posix: simplify checkexec check
Use a slightly simpler logic that in some cases can avoid an unnecessary chmod
and stat.
Instead of flipping the X bits, make it more clear that we rely on no X bits
being set on initial file creation, and that at least some of them stick after
they all have been set.
Tests if hgweb can run without touching sys.stdin, as is required
by the WSGI standard and strictly implemented by mod_wsgi.
$ hg init repo
$ cd repo
$ echo foo > bar
$ hg add bar
$ hg commit -m "test"
$ cat > request.py <<EOF
> from __future__ import absolute_import
> import os
> import sys
> from mercurial import (
> dispatch,
> hg,
> ui as uimod,
> util,
> )
> ui = uimod.ui
> from mercurial.hgweb.hgweb_mod import (
> hgweb,
> )
> stringio = util.stringio
>
> class FileLike(object):
> def __init__(self, real):
> self.real = real
> def fileno(self):
> print >> sys.__stdout__, 'FILENO'
> return self.real.fileno()
> def read(self):
> print >> sys.__stdout__, 'READ'
> return self.real.read()
> def readline(self):
> print >> sys.__stdout__, 'READLINE'
> return self.real.readline()
>
> sys.stdin = FileLike(sys.stdin)
> errors = stringio()
> input = stringio()
> output = stringio()
>
> def startrsp(status, headers):
> print '---- STATUS'
> print status
> print '---- HEADERS'
> print [i for i in headers if i[0] != 'ETag']
> print '---- DATA'
> return output.write
>
> env = {
> 'wsgi.version': (1, 0),
> 'wsgi.url_scheme': 'http',
> 'wsgi.errors': errors,
> 'wsgi.input': input,
> 'wsgi.multithread': False,
> 'wsgi.multiprocess': False,
> 'wsgi.run_once': False,
> 'REQUEST_METHOD': 'GET',
> 'SCRIPT_NAME': '',
> 'PATH_INFO': '',
> 'QUERY_STRING': '',
> 'SERVER_NAME': '127.0.0.1',
> 'SERVER_PORT': os.environ['HGPORT'],
> 'SERVER_PROTOCOL': 'HTTP/1.0'
> }
>
> i = hgweb('.')
> for c in i(env, startrsp):
> pass
> print '---- ERRORS'
> print errors.getvalue()
> print '---- OS.ENVIRON wsgi variables'
> print sorted([x for x in os.environ if x.startswith('wsgi')])
> print '---- request.ENVIRON wsgi variables'
> with i._obtainrepo() as repo:
> print sorted([x for x in repo.ui.environ if x.startswith('wsgi')])
> EOF
$ python request.py
---- STATUS
200 Script output follows
---- HEADERS
[('Content-Type', 'text/html; charset=ascii')]
---- DATA
---- ERRORS
---- OS.ENVIRON wsgi variables
[]
---- request.ENVIRON wsgi variables
['wsgi.errors', 'wsgi.input', 'wsgi.multiprocess', 'wsgi.multithread', 'wsgi.run_once', 'wsgi.url_scheme', 'wsgi.version']
$ cd ..