parsers: avoid signed/unsigned comparison mismatch
Based on warning from Microsoft Visual C++ 2008.
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 mercurial import dispatch
> from mercurial.hgweb.hgweb_mod import hgweb
> from mercurial.ui import ui
> from mercurial import hg
> from StringIO import StringIO
> import os, sys
>
> 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('.')
> i(env, startrsp)
> 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'
> print sorted([x for x in i.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 ..