"""Macintosh-specific module for conversion between pathnames and URLs.

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

import urllib.parse
import os

__all__ = ["url2pathname","pathname2url"]

def url2pathname(pathname):
"""OS-specific conversion from a relative URL of the 'file' scheme
to a file system path; not recommended for general use."""
#
# XXXX The .. handling should be fixed...
#
tp = urllib.parse.splittype(pathname)[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 pathname[:3] == '///':
pathname = pathname[2:]
elif pathname[:2] == '//':
raise RuntimeError('Cannot convert non-local URL to pathname')
components = pathname.split('/')
# 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 = ':'.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 = ':' + ':'.join(components)
# and finally unquote slashes and other funny characters
return urllib.parse.unquote(rv)

def pathname2url(pathname):
"""OS-specific conversion from a file system path to a relative URL
of the 'file' scheme; not recommended for general use."""
if '/' in pathname:
raise RuntimeError("Cannot convert pathname containing slashes")
components = pathname.split(':')
# 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 '/' + '/'.join(components)
else:
return '/'.join(components)

def _pncomp2url(component):
# We want to quote slashes
return urllib.parse.quote(component[:31], safe='')