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