"""riscos specific module for conversion between pathnames and URLs.

Based on macurl2path.

Do not import directly, use urllib instead."""

import string

import urllib

__all__ = ["url2pathname","pathname2url"]

__slash_dot = string.maketrans("/.", "./")

def url2pathname(url):

    """OS-specific conversion from a relative URL of the 'file' scheme

    to a file system path; not recommended for general use."""

    tp = urllib.splittype(url)[0]

    if tp and tp <> 'file':

        raise RuntimeError, 'Cannot convert non-local URL to pathname'

    # Turn starting /// into /, an empty hostname means current host

    if url[:3] == '///':

        url = url[2:]

    elif url[:2] == '//':

        raise RuntimeError, 'Cannot convert non-local URL to pathname'

    components = string.split(url, '/')

    if not components[0]:

        if '$' in components:

            del components[0]

        else:

            components[0] = '$'

    # Remove . and embedded ..

    i = 0

    while i < len(components):

        if components[i] == '.':

            del components[i]

        elif components[i] == '..' and i > 0 and \

                                  components[i-1] not in ('', '..'):

            del components[i-1:i+1]

            i -= 1

        elif components[i] == '..':

            components[i] = '^'

            i += 1

        elif components[i] == '' and i > 0 and components[i-1] <> '':

            del components[i]

        else:

            i += 1

    components = map(lambda x: urllib.unquote(x).translate(__slash_dot), components)

    return '.'.join(components)

def pathname2url(pathname):

    """OS-specific conversion from a file system path to a relative URL

    of the 'file' scheme; not recommended for general use."""

    return urllib.quote('///' + pathname.translate(__slash_dot), "/$:")

def test():

    for url in ["index.html",

                "/SCSI::SCSI4/$/Anwendung/Comm/Apps/!Fresco/Welcome",

                "/SCSI::SCSI4/$/Anwendung/Comm/Apps/../!Fresco/Welcome",

                "../index.html",

                "bar/index.html",

                "/foo/bar/index.html",

                "/foo/bar/",

                "/"]:

        print '%r -> %r' % (url, url2pathname(url))

    print "*******************************************************"

    for path in ["SCSI::SCSI4.$.Anwendung",

                 "PythonApp:Lib",

                 "PythonApp:Lib.rourl2path/py"]:

        print '%r -> %r' % (path, pathname2url(path))

if __name__ == '__main__':

    test()