"""

Path operations common to more than one OS

Do not use directly.  The OS specific modules import the appropriate

functions from this module themselves.

"""

from os import error, stat

from stat import *

__all__ = ['commonprefix', 'exists', 'getatime', 'getctime', 'getmtime',

           'getsize', 'isdir', 'isfile']

# 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:

        stat(path)

    except error:

        return False

    return True

# This follows symbolic links, so both islink() and isdir() can be true

# for the same path ono systems that support symlinks

def isfile(path):

    """Test whether a path is a regular file"""

    try:

        st = stat(path)

    except 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 = stat(s)

    except error:

        return False

    return stat.S_ISDIR(st.st_mode)

def getsize(filename):

    """Return the size of a file, reported by os.stat()."""

    return stat(filename).st_size

def getmtime(filename):

    """Return the last modification time of a file, reported by os.stat()."""

    return stat(filename).st_mtime

def getatime(filename):

    """Return the last access time of a file, reported by os.stat()."""

    return stat(filename).st_atime

def getctime(filename):

    """Return the metadata change time of a file, reported by os.stat()."""

    return 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, ''