mirror of
https://github.com/opencv/opencv.git
synced 2024-11-30 06:10:02 +08:00
103 lines
4.0 KiB
Python
103 lines
4.0 KiB
Python
# -*- coding: utf-8 -*-
|
|
"""
|
|
jinja2.meta
|
|
~~~~~~~~~~~
|
|
|
|
This module implements various functions that exposes information about
|
|
templates that might be interesting for various kinds of applications.
|
|
|
|
:copyright: (c) 2010 by the Jinja Team, see AUTHORS for more details.
|
|
:license: BSD, see LICENSE for more details.
|
|
"""
|
|
from jinja2 import nodes
|
|
from jinja2.compiler import CodeGenerator
|
|
|
|
|
|
class TrackingCodeGenerator(CodeGenerator):
|
|
"""We abuse the code generator for introspection."""
|
|
|
|
def __init__(self, environment):
|
|
CodeGenerator.__init__(self, environment, '<introspection>',
|
|
'<introspection>')
|
|
self.undeclared_identifiers = set()
|
|
|
|
def write(self, x):
|
|
"""Don't write."""
|
|
|
|
def pull_locals(self, frame):
|
|
"""Remember all undeclared identifiers."""
|
|
self.undeclared_identifiers.update(frame.identifiers.undeclared)
|
|
|
|
|
|
def find_undeclared_variables(ast):
|
|
"""Returns a set of all variables in the AST that will be looked up from
|
|
the context at runtime. Because at compile time it's not known which
|
|
variables will be used depending on the path the execution takes at
|
|
runtime, all variables are returned.
|
|
|
|
>>> from jinja2 import Environment, meta
|
|
>>> env = Environment()
|
|
>>> ast = env.parse('{% set foo = 42 %}{{ bar + foo }}')
|
|
>>> meta.find_undeclared_variables(ast)
|
|
set(['bar'])
|
|
|
|
.. admonition:: Implementation
|
|
|
|
Internally the code generator is used for finding undeclared variables.
|
|
This is good to know because the code generator might raise a
|
|
:exc:`TemplateAssertionError` during compilation and as a matter of
|
|
fact this function can currently raise that exception as well.
|
|
"""
|
|
codegen = TrackingCodeGenerator(ast.environment)
|
|
codegen.visit(ast)
|
|
return codegen.undeclared_identifiers
|
|
|
|
|
|
def find_referenced_templates(ast):
|
|
"""Finds all the referenced templates from the AST. This will return an
|
|
iterator over all the hardcoded template extensions, inclusions and
|
|
imports. If dynamic inheritance or inclusion is used, `None` will be
|
|
yielded.
|
|
|
|
>>> from jinja2 import Environment, meta
|
|
>>> env = Environment()
|
|
>>> ast = env.parse('{% extends "layout.html" %}{% include helper %}')
|
|
>>> list(meta.find_referenced_templates(ast))
|
|
['layout.html', None]
|
|
|
|
This function is useful for dependency tracking. For example if you want
|
|
to rebuild parts of the website after a layout template has changed.
|
|
"""
|
|
for node in ast.find_all((nodes.Extends, nodes.FromImport, nodes.Import,
|
|
nodes.Include)):
|
|
if not isinstance(node.template, nodes.Const):
|
|
# a tuple with some non consts in there
|
|
if isinstance(node.template, (nodes.Tuple, nodes.List)):
|
|
for template_name in node.template.items:
|
|
# something const, only yield the strings and ignore
|
|
# non-string consts that really just make no sense
|
|
if isinstance(template_name, nodes.Const):
|
|
if isinstance(template_name.value, basestring):
|
|
yield template_name.value
|
|
# something dynamic in there
|
|
else:
|
|
yield None
|
|
# something dynamic we don't know about here
|
|
else:
|
|
yield None
|
|
continue
|
|
# constant is a basestring, direct template name
|
|
if isinstance(node.template.value, basestring):
|
|
yield node.template.value
|
|
# a tuple or list (latter *should* not happen) made of consts,
|
|
# yield the consts that are strings. We could warn here for
|
|
# non string values
|
|
elif isinstance(node, nodes.Include) and \
|
|
isinstance(node.template.value, (tuple, list)):
|
|
for template_name in node.template.value:
|
|
if isinstance(template_name, basestring):
|
|
yield template_name
|
|
# something else we don't care about, we could warn here
|
|
else:
|
|
yield None
|