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', 'samefile', 'sameopenfile',
11 'samestat']
12
13
14 # Does a path exist?
15 # This is false for dangling symbolic links on systems that support them.
16 def exists(path):
17 """Test whether a path exists. Returns False for broken symbolic links"""
18 try:
19 os.stat(path)
20 except (OSError, ValueError):
21 return False
22 return True
23
24
25 # This follows symbolic links, so both islink() and isdir() can be true
26 # for the same path on systems that support symlinks
27 def isfile(path):
28 """Test whether a path is a regular file"""
29 try:
30 st = os.stat(path)
31 except (OSError, ValueError):
32 return False
33 return stat.S_ISREG(st.st_mode)
34
35
36 # Is a path a directory?
37 # This follows symbolic links, so both islink() and isdir()
38 # can be true for the same path on systems that support symlinks
39 def isdir(s):
40 """Return true if the pathname refers to an existing directory."""
41 try:
42 st = os.stat(s)
43 except (OSError, ValueError):
44 return False
45 return stat.S_ISDIR(st.st_mode)
46
47
48 def getsize(filename):
49 """Return the size of a file, reported by os.stat()."""
50 return os.stat(filename).st_size
51
52
53 def getmtime(filename):
54 """Return the last modification time of a file, reported by os.stat()."""
55 return os.stat(filename).st_mtime
56
57
58 def getatime(filename):
59 """Return the last access time of a file, reported by os.stat()."""
60 return os.stat(filename).st_atime
61
62
63 def getctime(filename):
64 """Return the metadata change time of a file, reported by os.stat()."""
65 return os.stat(filename).st_ctime
66
67
68 # Return the longest prefix of all list elements.
69 def commonprefix(m):
70 "Given a list of pathnames, returns the longest common leading component"
71 if not m: return ''
72 # Some people pass in a list of pathname parts to operate in an OS-agnostic
73 # fashion; don't try to translate in that case as that's an abuse of the
74 # API and they are already doing what they need to be OS-agnostic and so
75 # they most likely won't be using an os.PathLike object in the sublists.
76 if not isinstance(m[0], (list, tuple)):
77 m = tuple(map(os.fspath, m))
78 s1 = min(m)
79 s2 = max(m)
80 for i, c in enumerate(s1):
81 if c != s2[i]:
82 return s1[:i]
83 return s1
84
85 # Are two stat buffers (obtained from stat, fstat or lstat)
86 # describing the same file?
87 def samestat(s1, s2):
88 """Test whether two stat buffers reference the same file"""
89 return (s1.st_ino == s2.st_ino and
90 s1.st_dev == s2.st_dev)
91
92
93 # Are two filenames really pointing to the same file?
94 def samefile(f1, f2):
95 """Test whether two pathnames reference the same actual file or directory
96
97 This is determined by the device number and i-node number and
98 raises an exception if an os.stat() call on either pathname fails.
99 """
100 s1 = os.stat(f1)
101 s2 = os.stat(f2)
102 return samestat(s1, s2)
103
104
105 # Are two open files really referencing the same file?
106 # (Not necessarily the same file descriptor!)
107 def sameopenfile(fp1, fp2):
108 """Test whether two open file objects reference the same file"""
109 s1 = os.fstat(fp1)
110 s2 = os.fstat(fp2)
111 return samestat(s1, s2)
112
113
114 # Split a path in root and extension.
115 # The extension is everything starting at the last dot in the last
116 # pathname component; the root is everything before that.
117 # It is always true that root + ext == p.
118
119 # Generic implementation of splitext, to be parametrized with
120 # the separators
121 def _splitext(p, sep, altsep, extsep):
122 """Split the extension from a pathname.
123
124 Extension is everything from the last dot to the end, ignoring
125 leading dots. Returns "(root, ext)"; ext may be empty."""
126 # NOTE: This code must work for text and bytes strings.
127
128 sepIndex = p.rfind(sep)
129 if altsep:
130 altsepIndex = p.rfind(altsep)
131 sepIndex = max(sepIndex, altsepIndex)
132
133 dotIndex = p.rfind(extsep)
134 if dotIndex > sepIndex:
135 # skip all leading dots
136 filenameIndex = sepIndex + 1
137 while filenameIndex < dotIndex:
138 if p[filenameIndex:filenameIndex+1] != extsep:
139 return p[:dotIndex], p[dotIndex:]
140 filenameIndex += 1
141
142 return p, p[:0]
143
144 def _check_arg_types(funcname, *args):
145 hasstr = hasbytes = False
146 for s in args:
147 if isinstance(s, str):
148 hasstr = True
149 elif isinstance(s, bytes):
150 hasbytes = True
151 else:
152 raise TypeError(f'{funcname}() argument must be str, bytes, or '
153 f'os.PathLike object, not {s.__class__.__name__!r}') from None
154 if hasstr and hasbytes:
155 raise TypeError("Can't mix strings and bytes in path components") from None