mercurial/urllibcompat.py

interfaces: introduce and use a protocol class for the `mpatch` module

See f2832de2a46c for details when this was done for the `bdiff` module.

Two things worth pointing out-

  1) The `cffi` module "inherits" the `pure` implementation of `patchedsize()`
     because of its wildcard import.
  2) It's odd that the `mpatchError` lives in both `pure` and `cext` modules.

I initially thought to move the exception into the new class, and make the
existing class name an alias to the class in the new location, but the exception
is created in C code by the `cext` module, so that won't work.  I don't think a
protocol class is approriate, because there's nothing special about the class to
distinguish from any other `Exception`.  Fortunately, nobody is catching this
exception in core, so we can kick the can down the road.

# urllibcompat.py - adapters to ease using urllib2 on Py2 and urllib on Py3
#
# Copyright 2017 Google, Inc.
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import annotations

import http.server
import urllib.error
import urllib.parse
import urllib.request
import urllib.response

from . import pycompat

_sysstr = pycompat.sysstr


class _pycompatstub:
    def __init__(self):
        self._aliases = {}

    def _registeraliases(self, origin, items):
        """Add items that will be populated at the first access"""
        items = map(_sysstr, items)
        self._aliases.update(
            (item.replace('_', '').lower(), (origin, item)) for item in items
        )

    def _registeralias(self, origin, attr, name):
        """Alias ``origin``.``attr`` as ``name``"""
        self._aliases[_sysstr(name)] = (origin, _sysstr(attr))

    def __getattr__(self, name):
        try:
            origin, item = self._aliases[name]
        except KeyError:
            raise AttributeError(name)
        self.__dict__[name] = obj = getattr(origin, item)
        return obj


httpserver = _pycompatstub()
urlreq = _pycompatstub()
urlerr = _pycompatstub()

urlreq._registeraliases(
    urllib.parse,
    (
        b"splitattr",
        b"splitpasswd",
        b"splitport",
        b"splituser",
        b"urlparse",
        b"urlunparse",
    ),
)
urlreq._registeralias(urllib.parse, b"parse_qs", b"parseqs")
urlreq._registeralias(urllib.parse, b"parse_qsl", b"parseqsl")
urlreq._registeralias(urllib.parse, b"unquote_to_bytes", b"unquote")

urlreq._registeraliases(
    urllib.request,
    (
        b"AbstractHTTPHandler",
        b"BaseHandler",
        b"build_opener",
        b"FileHandler",
        b"FTPHandler",
        b"ftpwrapper",
        b"HTTPCookieProcessor",
        b"HTTPHandler",
        b"HTTPSHandler",
        b"install_opener",
        b"pathname2url",
        b"HTTPBasicAuthHandler",
        b"HTTPDigestAuthHandler",
        b"HTTPPasswordMgrWithDefaultRealm",
        b"ProxyHandler",
        b"Request",
        b"url2pathname",
        b"urlopen",
    ),
)


urlreq._registeraliases(
    urllib.response,
    (
        b"addclosehook",
        b"addinfourl",
    ),
)

urlerr._registeraliases(
    urllib.error,
    (
        b"HTTPError",
        b"URLError",
    ),
)

httpserver._registeraliases(
    http.server,
    (
        b"HTTPServer",
        b"BaseHTTPRequestHandler",
        b"SimpleHTTPRequestHandler",
        b"CGIHTTPRequestHandler",
    ),
)


# urllib.parse.quote() accepts both str and bytes, decodes bytes
# (if necessary), and returns str. This is wonky. We provide a custom
# implementation that only accepts bytes and emits bytes.
def quote(s, safe='/'):
    # bytestr has an __iter__ that emits characters. quote_from_bytes()
    # does an iteration and expects ints. We coerce to bytes to appease it.
    if isinstance(s, pycompat.bytestr):
        s = bytes(s)
    s = urllib.parse.quote_from_bytes(s, safe=safe)
    return s.encode('ascii', 'strict')


# urllib.parse.urlencode() returns str. We use this function to make
# sure we return bytes.
def urlencode(query, doseq=False):
    s = urllib.parse.urlencode(query, doseq=doseq)
    return s.encode('ascii')


urlreq.quote = quote
urlreq.urlencode = urlencode


def getfullurl(req):
    return req.full_url


def gethost(req):
    return req.host


def getselector(req):
    return req.selector


def getdata(req):
    return req.data


def hasdata(req):
    return req.data is not None