[PATCH 2 of 2 chg-port] osutil: implement pure version of recvfds() for PyPy

[Sean Farley]

Yuya Nishihara <yuya at tcha.org> writes:

> # HG changeset patch
> # User Yuya Nishihara <yuya at tcha.org>
> # Date 1450363989 -32400
> #      Thu Dec 17 23:53:09 2015 +0900
> # Node ID 9726608c61dd53832c821d8bb9ce15b8aa268466
> # Parent  076525f412e74c913f72ff52034aa7ea046af74b
> osutil: implement pure version of recvfds() for PyPy
>
> This is less portable than the C version, but PyPy can't load CPython
> extensions. So for now, this will be used on PyPy.
>
> I've tested it on Linux amd64 and Mac OS X.
>
> diff --git a/mercurial/pure/osutil.py b/mercurial/pure/osutil.py
> --- a/mercurial/pure/osutil.py
> +++ b/mercurial/pure/osutil.py
> @@ -7,8 +7,12 @@
>  
>  from __future__ import absolute_import
>  
> +import ctypes
> +import ctypes.util
>  import os
> +import socket
>  import stat as statmod
> +import sys
>  
>  def _mode_to_kind(mode):
>      if statmod.S_ISREG(mode):
> @@ -59,8 +63,87 @@ def listdir(path, stat=False, skip=None)
>  
>  if os.name != 'nt':
>      posixfile = open
> +
> +    _SCM_RIGHTS = 0x01
> +    _socklen_t = ctypes.c_uint
> +
> +    if sys.platform == 'linux2':
> +        # socket.h says "the type should be socklen_t but the definition of
> +        # the kernel is incompatible with this."
> +        _cmsg_len_t = ctypes.c_size_t
> +        _msg_controllen_t = ctypes.c_size_t
> +        _msg_iovlen_t = ctypes.c_size_t
> +    else:
> +        _cmsg_len_t = _socklen_t
> +        _msg_controllen_t = _socklen_t
> +        _msg_iovlen_t = ctypes.c_int

I think we usually write the above without the else clause:

    _cmsg_len_t = _socklen_t
    _msg_controllen_t = _socklen_t
    _msg_iovlen_t = ctypes.c_int
    if sys.platform == 'linux2':
        # socket.h says "the type should be socklen_t but the definition of
        # the kernel is incompatible with this."
        _cmsg_len_t = ctypes.c_size_t
        _msg_controllen_t = ctypes.c_size_t
        _msg_iovlen_t = ctypes.c_size_t

But that's a minor nit. Otherwise, both these patches look good to me.