text: """
  This module converts requested URLs to callback view functions.
  
  RegexURLResolver is the main class here. Its resolve() method takes a URL (as
  a string) and returns a tuple in this format:
  
      (view_function, function_args, function_kwargs)
  """
  from __future__ import unicode_literals
  
  import functools
  import re
  import warnings
  from importlib import import_module
  from threading import local
  
  from django.core.exceptions import ImproperlyConfigured, ViewDoesNotExist
  from django.http import Http404
  from django.utils import lru_cache, six
  from django.utils.datastructures import MultiValueDict
  from django.utils.deprecation import RemovedInDjango20Warning
  from django.utils.encoding import force_str, force_text, iri_to_uri
  from django.utils.functional import cached_property, lazy
  from django.utils.http import RFC3986_SUBDELIMS, urlquote
  from django.utils.module_loading import module_has_submodule
  from django.utils.regex_helper import normalize
  from django.utils.six.moves.urllib.parse import urlsplit, urlunsplit
  from django.utils.translation import get_language, override
  
  # SCRIPT_NAME prefixes for each thread are stored here. If there's no entry for
  # the current thread (which is the only one we ever access), it is assumed to
  # be empty.
  _prefixes = local()
  
  # Overridden URLconfs for each thread are stored here.
  _urlconfs = local()
  
  
  class ResolverMatch(object):
      def __init__(self, func, args, kwargs, url_name=None, app_name=None, namespaces=None):
          self.func = func
          self.args = args
          self.kwargs = kwargs
          self.url_name = url_name
          self.app_name = app_name
  
          if namespaces:
              self.namespaces = [x for x in namespaces if x]
          else:
              self.namespaces = []
          self.namespace = ':'.join(self.namespaces)
  
          if not hasattr(func, '__name__'):
              # A class-based view
              self._func_path = '.'.join([func.__class__.__module__, func.__class__.__name__])
          else:
              # A function-based view
              self._func_path = '.'.join([func.__module__, func.__name__])
  
          view_path = url_name or self._func_path
          self.view_name = ':'.join(self.namespaces + [view_path])
  
      def __getitem__(self, index):
          return (self.func, self.args, self.kwargs)[index]
  
      def __repr__(self):
          return "ResolverMatch(func=%s, args=%s, kwargs=%s, url_name=%s, app_name=%s, namespaces=%s)" % (
              self._func_path, self.args, self.kwargs, self.url_name, self.app_name, self.namespaces)
  
  
  class Resolver404(Http404):
      pass
  
  
  class NoReverseMatch(Exception):
      pass
  
  
  @lru_cache.lru_cache(maxsize=None)
  def get_callable(lookup_view, can_fail=False):
      """
      Return a callable corresponding to lookup_view. This function is used
      by both resolve() and reverse(), so can_fail allows the caller to choose
      between returning the input as is and raising an exception when the input
      string can't be interpreted as an import path.
  
      If lookup_view is already a callable, return it.
      If lookup_view is a string import path that can be resolved to a callable,
        import that callable and return it.
      If lookup_view is some other kind of string and can_fail is True, the string
        is returned as is. If can_fail is False, an exception is raised (either
        ImportError or ViewDoesNotExist).
      """
      if callable(lookup_view):
          return lookup_view
  
      mod_name, func_name = get_mod_func(lookup_view)
      if not func_name:  # No '.' in lookup_view
          if can_fail:
              return lookup_view
          else:
              raise ImportError(
                  "Could not import '%s'. The path must be fully qualified." %
                  lookup_view)
  
      try:
          mod = import_module(mod_name)
      except ImportError:
          if can_fail:
              return lookup_view
          else:
              parentmod, submod = get_mod_func(mod_name)
              if submod and not module_has_submodule(import_module(parentmod), submod):
                  raise ViewDoesNotExist(
                      "Could not import '%s'. Parent module %s does not exist." %
                      (lookup_view, mod_name))
              else:
                  raise
      else:
          try:
              view_func = getattr(mod, func_name)
          except AttributeError:
              if can_fail:
                  return lookup_view
              else:
                  raise ViewDoesNotExist(
                      "Could not import '%s'. View does not exist in module %s." %
                      (lookup_view, mod_name))
          else:
              if not callable(view_func):
                  # For backwards compatibility this is raised regardless of can_fail
                  raise ViewDoesNotExist(
                      "Could not import '%s.%s'. View is not callable." %
                      (mod_name, func_name))
  
              return view_func
  
  
  @lru_cache.lru_cache(maxsize=None)
  def get_resolver(urlconf):
      if urlconf is None:
          from django.conf import settings
          urlconf = settings.ROOT_URLCONF
      return RegexURLResolver(r'^/', urlconf)
  
  
  @lru_cache.lru_cache(maxsize=None)
  def get_ns_resolver(ns_pattern, resolver):
      # Build a namespaced resolver for the given parent urlconf pattern.
      # This makes it possible to have captured parameters in the parent
      # urlconf pattern.
      ns_resolver = RegexURLResolver(ns_pattern, resolver.url_patterns)
      return RegexURLResolver(r'^/', [ns_resolver])
  
  
  def get_mod_func(callback):
      # Converts 'django.views.news.stories.story_detail' to
      # ['django.views.news.stories', 'story_detail']
      try:
          dot = callback.rindex('.')
      except ValueError:
          return callback, ''
      return callback[:dot], callback[dot + 1:]
  
  
  class LocaleRegexProvider(object):
      """
      A mixin to provide a default regex property which can vary by active
      language.
  
      """
      def __init__(self, regex):
          # regex is either a string representing a regular expression, or a
          # translatable string (using ugettext_lazy) representing a regular
          # expression.
          self._regex = regex
          self._regex_dict = {}
  
      @property
      def regex(self):
          """
          Returns a compiled regular expression, depending upon the activated
          language-code.
          """
          language_code = get_language()
          if language_code not in self._regex_dict:
              if isinstance(self._regex, six.string_types):
                  regex = self._regex
              else:
                  regex = force_text(self._regex)
              try:
                  compiled_regex = re.compile(regex, re.UNICODE)
              except re.error as e:
                  raise ImproperlyConfigured(
                      '"%s" is not a valid regular expression: %s' %
                      (regex, six.text_type(e)))
  
              self._regex_dict[language_code] = compiled_regex
          return self._regex_dict[language_code]
  
  
  class RegexURLPattern(LocaleRegexProvider):
      def __init__(self, regex, callback, default_args=None, name=None):
          LocaleRegexProvider.__init__(self, regex)
          # callback is either a string like 'foo.views.news.stories.story_detail'
          # which represents the path to a module and a view function name, or a
          # callable object (view).
          if callable(callback):
              self._callback = callback
          else:
              self._callback = None
              self._callback_str = callback
          self.default_args = default_args or {}
          self.name = name
  
      def __repr__(self):
          return force_str('<%s %s %s>' % (self.__class__.__name__, self.name, self.regex.pattern))
  
      def add_prefix(self, prefix):
          """
          Adds the prefix string to a string-based callback.
          """
          if not prefix or not hasattr(self, '_callback_str'):
              return
          self._callback_str = prefix + '.' + self._callback_str
  
      def resolve(self, path):
          match = self.regex.search(path)
          if match:
              # If there are any named groups, use those as kwargs, ignoring
              # non-named groups. Otherwise, pass all non-named arguments as
              # positional arguments.
              kwargs = match.groupdict()
              if kwargs:
                  args = ()
              else:
                  args = match.groups()
              # In both cases, pass any extra_kwargs as **kwargs.
              kwargs.update(self.default_args)
  
              return ResolverMatch(self.callback, args, kwargs, self.name)
  
      @property
      def callback(self):
          if self._callback is not None:
              return self._callback
  
          self._callback = get_callable(self._callback_str)
          return self._callback
  
  
  class RegexURLResolver(LocaleRegexProvider):
      def __init__(self, regex, urlconf_name, default_kwargs=None, app_name=None, namespace=None):
          LocaleRegexProvider.__init__(self, regex)
          # urlconf_name is the dotted Python path to the module defining
          # urlpatterns. It may also be an object with an urlpatterns attribute
          # or urlpatterns itself.
          self.urlconf_name = urlconf_name
          self.callback = None
          self.default_kwargs = default_kwargs or {}
          self.namespace = namespace
          self.app_name = app_name
          self._reverse_dict = {}
          self._namespace_dict = {}
          self._app_dict = {}
          # set of dotted paths to all functions and classes that are used in
          # urlpatterns
          self._callback_strs = set()
          self._populated = False
  
      def __repr__(self):
          if isinstance(self.urlconf_name, list) and len(self.urlconf_name):
              # Don't bother to output the whole list, it can be huge
              urlconf_repr = '<%s list>' % self.urlconf_name[0].__class__.__name__
          else:
              urlconf_repr = repr(self.urlconf_name)
          return str('<%s %s (%s:%s) %s>') % (
              self.__class__.__name__, urlconf_repr, self.app_name,
              self.namespace, self.regex.pattern)
  
      def _populate(self):
          lookups = MultiValueDict()
          namespaces = {}
          apps = {}
          language_code = get_language()
          for pattern in reversed(self.url_patterns):
              if hasattr(pattern, '_callback_str'):
                  self._callback_strs.add(pattern._callback_str)
              elif hasattr(pattern, '_callback'):
                  callback = pattern._callback
                  if isinstance(callback, functools.partial):
                      callback = callback.func
  
                  if not hasattr(callback, '__name__'):
                      lookup_str = callback.__module__ + "." + callback.__class__.__name__
                  else:
                      lookup_str = callback.__module__ + "." + callback.__name__
                  self._callback_strs.add(lookup_str)
              p_pattern = pattern.regex.pattern
              if p_pattern.startswith('^'):
                  p_pattern = p_pattern[1:]
              if isinstance(pattern, RegexURLResolver):
                  if pattern.namespace:
                      namespaces[pattern.namespace] = (p_pattern, pattern)
                      if pattern.app_name:
                          apps.setdefault(pattern.app_name, []).append(pattern.namespace)
                  else:
                      parent_pat = pattern.regex.pattern
                      for name in pattern.reverse_dict:
                          for matches, pat, defaults in pattern.reverse_dict.getlist(name):
                              new_matches = normalize(parent_pat + pat)
                              lookups.appendlist(
                                  name,
                                  (
                                      new_matches,
                                      p_pattern + pat,
                                      dict(defaults, **pattern.default_kwargs),
                                  )
                              )
                      for namespace, (prefix, sub_pattern) in pattern.namespace_dict.items():
                          namespaces[namespace] = (p_pattern + prefix, sub_pattern)
                      for app_name, namespace_list in pattern.app_dict.items():
                          apps.setdefault(app_name, []).extend(namespace_list)
                      self._callback_strs.update(pattern._callback_strs)
              else:
                  bits = normalize(p_pattern)
                  lookups.appendlist(pattern.callback, (bits, p_pattern, pattern.default_args))
                  if pattern.name is not None:
                      lookups.appendlist(pattern.name, (bits, p_pattern, pattern.default_args))
          self._reverse_dict[language_code] = lookups
          self._namespace_dict[language_code] = namespaces
          self._app_dict[language_code] = apps
          self._populated = True
  
      @property
      def reverse_dict(self):
          language_code = get_language()
          if language_code not in self._reverse_dict:
              self._populate()
          return self._reverse_dict[language_code]
  
      @property
      def namespace_dict(self):
          language_code = get_language()
          if language_code not in self._namespace_dict:
              self._populate()
          return self._namespace_dict[language_code]
  
      @property
      def app_dict(self):
          language_code = get_language()
          if language_code not in self._app_dict:
              self._populate()
          return self._app_dict[language_code]
  
      def _is_callback(self, name):
          if not self._populated:
              self._populate()
          return name in self._callback_strs
  
      def resolve(self, path):
          path = force_text(path)  # path may be a reverse_lazy object
          tried = []
          match = self.regex.search(path)
          if match:
              new_path = path[match.end():]
              for pattern in self.url_patterns:
                  try:
                      sub_match = pattern.resolve(new_path)
                  except Resolver404 as e:
                      sub_tried = e.args[0].get('tried')
                      if sub_tried is not None:
                          tried.extend([pattern] + t for t in sub_tried)
                      else:
                          tried.append([pattern])
                  else:
                      if sub_match:
                          # Merge captured arguments in match with submatch
                          sub_match_dict = dict(match.groupdict(), **self.default_kwargs)
                          sub_match_dict.update(sub_match.kwargs)
  
                          # If there are *any* named groups, ignore all non-named groups.
                          # Otherwise, pass all non-named arguments as positional arguments.
                          sub_match_args = sub_match.args
                          if not sub_match_dict:
                              sub_match_args = match.groups() + sub_match.args
  
                          return ResolverMatch(
                              sub_match.func,
                              sub_match_args,
                              sub_match_dict,
                              sub_match.url_name,
                              self.app_name or sub_match.app_name,
                              [self.namespace] + sub_match.namespaces
                          )
                      tried.append([pattern])
              raise Resolver404({'tried': tried, 'path': new_path})
          raise Resolver404({'path': path})
  
      @cached_property
      def urlconf_module(self):
          if isinstance(self.urlconf_name, six.string_types):
              return import_module(self.urlconf_name)
          else:
              return self.urlconf_name
  
      @cached_property
      def url_patterns(self):
          # urlconf_module might be a valid set of patterns, so we default to it
          patterns = getattr(self.urlconf_module, "urlpatterns", self.urlconf_module)
          try:
              iter(patterns)
          except TypeError:
              msg = (
                  "The included urlconf '{name}' does not appear to have any "
                  "patterns in it. If you see valid patterns in the file then "
                  "the issue is probably caused by a circular import."
              )
              raise ImproperlyConfigured(msg.format(name=self.urlconf_name))
          return patterns
  
      def resolve_error_handler(self, view_type):
          callback = getattr(self.urlconf_module, 'handler%s' % view_type, None)
          if not callback:
              # No handler specified in file; use default
              # Lazy import, since django.urls imports this file
              from django.conf import urls
              callback = getattr(urls, 'handler%s' % view_type)
          return get_callable(callback), {}
  
      def reverse(self, lookup_view, *args, **kwargs):
          return self._reverse_with_prefix(lookup_view, '', *args, **kwargs)
  
      def _reverse_with_prefix(self, lookup_view, _prefix, *args, **kwargs):
          if args and kwargs:
              raise ValueError("Don't mix *args and **kwargs in call to reverse()!")
          text_args = [force_text(v) for v in args]
          text_kwargs = {k: force_text(v) for (k, v) in kwargs.items()}
  
          if not self._populated:
              self._populate()
  
          original_lookup = lookup_view
          try:
              if self._is_callback(lookup_view):
                  lookup_view = get_callable(lookup_view, True)
          except (ImportError, AttributeError) as e:
              raise NoReverseMatch("Error importing '%s': %s." % (lookup_view, e))
          else:
              if not callable(original_lookup) and callable(lookup_view):
                  warnings.warn(
                      'Reversing by dotted path is deprecated (%s).' % original_lookup,
                      RemovedInDjango20Warning, stacklevel=3
                  )
          possibilities = self.reverse_dict.getlist(lookup_view)
  
          for possibility, pattern, defaults in possibilities:
              for result, params in possibility:
                  if args:
                      if len(args) != len(params):
                          continue
                      candidate_subs = dict(zip(params, text_args))
                  else:
                      if (set(kwargs.keys()) | set(defaults.keys()) != set(params) |
                              set(defaults.keys())):
                          continue
                      matches = True
                      for k, v in defaults.items():
                          if kwargs.get(k, v) != v:
                              matches = False
                              break
                      if not matches:
                          continue
                      candidate_subs = text_kwargs
                  # WSGI provides decoded URLs, without %xx escapes, and the URL
                  # resolver operates on such URLs. First substitute arguments
                  # without quoting to build a decoded URL and look for a match.
                  # Then, if we have a match, redo the substitution with quoted
                  # arguments in order to return a properly encoded URL.
                  candidate_pat = _prefix.replace('%', '%%') + result
                  if re.search('^%s%s' % (re.escape(_prefix), pattern), candidate_pat % candidate_subs, re.UNICODE):
                      # safe characters from `pchar` definition of RFC 3986
                      url = urlquote(candidate_pat % candidate_subs, safe=RFC3986_SUBDELIMS + str('/~:@'))
                      # Don't allow construction of scheme relative urls.
                      if url.startswith('//'):
                          url = '/%%2F%s' % url[2:]
                      return url
          # lookup_view can be URL label, or dotted path, or callable, Any of
          # these can be passed in at the top, but callables are not friendly in
          # error messages.
          m = getattr(lookup_view, '__module__', None)
          n = getattr(lookup_view, '__name__', None)
          if m is not None and n is not None:
              lookup_view_s = "%s.%s" % (m, n)
          else:
              lookup_view_s = lookup_view
  
          patterns = [pattern for (possibility, pattern, defaults) in possibilities]
          raise NoReverseMatch("Reverse for '%s' with arguments '%s' and keyword "
                  "arguments '%s' not found. %d pattern(s) tried: %s" %
                               (lookup_view_s, args, kwargs, len(patterns), patterns))
  
  
  class LocaleRegexURLResolver(RegexURLResolver):
      """
      A URL resolver that always matches the active language code as URL prefix.
  
      Rather than taking a regex argument, we just override the ``regex``
      function to always return the active language-code as regex.
      """
      def __init__(self, urlconf_name, default_kwargs=None, app_name=None, namespace=None):
          super(LocaleRegexURLResolver, self).__init__(
              None, urlconf_name, default_kwargs, app_name, namespace)
  
      @property
      def regex(self):
          language_code = get_language()
          if language_code not in self._regex_dict:
              regex_compiled = re.compile('^%s/' % language_code, re.UNICODE)
              self._regex_dict[language_code] = regex_compiled
          return self._regex_dict[language_code]
  
  
  def resolve(path, urlconf=None):
      if urlconf is None:
          urlconf = get_urlconf()
      return get_resolver(urlconf).resolve(path)
  
  
  def reverse(viewname, urlconf=None, args=None, kwargs=None, current_app=None):
      if urlconf is None:
          urlconf = get_urlconf()
      resolver = get_resolver(urlconf)
      args = args or []
      kwargs = kwargs or {}
  
      prefix = get_script_prefix()
  
      if not isinstance(viewname, six.string_types):
          view = viewname
      else:
          parts = viewname.split(':')
          parts.reverse()
          view = parts[0]
          path = parts[1:]
  
          resolved_path = []
          ns_pattern = ''
          while path:
              ns = path.pop()
  
              # Lookup the name to see if it could be an app identifier
              try:
                  app_list = resolver.app_dict[ns]
                  # Yes! Path part matches an app in the current Resolver
                  if current_app and current_app in app_list:
                      # If we are reversing for a particular app,
                      # use that namespace
                      ns = current_app
                  elif ns not in app_list:
                      # The name isn't shared by one of the instances
                      # (i.e., the default) so just pick the first instance
                      # as the default.
                      ns = app_list[0]
              except KeyError:
                  pass
  
              try:
                  extra, resolver = resolver.namespace_dict[ns]
                  resolved_path.append(ns)
                  ns_pattern = ns_pattern + extra
              except KeyError as key:
                  if resolved_path:
                      raise NoReverseMatch(
                          "%s is not a registered namespace inside '%s'" %
                          (key, ':'.join(resolved_path)))
                  else:
                      raise NoReverseMatch("%s is not a registered namespace" %
                                           key)
          if ns_pattern:
              resolver = get_ns_resolver(ns_pattern, resolver)
  
      return force_text(iri_to_uri(resolver._reverse_with_prefix(view, prefix, *args, **kwargs)))
  
  reverse_lazy = lazy(reverse, six.text_type)
  
  
  def clear_url_caches():
      get_callable.cache_clear()
      get_resolver.cache_clear()
      get_ns_resolver.cache_clear()
  
  
  def set_script_prefix(prefix):
      """
      Sets the script prefix for the current thread.
      """
      if not prefix.endswith('/'):
          prefix += '/'
      _prefixes.value = prefix
  
  
  def get_script_prefix():
      """
      Returns the currently active script prefix. Useful for client code that
      wishes to construct their own URLs manually (although accessing the request
      instance is normally going to be a lot cleaner).
      """
      return getattr(_prefixes, "value", '/')
  
  
  def clear_script_prefix():
      """
      Unsets the script prefix for the current thread.
      """
      try:
          del _prefixes.value
      except AttributeError:
          pass
  
  
  def set_urlconf(urlconf_name):
      """
      Sets the URLconf for the current thread (overriding the default one in
      settings). Set to None to revert back to the default.
      """
      if urlconf_name:
          _urlconfs.value = urlconf_name
      else:
          if hasattr(_urlconfs, "value"):
              del _urlconfs.value
  
  
  def get_urlconf(default=None):
      """
      Returns the root URLconf to use for the current thread if it has been
      changed from the default one.
      """
      return getattr(_urlconfs, "value", default)
  
  
  def is_valid_path(path, urlconf=None):
      """
      Returns True if the given path resolves against the default URL resolver,
      False otherwise.
  
      This is a convenience method to make working with "is this a match?" cases
      easier, avoiding unnecessarily indented try...except blocks.
      """
      try:
          resolve(path, urlconf)
          return True
      except Resolver404:
          return False
  
  
  def translate_url(url, lang_code):
      """
      Given a URL (absolute or relative), try to get its translated version in
      the `lang_code` language (either by i18n_patterns or by translated regex).
      Return the original URL if no translated version is found.
      """
      parsed = urlsplit(url)
      try:
          match = resolve(parsed.path)
      except Resolver404:
          pass
      else:
          to_be_reversed = "%s:%s" % (match.namespace, match.url_name) if match.namespace else match.url_name
          with override(lang_code):
              try:
                  url = reverse(to_be_reversed, args=match.args, kwargs=match.kwargs)
              except NoReverseMatch:
                  pass
              else:
                  url = urlunsplit((parsed.scheme, parsed.netloc, url, parsed.query, parsed.fragment))
      return url
  