1 """ 2 Path operations common to more than one OS 3 Do not use directly. The OS specific modules import the appropriate 4 functions from this module themselves. 5 """ 6 import os 7 import stat 8 9 __all__ = ['commonprefix', 'exists', 'getatime', 'getctime', 'getmtime', 10 'getsize', 'isdir', 'isfile'] 11 12 13 try: 14 _unicode = unicode 15 except NameError: 16 # If Python is built without Unicode support, the unicode type 17 # will not exist. Fake one. 18 class _unicode(object): 19 pass 20 21 # Does a path exist? 22 # This is false for dangling symbolic links on systems that support them. 23 def exists(path): 24 """Test whether a path exists. Returns False for broken symbolic links""" 25 try: 26 os.stat(path) 27 except os.error: 28 return False 29 return True 30 31 32 # This follows symbolic links, so both islink() and isdir() can be true 33 # for the same path on systems that support symlinks 34 def isfile(path): 35 """Test whether a path is a regular file""" 36 try: 37 st = os.stat(path) 38 except os.error: 39 return False 40 return stat.S_ISREG(st.st_mode) 41 42 43 # Is a path a directory? 44 # This follows symbolic links, so both islink() and isdir() 45 # can be true for the same path on systems that support symlinks 46 def isdir(s): 47 """Return true if the pathname refers to an existing directory.""" 48 try: 49 st = os.stat(s) 50 except os.error: 51 return False 52 return stat.S_ISDIR(st.st_mode) 53 54 55 def getsize(filename): 56 """Return the size of a file, reported by os.stat().""" 57 return os.stat(filename).st_size 58 59 60 def getmtime(filename): 61 """Return the last modification time of a file, reported by os.stat().""" 62 return os.stat(filename).st_mtime 63 64 65 def getatime(filename): 66 """Return the last access time of a file, reported by os.stat().""" 67 return os.stat(filename).st_atime 68 69 70 def getctime(filename): 71 """Return the metadata change time of a file, reported by os.stat().""" 72 return os.stat(filename).st_ctime 73 74 75 # Return the longest prefix of all list elements. 76 def commonprefix(m): 77 "Given a list of pathnames, returns the longest common leading component" 78 if not m: return '' 79 s1 = min(m) 80 s2 = max(m) 81 for i, c in enumerate(s1): 82 if c != s2[i]: 83 return s1[:i] 84 return s1 85 86 # Split a path in root and extension. 87 # The extension is everything starting at the last dot in the last 88 # pathname component; the root is everything before that. 89 # It is always true that root + ext == p. 90 91 # Generic implementation of splitext, to be parametrized with 92 # the separators 93 def _splitext(p, sep, altsep, extsep): 94 """Split the extension from a pathname. 95 96 Extension is everything from the last dot to the end, ignoring 97 leading dots. Returns "(root, ext)"; ext may be empty.""" 98 99 sepIndex = p.rfind(sep) 100 if altsep: 101 altsepIndex = p.rfind(altsep) 102 sepIndex = max(sepIndex, altsepIndex) 103 104 dotIndex = p.rfind(extsep) 105 if dotIndex > sepIndex: 106 # skip all leading dots 107 filenameIndex = sepIndex + 1 108 while filenameIndex < dotIndex: 109 if p[filenameIndex] != extsep: 110 return p[:dotIndex], p[dotIndex:] 111 filenameIndex += 1 112 113 return p, '' 114
