicode/bytes filenames. > Crazy idea: would it be possible to "convert" a DirEntry object to a > pathlib.Path object without losing the cache? I guess that > pathlib.Path expects a full stat_result object. The main problem is that pathlib.Path objects explicitly don't cache stat info (and Guido doesn't want them to, for good reason I think). There's a thread on python-dev about this earlier. I'll add it to a "Rejected ideas" section. > I don't understand how you can build a full lstat() result without > really calling stat. I see that WIN32_FIND_DATA contains the size, but > here you call lstat(). See above. > Do you plan to continue to maintain your module for Python < 3.5, but > upgrade your module for the final PEP? Yes, I intend to maintain the standalone scandir module for 2.6 <= Python < 3.5, at least for a good while. For integration into the Python 3.5 stdlib, the implementation will be integrated into posixmodule.c, of course. >> Should there be a way to access the full path? >> ---------------------------------------------- >> >> Should ``DirEntry``'s have a way to get the full path without using >> ``os.path.join(path, entry.name)``? This is a pretty common pattern, >> and it may be useful to add pathlib-like ``str(entry)`` functionality. >> This functionality has also been requested in `issue 13`_ on GitHub. >> >> .. _`issue 13`: https://github.com/benhoyt/scandir/issues/13 > > I think that it would be very convinient to store the directory name > in the DirEntry. It should be light, it's just a reference. > > And provide a fullname() name which would just return > os.path.join(path, entry.name) without trying to resolve path to get > an absolute path. Yeah, fair suggestion. I'm still slightly on the fence about this, but I think an explicit fullname() is a good suggestion. Ideally I think it'd be better to mimic pathlib.Path.__str__() which is kind of the equivalent of fullname(). But how does pathlib deal with unicode/bytes issues if it's the str function which has to return a str object? Or at least, it'd be very weird if __str__() returned bytes. But I think it'd need to if you passed bytes into scandir(). Do others have thoughts? > Would it be hard to implement the wildcard feature on UNIX to compare > performances of scandir('*.jpg') with and without the wildcard built > in os.scandir? It's a good idea, the problem with this is that the Windows wildcard implementation has a bunch of crazy edge cases where *.ext will catch more things than just a simple regex/glob. This was discussed on python-dev or python-ideas previously, so I'll dig it up and add to a Rejected Ideas section. In any case, this could be added later if there's a way to iron out the Windows quirks. -Ben _______________________________________________ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com