1# Copyright 2014 The Chromium Authors. All rights reserved. 2# Use of this source code is governed by a BSD-style license that can be 3# found in the LICENSE file. 4 5"""Process Chrome resources (HTML/CSS/JS) to handle <include> and <if> tags.""" 6 7from collections import defaultdict 8import re 9import os 10 11 12class LineNumber(object): 13 """A simple wrapper to hold line information (e.g. file.js:32). 14 15 Args: 16 source_file: A file path. 17 line_number: The line in |file|. 18 """ 19 def __init__(self, source_file, line_number): 20 self.file = source_file 21 self.line_number = int(line_number) 22 23 24class FileCache(object): 25 """An in-memory cache to speed up reading the same files over and over. 26 27 Usage: 28 FileCache.read(path_to_file) 29 """ 30 31 _cache = defaultdict(str) 32 33 @classmethod 34 def read(self, source_file): 35 """Read a file and return it as a string. 36 37 Args: 38 source_file: a file to read and return the contents of. 39 40 Returns: 41 |file| as a string. 42 """ 43 abs_file = os.path.abspath(source_file) 44 self._cache[abs_file] = self._cache[abs_file] or open(abs_file, "r").read() 45 return self._cache[abs_file] 46 47 48class Processor(object): 49 """Processes resource files, inlining the contents of <include> tags, removing 50 <if> tags, and retaining original line info. 51 52 For example 53 54 1: /* blah.js */ 55 2: <if expr="is_win"> 56 3: <include src="win.js"> 57 4: </if> 58 59 would be turned into: 60 61 1: /* blah.js */ 62 2: 63 3: /* win.js */ 64 4: alert('Ew; Windows.'); 65 5: 66 67 Args: 68 source_file: A file to process. 69 70 Attributes: 71 contents: Expanded contents after inlining <include>s and stripping <if>s. 72 included_files: A list of files that were inlined via <include>. 73 """ 74 75 _IF_TAGS_REG = "</?if[^>]*?>" 76 _INCLUDE_REG = "<include[^>]+src=['\"]([^>]*)['\"]>" 77 78 def __init__(self, source_file): 79 self._included_files = set() 80 self._index = 0 81 self._lines = self._get_file(source_file) 82 83 while self._index < len(self._lines): 84 current_line = self._lines[self._index] 85 match = re.search(self._INCLUDE_REG, current_line[2]) 86 if match: 87 file_dir = os.path.dirname(current_line[0]) 88 self._include_file(os.path.join(file_dir, match.group(1))) 89 else: 90 self._index += 1 91 92 for i, line in enumerate(self._lines): 93 self._lines[i] = line[:2] + (re.sub(self._IF_TAGS_REG, "", line[2]),) 94 95 self.contents = "\n".join(l[2] for l in self._lines) 96 97 # Returns a list of tuples in the format: (file, line number, line contents). 98 def _get_file(self, source_file): 99 lines = FileCache.read(source_file).splitlines() 100 return [(source_file, lnum + 1, line) for lnum, line in enumerate(lines)] 101 102 def _include_file(self, source_file): 103 self._included_files.add(source_file) 104 f = self._get_file(source_file) 105 self._lines = self._lines[:self._index] + f + self._lines[self._index + 1:] 106 107 def get_file_from_line(self, line_number): 108 """Get the original file and line number for an expanded file's line number. 109 110 Args: 111 line_number: A processed file's line number. 112 """ 113 line_number = int(line_number) - 1 114 return LineNumber(self._lines[line_number][0], self._lines[line_number][1]) 115 116 @property 117 def included_files(self): 118 """A list of files that were inlined via <include>.""" 119 return self._included_files 120