Add Python templating engine Jinja2 to third_party

third_party/jinja2/filters.py

Index: third_party/jinja2/filters.py
diff --git a/third_party/jinja2/filters.py b/third_party/jinja2/filters.py
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+# -*- coding: utf-8 -*-
+"""
+    jinja2.filters
+    ~~~~~~~~~~~~~~
+
+    Bundled jinja filters.
+
+    :copyright: (c) 2010 by the Jinja Team.
+    :license: BSD, see LICENSE for more details.
+"""
+import re
+import math
+from random import choice
+from operator import itemgetter
+from itertools import imap, groupby
+from jinja2.utils import Markup, escape, pformat, urlize, soft_unicode
+from jinja2.runtime import Undefined
+from jinja2.exceptions import FilterArgumentError, SecurityError
+
+
+_word_re = re.compile(r'\w+(?u)')
+
+
+def contextfilter(f):
+    """Decorator for marking context dependent filters. The current
+    :class:`Context` will be passed as first argument.
+    """
+    f.contextfilter = True
+    return f
+
+
+def evalcontextfilter(f):
+    """Decorator for marking eval-context dependent filters.  An eval
+    context object is passed as first argument.  For more information
+    about the eval context, see :ref:`eval-context`.
+
+    .. versionadded:: 2.4
+    """
+    f.evalcontextfilter = True
+    return f
+
+
+def environmentfilter(f):
+    """Decorator for marking evironment dependent filters.  The current
+    :class:`Environment` is passed to the filter as first argument.
+    """
+    f.environmentfilter = True
+    return f
+
+
+def make_attrgetter(environment, attribute):
+    """Returns a callable that looks up the given attribute from a
+    passed object with the rules of the environment.  Dots are allowed
+    to access attributes of attributes.
+    """
+    if not isinstance(attribute, basestring) or '.' not in attribute:
+        return lambda x: environment.getitem(x, attribute)
+    attribute = attribute.split('.')
+    def attrgetter(item):
+        for part in attribute:
+            item = environment.getitem(item, part)
+        return item
+    return attrgetter
+
+
+def do_forceescape(value):
+    """Enforce HTML escaping.  This will probably double escape variables."""
+    if hasattr(value, '__html__'):
+        value = value.__html__()
+    return escape(unicode(value))
+
+
+@evalcontextfilter
+def do_replace(eval_ctx, s, old, new, count=None):
+    """Return a copy of the value with all occurrences of a substring
+    replaced with a new one. The first argument is the substring
+    that should be replaced, the second is the replacement string.
+    If the optional third argument ``count`` is given, only the first
+    ``count`` occurrences are replaced:
+
+    .. sourcecode:: jinja
+
+        {{ "Hello World"|replace("Hello", "Goodbye") }}
+            -> Goodbye World
+
+        {{ "aaaaargh"|replace("a", "d'oh, ", 2) }}
+            -> d'oh, d'oh, aaargh
+    """
+    if count is None:
+        count = -1
+    if not eval_ctx.autoescape:
+        return unicode(s).replace(unicode(old), unicode(new), count)
+    if hasattr(old, '__html__') or hasattr(new, '__html__') and \
+       not hasattr(s, '__html__'):
+        s = escape(s)
+    else:
+        s = soft_unicode(s)
+    return s.replace(soft_unicode(old), soft_unicode(new), count)
+
+
+def do_upper(s):
+    """Convert a value to uppercase."""
+    return soft_unicode(s).upper()
+
+
+def do_lower(s):
+    """Convert a value to lowercase."""
+    return soft_unicode(s).lower()
+
+
+@evalcontextfilter
+def do_xmlattr(_eval_ctx, d, autospace=True):
+    """Create an SGML/XML attribute string based on the items in a dict.
+    All values that are neither `none` nor `undefined` are automatically
+    escaped:
+
+    .. sourcecode:: html+jinja
+
+        <ul{{ {'class': 'my_list', 'missing': none,
+                'id': 'list-%d'|format(variable)}|xmlattr }}>
+        ...
+        </ul>
+
+    Results in something like this:
+
+    .. sourcecode:: html
+
+        <ul class="my_list" id="list-42">
+        ...
+        </ul>
+
+    As you can see it automatically prepends a space in front of the item
+    if the filter returned something unless the second parameter is false.
+    """
+    rv = u' '.join(
+        u'%s="%s"' % (escape(key), escape(value))
+        for key, value in d.iteritems()
+        if value is not None and not isinstance(value, Undefined)
+    )
+    if autospace and rv:
+        rv = u' ' + rv
+    if _eval_ctx.autoescape:
+        rv = Markup(rv)
+    return rv
+
+
+def do_capitalize(s):
+    """Capitalize a value. The first character will be uppercase, all others
+    lowercase.
+    """
+    return soft_unicode(s).capitalize()
+
+
+def do_title(s):
+    """Return a titlecased version of the value. I.e. words will start with
+    uppercase letters, all remaining characters are lowercase.
+    """
+    return soft_unicode(s).title()
+
+
+def do_dictsort(value, case_sensitive=False, by='key'):
+    """Sort a dict and yield (key, value) pairs. Because python dicts are
+    unsorted you may want to use this function to order them by either
+    key or value:
+
+    .. sourcecode:: jinja
+
+        {% for item in mydict|dictsort %}
+            sort the dict by key, case insensitive
+
+        {% for item in mydict|dicsort(true) %}
+            sort the dict by key, case sensitive
+
+        {% for item in mydict|dictsort(false, 'value') %}
+            sort the dict by key, case insensitive, sorted
+            normally and ordered by value.
+    """
+    if by == 'key':
+        pos = 0
+    elif by == 'value':
+        pos = 1
+    else:
+        raise FilterArgumentError('You can only sort by either '
+                                  '"key" or "value"')
+    def sort_func(item):
+        value = item[pos]
+        if isinstance(value, basestring) and not case_sensitive:
+            value = value.lower()
+        return value
+
+    return sorted(value.items(), key=sort_func)
+
+
+@environmentfilter
+def do_sort(environment, value, reverse=False, case_sensitive=False,
+            attribute=None):
+    """Sort an iterable.  Per default it sorts ascending, if you pass it
+    true as first argument it will reverse the sorting.
+
+    If the iterable is made of strings the third parameter can be used to
+    control the case sensitiveness of the comparison which is disabled by
+    default.
+
+    .. sourcecode:: jinja
+
+        {% for item in iterable|sort %}
+            ...
+        {% endfor %}
+
+    It is also possible to sort by an attribute (for example to sort
+    by the date of an object) by specifying the `attribute` parameter:
+
+    .. sourcecode:: jinja
+
+        {% for item in iterable|sort(attribute='date') %}
+            ...
+        {% endfor %}
+
+    .. versionchanged:: 2.6
+       The `attribute` parameter was added.
+    """
+    if not case_sensitive:
+        def sort_func(item):
+            if isinstance(item, basestring):
+                item = item.lower()
+            return item
+    else:
+        sort_func = None
+    if attribute is not None:
+        getter = make_attrgetter(environment, attribute)
+        def sort_func(item, processor=sort_func or (lambda x: x)):
+            return processor(getter(item))
+    return sorted(value, key=sort_func, reverse=reverse)
+
+
+def do_default(value, default_value=u'', boolean=False):
+    """If the value is undefined it will return the passed default value,
+    otherwise the value of the variable:
+
+    .. sourcecode:: jinja
+
+        {{ my_variable|default('my_variable is not defined') }}
+
+    This will output the value of ``my_variable`` if the variable was
+    defined, otherwise ``'my_variable is not defined'``. If you want
+    to use default with variables that evaluate to false you have to
+    set the second parameter to `true`:
+
+    .. sourcecode:: jinja
+
+        {{ ''|default('the string was empty', true) }}
+    """
+    if (boolean and not value) or isinstance(value, Undefined):
+        return default_value
+    return value
+
+
+@evalcontextfilter
+def do_join(eval_ctx, value, d=u'', attribute=None):
+    """Return a string which is the concatenation of the strings in the
+    sequence. The separator between elements is an empty string per
+    default, you can define it with the optional parameter:
+
+    .. sourcecode:: jinja
+
+        {{ [1, 2, 3]|join('|') }}
+            -> 1|2|3
+
+        {{ [1, 2, 3]|join }}
+            -> 123
+
+    It is also possible to join certain attributes of an object:
+
+    .. sourcecode:: jinja
+
+        {{ users|join(', ', attribute='username') }}
+
+    .. versionadded:: 2.6
+       The `attribute` parameter was added.
+    """
+    if attribute is not None:
+        value = imap(make_attrgetter(eval_ctx.environment, attribute), value)
+
+    # no automatic escaping?  joining is a lot eaiser then
+    if not eval_ctx.autoescape:
+        return unicode(d).join(imap(unicode, value))
+
+    # if the delimiter doesn't have an html representation we check
+    # if any of the items has.  If yes we do a coercion to Markup
+    if not hasattr(d, '__html__'):
+        value = list(value)
+        do_escape = False
+        for idx, item in enumerate(value):
+            if hasattr(item, '__html__'):
+                do_escape = True
+            else:
+                value[idx] = unicode(item)
+        if do_escape:
+            d = escape(d)
+        else:
+            d = unicode(d)
+        return d.join(value)
+
+    # no html involved, to normal joining
+    return soft_unicode(d).join(imap(soft_unicode, value))
+
+
+def do_center(value, width=80):
+    """Centers the value in a field of a given width."""
+    return unicode(value).center(width)
+
+
+@environmentfilter
+def do_first(environment, seq):
+    """Return the first item of a sequence."""
+    try:
+        return iter(seq).next()
+    except StopIteration:
+        return environment.undefined('No first item, sequence was empty.')
+
+
+@environmentfilter
+def do_last(environment, seq):
+    """Return the last item of a sequence."""
+    try:
+        return iter(reversed(seq)).next()
+    except StopIteration:
+        return environment.undefined('No last item, sequence was empty.')
+
+
+@environmentfilter
+def do_random(environment, seq):
+    """Return a random item from the sequence."""
+    try:
+        return choice(seq)
+    except IndexError:
+        return environment.undefined('No random item, sequence was empty.')
+
+
+def do_filesizeformat(value, binary=False):
+    """Format the value like a 'human-readable' file size (i.e. 13 kB,
+    4.1 MB, 102 Bytes, etc).  Per default decimal prefixes are used (Mega,
+    Giga, etc.), if the second parameter is set to `True` the binary
+    prefixes are used (Mebi, Gibi).
+    """
+    bytes = float(value)
+    base = binary and 1024 or 1000
+    prefixes = [
+        (binary and "KiB" or "kB"),
+        (binary and "MiB" or "MB"),
+        (binary and "GiB" or "GB"),
+        (binary and "TiB" or "TB"),
+        (binary and "PiB" or "PB"),
+        (binary and "EiB" or "EB"),
+        (binary and "ZiB" or "ZB"),
+        (binary and "YiB" or "YB")
+    ]
+    if bytes == 1:
+        return "1 Byte"
+    elif bytes < base:
+        return "%d Bytes" % bytes
+    else:
+        for i, prefix in enumerate(prefixes):
+            unit = base * base ** (i + 1)
+            if bytes < unit:
+                return "%.1f %s" % ((bytes / unit), prefix)
+        return "%.1f %s" % ((bytes / unit), prefix)
+
+
+def do_pprint(value, verbose=False):
+    """Pretty print a variable. Useful for debugging.
+
+    With Jinja 1.2 onwards you can pass it a parameter.  If this parameter
+    is truthy the output will be more verbose (this requires `pretty`)
+    """
+    return pformat(value, verbose=verbose)
+
+
+@evalcontextfilter
+def do_urlize(eval_ctx, value, trim_url_limit=None, nofollow=False):
+    """Converts URLs in plain text into clickable links.
+
+    If you pass the filter an additional integer it will shorten the urls
+    to that number. Also a third argument exists that makes the urls
+    "nofollow":
+
+    .. sourcecode:: jinja
+
+        {{ mytext|urlize(40, true) }}
+            links are shortened to 40 chars and defined with rel="nofollow"
+    """
+    rv = urlize(value, trim_url_limit, nofollow)
+    if eval_ctx.autoescape:
+        rv = Markup(rv)
+    return rv
+
+
+def do_indent(s, width=4, indentfirst=False):
+    """Return a copy of the passed string, each line indented by
+    4 spaces. The first line is not indented. If you want to
+    change the number of spaces or indent the first line too
+    you can pass additional parameters to the filter:
+
+    .. sourcecode:: jinja
+
+        {{ mytext|indent(2, true) }}
+            indent by two spaces and indent the first line too.
+    """
+    indention = u' ' * width
+    rv = (u'\n' + indention).join(s.splitlines())
+    if indentfirst:
+        rv = indention + rv
+    return rv
+
+
+def do_truncate(s, length=255, killwords=False, end='...'):
+    """Return a truncated copy of the string. The length is specified
+    with the first parameter which defaults to ``255``. If the second
+    parameter is ``true`` the filter will cut the text at length. Otherwise
+    it will try to save the last word. If the text was in fact
+    truncated it will append an ellipsis sign (``"..."``). If you want a
+    different ellipsis sign than ``"..."`` you can specify it using the
+    third parameter.
+
+    .. sourcecode jinja::
+
+        {{ mytext|truncate(300, false, '&raquo;') }}
+            truncate mytext to 300 chars, don't split up words, use a
+            right pointing double arrow as ellipsis sign.
+    """
+    if len(s) <= length:
+        return s
+    elif killwords:
+        return s[:length] + end
+    words = s.split(' ')
+    result = []
+    m = 0
+    for word in words:
+        m += len(word) + 1
+        if m > length:
+            break
+        result.append(word)
+    result.append(end)
+    return u' '.join(result)
+
+@environmentfilter
+def do_wordwrap(environment, s, width=79, break_long_words=True):
+    """
+    Return a copy of the string passed to the filter wrapped after
+    ``79`` characters.  You can override this default using the first
+    parameter.  If you set the second parameter to `false` Jinja will not
+    split words apart if they are longer than `width`.
+    """
+    import textwrap
+    return environment.newline_sequence.join(textwrap.wrap(s, width=width, expand_tabs=False,
+                                   replace_whitespace=False,
+                                   break_long_words=break_long_words))
+
+
+def do_wordcount(s):
+    """Count the words in that string."""
+    return len(_word_re.findall(s))
+
+
+def do_int(value, default=0):
+    """Convert the value into an integer. If the
+    conversion doesn't work it will return ``0``. You can
+    override this default using the first parameter.
+    """
+    try:
+        return int(value)
+    except (TypeError, ValueError):
+        # this quirk is necessary so that "42.23"|int gives 42.
+        try:
+            return int(float(value))
+        except (TypeError, ValueError):
+            return default
+
+
+def do_float(value, default=0.0):
+    """Convert the value into a floating point number. If the
+    conversion doesn't work it will return ``0.0``. You can
+    override this default using the first parameter.
+    """
+    try:
+        return float(value)
+    except (TypeError, ValueError):
+        return default
+
+
+def do_format(value, *args, **kwargs):
+    """
+    Apply python string formatting on an object:
+
+    .. sourcecode:: jinja
+
+        {{ "%s - %s"|format("Hello?", "Foo!") }}
+            -> Hello? - Foo!
+    """
+    if args and kwargs:
+        raise FilterArgumentError('can\'t handle positional and keyword '
+                                  'arguments at the same time')
+    return soft_unicode(value) % (kwargs or args)
+
+
+def do_trim(value):
+    """Strip leading and trailing whitespace."""
+    return soft_unicode(value).strip()
+
+
+def do_striptags(value):
+    """Strip SGML/XML tags and replace adjacent whitespace by one space.
+    """
+    if hasattr(value, '__html__'):
+        value = value.__html__()
+    return Markup(unicode(value)).striptags()
+
+
+def do_slice(value, slices, fill_with=None):
+    """Slice an iterator and return a list of lists containing
+    those items. Useful if you want to create a div containing
+    three ul tags that represent columns:
+
+    .. sourcecode:: html+jinja
+
+        <div class="columwrapper">
+          {%- for column in items|slice(3) %}
+            <ul class="column-{{ loop.index }}">
+            {%- for item in column %}
+              <li>{{ item }}</li>
+            {%- endfor %}
+            </ul>
+          {%- endfor %}
+        </div>
+
+    If you pass it a second argument it's used to fill missing
+    values on the last iteration.
+    """
+    seq = list(value)
+    length = len(seq)
+    items_per_slice = length // slices
+    slices_with_extra = length % slices
+    offset = 0
+    for slice_number in xrange(slices):
+        start = offset + slice_number * items_per_slice
+        if slice_number < slices_with_extra:
+            offset += 1
+        end = offset + (slice_number + 1) * items_per_slice
+        tmp = seq[start:end]
+        if fill_with is not None and slice_number >= slices_with_extra:
+            tmp.append(fill_with)
+        yield tmp
+
+
+def do_batch(value, linecount, fill_with=None):
+    """
+    A filter that batches items. It works pretty much like `slice`
+    just the other way round. It returns a list of lists with the
+    given number of items. If you provide a second parameter this
+    is used to fill missing items. See this example:
+
+    .. sourcecode:: html+jinja
+
+        <table>
+        {%- for row in items|batch(3, '&nbsp;') %}
+          <tr>
+          {%- for column in row %}
+            <td>{{ column }}</td>
+          {%- endfor %}
+          </tr>
+        {%- endfor %}
+        </table>
+    """
+    result = []
+    tmp = []
+    for item in value:
+        if len(tmp) == linecount:
+            yield tmp
+            tmp = []
+        tmp.append(item)
+    if tmp:
+        if fill_with is not None and len(tmp) < linecount:
+            tmp += [fill_with] * (linecount - len(tmp))
+        yield tmp
+
+
+def do_round(value, precision=0, method='common'):
+    """Round the number to a given precision. The first
+    parameter specifies the precision (default is ``0``), the
+    second the rounding method:
+
+    - ``'common'`` rounds either up or down
+    - ``'ceil'`` always rounds up
+    - ``'floor'`` always rounds down
+
+    If you don't specify a method ``'common'`` is used.
+
+    .. sourcecode:: jinja
+
+        {{ 42.55|round }}
+            -> 43.0
+        {{ 42.55|round(1, 'floor') }}
+            -> 42.5
+
+    Note that even if rounded to 0 precision, a float is returned.  If
+    you need a real integer, pipe it through `int`:
+
+    .. sourcecode:: jinja
+
+        {{ 42.55|round|int }}
+            -> 43
+    """
+    if not method in ('common', 'ceil', 'floor'):
+        raise FilterArgumentError('method must be common, ceil or floor')
+    if method == 'common':
+        return round(value, precision)
+    func = getattr(math, method)
+    return func(value * (10 ** precision)) / (10 ** precision)
+
+
+@environmentfilter
+def do_groupby(environment, value, attribute):
+    """Group a sequence of objects by a common attribute.
+
+    If you for example have a list of dicts or objects that represent persons
+    with `gender`, `first_name` and `last_name` attributes and you want to
+    group all users by genders you can do something like the following
+    snippet:
+
+    .. sourcecode:: html+jinja
+
+        <ul>
+        {% for group in persons|groupby('gender') %}
+            <li>{{ group.grouper }}<ul>
+            {% for person in group.list %}
+                <li>{{ person.first_name }} {{ person.last_name }}</li>
+            {% endfor %}</ul></li>
+        {% endfor %}
+        </ul>
+
+    Additionally it's possible to use tuple unpacking for the grouper and
+    list:
+
+    .. sourcecode:: html+jinja
+
+        <ul>
+        {% for grouper, list in persons|groupby('gender') %}
+            ...
+        {% endfor %}
+        </ul>
+
+    As you can see the item we're grouping by is stored in the `grouper`
+    attribute and the `list` contains all the objects that have this grouper
+    in common.
+
+    .. versionchanged:: 2.6
+       It's now possible to use dotted notation to group by the child
+       attribute of another attribute.
+    """
+    expr = make_attrgetter(environment, attribute)
+    return sorted(map(_GroupTuple, groupby(sorted(value, key=expr), expr)))
+
+
+class _GroupTuple(tuple):
+    __slots__ = ()
+    grouper = property(itemgetter(0))
+    list = property(itemgetter(1))
+
+    def __new__(cls, (key, value)):
+        return tuple.__new__(cls, (key, list(value)))
+
+
+@environmentfilter
+def do_sum(environment, iterable, attribute=None, start=0):
+    """Returns the sum of a sequence of numbers plus the value of parameter
+    'start' (which defaults to 0).  When the sequence is empty it returns
+    start.
+
+    It is also possible to sum up only certain attributes:
+
+    .. sourcecode:: jinja
+
+        Total: {{ items|sum(attribute='price') }}
+
+    .. versionchanged:: 2.6
+       The `attribute` parameter was added to allow suming up over
+       attributes.  Also the `start` parameter was moved on to the right.
+    """
+    if attribute is not None:
+        iterable = imap(make_attrgetter(environment, attribute), iterable)
+    return sum(iterable, start)
+
+
+def do_list(value):
+    """Convert the value into a list.  If it was a string the returned list
+    will be a list of characters.
+    """
+    return list(value)
+
+
+def do_mark_safe(value):
+    """Mark the value as safe which means that in an environment with automatic
+    escaping enabled this variable will not be escaped.
+    """
+    return Markup(value)
+
+
+def do_mark_unsafe(value):
+    """Mark a value as unsafe.  This is the reverse operation for :func:`safe`."""
+    return unicode(value)
+
+
+def do_reverse(value):
+    """Reverse the object or return an iterator the iterates over it the other
+    way round.
+    """
+    if isinstance(value, basestring):
+        return value[::-1]
+    try:
+        return reversed(value)
+    except TypeError:
+        try:
+            rv = list(value)
+            rv.reverse()
+            return rv
+        except TypeError:
+            raise FilterArgumentError('argument must be iterable')
+
+
+@environmentfilter
+def do_attr(environment, obj, name):
+    """Get an attribute of an object.  ``foo|attr("bar")`` works like
+    ``foo["bar"]`` just that always an attribute is returned and items are not
+    looked up.
+
+    See :ref:`Notes on subscriptions <notes-on-subscriptions>` for more details.
+    """
+    try:
+        name = str(name)
+    except UnicodeError:
+        pass
+    else:
+        try:
+            value = getattr(obj, name)
+        except AttributeError:
+            pass
+        else:
+            if environment.sandboxed and not \
+               environment.is_safe_attribute(obj, name, value):
+                return environment.unsafe_undefined(obj, name)
+            return value
+    return environment.undefined(obj=obj, name=name)
+
+
+FILTERS = {
+    'attr':                 do_attr,
+    'replace':              do_replace,
+    'upper':                do_upper,
+    'lower':                do_lower,
+    'escape':               escape,
+    'e':                    escape,
+    'forceescape':          do_forceescape,
+    'capitalize':           do_capitalize,
+    'title':                do_title,
+    'default':              do_default,
+    'd':                    do_default,
+    'join':                 do_join,
+    'count':                len,
+    'dictsort':             do_dictsort,
+    'sort':                 do_sort,
+    'length':               len,
+    'reverse':              do_reverse,
+    'center':               do_center,
+    'indent':               do_indent,
+    'title':                do_title,
+    'capitalize':           do_capitalize,
+    'first':                do_first,
+    'last':                 do_last,
+    'random':               do_random,
+    'filesizeformat':       do_filesizeformat,
+    'pprint':               do_pprint,
+    'truncate':             do_truncate,
+    'wordwrap':             do_wordwrap,
+    'wordcount':            do_wordcount,
+    'int':                  do_int,
+    'float':                do_float,
+    'string':               soft_unicode,
+    'list':                 do_list,
+    'urlize':               do_urlize,
+    'format':               do_format,
+    'trim':                 do_trim,
+    'striptags':            do_striptags,
+    'slice':                do_slice,
+    'batch':                do_batch,
+    'sum':                  do_sum,
+    'abs':                  abs,
+    'round':                do_round,
+    'groupby':              do_groupby,
+    'safe':                 do_mark_safe,
+    'xmlattr':              do_xmlattr
+}