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"""
Path operations common to more than one OS
Do not use directly. The OS specific modules import the appropriate
functions from this module themselves.
"""
import os
import stat
__all__ = ['commonprefix', 'exists', 'getatime', 'getctime', 'getmtime',
'getsize', 'isdir', 'isfile', 'samefile', 'sameopenfile',
'samestat']
# Does a path exist?
# This is false for dangling symbolic links on systems that support them.
def exists(path):
"""Test whether a path exists. Returns False for broken symbolic links"""
try:
os.stat(path)
except OSError:
return False
return True
# This follows symbolic links, so both islink() and isdir() can be true
# for the same path on systems that support symlinks
def isfile(path):
"""Test whether a path is a regular file"""
try:
st = os.stat(path)
except OSError:
return False
return stat.S_ISREG(st.st_mode)
# Is a path a directory?
# This follows symbolic links, so both islink() and isdir()
# can be true for the same path on systems that support symlinks
def isdir(s):
"""Return true if the pathname refers to an existing directory."""
try:
st = os.stat(s)
except OSError:
return False
return stat.S_ISDIR(st.st_mode)
def getsize(filename):
"""Return the size of a file, reported by os.stat()."""
return os.stat(filename).st_size
def getmtime(filename):
"""Return the last modification time of a file, reported by os.stat()."""
return os.stat(filename).st_mtime
def getatime(filename):
"""Return the last access time of a file, reported by os.stat()."""
return os.stat(filename).st_atime
def getctime(filename):
"""Return the metadata change time of a file, reported by os.stat()."""
return os.stat(filename).st_ctime
# Return the longest prefix of all list elements.
def commonprefix(m):
"Given a list of pathnames, returns the longest common leading component"
if not m: return ''
s1 = min(m)
s2 = max(m)
for i, c in enumerate(s1):
if c != s2[i]:
return s1[:i]
return s1
# Are two stat buffers (obtained from stat, fstat or lstat)
# describing the same file?
def samestat(s1, s2):
"""Test whether two stat buffers reference the same file"""
return (s1.st_ino == s2.st_ino and
s1.st_dev == s2.st_dev)
# Are two filenames really pointing to the same file?
def samefile(f1, f2):
"""Test whether two pathnames reference the same actual file"""
s1 = os.stat(f1)
s2 = os.stat(f2)
return samestat(s1, s2)
# Are two open files really referencing the same file?
# (Not necessarily the same file descriptor!)
def sameopenfile(fp1, fp2):
"""Test whether two open file objects reference the same file"""
s1 = os.fstat(fp1)
s2 = os.fstat(fp2)
return samestat(s1, s2)
# Split a path in root and extension.
# The extension is everything starting at the last dot in the last
# pathname component; the root is everything before that.
# It is always true that root + ext == p.
# Generic implementation of splitext, to be parametrized with
# the separators
def _splitext(p, sep, altsep, extsep):
"""Split the extension from a pathname.
Extension is everything from the last dot to the end, ignoring
leading dots. Returns "(root, ext)"; ext may be empty."""
# NOTE: This code must work for text and bytes strings.
sepIndex = p.rfind(sep)
if altsep:
altsepIndex = p.rfind(altsep)
sepIndex = max(sepIndex, altsepIndex)
dotIndex = p.rfind(extsep)
if dotIndex > sepIndex:
# skip all leading dots
filenameIndex = sepIndex + 1
while filenameIndex < dotIndex:
if p[filenameIndex:filenameIndex+1] != extsep:
return p[:dotIndex], p[dotIndex:]
filenameIndex += 1
return p, p[:0]
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