"""
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']


try:
_unicode = unicode
except NameError:
# If Python is built without Unicode support, the unicode type
# will not exist. Fake one.
class _unicode(object):
pass

# 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 os.error:
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 os.error:
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 os.error:
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

# 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."""

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] != extsep:
return p[:dotIndex], p[dotIndex:]
filenameIndex += 1

return p, ''