829 def _statfiles(files):

   830     'Stat each file in files and yield stat or None if file does not exist.'

   831     lstat = os.lstat

   832     for nf in files:

   833         try:

   834             st = lstat(nf)

   835         except OSError, err:

   836             if err.errno not in (errno.ENOENT, errno.ENOTDIR):

   837                 raise

   838             st = None

   839         yield st

   840 

   841 def _statfiles_clustered(files):

   842     '''Stat each file in files and yield stat or None if file does not exist.

   843     Cluster and cache stat per directory to minimize number of OS stat calls.'''

   844     lstat = os.lstat

   845     ncase = os.path.normcase

   846     sep   = os.sep

   847     dircache = {} # dirname -> filename -> status | None if file does not exist

   848     for nf in files:

   849         nf  = ncase(nf)

   850         pos = nf.rfind(sep)

   851         if pos == -1:

   852             dir, base = '.', nf

   853         else:

   854             dir, base = nf[:pos], nf[pos+1:]

   855         cache = dircache.get(dir, None)

   856         if cache is None:

   857             try:

   858                 dmap = dict([(ncase(n), s)

   859                     for n, k, s in osutil.listdir(dir, True)])

   860             except OSError, err:

   861                 # handle directory not found in Python version prior to 2.5

   862                 # Python <= 2.4 returns native Windows code 3 in errno

   863                 # Python >= 2.5 returns ENOENT and adds winerror field

   864                 if err.errno not in (3, errno.ENOENT, errno.ENOTDIR):

   865                     raise

   866                 dmap = {}

   867             cache = dircache.setdefault(dir, dmap)

   868         yield cache.get(base, None)

   869 

   870 if sys.platform == 'win32':

   871     statfiles = _statfiles_clustered

   872 else:

   873     statfiles = _statfiles

   874