Initial revision

Lib/posixpath.py

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+# Module 'path' -- common operations on POSIX pathnames
+
+import posix
+
+
+# Intelligent pathname concatenation.
+# Inserts a '/' unless the first part is empty or already ends in '/'.
+# Ignores the first part altogether if the second part is absolute
+# (begins with '/').
+#
+def cat(a, b):
+	if b[:1] = '/': return b
+	if a = '' or a[-1:] = '/': return a + b
+	return a + '/' + b
+
+
+# Split a path in head (empty or ending in '/') and tail (no '/').
+# The tail will be empty if the path ends in '/'.
+#
+def split(p):
+	head, tail = '', ''
+	for c in p:
+		tail = tail + c
+		if c = '/':
+			head, tail = head + tail, ''
+	return head, tail
+
+
+# Return the tail (basename) part of a path.
+#
+def basename(p):
+	return split(p)[1]
+
+
+# Return the longest prefix of all list elements.
+#
+def commonprefix(m):
+	if not m: return ''
+	prefix = m[0]
+	for item in m:
+		for i in range(len(prefix)):
+			if prefix[:i+1] <> item[:i+1]:
+				prefix = prefix[:i]
+				if i = 0: return ''
+				break
+	return prefix
+
+
+# Does a file/directory exist?
+#
+def exists(path):
+	try:
+		st = posix.stat(path)
+	except posix.error:
+		return 0
+	return 1
+
+
+# Is a path a posix directory?
+#
+def isdir(path):
+	try:
+		st = posix.stat(path)
+	except posix.error:
+		return 0
+	return st[0] / 4096 = 4 # S_IFDIR
+
+
+# Is a path a symbolic link?
+# This will always return false on systems where posix.lstat doesn't exist.
+#
+def islink(path):
+	try:
+		st = posix.lstat(path)
+	except (posix.error, NameError):
+		return 0
+	return st[0] / 4096 = 10 # S_IFLNK
+
+
+_mounts = []
+
+def _getmounts():
+	import commands, string
+	mounts = []
+	data = commands.getoutput('/etc/mount')
+	lines = string.splitfields(data, '\n')
+	for line in lines:
+		words = string.split(line)
+		if len(words) >= 3 and words[1] = 'on':
+			mounts.append(words[2])
+	return mounts
+
+
+# Is a path a mount point?
+# This only works for normalized, absolute paths,
+# and only if the mount table as printed by /etc/mount is correct.
+# Sorry.
+#
+def ismount(path):
+	if not _mounts:
+		_mounts[:] = _getmounts()
+	return path in _mounts
+
+
+# Directory tree walk.
+# For each directory under top (including top itself),
+# func(arg, dirname, filenames) is called, where dirname
+# is the name of the directory and filenames is the list of
+# files (and subdirectories etc.) in the directory.
+# func may modify the filenames list, to implement a filter,
+# or to impose a different order of visiting.
+#
+def walk(top, func, arg):
+	try:
+		names = posix.listdir(top)
+	except posix.error:
+		return
+	func(arg, top, names)
+	exceptions = ('.', '..')
+	for name in names:
+		if name not in exceptions:
+			name = cat(top, name)
+			if isdir(name):
+				walk(name, func, arg)