Chromium Code Reviews
chromiumcodereview-hr@appspot.gserviceaccount.com (chromiumcodereview-hr) | Please choose your nickname with Settings | Help | Chromium Project | Gerrit Changes | Sign out
(1666)

Unified Diff: third_party/jinja2/meta.py

Issue 14761007: Add Python templating engine Jinja2 to third_party (Closed) Base URL: svn://svn.chromium.org/chrome/trunk/src
Patch Set: Created 7 years, 7 months ago
Use n/p to move between diff chunks; N/P to move between comments. Draft comments are only viewable by you.
Jump to:
View side-by-side diff with in-line comments
Download patch
« no previous file with comments | « third_party/jinja2/loaders.py ('k') | third_party/jinja2/nodes.py » ('j') | no next file with comments »
Expand Comments ('e') | Collapse Comments ('c') | Show Comments Hide Comments ('s')
Index: third_party/jinja2/meta.py
diff --git a/third_party/jinja2/meta.py b/third_party/jinja2/meta.py
new file mode 100644
index 0000000000000000000000000000000000000000..3a779a5e9a81a6b59b0fa1685c63e62e38a70b9c
--- /dev/null
+++ b/third_party/jinja2/meta.py
@@ -0,0 +1,102 @@
+# -*- 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
« no previous file with comments | « third_party/jinja2/loaders.py ('k') | third_party/jinja2/nodes.py » ('j') | no next file with comments »

Powered by Google App Engine
This is Rietveld 408576698