jinja2-main / file revision

 # -*- coding: utf-8 -*-

 """

     jinja2.utils

     ~~~~~~~~~~~~

     Utility functions.

     :copyright: (c) 2010 by the Jinja Team.

     :license: BSD, see LICENSE for more details.

 """

 import re

 import sys

 import errno

 try:

     from thread import allocate_lock

 except ImportError:

     from dummy_thread import allocate_lock

 from collections import deque

 from itertools import imap

 _word_split_re = re.compile(r'(\s+)')

 _punctuation_re = re.compile(

     '^(?P<lead>(?:%s)*)(?P<middle>.*?)(?P<trail>(?:%s)*)$' % (

         '|'.join(imap(re.escape, ('(', '<', '&lt;'))),

         '|'.join(imap(re.escape, ('.', ',', ')', '>', '\n', '>')))

     )

 )

 _simple_email_re = re.compile(r'^\S+@[a-zA-Z0-9._-]+\.[a-zA-Z0-9._-]+$')

 _striptags_re = re.compile(r'(<!--.*?-->|<[^>]*>)')

 _entity_re = re.compile(r'&([^;]+);')

 _letters = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'

 _digits = '0123456789'

 # special singleton representing missing values for the runtime

 missing = type('MissingType', (), {'__repr__': lambda x: 'missing'})()

 # internal code

 internal_code = set()

 # concatenate a list of strings and convert them to unicode.

 # unfortunately there is a bug in python 2.4 and lower that causes

 # unicode.join trash the traceback.

 _concat = u''.join

 try:

     def _test_gen_bug():

         raise TypeError(_test_gen_bug)

         yield None

     _concat(_test_gen_bug())

 except TypeError, _error:

     if not _error.args or _error.args[0] is not _test_gen_bug:

         def concat(gen):

             try:

                 return _concat(list(gen))

             except:

                 # this hack is needed so that the current frame

                 # does not show up in the traceback.

                 exc_type, exc_value, tb = sys.exc_info()

                 raise exc_type, exc_value, tb.tb_next

     else:

         concat = _concat

     del _test_gen_bug, _error

 # for python 2.x we create outselves a next() function that does the

 # basics without exception catching.

 try:

     next = next

 except NameError:

     def next(x):

         return x.next()

 # if this python version is unable to deal with unicode filenames

 # when passed to encode we let this function encode it properly.

 # This is used in a couple of places.  As far as Jinja is concerned

 # filenames are unicode *or* bytestrings in 2.x and unicode only in

 # 3.x because compile cannot handle bytes

 if sys.version_info < (3, 0):

     def _encode_filename(filename):

         if isinstance(filename, unicode):

             return filename.encode('utf-8')

         return filename

 else:

     def _encode_filename(filename):

         assert filename is None or isinstance(filename, str), \

             'filenames must be strings'

         return filename

 from keyword import iskeyword as is_python_keyword

 # common types.  These do exist in the special types module too which however

 # does not exist in IronPython out of the box.  Also that way we don't have

 # to deal with implementation specific stuff here

 class _C(object):

     def method(self): pass

 def _func():

     yield None

 FunctionType = type(_func)

 GeneratorType = type(_func())

 MethodType = type(_C.method)

 CodeType = type(_C.method.func_code)

 try:

     raise TypeError()

 except TypeError:

     _tb = sys.exc_info()[2]

     TracebackType = type(_tb)

     FrameType = type(_tb.tb_frame)

 del _C, _tb, _func

 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 decoraotr 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.func_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 jinja2.runtime import Undefined

     return isinstance(obj, Undefined)

 def consume(iterable):

     """Consumes an iterable without doing anything with it."""

     for event in iterable:

         pass

 def clear_caches():

     """Jinja2 keeps internal caches for environments and lexers.  These are

     used so that Jinja2 doesn't have to recreate environments and lexers all

     the time.  Normally you don't have to care about that but if you are

     messuring memory consumption you may want to clean the caches.

     """

     from jinja2.environment import _spontaneous_environments

     from jinja2.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 use 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:

             items = import_name.split('.')

             module = '.'.join(items[:-1])

             obj = items[-1]

         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`.

     """

     try:

         return open(filename, mode)

     except IOError, e:

         if e.errno not in (errno.ENOENT, errno.EISDIR):

             raise

 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'

     # __builtin__ in 2.x, builtins in 3.x

     if obj.__class__.__module__ in ('__builtin__', 'builtins'):

         name = obj.__class__.__name__

     else:

         name = obj.__class__.__module__ + '.' + obj.__class__.__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, nofollow=False):

     """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.

     """

     trim_url = lambda x, limit=trim_url_limit: limit is not None \

                          and (x[:limit] + (len(x) >=limit and '...'

                          or '')) or x

     words = _word_split_re.split(unicode(escape(text)))

     nofollow_attr = nofollow and ' rel="nofollow"' or ''

     for i, word in enumerate(words):

         match = _punctuation_re.match(word)

         if match:

             lead, middle, trail = match.groups()

             if middle.startswith('www.') or (

                 '@' not in middle and

                 not middle.startswith('http://') 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</a>' % (middle,

                     nofollow_attr, trim_url(middle))

             if middle.startswith('http://') or \

                middle.startswith('https://'):

                 middle = '<a href="%s"%s>%s</a>' % (middle,

                     nofollow_attr, trim_url(middle))

             if '@' in middle and not middle.startswith('www.') and \

                not ':' in middle and _simple_email_re.match(middle):

                 middle = '<a href="mailto:%s">%s</a>' % (middle, middle)

             if lead + middle + trail != word:

                 words[i] = lead + middle + trail

     return u''.join(words)

 def generate_lorem_ipsum(n=5, html=True, min=20, max=100):

     """Generate some lorem impsum for the template."""

     from jinja2.constants import LOREM_IPSUM_WORDS

     from random import choice, randrange

     words = LOREM_IPSUM_WORDS.split()

     result = []

     for _ in xrange(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(xrange(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))

 class Markup(unicode):

     r"""Marks a string as being safe for inclusion in HTML/XML output without

     needing to be escaped.  This implements the `__html__` interface a couple

     of frameworks and web applications use.  :class:`Markup` is a direct

     subclass of `unicode` and provides all the methods of `unicode` just that

     it escapes arguments passed and always returns `Markup`.

     The `escape` function returns markup objects so that double escaping can't

     happen.  If you want to use autoescaping in Jinja just enable the

     autoescaping feature in the environment.

     The constructor of the :class:`Markup` class can be used for three

     different things:  When passed an unicode object it's assumed to be safe,

     when passed an object with an HTML representation (has an `__html__`

     method) that representation is used, otherwise the object passed is

     converted into a unicode string and then assumed to be safe:

     >>> Markup("Hello <em>World</em>!")

     Markup(u'Hello <em>World</em>!')

     >>> class Foo(object):

     ...  def __html__(self):

     ...   return '<a href="#">foo</a>'

     ... 

     >>> Markup(Foo())

     Markup(u'<a href="#">foo</a>')

     If you want object passed being always treated as unsafe you can use the

     :meth:`escape` classmethod to create a :class:`Markup` object:

     >>> Markup.escape("Hello <em>World</em>!")

     Markup(u'Hello <em>World</em>!')

     Operations on a markup string are markup aware which means that all

     arguments are passed through the :func:`escape` function:

     >>> em = Markup("<em>%s</em>")

     >>> em % "foo & bar"

     Markup(u'<em>foo &amp; bar</em>')

     >>> strong = Markup("<strong>%(text)s</strong>")

     >>> strong % {'text': '<blink>hacker here</blink>'}

     Markup(u'<strong>&lt;blink&gt;hacker here&lt;/blink&gt;</strong>')

     >>> Markup("<em>Hello</em> ") + "<foo>"

     Markup(u'<em>Hello</em> &lt;foo&gt;')

     """

     __slots__ = ()

     def __new__(cls, base=u'', encoding=None, errors='strict'):

         if hasattr(base, '__html__'):

             base = base.__html__()

         if encoding is None:

             return unicode.__new__(cls, base)

         return unicode.__new__(cls, base, encoding, errors)

     def __html__(self):

         return self

     def __add__(self, other):

         if hasattr(other, '__html__') or isinstance(other, basestring):

             return self.__class__(unicode(self) + unicode(escape(other)))

         return NotImplemented

     def __radd__(self, other):

         if hasattr(other, '__html__') or isinstance(other, basestring):

             return self.__class__(unicode(escape(other)) + unicode(self))

         return NotImplemented

     def __mul__(self, num):

         if isinstance(num, (int, long)):

             return self.__class__(unicode.__mul__(self, num))

         return NotImplemented

     __rmul__ = __mul__

     def __mod__(self, arg):

         if isinstance(arg, tuple):

             arg = tuple(imap(_MarkupEscapeHelper, arg))

         else:

             arg = _MarkupEscapeHelper(arg)

         return self.__class__(unicode.__mod__(self, arg))

     def __repr__(self):

         return '%s(%s)' % (

             self.__class__.__name__,

             unicode.__repr__(self)

         )

     def join(self, seq):

         return self.__class__(unicode.join(self, imap(escape, seq)))

     join.__doc__ = unicode.join.__doc__

     def split(self, *args, **kwargs):

         return map(self.__class__, unicode.split(self, *args, **kwargs))

     split.__doc__ = unicode.split.__doc__

     def rsplit(self, *args, **kwargs):

         return map(self.__class__, unicode.rsplit(self, *args, **kwargs))

     rsplit.__doc__ = unicode.rsplit.__doc__

     def splitlines(self, *args, **kwargs):

         return map(self.__class__, unicode.splitlines(self, *args, **kwargs))

     splitlines.__doc__ = unicode.splitlines.__doc__

     def unescape(self):

         r"""Unescape markup again into an unicode string.  This also resolves

         known HTML4 and XHTML entities:

         >>> Markup("Main &raquo; <em>About</em>").unescape()

         u'Main \xbb <em>About</em>'

         """

         from jinja2.constants import HTML_ENTITIES

         def handle_match(m):

             name = m.group(1)

             if name in HTML_ENTITIES:

                 return unichr(HTML_ENTITIES[name])

             try:

                 if name[:2] in ('#x', '#X'):

                     return unichr(int(name[2:], 16))

                 elif name.startswith('#'):

                     return unichr(int(name[1:]))

             except ValueError:

                 pass

             return u''

         return _entity_re.sub(handle_match, unicode(self))

     def striptags(self):

         r"""Unescape markup into an unicode string and strip all tags.  This

         also resolves known HTML4 and XHTML entities.  Whitespace is

         normalized to one:

         >>> Markup("Main &raquo;  <em>About</em>").striptags()

         u'Main \xbb About'

         """

         stripped = u' '.join(_striptags_re.sub('', self).split())

         return Markup(stripped).unescape()

     @classmethod

     def escape(cls, s):

         """Escape the string.  Works like :func:`escape` with the difference

         that for subclasses of :class:`Markup` this function would return the

         correct subclass.

         """

         rv = escape(s)

         if rv.__class__ is not cls:

             return cls(rv)

         return rv

     def make_wrapper(name):

         orig = getattr(unicode, name)

         def func(self, *args, **kwargs):

             args = _escape_argspec(list(args), enumerate(args))

             _escape_argspec(kwargs, kwargs.iteritems())

             return self.__class__(orig(self, *args, **kwargs))

         func.__name__ = orig.__name__

         func.__doc__ = orig.__doc__

         return func

     for method in '__getitem__', 'capitalize', \

                   'title', 'lower', 'upper', 'replace', 'ljust', \

                   'rjust', 'lstrip', 'rstrip', 'center', 'strip', \

                   'translate', 'expandtabs', 'swapcase', 'zfill':

         locals()[method] = make_wrapper(method)

     # new in python 2.5

     if hasattr(unicode, 'partition'):

         partition = make_wrapper('partition'),

         rpartition = make_wrapper('rpartition')

     # new in python 2.6

     if hasattr(unicode, 'format'):

         format = make_wrapper('format')

     # not in python 3

     if hasattr(unicode, '__getslice__'):

         __getslice__ = make_wrapper('__getslice__')

     del method, make_wrapper

 def _escape_argspec(obj, iterable):

     """Helper for various string-wrapped functions."""

     for key, value in iterable:

         if hasattr(value, '__html__') or isinstance(value, basestring):

             obj[key] = escape(value)

     return obj

 class _MarkupEscapeHelper(object):

     """Helper for Markup.__mod__"""

     def __init__(self, obj):

         self.obj = obj

     __getitem__ = lambda s, x: _MarkupEscapeHelper(s.obj[x])

     __str__ = lambda s: str(escape(s.obj))

     __unicode__ = lambda s: unicode(escape(s.obj))

     __repr__ = lambda s: str(escape(repr(s.obj)))

     __int__ = lambda s: int(s.obj)

     __float__ = lambda s: float(s.obj)

 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

         if hasattr(self._queue, 'remove'):

             self._remove = self._queue.remove

         self._wlock = allocate_lock()

         self._append = self._queue.append

     def _remove(self, obj):

         """Python 2.4 compatibility."""

         for idx, item in enumerate(self._queue):

             if item == obj:

                 del self._queue[idx]

                 break

     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 an shallow copy of the instance."""

         rv = self.__class__(self.capacity)

         rv._mapping.update(self._mapping)

         rv._queue = deque(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 an `KeyError` if it does not exist.

         """

         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

     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:

                 try:

                     self._remove(key)

                 except ValueError:

                     # __getitem__ is not locked, it might happen

                     pass

             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 an `KeyError` if it does not exist.

         """

         self._wlock.acquire()

         try:

             del self._mapping[key]

             try:

                 self._remove(key)

             except ValueError:

                 # __getitem__ is not locked, it might happen

                 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."""

         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."""

         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.

         """

         return reversed(tuple(self._queue))

     __iter__ = iterkeys

     def __reversed__(self):

         """Iterate over the values in the cache dict, oldest items

         coming first.

         """

         return iter(tuple(self._queue))

     __copy__ = copy

 # register the LRU cache as mutable mapping if possible

 try:

     from collections import MutableMapping

     MutableMapping.register(LRUCache)

 except ImportError:

     pass

 class Cycler(object):

     """A cycle helper for templates."""

     def __init__(self, *items):

         if not items:

             raise RuntimeError('at least one item has to be provided')

         self.items = items

         self.reset()

     def reset(self):

         """Resets the cycle."""

         self.pos = 0

     @property

     def current(self):

         """Returns the current item."""

         return self.items[self.pos]

     def next(self):

         """Goes one item ahead and returns it."""

         rv = self.current

         self.pos = (self.pos + 1) % len(self.items)

         return rv

 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

 # we have to import it down here as the speedups module imports the

 # markup type which is define above.

 try:

     from jinja2._speedups import escape, soft_unicode

 except ImportError:

     def escape(s):

         """Convert the characters &, <, >, ' and " in string s to HTML-safe

         sequences.  Use this if you need to display text that might contain

         such characters in HTML.  Marks return value as markup string.

         """

         if hasattr(s, '__html__'):

             return s.__html__()

         return Markup(unicode(s)

             .replace('&', '&')

             .replace('>', '>')

             .replace('<', '&lt;')

             .replace("'", ''')

             .replace('"', '"')

         )

     def soft_unicode(s):

         """Make a string unicode if it isn't already.  That way a markup

         string is not converted back to unicode.

         """

         if not isinstance(s, unicode):

             s = unicode(s)

         return s

 # partials

 try:

     from functools import partial

 except ImportError:

     class partial(object):

         def __init__(self, _func, *args, **kwargs):

             self._func = _func

             self._args = args

             self._kwargs = kwargs

         def __call__(self, *args, **kwargs):

             kwargs.update(self._kwargs)

             return self._func(*(self._args + args), **kwargs)