view mercurial/urllibcompat.py @ 45095:8e04607023e5

procutil: ensure that procutil.std{out,err}.write() writes all bytes

Python 3 offers different kind of streams and it’s not guaranteed for all of
them that calling write() writes all bytes.

When Python is started in unbuffered mode, sys.std{out,err}.buffer are
instances of io.FileIO, whose write() can write less bytes for
platform-specific reasons (e.g. Linux has a 0x7ffff000 bytes maximum and could
write less if interrupted by a signal; when writing to Windows consoles, it’s
limited to 32767 bytes to avoid the "not enough space" error). This can lead to
silent loss of data, both when using sys.std{out,err}.buffer (which may in fact
not be a buffered stream) and when using the text streams sys.std{out,err}
(I’ve created a CPython bug report for that:
https://bugs.python.org/issue41221).

Python may fix the problem at some point. For now, we implement our own wrapper
for procutil.std{out,err} that calls the raw stream’s write() method until all
bytes have been written. We don’t use sys.std{out,err} for larger writes, so I
think it’s not worth the effort to patch them.

# 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 absolute_import

from .pycompat import getattr
from . import pycompat

_sysstr = pycompat.sysstr


class _pycompatstub(object):
    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()

if pycompat.ispy3:
    import urllib.parse

    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")
    import urllib.request

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

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

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

    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


else:
    import BaseHTTPServer
    import CGIHTTPServer
    import SimpleHTTPServer
    import urllib2
    import urllib
    import urlparse

    urlreq._registeraliases(
        urllib,
        (
            b"addclosehook",
            b"addinfourl",
            b"ftpwrapper",
            b"pathname2url",
            b"quote",
            b"splitattr",
            b"splitpasswd",
            b"splitport",
            b"splituser",
            b"unquote",
            b"url2pathname",
            b"urlencode",
        ),
    )
    urlreq._registeraliases(
        urllib2,
        (
            b"AbstractHTTPHandler",
            b"BaseHandler",
            b"build_opener",
            b"FileHandler",
            b"FTPHandler",
            b"HTTPBasicAuthHandler",
            b"HTTPDigestAuthHandler",
            b"HTTPHandler",
            b"HTTPPasswordMgrWithDefaultRealm",
            b"HTTPSHandler",
            b"install_opener",
            b"ProxyHandler",
            b"Request",
            b"urlopen",
        ),
    )
    urlreq._registeraliases(urlparse, (b"urlparse", b"urlunparse",))
    urlreq._registeralias(urlparse, b"parse_qs", b"parseqs")
    urlreq._registeralias(urlparse, b"parse_qsl", b"parseqsl")
    urlerr._registeraliases(urllib2, (b"HTTPError", b"URLError",))
    httpserver._registeraliases(
        BaseHTTPServer, (b"HTTPServer", b"BaseHTTPRequestHandler",)
    )
    httpserver._registeraliases(
        SimpleHTTPServer, (b"SimpleHTTPRequestHandler",)
    )
    httpserver._registeraliases(CGIHTTPServer, (b"CGIHTTPRequestHandler",))

    def gethost(req):
        return req.get_host()

    def getselector(req):
        return req.get_selector()

    def getfullurl(req):
        return req.get_full_url()

    def getdata(req):
        return req.get_data()

    def hasdata(req):
        return req.has_data()