mirror of
https://gitee.com/openharmony/third_party_jinja2
synced 2024-11-23 23:29:58 +00:00
807 lines
23 KiB
Python
807 lines
23 KiB
Python
# -*- coding: utf-8 -*-
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"""
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jinja2.nodes
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~~~~~~~~~~~~
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This module implements additional nodes derived from the ast base node.
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It also provides some node tree helper functions like `in_lineno` and
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`get_nodes` used by the parser and translator in order to normalize
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python and jinja nodes.
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:copyright: 2008 by Armin Ronacher.
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:license: BSD, see LICENSE for more details.
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"""
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import operator
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from copy import copy
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from itertools import chain, izip
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from collections import deque
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from jinja2.utils import Markup
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_binop_to_func = {
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'*': operator.mul,
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'/': operator.truediv,
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'//': operator.floordiv,
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'**': operator.pow,
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'%': operator.mod,
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'+': operator.add,
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'-': operator.sub
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}
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_uaop_to_func = {
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'not': operator.not_,
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'+': operator.pos,
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'-': operator.neg
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}
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_cmpop_to_func = {
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'eq': operator.eq,
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'ne': operator.ne,
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'gt': operator.gt,
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'gteq': operator.ge,
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'lt': operator.lt,
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'lteq': operator.le,
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'in': lambda a, b: a in b,
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'notin': lambda a, b: a not in b
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}
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class Impossible(Exception):
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"""Raised if the node could not perform a requested action."""
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class NodeType(type):
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"""A metaclass for nodes that handles the field and attribute
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inheritance. fields and attributes from the parent class are
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automatically forwarded to the child."""
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def __new__(cls, name, bases, d):
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for attr in 'fields', 'attributes':
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storage = []
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storage.extend(getattr(bases[0], attr, ()))
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storage.extend(d.get(attr, ()))
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assert len(bases) == 1, 'multiple inheritance not allowed'
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assert len(storage) == len(set(storage)), 'layout conflict'
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d[attr] = tuple(storage)
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d.setdefault('abstract', False)
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return type.__new__(cls, name, bases, d)
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class Node(object):
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"""Baseclass for all Jinja2 nodes. There are a number of nodes available
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of different types. There are three major types:
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- :class:`Stmt`: statements
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- :class:`Expr`: expressions
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- :class:`Helper`: helper nodes
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- :class:`Template`: the outermost wrapper node
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All nodes have fields and attributes. Fields may be other nodes, lists,
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or arbitrary values. Fields are passed to the constructor as regular
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positional arguments, attributes as keyword arguments. Each node has
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two attributes: `lineno` (the line number of the node) and `environment`.
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The `environment` attribute is set at the end of the parsing process for
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all nodes automatically.
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"""
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__metaclass__ = NodeType
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fields = ()
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attributes = ('lineno', 'environment')
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abstract = True
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def __init__(self, *fields, **attributes):
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if self.abstract:
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raise TypeError('abstract nodes are not instanciable')
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if fields:
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if len(fields) != len(self.fields):
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if not self.fields:
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raise TypeError('%r takes 0 arguments' %
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self.__class__.__name__)
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raise TypeError('%r takes 0 or %d argument%s' % (
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self.__class__.__name__,
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len(self.fields),
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len(self.fields) != 1 and 's' or ''
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))
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for name, arg in izip(self.fields, fields):
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setattr(self, name, arg)
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for attr in self.attributes:
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setattr(self, attr, attributes.pop(attr, None))
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if attributes:
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raise TypeError('unknown attribute %r' %
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iter(attributes).next())
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def iter_fields(self, exclude=None, only=None):
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"""This method iterates over all fields that are defined and yields
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``(key, value)`` tuples. Per default all fields are returned, but
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it's possible to limit that to some fields by providing the `only`
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parameter or to exclude some using the `exclude` parameter. Both
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should be sets or tuples of field names.
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"""
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for name in self.fields:
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if (exclude is only is None) or \
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(exclude is not None and name not in exclude) or \
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(only is not None and name in only):
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try:
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yield name, getattr(self, name)
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except AttributeError:
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pass
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def iter_child_nodes(self, exclude=None, only=None):
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"""Iterates over all direct child nodes of the node. This iterates
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over all fields and yields the values of they are nodes. If the value
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of a field is a list all the nodes in that list are returned.
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"""
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for field, item in self.iter_fields(exclude, only):
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if isinstance(item, list):
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for n in item:
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if isinstance(n, Node):
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yield n
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elif isinstance(item, Node):
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yield item
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def find(self, node_type):
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"""Find the first node of a given type. If no such node exists the
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return value is `None`.
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"""
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for result in self.find_all(node_type):
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return result
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def find_all(self, node_type):
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"""Find all the nodes of a given type."""
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for child in self.iter_child_nodes():
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if isinstance(child, node_type):
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yield child
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for result in child.find_all(node_type):
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yield result
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def copy(self):
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"""Return a deep copy of the node."""
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result = object.__new__(self.__class__)
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for field, value in self.iter_fields():
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if isinstance(value, Node):
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new_value = value.copy()
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elif isinstance(value, list):
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new_value = []
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for item in value:
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if isinstance(item, Node):
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item = item.copy()
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else:
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item = copy(item)
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new_value.append(item)
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else:
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new_value = copy(value)
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setattr(result, field, new_value)
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for attr in self.attributes:
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try:
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setattr(result, attr, getattr(self, attr))
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except AttributeError:
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pass
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return result
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def set_ctx(self, ctx):
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"""Reset the context of a node and all child nodes. Per default the
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parser will all generate nodes that have a 'load' context as it's the
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most common one. This method is used in the parser to set assignment
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targets and other nodes to a store context.
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"""
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todo = deque([self])
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while todo:
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node = todo.popleft()
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if 'ctx' in node.fields:
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node.ctx = ctx
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todo.extend(node.iter_child_nodes())
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return self
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def set_lineno(self, lineno, override=False):
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"""Set the line numbers of the node and children."""
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todo = deque([self])
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while todo:
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node = todo.popleft()
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if 'lineno' in node.attributes:
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if node.lineno is None or override:
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node.lineno = lineno
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todo.extend(node.iter_child_nodes())
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return self
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def set_environment(self, environment):
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"""Set the environment for all nodes."""
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todo = deque([self])
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while todo:
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node = todo.popleft()
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node.environment = environment
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todo.extend(node.iter_child_nodes())
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return self
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def __eq__(self, other):
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return type(self) is type(other) and \
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tuple(self.iter_fields()) == tuple(other.iter_fields())
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def __ne__(self, other):
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return not self.__eq__(other)
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def __repr__(self):
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return '%s(%s)' % (
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self.__class__.__name__,
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', '.join('%s=%r' % (arg, getattr(self, arg, None)) for
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arg in self.fields)
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)
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class Stmt(Node):
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"""Base node for all statements."""
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abstract = True
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class Helper(Node):
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"""Nodes that exist in a specific context only."""
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abstract = True
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class Template(Node):
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"""Node that represents a template. This must be the outermost node that
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is passed to the compiler.
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"""
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fields = ('body',)
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class Output(Stmt):
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"""A node that holds multiple expressions which are then printed out.
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This is used both for the `print` statement and the regular template data.
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"""
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fields = ('nodes',)
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class Extends(Stmt):
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"""Represents an extends statement."""
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fields = ('template',)
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class For(Stmt):
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"""The for loop. `target` is the target for the iteration (usually a
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:class:`Name` or :class:`Tuple`), `iter` the iterable. `body` is a list
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of nodes that are used as loop-body, and `else_` a list of nodes for the
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`else` block. If no else node exists it has to be an empty list.
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For filtered nodes an expression can be stored as `test`, otherwise `None`.
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"""
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fields = ('target', 'iter', 'body', 'else_', 'test', 'recursive')
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class If(Stmt):
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"""If `test` is true, `body` is rendered, else `else_`."""
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fields = ('test', 'body', 'else_')
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class Macro(Stmt):
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"""A macro definition. `name` is the name of the macro, `args` a list of
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arguments and `defaults` a list of defaults if there are any. `body` is
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a list of nodes for the macro body.
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"""
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fields = ('name', 'args', 'defaults', 'body')
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class CallBlock(Stmt):
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"""Like a macro without a name but a call instead. `call` is called with
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the unnamed macro as `caller` argument this node holds.
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"""
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fields = ('call', 'args', 'defaults', 'body')
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class Set(Stmt):
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"""Allows defining own variables."""
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fields = ('name', 'expr')
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class FilterBlock(Stmt):
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"""Node for filter sections."""
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fields = ('body', 'filter')
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class Block(Stmt):
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"""A node that represents a block."""
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fields = ('name', 'body')
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class Include(Stmt):
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"""A node that represents the include tag."""
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fields = ('template', 'with_context')
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class Import(Stmt):
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"""A node that represents the import tag."""
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fields = ('template', 'target', 'with_context')
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class FromImport(Stmt):
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"""A node that represents the from import tag. It's important to not
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pass unsafe names to the name attribute. The compiler translates the
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attribute lookups directly into getattr calls and does *not* use the
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subscript callback of the interface. As exported variables may not
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start with double underscores (which the parser asserts) this is not a
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problem for regular Jinja code, but if this node is used in an extension
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extra care must be taken.
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The list of names may contain tuples if aliases are wanted.
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"""
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fields = ('template', 'names', 'with_context')
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class ExprStmt(Stmt):
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"""A statement that evaluates an expression and discards the result."""
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fields = ('node',)
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class Assign(Stmt):
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"""Assigns an expression to a target."""
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fields = ('target', 'node')
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class Expr(Node):
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"""Baseclass for all expressions."""
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abstract = True
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def as_const(self):
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"""Return the value of the expression as constant or raise
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:exc:`Impossible` if this was not possible:
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>>> Add(Const(23), Const(42)).as_const()
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65
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>>> Add(Const(23), Name('var', 'load')).as_const()
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Traceback (most recent call last):
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...
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Impossible
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This requires the `environment` attribute of all nodes to be
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set to the environment that created the nodes.
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"""
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raise Impossible()
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def can_assign(self):
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"""Check if it's possible to assign something to this node."""
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return False
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class BinExpr(Expr):
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"""Baseclass for all binary expressions."""
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fields = ('left', 'right')
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operator = None
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abstract = True
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def as_const(self):
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f = _binop_to_func[self.operator]
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try:
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return f(self.left.as_const(), self.right.as_const())
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except:
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raise Impossible()
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class UnaryExpr(Expr):
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"""Baseclass for all unary expressions."""
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fields = ('node',)
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operator = None
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abstract = True
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def as_const(self):
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f = _uaop_to_func[self.operator]
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try:
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return f(self.node.as_const())
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except:
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raise Impossible()
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class Name(Expr):
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"""Looks up a name or stores a value in a name.
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The `ctx` of the node can be one of the following values:
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- `store`: store a value in the name
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- `load`: load that name
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- `param`: like `store` but if the name was defined as function parameter.
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"""
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fields = ('name', 'ctx')
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def can_assign(self):
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return self.name not in ('true', 'false', 'none',
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'True', 'False', 'None')
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class Literal(Expr):
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"""Baseclass for literals."""
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abstract = True
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class Const(Literal):
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"""All constant values. The parser will return this node for simple
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constants such as ``42`` or ``"foo"`` but it can be used to store more
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complex values such as lists too. Only constants with a safe
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representation (objects where ``eval(repr(x)) == x`` is true).
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"""
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fields = ('value',)
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def as_const(self):
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return self.value
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@classmethod
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def from_untrusted(cls, value, lineno=None, environment=None):
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"""Return a const object if the value is representable as
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constant value in the generated code, otherwise it will raise
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an `Impossible` exception.
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"""
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from compiler import has_safe_repr
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if not has_safe_repr(value):
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raise Impossible()
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return cls(value, lineno=lineno, environment=environment)
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class TemplateData(Literal):
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"""A constant template string."""
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fields = ('data',)
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def as_const(self):
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if self.environment.autoescape:
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return Markup(self.data)
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return self.data
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class Tuple(Literal):
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"""For loop unpacking and some other things like multiple arguments
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for subscripts. Like for :class:`Name` `ctx` specifies if the tuple
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is used for loading the names or storing.
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"""
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fields = ('items', 'ctx')
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def as_const(self):
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return tuple(x.as_const() for x in self.items)
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def can_assign(self):
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for item in self.items:
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if not item.can_assign():
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return False
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return True
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class List(Literal):
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"""Any list literal such as ``[1, 2, 3]``"""
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fields = ('items',)
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def as_const(self):
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return [x.as_const() for x in self.items]
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class Dict(Literal):
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"""Any dict literal such as ``{1: 2, 3: 4}``. The items must be a list of
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:class:`Pair` nodes.
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"""
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fields = ('items',)
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def as_const(self):
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return dict(x.as_const() for x in self.items)
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class Pair(Helper):
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"""A key, value pair for dicts."""
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fields = ('key', 'value')
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def as_const(self):
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return self.key.as_const(), self.value.as_const()
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class Keyword(Helper):
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"""A key, value pair for keyword arguments where key is a string."""
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fields = ('key', 'value')
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class CondExpr(Expr):
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"""A conditional expression (inline if expression). (``{{
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foo if bar else baz }}``)
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"""
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fields = ('test', 'expr1', 'expr2')
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def as_const(self):
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if self.test.as_const():
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return self.expr1.as_const()
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return self.expr2.as_const()
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class Filter(Expr):
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"""This node applies a filter on an expression. `name` is the name of
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the filter, the rest of the fields are the same as for :class:`Call`.
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If the `node` of a filter is `None` the contents of the last buffer are
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filtered. Buffers are created by macros and filter blocks.
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"""
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fields = ('node', 'name', 'args', 'kwargs', 'dyn_args', 'dyn_kwargs')
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def as_const(self, obj=None):
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if self.node is obj is None:
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raise Impossible()
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filter = self.environment.filters.get(self.name)
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if filter is None or getattr(filter, 'contextfilter', False):
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raise Impossible()
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if obj is None:
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obj = self.node.as_const()
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args = [x.as_const() for x in self.args]
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if getattr(filter, 'environmentfilter', False):
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args.insert(0, self.environment)
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kwargs = dict(x.as_const() for x in self.kwargs)
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if self.dyn_args is not None:
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try:
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args.extend(self.dyn_args.as_const())
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except:
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raise Impossible()
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if self.dyn_kwargs is not None:
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try:
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kwargs.update(self.dyn_kwargs.as_const())
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except:
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raise Impossible()
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try:
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return filter(obj, *args, **kwargs)
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except:
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raise Impossible()
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class Test(Expr):
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"""Applies a test on an expression. `name` is the name of the test, the
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rest of the fields are the same as for :class:`Call`.
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"""
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fields = ('node', 'name', 'args', 'kwargs', 'dyn_args', 'dyn_kwargs')
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class Call(Expr):
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"""Calls an expression. `args` is a list of arguments, `kwargs` a list
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of keyword arguments (list of :class:`Keyword` nodes), and `dyn_args`
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and `dyn_kwargs` has to be either `None` or a node that is used as
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node for dynamic positional (``*args``) or keyword (``**kwargs``)
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arguments.
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"""
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fields = ('node', 'args', 'kwargs', 'dyn_args', 'dyn_kwargs')
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def as_const(self):
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obj = self.node.as_const()
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|
|
|
# don't evaluate context functions
|
|
args = [x.as_const() for x in self.args]
|
|
if getattr(obj, 'contextfunction', False):
|
|
raise Impossible()
|
|
elif getattr(obj, 'environmentfunction', False):
|
|
args.insert(0, self.environment)
|
|
|
|
kwargs = dict(x.as_const() for x in self.kwargs)
|
|
if self.dyn_args is not None:
|
|
try:
|
|
args.extend(self.dyn_args.as_const())
|
|
except:
|
|
raise Impossible()
|
|
if self.dyn_kwargs is not None:
|
|
try:
|
|
kwargs.update(self.dyn_kwargs.as_const())
|
|
except:
|
|
raise Impossible()
|
|
try:
|
|
return obj(*args, **kwargs)
|
|
except:
|
|
raise Impossible()
|
|
|
|
|
|
class Getitem(Expr):
|
|
"""Get an attribute or item from an expression and prefer the item."""
|
|
fields = ('node', 'arg', 'ctx')
|
|
|
|
def as_const(self):
|
|
if self.ctx != 'load':
|
|
raise Impossible()
|
|
try:
|
|
return self.environment.getitem(self.node.as_const(),
|
|
self.arg.as_const())
|
|
except:
|
|
raise Impossible()
|
|
|
|
def can_assign(self):
|
|
return False
|
|
|
|
|
|
class Getattr(Expr):
|
|
"""Get an attribute or item from an expression that is a ascii-only
|
|
bytestring and prefer the attribute.
|
|
"""
|
|
fields = ('node', 'attr', 'ctx')
|
|
|
|
def as_const(self):
|
|
if self.ctx != 'load':
|
|
raise Impossible()
|
|
try:
|
|
return self.environment.getattr(self.node.as_const(), arg)
|
|
except:
|
|
raise Impossible()
|
|
|
|
def can_assign(self):
|
|
return False
|
|
|
|
|
|
class Slice(Expr):
|
|
"""Represents a slice object. This must only be used as argument for
|
|
:class:`Subscript`.
|
|
"""
|
|
fields = ('start', 'stop', 'step')
|
|
|
|
def as_const(self):
|
|
def const(obj):
|
|
if obj is None:
|
|
return obj
|
|
return obj.as_const()
|
|
return slice(const(self.start), const(self.stop), const(self.step))
|
|
|
|
|
|
class Concat(Expr):
|
|
"""Concatenates the list of expressions provided after converting them to
|
|
unicode.
|
|
"""
|
|
fields = ('nodes',)
|
|
|
|
def as_const(self):
|
|
return ''.join(unicode(x.as_const()) for x in self.nodes)
|
|
|
|
|
|
class Compare(Expr):
|
|
"""Compares an expression with some other expressions. `ops` must be a
|
|
list of :class:`Operand`\s.
|
|
"""
|
|
fields = ('expr', 'ops')
|
|
|
|
def as_const(self):
|
|
result = value = self.expr.as_const()
|
|
try:
|
|
for op in self.ops:
|
|
new_value = op.expr.as_const()
|
|
result = _cmpop_to_func[op.op](value, new_value)
|
|
value = new_value
|
|
except:
|
|
raise Impossible()
|
|
return result
|
|
|
|
|
|
class Operand(Helper):
|
|
"""Holds an operator and an expression."""
|
|
fields = ('op', 'expr')
|
|
|
|
if __debug__:
|
|
Operand.__doc__ += '\nThe following operators are available: ' + \
|
|
', '.join(sorted('``%s``' % x for x in set(_binop_to_func) |
|
|
set(_uaop_to_func) | set(_cmpop_to_func)))
|
|
|
|
|
|
class Mul(BinExpr):
|
|
"""Multiplies the left with the right node."""
|
|
operator = '*'
|
|
|
|
|
|
class Div(BinExpr):
|
|
"""Divides the left by the right node."""
|
|
operator = '/'
|
|
|
|
|
|
class FloorDiv(BinExpr):
|
|
"""Divides the left by the right node and truncates conver the
|
|
result into an integer by truncating.
|
|
"""
|
|
operator = '//'
|
|
|
|
|
|
class Add(BinExpr):
|
|
"""Add the left to the right node."""
|
|
operator = '+'
|
|
|
|
|
|
class Sub(BinExpr):
|
|
"""Substract the right from the left node."""
|
|
operator = '-'
|
|
|
|
|
|
class Mod(BinExpr):
|
|
"""Left modulo right."""
|
|
operator = '%'
|
|
|
|
|
|
class Pow(BinExpr):
|
|
"""Left to the power of right."""
|
|
operator = '**'
|
|
|
|
|
|
class And(BinExpr):
|
|
"""Short circuited AND."""
|
|
operator = 'and'
|
|
|
|
def as_const(self):
|
|
return self.left.as_const() and self.right.as_const()
|
|
|
|
|
|
class Or(BinExpr):
|
|
"""Short circuited OR."""
|
|
operator = 'or'
|
|
|
|
def as_const(self):
|
|
return self.left.as_const() or self.right.as_const()
|
|
|
|
|
|
class Not(UnaryExpr):
|
|
"""Negate the expression."""
|
|
operator = 'not'
|
|
|
|
|
|
class Neg(UnaryExpr):
|
|
"""Make the expression negative."""
|
|
operator = '-'
|
|
|
|
|
|
class Pos(UnaryExpr):
|
|
"""Make the expression positive (noop for most expressions)"""
|
|
operator = '+'
|
|
|
|
|
|
# Helpers for extensions
|
|
|
|
|
|
class EnvironmentAttribute(Expr):
|
|
"""Loads an attribute from the environment object. This is useful for
|
|
extensions that want to call a callback stored on the environment.
|
|
"""
|
|
fields = ('name',)
|
|
|
|
|
|
class ExtensionAttribute(Expr):
|
|
"""Returns the attribute of an extension bound to the environment.
|
|
The identifier is the identifier of the :class:`Extension`.
|
|
|
|
This node is usually constructed by calling the
|
|
:meth:`~jinja2.ext.Extension.attr` method on an extension.
|
|
"""
|
|
fields = ('identifier', 'name')
|
|
|
|
|
|
class ImportedName(Expr):
|
|
"""If created with an import name the import name is returned on node
|
|
access. For example ``ImportedName('cgi.escape')`` returns the `escape`
|
|
function from the cgi module on evaluation. Imports are optimized by the
|
|
compiler so there is no need to assign them to local variables.
|
|
"""
|
|
fields = ('importname',)
|
|
|
|
|
|
class InternalName(Expr):
|
|
"""An internal name in the compiler. You cannot create these nodes
|
|
yourself but the parser provides a
|
|
:meth:`~jinja2.parser.Parser.free_identifier` method that creates
|
|
a new identifier for you. This identifier is not available from the
|
|
template and is not threated specially by the compiler.
|
|
"""
|
|
fields = ('name',)
|
|
|
|
def __init__(self):
|
|
raise TypeError('Can\'t create internal names. Use the '
|
|
'`free_identifier` method on a parser.')
|
|
|
|
|
|
class MarkSafe(Expr):
|
|
"""Mark the wrapped expression as safe (wrap it as `Markup`)."""
|
|
fields = ('expr',)
|
|
|
|
def as_const(self):
|
|
return Markup(self.expr.as_const())
|
|
|
|
|
|
class ContextReference(Expr):
|
|
"""Returns the current template context."""
|
|
|
|
|
|
class Continue(Stmt):
|
|
"""Continue a loop."""
|
|
|
|
|
|
class Break(Stmt):
|
|
"""Break a loop."""
|
|
|
|
|
|
# make sure nobody creates custom nodes
|
|
def _failing_new(*args, **kwargs):
|
|
raise TypeError('can\'t create custom node types')
|
|
NodeType.__new__ = staticmethod(_failing_new); del _failing_new
|