class rx:
    dump_includes = re.compile("^\s*\([\d*]+\)\s+(.+)$", re.M)
    # directives we care about
    interesting = re.compile(
        "^ \s* (ErrorLog | CustomLog | Server(Name|Alias) | (Virtual)?DocumentRoot | Sec\w* | Use\sSec\w+ | modsecurity\w* ) \\b",
        re.M|re.I|re.X
    )
    # count <VirtualHost>s
    count_virtualhost = re.compile("""
        ^ \s*(<VirtualHost)\\b
    """, re.X|re.M|re.I)
    # extract directive line including line continuations (<\><NL>)
    configline = re.compile(
        """ ^
        [\ \\t]*                          # whitespace \h*
        # (?:Use \s{1,4})?                  # optional: `Use␣` to find custom macros like `Use SecRuleRemoveByPath…`
        (
          \w+ |                           # alphanumeric directive 

                SecRuleRemove* states (id→0)
        ruledecl : dict
                Map contained SecRules id into vhosts.rules{}
        update : dict
                Map of SecRuleUpdate…By…  { id→{vars:[],action:[]} }
        linemap : dict
                Line number → RuleID (for looking up chained rules in error.log)
        warn : str
                Textual notice on conf file, e.g. "more than VirtualHost defined"
    """

    # split *.conf directives, dispatch onto assignment/extract methods
    def __init__(self, fn, src, cfg_only=False):

        # vhost properties
        self.fn = fn
        self.t = "cfg"
        self.name = ""
        self.logs = []
        self.cfg = {}
        self.rulestate = {}    # ➗ ❌  undef=✅
        self.ruledecl = {}
        self.update = {}       # SecRuleUpdate… map
        self.warn = ""
        # internal state
        self.linemap = {}      # lineno → first id: occurence
        self.mk_linemap(src)   # fill .linemap{}
        self.wrap = []         # history of <Wrap>
        
        # extract directive lines
        for dir,args  in rx.configline.findall(src):    # or .finditer()? to record positions right away?

        # determine config file type
        if self.name:
            self.t = "vhost"
        elif len(self.rulestate) >= 5:
            self.t = "cfg"
        elif len(self.ruledecl) >= 5:
            self.t = "rules"
        # notice
        num = len(rx.count_virtualhost.findall(src))
        if num == 2:
            self.warn = "Two <VirtualHost>s defined. Only first will be updated by modseccfg."
        elif num > 2:
            self.warn = "Unreasonable number of <VirtualHost> entries in conf. It probably shouldn't be edited through modseccfg."
        elif not os.access(self.fn, os.W_OK):
            self.warn = "Config file isn't writable. Don't even try."

    # strip \\ \n line continuations, split all "args"
    def split_args(self, args):
        args = re.sub(rx.escnewline, " ", args)
        args = rx.split_args.findall(args)
        args = [s[1] or s[0] for s in args]
        args = [s for s in args if len(s)]