238 lines
6.4 KiB
Python
238 lines
6.4 KiB
Python
"""Pathname and path-related operations for the Macintosh."""
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import os
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from stat import *
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__all__ = ["normcase","isabs","join","splitdrive","split","splitext",
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"basename","dirname","commonprefix","getsize","getmtime",
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"getatime","islink","exists","isdir","isfile",
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"walk","expanduser","expandvars","normpath","abspath"]
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# Normalize the case of a pathname. Dummy in Posix, but <s>.lower() here.
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def normcase(path):
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return path.lower()
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def isabs(s):
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"""Return true if a path is absolute.
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On the Mac, relative paths begin with a colon,
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but as a special case, paths with no colons at all are also relative.
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Anything else is absolute (the string up to the first colon is the
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volume name)."""
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return ':' in s and s[0] != ':'
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def join(s, *p):
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path = s
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for t in p:
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if (not s) or isabs(t):
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path = t
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continue
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if t[:1] == ':':
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t = t[1:]
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if ':' not in path:
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path = ':' + path
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if path[-1:] != ':':
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path = path + ':'
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path = path + t
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return path
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def split(s):
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"""Split a pathname into two parts: the directory leading up to the final
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bit, and the basename (the filename, without colons, in that directory).
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The result (s, t) is such that join(s, t) yields the original argument."""
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if ':' not in s: return '', s
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colon = 0
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for i in range(len(s)):
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if s[i] == ':': colon = i + 1
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path, file = s[:colon-1], s[colon:]
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if path and not ':' in path:
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path = path + ':'
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return path, file
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def splitext(p):
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"""Split a path into 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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root, ext = '', ''
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for c in p:
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if c == ':':
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root, ext = root + ext + c, ''
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elif c == '.':
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if ext:
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root, ext = root + ext, c
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else:
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ext = c
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elif ext:
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ext = ext + c
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else:
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root = root + c
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return root, ext
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def splitdrive(p):
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"""Split a pathname into a drive specification and the rest of the
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path. Useful on DOS/Windows/NT; on the Mac, the drive is always
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empty (don't use the volume name -- it doesn't have the same
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syntactic and semantic oddities as DOS drive letters, such as there
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being a separate current directory per drive)."""
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return '', p
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# Short interfaces to split()
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def dirname(s): return split(s)[0]
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def basename(s): return split(s)[1]
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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 os.error:
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return 0
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return S_ISDIR(st[ST_MODE])
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# Get size, mtime, atime of files.
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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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st = os.stat(filename)
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return st[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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st = os.stat(filename)
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return st[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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st = os.stat(filename)
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return st[ST_ATIME]
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def islink(s):
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"""Return true if the pathname refers to a symbolic link.
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Always false on the Mac, until we understand Aliases.)"""
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return 0
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def isfile(s):
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"""Return true if the pathname refers to an existing regular file."""
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try:
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st = os.stat(s)
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except os.error:
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return 0
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return S_ISREG(st[ST_MODE])
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def exists(s):
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"""Return True if the pathname refers to an existing file or directory."""
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try:
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st = os.stat(s)
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except os.error:
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return False
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return True
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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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prefix = m[0]
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for item in m:
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for i in range(len(prefix)):
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if prefix[:i+1] != item[:i+1]:
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prefix = prefix[:i]
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if i == 0: return ''
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break
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return prefix
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def expandvars(path):
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"""Dummy to retain interface-compatibility with other operating systems."""
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return path
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def expanduser(path):
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"""Dummy to retain interface-compatibility with other operating systems."""
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return path
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class norm_error(Exception):
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"""Path cannot be normalized"""
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def normpath(s):
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"""Normalize a pathname. Will return the same result for
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equivalent paths."""
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if ":" not in s:
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return ":"+s
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comps = s.split(":")
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i = 1
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while i < len(comps)-1:
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if comps[i] == "" and comps[i-1] != "":
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if i > 1:
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del comps[i-1:i+1]
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i = i - 1
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else:
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# best way to handle this is to raise an exception
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raise norm_error, 'Cannot use :: immediately after volume name'
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else:
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i = i + 1
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s = ":".join(comps)
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# remove trailing ":" except for ":" and "Volume:"
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if s[-1] == ":" and len(comps) > 2 and s != ":"*len(s):
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s = s[:-1]
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return s
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def walk(top, func, arg):
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"""Directory tree walk with callback function.
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For each directory in the directory tree rooted at top (including top
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itself, but excluding '.' and '..'), call func(arg, dirname, fnames).
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dirname is the name of the directory, and fnames a list of the names of
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the files and subdirectories in dirname (excluding '.' and '..'). func
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may modify the fnames list in-place (e.g. via del or slice assignment),
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and walk will only recurse into the subdirectories whose names remain in
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fnames; this can be used to implement a filter, or to impose a specific
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order of visiting. No semantics are defined for, or required of, arg,
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beyond that arg is always passed to func. It can be used, e.g., to pass
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a filename pattern, or a mutable object designed to accumulate
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statistics. Passing None for arg is common."""
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try:
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names = os.listdir(top)
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except os.error:
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return
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func(arg, top, names)
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for name in names:
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name = join(top, name)
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if isdir(name):
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walk(name, func, arg)
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def abspath(path):
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"""Return an absolute path."""
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if not isabs(path):
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path = join(os.getcwd(), path)
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return normpath(path)
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# realpath is a no-op on systems without islink support
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realpath = abspath
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