"""

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']

# 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:

        st = 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 ono 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, ''