ishg_path = False

    log.debug('pathinfo: %s detected as Mercurial %s',

        path_info, ishg_path

    )

    return ishg_path

def get_header_hgarg(environ):

    """Decode the special Mercurial encoding of big requests over multiple headers.

    >>> get_header_hgarg({})

    ''

    >>> get_header_hgarg({'HTTP_X_HGARG_0': ' ', 'HTTP_X_HGARG_1': 'a','HTTP_X_HGARG_2': '','HTTP_X_HGARG_3': 'b+c %20'})

    'ab+c %20'

    """

    chunks = []

    i = 1

    while True:

        v = environ.get('HTTP_X_HGARG_%d' % i)

        if v is None:

            break

        chunks.append(v)

        i += 1

    return ''.join(chunks)

class SimpleHg(BaseVCSController):

    def _handle_request(self, environ, start_response):

        if not is_mercurial(environ):

            return self.application(environ, start_response)

        ip_addr = self._get_ip_addr(environ)

        # skip passing error to error controller

        environ['pylons.status_code_redirect'] = True

        #======================================================================

        # EXTRACT REPOSITORY NAME FROM ENV

        #======================================================================

        try:

            str_repo_name = self.__get_repository(environ)

            repo_name = safe_unicode(str_repo_name)

            log.debug('Extracted repo name is %s', repo_name)

        except Exception as e:

            log.error('error extracting repo_name: %r', e)

            return HTTPInternalServerError()(environ, start_response)

        # quick check if that dir exists...

        if not is_valid_repo(repo_name, self.basepath, 'hg'):

            return HTTPNotFound()(environ, start_response)

        #======================================================================

        # GET ACTION PULL or PUSH

        #======================================================================

        try:

            action = self.__get_action(environ)

        except HTTPBadRequest as e:

            return e(environ, start_response)

        #======================================================================

        # CHECK PERMISSIONS

        #======================================================================

        user, response_app = self._authorize(environ, start_response, action, repo_name, ip_addr)

        if response_app is not None:

            return response_app(environ, start_response)

        # extras are injected into Mercurial UI object and later available

        # in hooks executed by Kallithea

        from kallithea import CONFIG

        server_url = get_server_url(environ)

        extras = {

            'ip': ip_addr,

            'username': user.username,

            'action': action,

            'repository': repo_name,

            'scm': 'hg',

            'config': CONFIG['__file__'],

            'server_url': server_url,

        }

        #======================================================================

        # MERCURIAL REQUEST HANDLING

        #======================================================================

        repo_path = os.path.join(safe_str(self.basepath), str_repo_name)

        log.debug('Repository path is %s', repo_path)

        fix_PATH()

        log.debug('HOOKS extras is %s', extras)

        baseui = make_ui(repo_path=repo_path)

        _set_extras(extras or {})

        try:

            log.info('%s action on Mercurial repo "%s" by "%s" from %s',

                     action, str_repo_name, safe_str(user.username), ip_addr)

            environ['REPO_NAME'] = str_repo_name # used by hgweb_mod.hgweb

            app = self.__make_app(repo_path, baseui)

            return app(environ, start_response)

        except Exception:

            log.error(traceback.format_exc())

            return HTTPInternalServerError()(environ, start_response)

    def __make_app(self, repo_name, baseui):

        """

        Make an hgweb wsgi application using baseui.

        """

        return hgweb_mod.hgweb(repo_name, name=repo_name, baseui=baseui)

    def __get_repository(self, environ):

        """

        Gets repository name out of PATH_INFO header

        :param environ: environ where PATH_INFO is stored

        """

        try:

            environ['PATH_INFO'] = self._get_by_id(environ['PATH_INFO'])

            repo_name = '/'.join(environ['PATH_INFO'].split('/')[1:])

            if repo_name.endswith('/'):

                repo_name = repo_name.rstrip('/')

        except Exception:

            log.error(traceback.format_exc())

            raise

        return repo_name

    def __get_action(self, environ):

        """

        Maps Mercurial request commands into 'pull' or 'push'.

        Raises HTTPBadRequest if the request environment doesn't look like a hg client.

        """

        mapping = {

            # 'batch' is not in this list - it is handled explicitly

            'between': 'pull',

            'branches': 'pull',

            'branchmap': 'pull',

            'capabilities': 'pull',

            'changegroup': 'pull',

            'changegroupsubset': 'pull',

            'changesetdata': 'pull',

            'clonebundles': 'pull',

            'debugwireargs': 'pull',

            'filedata': 'pull',

            'getbundle': 'pull',

            'getlfile': 'pull',

            'heads': 'pull',

            'hello': 'pull',

            'known': 'pull',

            'lheads': 'pull',

            'listkeys': 'pull',

            'lookup': 'pull',

            'manifestdata': 'pull',

            'narrow_widen': 'pull',

            'protocaps': 'pull',

            'statlfile': 'pull',

            'stream_out': 'pull',

            'pushkey': 'push',

            'putlfile': 'push',

            'unbundle': 'push',

            }

        for qry in environ['QUERY_STRING'].split('&'):

            parts = qry.split('=', 1)

            if len(parts) == 2 and parts[0] == 'cmd':

                cmd = parts[1]

                if cmd == 'batch':

                    hgarg = get_header_hgarg(environ)

                    if not hgarg.startswith('cmds='):

                        return 'push' # paranoid and safe

                    for cmd_arg in hgarg[5:].split(';'):

                        cmd, _args = urllib.unquote_plus(cmd_arg).split(' ', 1)

                        op = mapping.get(cmd, 'push')

                        if op != 'pull':

                            assert op == 'push'

                            return 'push'

                    return 'pull'

                return mapping.get(cmd, 'push')

        # Note: the client doesn't get the helpful error message

        raise HTTPBadRequest('Unable to detect pull/push action! Are you using non standard command or client?')