blob: d7163e487efff258b5f3ccf4a112ec3de3f7958c [file] [log] [blame]
# Copyright 2014 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
"""Process Chrome resources (HTML/CSS/JS) to handle <include> and <if> tags."""
from collections import defaultdict
import re
import os
class LineNumber(object):
"""A simple wrapper to hold line information (e.g. file.js:32)."""
def __init__(self, source_file, line_number):
source_file: A file path (as a string).
line_number: The line in |file| (as an integer).
self.file = source_file
self.line_number = int(line_number)
class FileCache(object):
"""An in-memory cache to speed up reading the same files over and over.
_cache = defaultdict(str)
def read(self, source_file):
"""Read a file and return it as a string.
source_file: a file path (as a string) to read and return the contents.
The contents of |source_file| (as a string).
abs_file = os.path.abspath(source_file)
self._cache[abs_file] = self._cache[abs_file] or open(abs_file, "r").read()
return self._cache[abs_file]
class Processor(object):
"""Processes resource files, inlining the contents of <include> tags, removing
<if> tags, and retaining original line info.
For example
1: /* blah.js */
2: <if expr="is_win">
3: <include src="win.js">
4: </if>
would be turned into:
1: /* blah.js */
3: /* win.js */
4: alert('Ew; Windows.');
_IF_TAGS_REG = "</?if[^>]*?>"
_INCLUDE_REG = "<include[^>]+src=['\"]([^>]*)['\"]>"
def __init__(self, source_file):
source_file: A file path to process (as a string).
self.included_files = set()
self._index = 0
self._lines = self._get_file(source_file)
# Can't enumerate(self._lines) here because some lines are re-processed.
while self._index < len(self._lines):
current_line = self._lines[self._index]
match =, current_line[2])
if match:
file_dir = os.path.dirname(current_line[0])
file_name = os.path.abspath(os.path.join(file_dir,
if file_name not in self.included_files:
continue # Stay on the same line.
# Found a duplicate <include>. Ignore and insert a blank line to
# preserve line numbers.
self._lines[self._index] = self._lines[self._index][:2] + ("",)
self._index += 1
for i, line in enumerate(self._lines):
self._lines[i] = line[:2] + (re.sub(self._IF_TAGS_REG, "", line[2]),)
self.contents = "\n".join(l[2] for l in self._lines)
# Returns a list of tuples in the format: (file, line number, line contents).
def _get_file(self, source_file):
lines =
return [(source_file, lnum + 1, line) for lnum, line in enumerate(lines)]
def _include_file(self, source_file):
f = self._get_file(source_file)
self._lines = self._lines[:self._index] + f + self._lines[self._index + 1:]
def get_file_from_line(self, line_number):
"""Get the original file and line number for an expanded file's line number.
line_number: A processed file's line number (as an integer or string).
line_number = int(line_number) - 1
return LineNumber(self._lines[line_number][0], self._lines[line_number][1])