third_party/jinja2/utils.py - cobalt - Git at Google

 # -*- coding: utf-8 -*-
 import json
 import os
 import re
 import warnings
 from collections import deque
 from random import choice
 from random import randrange
 from string import ascii_letters as _letters
 from string import digits as _digits
 from threading import Lock

 from markupsafe import escape
 from markupsafe import Markup

 from ._compat import abc
 from ._compat import string_types
 from ._compat import text_type
 from ._compat import url_quote

 # special singleton representing missing values for the runtime
 missing = type("MissingType", (), {"__repr__": lambda x: "missing"})()

 # internal code
 internal_code = set()

 concat = u"".join

 _slash_escape = "\\/" not in json.dumps("/")


 def contextfunction(f):
     """This decorator can be used to mark a function or method context callable.
     A context callable is passed the active :class:`Context` as first argument when
     called from the template.  This is useful if a function wants to get access
     to the context or functions provided on the context object.  For example
     a function that returns a sorted list of template variables the current
     template exports could look like this::

         @contextfunction
         def get_exported_names(context):
             return sorted(context.exported_vars)
     """
     f.contextfunction = True
     return f


 def evalcontextfunction(f):
     """This decorator can be used to mark a function or method as an eval
     context callable.  This is similar to the :func:`contextfunction`
     but instead of passing the context, an evaluation context object is
     passed.  For more information about the eval context, see
     :ref:`eval-context`.

     .. versionadded:: 2.4
     """
     f.evalcontextfunction = True
     return f


 def environmentfunction(f):
     """This decorator can be used to mark a function or method as environment
     callable.  This decorator works exactly like the :func:`contextfunction`
     decorator just that the first argument is the active :class:`Environment`
     and not context.
     """
     f.environmentfunction = True
     return f


 def internalcode(f):
     """Marks the function as internally used"""
     internal_code.add(f.__code__)
     return f


 def is_undefined(obj):
     """Check if the object passed is undefined.  This does nothing more than
     performing an instance check against :class:`Undefined` but looks nicer.
     This can be used for custom filters or tests that want to react to
     undefined variables.  For example a custom default filter can look like
     this::

         def default(var, default=''):
             if is_undefined(var):
                 return default
             return var
     """
     from .runtime import Undefined

     return isinstance(obj, Undefined)


 def consume(iterable):
     """Consumes an iterable without doing anything with it."""
     for _ in iterable:
         pass


 def clear_caches():
     """Jinja keeps internal caches for environments and lexers.  These are
     used so that Jinja doesn't have to recreate environments and lexers all
     the time.  Normally you don't have to care about that but if you are
     measuring memory consumption you may want to clean the caches.
     """
     from .environment import _spontaneous_environments
     from .lexer import _lexer_cache

     _spontaneous_environments.clear()
     _lexer_cache.clear()


 def import_string(import_name, silent=False):
     """Imports an object based on a string.  This is useful if you want to
     use import paths as endpoints or something similar.  An import path can
     be specified either in dotted notation (``xml.sax.saxutils.escape``)
     or with a colon as object delimiter (``xml.sax.saxutils:escape``).

     If the `silent` is True the return value will be `None` if the import
     fails.

     :return: imported object
     """
     try:
         if ":" in import_name:
             module, obj = import_name.split(":", 1)
         elif "." in import_name:
             module, _, obj = import_name.rpartition(".")
         else:
             return __import__(import_name)
         return getattr(__import__(module, None, None, [obj]), obj)
     except (ImportError, AttributeError):
         if not silent:
             raise


 def open_if_exists(filename, mode="rb"):
     """Returns a file descriptor for the filename if that file exists,
     otherwise ``None``.
     """
     if not os.path.isfile(filename):
         return None

     return open(filename, mode)


 def object_type_repr(obj):
     """Returns the name of the object's type.  For some recognized
     singletons the name of the object is returned instead. (For
     example for `None` and `Ellipsis`).
     """
     if obj is None:
         return "None"
     elif obj is Ellipsis:
         return "Ellipsis"

     cls = type(obj)

     # __builtin__ in 2.x, builtins in 3.x
     if cls.__module__ in ("__builtin__", "builtins"):
         name = cls.__name__
     else:
         name = cls.__module__ + "." + cls.__name__

     return "%s object" % name


 def pformat(obj, verbose=False):
     """Prettyprint an object.  Either use the `pretty` library or the
     builtin `pprint`.
     """
     try:
         from pretty import pretty

         return pretty(obj, verbose=verbose)
     except ImportError:
         from pprint import pformat

         return pformat(obj)


 def urlize(text, trim_url_limit=None, rel=None, target=None):
     """Converts any URLs in text into clickable links. Works on http://,
     https:// and www. links. Links can have trailing punctuation (periods,
     commas, close-parens) and leading punctuation (opening parens) and
     it'll still do the right thing.

     If trim_url_limit is not None, the URLs in link text will be limited
     to trim_url_limit characters.

     If nofollow is True, the URLs in link text will get a rel="nofollow"
     attribute.

     If target is not None, a target attribute will be added to the link.
     """
     trim_url = (
         lambda x, limit=trim_url_limit: limit is not None
         and (x[:limit] + (len(x) >= limit and "..." or ""))
         or x
     )
     words = re.split(r"(\s+)", text_type(escape(text)))
     rel_attr = rel and ' rel="%s"' % text_type(escape(rel)) or ""
     target_attr = target and ' target="%s"' % escape(target) or ""

     for i, word in enumerate(words):
         head, middle, tail = "", word, ""
         match = re.match(r"^([(<]|&lt;)+", middle)

         if match:
             head = match.group()
             middle = middle[match.end() :]

         # Unlike lead, which is anchored to the start of the string,
         # need to check that the string ends with any of the characters
         # before trying to match all of them, to avoid backtracking.
         if middle.endswith((")", ">", ".", ",", "\n", "&gt;")):
             match = re.search(r"([)>.,\n]|&gt;)+$", middle)

             if match:
                 tail = match.group()
                 middle = middle[: match.start()]

         if middle.startswith("www.") or (
             "@" not in middle
             and not middle.startswith("http://")
             and not middle.startswith("https://")
             and len(middle) > 0
             and middle[0] in _letters + _digits
             and (
                 middle.endswith(".org")
                 or middle.endswith(".net")
                 or middle.endswith(".com")
             )
         ):
             middle = '<a href="http://%s"%s%s>%s</a>' % (
                 middle,
                 rel_attr,
                 target_attr,
                 trim_url(middle),
             )

         if middle.startswith("http://") or middle.startswith("https://"):
             middle = '<a href="%s"%s%s>%s</a>' % (
                 middle,
                 rel_attr,
                 target_attr,
                 trim_url(middle),
             )

         if (
             "@" in middle
             and not middle.startswith("www.")
             and ":" not in middle
             and re.match(r"^\S+@\w[\w.-]*\.\w+$", middle)
         ):
             middle = '<a href="mailto:%s">%s</a>' % (middle, middle)

         words[i] = head + middle + tail

     return u"".join(words)


 def generate_lorem_ipsum(n=5, html=True, min=20, max=100):
     """Generate some lorem ipsum for the template."""
     from .constants import LOREM_IPSUM_WORDS

     words = LOREM_IPSUM_WORDS.split()
     result = []

     for _ in range(n):
         next_capitalized = True
         last_comma = last_fullstop = 0
         word = None
         last = None
         p = []

         # each paragraph contains out of 20 to 100 words.
         for idx, _ in enumerate(range(randrange(min, max))):
             while True:
                 word = choice(words)
                 if word != last:
                     last = word
                     break
             if next_capitalized:
                 word = word.capitalize()
                 next_capitalized = False
             # add commas
             if idx - randrange(3, 8) > last_comma:
                 last_comma = idx
                 last_fullstop += 2
                 word += ","
             # add end of sentences
             if idx - randrange(10, 20) > last_fullstop:
                 last_comma = last_fullstop = idx
                 word += "."
                 next_capitalized = True
             p.append(word)

         # ensure that the paragraph ends with a dot.
         p = u" ".join(p)
         if p.endswith(","):
             p = p[:-1] + "."
         elif not p.endswith("."):
             p += "."
         result.append(p)

     if not html:
         return u"\n\n".join(result)
     return Markup(u"\n".join(u"<p>%s</p>" % escape(x) for x in result))


 def unicode_urlencode(obj, charset="utf-8", for_qs=False):
     """Quote a string for use in a URL using the given charset.

     This function is misnamed, it is a wrapper around
     :func:`urllib.parse.quote`.

     :param obj: String or bytes to quote. Other types are converted to
         string then encoded to bytes using the given charset.
     :param charset: Encode text to bytes using this charset.
     :param for_qs: Quote "/" and use "+" for spaces.
     """
     if not isinstance(obj, string_types):
         obj = text_type(obj)

     if isinstance(obj, text_type):
         obj = obj.encode(charset)

     safe = b"" if for_qs else b"/"
     rv = url_quote(obj, safe)

     if not isinstance(rv, text_type):
         rv = rv.decode("utf-8")

     if for_qs:
         rv = rv.replace("%20", "+")

     return rv


 class LRUCache(object):
     """A simple LRU Cache implementation."""

     # this is fast for small capacities (something below 1000) but doesn't
     # scale.  But as long as it's only used as storage for templates this
     # won't do any harm.

     def __init__(self, capacity):
         self.capacity = capacity
         self._mapping = {}
         self._queue = deque()
         self._postinit()

     def _postinit(self):
         # alias all queue methods for faster lookup
         self._popleft = self._queue.popleft
         self._pop = self._queue.pop
         self._remove = self._queue.remove
         self._wlock = Lock()
         self._append = self._queue.append

     def __getstate__(self):
         return {
             "capacity": self.capacity,
             "_mapping": self._mapping,
             "_queue": self._queue,
         }

     def __setstate__(self, d):
         self.__dict__.update(d)
         self._postinit()

     def __getnewargs__(self):
         return (self.capacity,)

     def copy(self):
         """Return a shallow copy of the instance."""
         rv = self.__class__(self.capacity)
         rv._mapping.update(self._mapping)
         rv._queue.extend(self._queue)
         return rv

     def get(self, key, default=None):
         """Return an item from the cache dict or `default`"""
         try:
             return self[key]
         except KeyError:
             return default

     def setdefault(self, key, default=None):
         """Set `default` if the key is not in the cache otherwise
         leave unchanged. Return the value of this key.
         """
         try:
             return self[key]
         except KeyError:
             self[key] = default
             return default

     def clear(self):
         """Clear the cache."""
         self._wlock.acquire()
         try:
             self._mapping.clear()
             self._queue.clear()
         finally:
             self._wlock.release()

     def __contains__(self, key):
         """Check if a key exists in this cache."""
         return key in self._mapping

     def __len__(self):
         """Return the current size of the cache."""
         return len(self._mapping)

     def __repr__(self):
         return "<%s %r>" % (self.__class__.__name__, self._mapping)

     def __getitem__(self, key):
         """Get an item from the cache. Moves the item up so that it has the
         highest priority then.

         Raise a `KeyError` if it does not exist.
         """
         self._wlock.acquire()
         try:
             rv = self._mapping[key]
             if self._queue[-1] != key:
                 try:
                     self._remove(key)
                 except ValueError:
                     # if something removed the key from the container
                     # when we read, ignore the ValueError that we would
                     # get otherwise.
                     pass
                 self._append(key)
             return rv
         finally:
             self._wlock.release()

     def __setitem__(self, key, value):
         """Sets the value for an item. Moves the item up so that it
         has the highest priority then.
         """
         self._wlock.acquire()
         try:
             if key in self._mapping:
                 self._remove(key)
             elif len(self._mapping) == self.capacity:
                 del self._mapping[self._popleft()]
             self._append(key)
             self._mapping[key] = value
         finally:
             self._wlock.release()

     def __delitem__(self, key):
         """Remove an item from the cache dict.
         Raise a `KeyError` if it does not exist.
         """
         self._wlock.acquire()
         try:
             del self._mapping[key]
             try:
                 self._remove(key)
             except ValueError:
                 pass
         finally:
             self._wlock.release()

     def items(self):
         """Return a list of items."""
         result = [(key, self._mapping[key]) for key in list(self._queue)]
         result.reverse()
         return result

     def iteritems(self):
         """Iterate over all items."""
         warnings.warn(
             "'iteritems()' will be removed in version 3.0. Use"
             " 'iter(cache.items())' instead.",
             DeprecationWarning,
             stacklevel=2,
         )
         return iter(self.items())

     def values(self):
         """Return a list of all values."""
         return [x[1] for x in self.items()]

     def itervalue(self):
         """Iterate over all values."""
         warnings.warn(
             "'itervalue()' will be removed in version 3.0. Use"
             " 'iter(cache.values())' instead.",
             DeprecationWarning,
             stacklevel=2,
         )
         return iter(self.values())

     def itervalues(self):
         """Iterate over all values."""
         warnings.warn(
             "'itervalues()' will be removed in version 3.0. Use"
             " 'iter(cache.values())' instead.",
             DeprecationWarning,
             stacklevel=2,
         )
         return iter(self.values())

     def keys(self):
         """Return a list of all keys ordered by most recent usage."""
         return list(self)

     def iterkeys(self):
         """Iterate over all keys in the cache dict, ordered by
         the most recent usage.
         """
         warnings.warn(
             "'iterkeys()' will be removed in version 3.0. Use"
             " 'iter(cache.keys())' instead.",
             DeprecationWarning,
             stacklevel=2,
         )
         return iter(self)

     def __iter__(self):
         return reversed(tuple(self._queue))

     def __reversed__(self):
         """Iterate over the keys in the cache dict, oldest items
         coming first.
         """
         return iter(tuple(self._queue))

     __copy__ = copy


 abc.MutableMapping.register(LRUCache)


 def select_autoescape(
     enabled_extensions=("html", "htm", "xml"),
     disabled_extensions=(),
     default_for_string=True,
     default=False,
 ):
     """Intelligently sets the initial value of autoescaping based on the
     filename of the template.  This is the recommended way to configure
     autoescaping if you do not want to write a custom function yourself.

     If you want to enable it for all templates created from strings or
     for all templates with `.html` and `.xml` extensions::

         from jinja2 import Environment, select_autoescape
         env = Environment(autoescape=select_autoescape(
             enabled_extensions=('html', 'xml'),
             default_for_string=True,
         ))

     Example configuration to turn it on at all times except if the template
     ends with `.txt`::

         from jinja2 import Environment, select_autoescape
         env = Environment(autoescape=select_autoescape(
             disabled_extensions=('txt',),
             default_for_string=True,
             default=True,
         ))

     The `enabled_extensions` is an iterable of all the extensions that
     autoescaping should be enabled for.  Likewise `disabled_extensions` is
     a list of all templates it should be disabled for.  If a template is
     loaded from a string then the default from `default_for_string` is used.
     If nothing matches then the initial value of autoescaping is set to the
     value of `default`.

     For security reasons this function operates case insensitive.

     .. versionadded:: 2.9
     """
     enabled_patterns = tuple("." + x.lstrip(".").lower() for x in enabled_extensions)
     disabled_patterns = tuple("." + x.lstrip(".").lower() for x in disabled_extensions)

     def autoescape(template_name):
         if template_name is None:
             return default_for_string
         template_name = template_name.lower()
         if template_name.endswith(enabled_patterns):
             return True
         if template_name.endswith(disabled_patterns):
             return False
         return default

     return autoescape


 def htmlsafe_json_dumps(obj, dumper=None, **kwargs):
     """Works exactly like :func:`dumps` but is safe for use in ``<script>``
     tags.  It accepts the same arguments and returns a JSON string.  Note that
     this is available in templates through the ``|tojson`` filter which will
     also mark the result as safe.  Due to how this function escapes certain
     characters this is safe even if used outside of ``<script>`` tags.

     The following characters are escaped in strings:

     -   ``<``
     -   ``>``
     -   ``&``
     -   ``'``

     This makes it safe to embed such strings in any place in HTML with the
     notable exception of double quoted attributes.  In that case single
     quote your attributes or HTML escape it in addition.
     """
     if dumper is None:
         dumper = json.dumps
     rv = (
         dumper(obj, **kwargs)
         .replace(u"<", u"\\u003c")
         .replace(u">", u"\\u003e")
         .replace(u"&", u"\\u0026")
         .replace(u"'", u"\\u0027")
     )
     return Markup(rv)


 class Cycler(object):
     """Cycle through values by yield them one at a time, then restarting
     once the end is reached. Available as ``cycler`` in templates.

     Similar to ``loop.cycle``, but can be used outside loops or across
     multiple loops. For example, render a list of folders and files in a
     list, alternating giving them "odd" and "even" classes.

     .. code-block:: html+jinja

         {% set row_class = cycler("odd", "even") %}
         <ul class="browser">
         {% for folder in folders %}
           <li class="folder {{ row_class.next() }}">{{ folder }}
         {% endfor %}
         {% for file in files %}
           <li class="file {{ row_class.next() }}">{{ file }}
         {% endfor %}
         </ul>

     :param items: Each positional argument will be yielded in the order
         given for each cycle.

     .. versionadded:: 2.1
     """

     def __init__(self, *items):
         if not items:
             raise RuntimeError("at least one item has to be provided")
         self.items = items
         self.pos = 0

     def reset(self):
         """Resets the current item to the first item."""
         self.pos = 0

     @property
     def current(self):
         """Return the current item. Equivalent to the item that will be
         returned next time :meth:`next` is called.
         """
         return self.items[self.pos]

     def next(self):
         """Return the current item, then advance :attr:`current` to the
         next item.
         """
         rv = self.current
         self.pos = (self.pos + 1) % len(self.items)
         return rv

     __next__ = next


 class Joiner(object):
     """A joining helper for templates."""

     def __init__(self, sep=u", "):
         self.sep = sep
         self.used = False

     def __call__(self):
         if not self.used:
             self.used = True
             return u""
         return self.sep


 class Namespace(object):
     """A namespace object that can hold arbitrary attributes.  It may be
     initialized from a dictionary or with keyword arguments."""

     def __init__(*args, **kwargs):  # noqa: B902
         self, args = args[0], args[1:]
         self.__attrs = dict(*args, **kwargs)

     def __getattribute__(self, name):
         # __class__ is needed for the awaitable check in async mode
         if name in {"_Namespace__attrs", "__class__"}:
             return object.__getattribute__(self, name)
         try:
             return self.__attrs[name]
         except KeyError:
             raise AttributeError(name)

     def __setitem__(self, name, value):
         self.__attrs[name] = value

     def __repr__(self):
         return "<Namespace %r>" % self.__attrs


 # does this python version support async for in and async generators?
 try:
     exec("async def _():\n async for _ in ():\n  yield _")
     have_async_gen = True
 except SyntaxError:
     have_async_gen = False


 def soft_unicode(s):
     from markupsafe import soft_unicode

     warnings.warn(
         "'jinja2.utils.soft_unicode' will be removed in version 3.0."
         " Use 'markupsafe.soft_unicode' instead.",
         DeprecationWarning,
         stacklevel=2,
     )
     return soft_unicode(s)
	# -- coding: utf-8 --
	import json
	import os
	import re
	import warnings
	from collections import deque
	from random import choice
	from random import randrange
	from string import ascii_letters as _letters
	from string import digits as _digits
	from threading import Lock

	from markupsafe import escape
	from markupsafe import Markup

	from ._compat import abc
	from ._compat import string_types
	from ._compat import text_type
	from ._compat import url_quote

	# special singleton representing missing values for the runtime
	missing = type("MissingType", (), {"__repr__": lambda x: "missing"})()

	# internal code
	internal_code = set()

	concat = u"".join

	_slash_escape = "\\/" not in json.dumps("/")


	def contextfunction(f):
	"""This decorator can be used to mark a function or method context callable.
	A context callable is passed the active :class:`Context` as first argument when
	called from the template. This is useful if a function wants to get access
	to the context or functions provided on the context object. For example
	a function that returns a sorted list of template variables the current
	template exports could look like this::

	@contextfunction
	def get_exported_names(context):
	return sorted(context.exported_vars)
	"""
	f.contextfunction = True
	return f


	def evalcontextfunction(f):
	"""This decorator can be used to mark a function or method as an eval
	context callable. This is similar to the :func:`contextfunction`
	but instead of passing the context, an evaluation context object is
	passed. For more information about the eval context, see
	:ref:`eval-context`.

	.. versionadded:: 2.4
	"""
	f.evalcontextfunction = True
	return f


	def environmentfunction(f):
	"""This decorator can be used to mark a function or method as environment
	callable. This decorator works exactly like the :func:`contextfunction`
	decorator just that the first argument is the active :class:`Environment`
	and not context.
	"""
	f.environmentfunction = True
	return f


	def internalcode(f):
	"""Marks the function as internally used"""
	internal_code.add(f.__code__)
	return f


	def is_undefined(obj):
	"""Check if the object passed is undefined. This does nothing more than
	performing an instance check against :class:`Undefined` but looks nicer.
	This can be used for custom filters or tests that want to react to
	undefined variables. For example a custom default filter can look like
	this::

	def default(var, default=''):
	if is_undefined(var):
	return default
	return var
	"""
	from .runtime import Undefined

	return isinstance(obj, Undefined)


	def consume(iterable):
	"""Consumes an iterable without doing anything with it."""
	for _ in iterable:
	pass


	def clear_caches():
	"""Jinja keeps internal caches for environments and lexers. These are
	used so that Jinja doesn't have to recreate environments and lexers all
	the time. Normally you don't have to care about that but if you are
	measuring memory consumption you may want to clean the caches.
	"""
	from .environment import _spontaneous_environments
	from .lexer import _lexer_cache

	_spontaneous_environments.clear()
	_lexer_cache.clear()


	def import_string(import_name, silent=False):
	"""Imports an object based on a string. This is useful if you want to
	use import paths as endpoints or something similar. An import path can
	be specified either in dotted notation (``xml.sax.saxutils.escape``)
	or with a colon as object delimiter (``xml.sax.saxutils:escape``).

	If the `silent` is True the return value will be `None` if the import
	fails.

	:return: imported object
	"""
	try:
	if ":" in import_name:
	module, obj = import_name.split(":", 1)
	elif "." in import_name:
	module, _, obj = import_name.rpartition(".")
	else:
	return __import__(import_name)
	return getattr(__import__(module, None, None, [obj]), obj)
	except (ImportError, AttributeError):
	if not silent:
	raise


	def open_if_exists(filename, mode="rb"):
	"""Returns a file descriptor for the filename if that file exists,
	otherwise ``None``.
	"""
	if not os.path.isfile(filename):
	return None

	return open(filename, mode)


	def object_type_repr(obj):
	"""Returns the name of the object's type. For some recognized
	singletons the name of the object is returned instead. (For
	example for `None` and `Ellipsis`).
	"""
	if obj is None:
	return "None"
	elif obj is Ellipsis:
	return "Ellipsis"

	cls = type(obj)

	# __builtin__ in 2.x, builtins in 3.x
	if cls.__module__ in ("__builtin__", "builtins"):
	name = cls.__name__
	else:
	name = cls.__module__ + "." + cls.__name__

	return "%s object" % name


	def pformat(obj, verbose=False):
	"""Prettyprint an object. Either use the `pretty` library or the
	builtin `pprint`.
	"""
	try:
	from pretty import pretty

	return pretty(obj, verbose=verbose)
	except ImportError:
	from pprint import pformat

	return pformat(obj)


	def urlize(text, trim_url_limit=None, rel=None, target=None):
	"""Converts any URLs in text into clickable links. Works on http://,
	https:// and www. links. Links can have trailing punctuation (periods,
	commas, close-parens) and leading punctuation (opening parens) and
	it'll still do the right thing.

	If trim_url_limit is not None, the URLs in link text will be limited
	to trim_url_limit characters.

	If nofollow is True, the URLs in link text will get a rel="nofollow"
	attribute.

	If target is not None, a target attribute will be added to the link.
	"""
	trim_url = (
	lambda x, limit=trim_url_limit: limit is not None
	and (x[:limit] + (len(x) >= limit and "..." or ""))
	or x
	)
	words = re.split(r"(\s+)", text_type(escape(text)))
	rel_attr = rel and ' rel="%s"' % text_type(escape(rel)) or ""
	target_attr = target and ' target="%s"' % escape(target) or ""

	for i, word in enumerate(words):
	head, middle, tail = "", word, ""
	match = re.match(r"^([(<]\|<)+", middle)

	if match:
	head = match.group()
	middle = middle[match.end() :]

	# Unlike lead, which is anchored to the start of the string,
	# need to check that the string ends with any of the characters
	# before trying to match all of them, to avoid backtracking.
	if middle.endswith((")", ">", ".", ",", "\n", ">")):
	match = re.search(r"([)>.,\n]\|>)+$", middle)

	if match:
	tail = match.group()
	middle = middle[: match.start()]

	if middle.startswith("www.") or (
	"@" not in middle
	and not middle.startswith("http://")
	and not middle.startswith("https://")
	and len(middle) > 0
	and middle[0] in _letters + _digits
	and (
	middle.endswith(".org")
	or middle.endswith(".net")
	or middle.endswith(".com")
	)
	):
	middle = '<a href="http://%s"%s%s>%s</a>' % (
	middle,
	rel_attr,
	target_attr,
	trim_url(middle),
	)

	if middle.startswith("http://") or middle.startswith("https://"):
	middle = '<a href="%s"%s%s>%s</a>' % (
	middle,
	rel_attr,
	target_attr,
	trim_url(middle),
	)

	if (
	"@" in middle
	and not middle.startswith("www.")
	and ":" not in middle
	and re.match(r"^\S+@\w[\w.-]*\.\w+$", middle)
	):
	middle = '<a href="mailto:%s">%s</a>' % (middle, middle)

	words[i] = head + middle + tail

	return u"".join(words)


	def generate_lorem_ipsum(n=5, html=True, min=20, max=100):
	"""Generate some lorem ipsum for the template."""
	from .constants import LOREM_IPSUM_WORDS

	words = LOREM_IPSUM_WORDS.split()
	result = []

	for _ in range(n):
	next_capitalized = True
	last_comma = last_fullstop = 0
	word = None
	last = None
	p = []

	# each paragraph contains out of 20 to 100 words.
	for idx, _ in enumerate(range(randrange(min, max))):
	while True:
	word = choice(words)
	if word != last:
	last = word
	break
	if next_capitalized:
	word = word.capitalize()
	next_capitalized = False
	# add commas
	if idx - randrange(3, 8) > last_comma:
	last_comma = idx
	last_fullstop += 2
	word += ","
	# add end of sentences
	if idx - randrange(10, 20) > last_fullstop:
	last_comma = last_fullstop = idx
	word += "."
	next_capitalized = True
	p.append(word)

	# ensure that the paragraph ends with a dot.
	p = u" ".join(p)
	if p.endswith(","):
	p = p[:-1] + "."
	elif not p.endswith("."):
	p += "."
	result.append(p)

	if not html:
	return u"\n\n".join(result)
	return Markup(u"\n".join(u"<p>%s</p>" % escape(x) for x in result))


	def unicode_urlencode(obj, charset="utf-8", for_qs=False):
	"""Quote a string for use in a URL using the given charset.

	This function is misnamed, it is a wrapper around
	:func:`urllib.parse.quote`.

	:param obj: String or bytes to quote. Other types are converted to
	string then encoded to bytes using the given charset.
	:param charset: Encode text to bytes using this charset.
	:param for_qs: Quote "/" and use "+" for spaces.
	"""
	if not isinstance(obj, string_types):
	obj = text_type(obj)

	if isinstance(obj, text_type):
	obj = obj.encode(charset)

	safe = b"" if for_qs else b"/"
	rv = url_quote(obj, safe)

	if not isinstance(rv, text_type):
	rv = rv.decode("utf-8")

	if for_qs:
	rv = rv.replace("%20", "+")

	return rv


	class LRUCache(object):
	"""A simple LRU Cache implementation."""

	# this is fast for small capacities (something below 1000) but doesn't
	# scale. But as long as it's only used as storage for templates this
	# won't do any harm.

	def __init__(self, capacity):
	self.capacity = capacity
	self._mapping = {}
	self._queue = deque()
	self._postinit()

	def _postinit(self):
	# alias all queue methods for faster lookup
	self._popleft = self._queue.popleft
	self._pop = self._queue.pop
	self._remove = self._queue.remove
	self._wlock = Lock()
	self._append = self._queue.append

	def __getstate__(self):
	return {
	"capacity": self.capacity,
	"_mapping": self._mapping,
	"_queue": self._queue,
	}

	def __setstate__(self, d):
	self.__dict__.update(d)
	self._postinit()

	def __getnewargs__(self):
	return (self.capacity,)

	def copy(self):
	"""Return a shallow copy of the instance."""
	rv = self.__class__(self.capacity)
	rv._mapping.update(self._mapping)
	rv._queue.extend(self._queue)
	return rv

	def get(self, key, default=None):
	"""Return an item from the cache dict or `default`"""
	try:
	return self[key]
	except KeyError:
	return default

	def setdefault(self, key, default=None):
	"""Set `default` if the key is not in the cache otherwise
	leave unchanged. Return the value of this key.
	"""
	try:
	return self[key]
	except KeyError:
	self[key] = default
	return default

	def clear(self):
	"""Clear the cache."""
	self._wlock.acquire()
	try:
	self._mapping.clear()
	self._queue.clear()
	finally:
	self._wlock.release()

	def __contains__(self, key):
	"""Check if a key exists in this cache."""
	return key in self._mapping

	def __len__(self):
	"""Return the current size of the cache."""
	return len(self._mapping)

	def __repr__(self):
	return "<%s %r>" % (self.__class__.__name__, self._mapping)

	def __getitem__(self, key):
	"""Get an item from the cache. Moves the item up so that it has the
	highest priority then.

	Raise a `KeyError` if it does not exist.
	"""
	self._wlock.acquire()
	try:
	rv = self._mapping[key]
	if self._queue[-1] != key:
	try:
	self._remove(key)
	except ValueError:
	# if something removed the key from the container
	# when we read, ignore the ValueError that we would
	# get otherwise.
	pass
	self._append(key)
	return rv
	finally:
	self._wlock.release()

	def __setitem__(self, key, value):
	"""Sets the value for an item. Moves the item up so that it
	has the highest priority then.
	"""
	self._wlock.acquire()
	try:
	if key in self._mapping:
	self._remove(key)
	elif len(self._mapping) == self.capacity:
	del self._mapping[self._popleft()]
	self._append(key)
	self._mapping[key] = value
	finally:
	self._wlock.release()

	def __delitem__(self, key):
	"""Remove an item from the cache dict.
	Raise a `KeyError` if it does not exist.
	"""
	self._wlock.acquire()
	try:
	del self._mapping[key]
	try:
	self._remove(key)
	except ValueError:
	pass
	finally:
	self._wlock.release()

	def items(self):
	"""Return a list of items."""
	result = [(key, self._mapping[key]) for key in list(self._queue)]
	result.reverse()
	return result

	def iteritems(self):
	"""Iterate over all items."""
	warnings.warn(
	"'iteritems()' will be removed in version 3.0. Use"
	" 'iter(cache.items())' instead.",
	DeprecationWarning,
	stacklevel=2,
	)
	return iter(self.items())

	def values(self):
	"""Return a list of all values."""
	return [x[1] for x in self.items()]

	def itervalue(self):
	"""Iterate over all values."""
	warnings.warn(
	"'itervalue()' will be removed in version 3.0. Use"
	" 'iter(cache.values())' instead.",
	DeprecationWarning,
	stacklevel=2,
	)
	return iter(self.values())

	def itervalues(self):
	"""Iterate over all values."""
	warnings.warn(
	"'itervalues()' will be removed in version 3.0. Use"
	" 'iter(cache.values())' instead.",
	DeprecationWarning,
	stacklevel=2,
	)
	return iter(self.values())

	def keys(self):
	"""Return a list of all keys ordered by most recent usage."""
	return list(self)

	def iterkeys(self):
	"""Iterate over all keys in the cache dict, ordered by
	the most recent usage.
	"""
	warnings.warn(
	"'iterkeys()' will be removed in version 3.0. Use"
	" 'iter(cache.keys())' instead.",
	DeprecationWarning,
	stacklevel=2,
	)
	return iter(self)

	def __iter__(self):
	return reversed(tuple(self._queue))

	def __reversed__(self):
	"""Iterate over the keys in the cache dict, oldest items
	coming first.
	"""
	return iter(tuple(self._queue))

	__copy__ = copy


	abc.MutableMapping.register(LRUCache)


	def select_autoescape(
	enabled_extensions=("html", "htm", "xml"),
	disabled_extensions=(),
	default_for_string=True,
	default=False,
	):
	"""Intelligently sets the initial value of autoescaping based on the
	filename of the template. This is the recommended way to configure
	autoescaping if you do not want to write a custom function yourself.

	If you want to enable it for all templates created from strings or
	for all templates with `.html` and `.xml` extensions::

	from jinja2 import Environment, select_autoescape
	env = Environment(autoescape=select_autoescape(
	enabled_extensions=('html', 'xml'),
	default_for_string=True,
	))

	Example configuration to turn it on at all times except if the template
	ends with `.txt`::

	from jinja2 import Environment, select_autoescape
	env = Environment(autoescape=select_autoescape(
	disabled_extensions=('txt',),
	default_for_string=True,
	default=True,
	))

	The `enabled_extensions` is an iterable of all the extensions that
	autoescaping should be enabled for. Likewise `disabled_extensions` is
	a list of all templates it should be disabled for. If a template is
	loaded from a string then the default from `default_for_string` is used.
	If nothing matches then the initial value of autoescaping is set to the
	value of `default`.

	For security reasons this function operates case insensitive.

	.. versionadded:: 2.9
	"""
	enabled_patterns = tuple("." + x.lstrip(".").lower() for x in enabled_extensions)
	disabled_patterns = tuple("." + x.lstrip(".").lower() for x in disabled_extensions)

	def autoescape(template_name):
	if template_name is None:
	return default_for_string
	template_name = template_name.lower()
	if template_name.endswith(enabled_patterns):
	return True
	if template_name.endswith(disabled_patterns):
	return False
	return default

	return autoescape


	def htmlsafe_json_dumps(obj, dumper=None, **kwargs):
	"""Works exactly like :func:`dumps` but is safe for use in ``<script>``
	tags. It accepts the same arguments and returns a JSON string. Note that
	this is available in templates through the ``\|tojson`` filter which will
	also mark the result as safe. Due to how this function escapes certain
	characters this is safe even if used outside of ``<script>`` tags.

	The following characters are escaped in strings:

	- ``<``
	- ``>``
	- ``&``
	- ``'``

	This makes it safe to embed such strings in any place in HTML with the
	notable exception of double quoted attributes. In that case single
	quote your attributes or HTML escape it in addition.
	"""
	if dumper is None:
	dumper = json.dumps
	rv = (
	dumper(obj, **kwargs)
	.replace(u"<", u"\\u003c")
	.replace(u">", u"\\u003e")
	.replace(u"&", u"\\u0026")
	.replace(u"'", u"\\u0027")
	)
	return Markup(rv)


	class Cycler(object):
	"""Cycle through values by yield them one at a time, then restarting
	once the end is reached. Available as ``cycler`` in templates.

	Similar to ``loop.cycle``, but can be used outside loops or across
	multiple loops. For example, render a list of folders and files in a
	list, alternating giving them "odd" and "even" classes.

	.. code-block:: html+jinja

	{% set row_class = cycler("odd", "even") %}
	<ul class="browser">
	{% for folder in folders %}
	<li class="folder {{ row_class.next() }}">{{ folder }}
	{% endfor %}
	{% for file in files %}
	<li class="file {{ row_class.next() }}">{{ file }}
	{% endfor %}
	</ul>

	:param items: Each positional argument will be yielded in the order
	given for each cycle.

	.. versionadded:: 2.1
	"""

	def __init__(self, *items):
	if not items:
	raise RuntimeError("at least one item has to be provided")
	self.items = items
	self.pos = 0

	def reset(self):
	"""Resets the current item to the first item."""
	self.pos = 0

	@property
	def current(self):
	"""Return the current item. Equivalent to the item that will be
	returned next time :meth:`next` is called.
	"""
	return self.items[self.pos]

	def next(self):
	"""Return the current item, then advance :attr:`current` to the
	next item.
	"""
	rv = self.current
	self.pos = (self.pos + 1) % len(self.items)
	return rv

	__next__ = next


	class Joiner(object):
	"""A joining helper for templates."""

	def __init__(self, sep=u", "):
	self.sep = sep
	self.used = False

	def __call__(self):
	if not self.used:
	self.used = True
	return u""
	return self.sep


	class Namespace(object):
	"""A namespace object that can hold arbitrary attributes. It may be
	initialized from a dictionary or with keyword arguments."""

	def __init__(args, *kwargs): # noqa: B902
	self, args = args[0], args[1:]
	self.__attrs = dict(args, *kwargs)

	def __getattribute__(self, name):
	# __class__ is needed for the awaitable check in async mode
	if name in {"_Namespace__attrs", "__class__"}:
	return object.__getattribute__(self, name)
	try:
	return self.__attrs[name]
	except KeyError:
	raise AttributeError(name)

	def __setitem__(self, name, value):
	self.__attrs[name] = value

	def __repr__(self):
	return "<Namespace %r>" % self.__attrs


	# does this python version support async for in and async generators?
	try:
	exec("async def _():\n async for _ in ():\n yield _")
	have_async_gen = True
	except SyntaxError:
	have_async_gen = False


	def soft_unicode(s):
	from markupsafe import soft_unicode

	warnings.warn(
	"'jinja2.utils.soft_unicode' will be removed in version 3.0."
	" Use 'markupsafe.soft_unicode' instead.",
	DeprecationWarning,
	stacklevel=2,
	)
	return soft_unicode(s)