macurl2p.py

minimal python variant for small footprint apps like embedded apps

"""Mac specific module for conversion between pathnames and URLs.
Do not import directly, use urllib instead."""

import string
import urllib
import os

def url2pathname(pathname):
    "Convert /-delimited pathname to mac pathname"
    #
    # XXXX The .. handling should be fixed...
    #
    tp = urllib.splittype(pathname)[0]
    if tp and tp <> 'file':
        raise RuntimeError, 'Cannot convert non-local URL to pathname'
    components = string.split(pathname, '/')
    # 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 = i-1
        elif components[i] == '' and i > 0 and components[i-1] <> '':
            del components[i]
        else:
            i = i+1
    if not components[0]:
        # Absolute unix path, don't start with colon
        rv = string.join(components[1:], ':')
    else:
        # relative unix path, start with colon. First replace
        # leading .. by empty strings (giving ::file)
        i = 0
        while i < len(components) and components[i] == '..':
            components[i] = ''
            i = i + 1
        rv = ':' + string.join(components, ':')
    # and finally unquote slashes and other funny characters
    return urllib.unquote(rv)

def pathname2url(pathname):
    "convert mac pathname to /-delimited pathname"
    if '/' in pathname:
        raise RuntimeError, "Cannot convert pathname containing slashes"
    components = string.split(pathname, ':')
    # Remove empty first and/or last component
    if components[0] == '':
        del components[0]
    if components[-1] == '':
        del components[-1]
    # Replace empty string ('::') by .. (will result in '/../' later)
    for i in range(len(components)):
        if components[i] == '':
            components[i] = '..'
    # Truncate names longer than 31 bytes
    components = map(_pncomp2url, components)

    if os.path.isabs(pathname):
        return '/' + string.join(components, '/')
    else:
        return string.join(components, '/')
        
def _pncomp2url(component):
	component = urllib.quote(component[:31], safe='')  # We want to quote slashes
	return component
	
def test():
    for url in ["index.html",
                "bar/index.html",
                "/foo/bar/index.html",
                "/foo/bar/",
                "/"]:
        print `url`, '->', `url2pathname(url)`
    for path in ["drive:",
                 "drive:dir:",
                 "drive:dir:file",
                 "drive:file",
                 "file",
                 ":file",
                 ":dir:",
                 ":dir:file"]:
        print `path`, '->', `pathname2url(path)`

if __name__ == '__main__':
    test()