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cpython/Lib/glob.py
Johannes Gijsbers 836f5433f7 Patch #943206:
`glob.glob()` currently calls itself recursively to build a list of matches of
the dirname part of the pattern and then filters by the basename part. This is
effectively BFS. ``glob.glob('*/*/*/*/*/foo')`` will build a huge list of all
directories 5 levels deep even if only a handful of them contain a ``foo``
entry. A generator-based recusion would never have to store these list at once
by implementing DFS. This patch converts the `glob` function to an `iglob`
recursive generator . `glob()` now just returns ``list(iglob(pattern))``.

I also cleaned up the code a bit (reduced duplicate `has_magic()` checks and
created a second `glob0` helper func so that the main loop need not be
duplicated).

Thanks to Cherniavsky Beni for the patch!
2005-01-08 13:13:19 +00:00

75 lines
2.0 KiB
Python

"""Filename globbing utility."""
import os
import fnmatch
import re
__all__ = ["glob", "iglob"]
def glob(pathname):
"""Return a list of paths matching a pathname pattern.
The pattern may contain simple shell-style wildcards a la fnmatch.
"""
return list(iglob(pathname))
def iglob(pathname):
"""Return a list of paths matching a pathname pattern.
The pattern may contain simple shell-style wildcards a la fnmatch.
"""
if not has_magic(pathname):
if os.path.lexists(pathname):
yield pathname
return
dirname, basename = os.path.split(pathname)
if not dirname:
for name in glob1(os.curdir, basename):
yield name
return
if has_magic(dirname):
dirs = iglob(dirname)
else:
dirs = [dirname]
if has_magic(basename):
glob_in_dir = glob1
else:
glob_in_dir = glob0
for dirname in dirs:
for name in glob_in_dir(dirname, basename):
yield os.path.join(dirname, name)
# These 2 helper functions non-recursively glob inside a literal directory.
# They return a list of basenames. `glob1` accepts a pattern while `glob0`
# takes a literal basename (so it only has to check for its existence).
def glob1(dirname, pattern):
if not dirname:
dirname = os.curdir
try:
names = os.listdir(dirname)
except os.error:
return []
if pattern[0]!='.':
names=filter(lambda x: x[0]!='.',names)
return fnmatch.filter(names,pattern)
def glob0(dirname, basename):
if basename == '':
# `os.path.split()` returns an empty basename for paths ending with a
# directory separator. 'q*x/' should match only directories.
if os.isdir(dirname):
return [basename]
else:
if os.path.lexists(os.path.join(dirname, basename)):
return [basename]
return []
magic_check = re.compile('[*?[]')
def has_magic(s):
return magic_check.search(s) is not None