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| author | rockot <rockot@chromium.org> | 2015-11-12 17:33:59 -0800 |
|---|---|---|
| committer | Commit bot <commit-bot@chromium.org> | 2015-11-13 01:34:47 +0000 |
| commit | 85dce086001825a2faa4e75755a669f5e08a1cad (patch) | |
| tree | 722de1d974f799b3d1ee1ca4c81bb8b0fa75a95d /mojo/public/third_party/jinja2/optimizer.py | |
| parent | 415b73b1a400a994a86e6f29709aa0271e895dd5 (diff) | |
| download | chromium_src-85dce086001825a2faa4e75755a669f5e08a1cad.zip chromium_src-85dce086001825a2faa4e75755a669f5e08a1cad.tar.gz chromium_src-85dce086001825a2faa4e75755a669f5e08a1cad.tar.bz2 | |
Move third_party/mojo/src/mojo/public to mojo/public
BUG=None
NOPRESUBMIT=true
Review URL: https://codereview.chromium.org/1410053006
Cr-Commit-Position: refs/heads/master@{#359461}
Diffstat (limited to 'mojo/public/third_party/jinja2/optimizer.py')
| -rw-r--r-- | mojo/public/third_party/jinja2/optimizer.py | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/mojo/public/third_party/jinja2/optimizer.py b/mojo/public/third_party/jinja2/optimizer.py new file mode 100644 index 0000000..00eab11 --- /dev/null +++ b/mojo/public/third_party/jinja2/optimizer.py @@ -0,0 +1,68 @@ +# -*- coding: utf-8 -*- +""" + jinja2.optimizer + ~~~~~~~~~~~~~~~~ + + The jinja optimizer is currently trying to constant fold a few expressions + and modify the AST in place so that it should be easier to evaluate it. + + Because the AST does not contain all the scoping information and the + compiler has to find that out, we cannot do all the optimizations we + want. For example loop unrolling doesn't work because unrolled loops would + have a different scoping. + + The solution would be a second syntax tree that has the scoping rules stored. + + :copyright: (c) 2010 by the Jinja Team. + :license: BSD. +""" +from jinja2 import nodes +from jinja2.visitor import NodeTransformer + + +def optimize(node, environment): + """The context hint can be used to perform an static optimization + based on the context given.""" + optimizer = Optimizer(environment) + return optimizer.visit(node) + + +class Optimizer(NodeTransformer): + + def __init__(self, environment): + self.environment = environment + + def visit_If(self, node): + """Eliminate dead code.""" + # do not optimize ifs that have a block inside so that it doesn't + # break super(). + if node.find(nodes.Block) is not None: + return self.generic_visit(node) + try: + val = self.visit(node.test).as_const() + except nodes.Impossible: + return self.generic_visit(node) + if val: + body = node.body + else: + body = node.else_ + result = [] + for node in body: + result.extend(self.visit_list(node)) + return result + + def fold(self, node): + """Do constant folding.""" + node = self.generic_visit(node) + try: + return nodes.Const.from_untrusted(node.as_const(), + lineno=node.lineno, + environment=self.environment) + except nodes.Impossible: + return node + + visit_Add = visit_Sub = visit_Mul = visit_Div = visit_FloorDiv = \ + visit_Pow = visit_Mod = visit_And = visit_Or = visit_Pos = visit_Neg = \ + visit_Not = visit_Compare = visit_Getitem = visit_Getattr = visit_Call = \ + visit_Filter = visit_Test = visit_CondExpr = fold + del fold |