1 #!/usr/bin/python 2 # Copyright 2014 The Chromium Authors. All rights reserved. 3 # Use of this source code is governed by a BSD-style license that can be 4 # found in the LICENSE file. 5 6 import collections 7 import hashlib 8 import operator 9 import os 10 import re 11 import sys 12 13 14 RESOURCE_EXTRACT_REGEX = re.compile('^#define (\S*) (\d*)$', re.MULTILINE) 15 16 class Error(Exception): 17 """Base error class for all exceptions in generated_resources_map.""" 18 19 20 class HashCollisionError(Error): 21 """Multiple resource names hash to the same value.""" 22 23 24 Resource = collections.namedtuple("Resource", ['hash', 'name', 'index']) 25 26 27 def _HashName(name): 28 """Returns the hash id for a name. 29 30 Args: 31 name: The name to hash. 32 33 Returns: 34 An int that is at most 32 bits. 35 """ 36 md5hash = hashlib.md5() 37 md5hash.update(name) 38 return int(md5hash.hexdigest()[:8], 16) 39 40 41 def _GetNameIndexPairsIter(string_to_scan): 42 """Gets an iterator of the resource name and index pairs of the given string. 43 44 Scans the input string for lines of the form "#define NAME INDEX" and returns 45 an iterator over all matching (NAME, INDEX) pairs. 46 47 Args: 48 string_to_scan: The input string to scan. 49 50 Yields: 51 A tuple of name and index. 52 """ 53 for match in RESOURCE_EXTRACT_REGEX.finditer(string_to_scan): 54 yield match.group(1, 2) 55 56 57 def _GetResourceListFromString(resources_content): 58 """Produces a list of |Resource| objects from a string. 59 60 The input string conaints lines of the form "#define NAME INDEX". The returned 61 list is sorted primarily by hash, then name, and then index. 62 63 Args: 64 resources_content: The input string to process, contains lines of the form 65 "#define NAME INDEX". 66 67 Returns: 68 A sorted list of |Resource| objects. 69 """ 70 resources = [Resource(_HashName(name), name, index) for name, index in 71 _GetNameIndexPairsIter(resources_content)] 72 73 # The default |Resource| order makes |resources| sorted by the hash, then 74 # name, then index. 75 resources.sort() 76 77 return resources 78 79 80 def _CheckForHashCollisions(sorted_resource_list): 81 """Checks a sorted list of |Resource| objects for hash collisions. 82 83 Args: 84 sorted_resource_list: A sorted list of |Resource| objects. 85 86 Returns: 87 A set of all |Resource| objects with collisions. 88 """ 89 collisions = set() 90 for i in xrange(len(sorted_resource_list) - 1): 91 resource = sorted_resource_list[i] 92 next_resource = sorted_resource_list[i+1] 93 if resource.hash == next_resource.hash: 94 collisions.add(resource) 95 collisions.add(next_resource) 96 97 return collisions 98 99 100 def _GenDataArray( 101 resources, entry_pattern, array_name, array_type, data_getter): 102 """Generates a C++ statement defining a literal array containing the hashes. 103 104 Args: 105 resources: A sorted list of |Resource| objects. 106 entry_pattern: A pattern to be used to generate each entry in the array. The 107 pattern is expected to have a place for data and one for a comment, in 108 that order. 109 array_name: The name of the array being generated. 110 array_type: The type of the array being generated. 111 data_getter: A function that gets the array data from a |Resource| object. 112 113 Returns: 114 A string containing a C++ statement defining the an array. 115 """ 116 lines = [entry_pattern % (data_getter(r), r.name) for r in resources] 117 pattern = """const %(type)s %(name)s[] = { 118 %(content)s 119 }; 120 """ 121 return pattern % {'type': array_type, 122 'name': array_name, 123 'content': '\n'.join(lines)} 124 125 126 def _GenerateFileContent(resources_content): 127 """Generates the .cc content from the given generated_resources.h content. 128 129 Args: 130 resources_content: The input string to process, contains lines of the form 131 "#define NAME INDEX". 132 133 Returns: 134 .cc file content defining the kResourceHashes and kResourceIndices arrays. 135 """ 136 hashed_tuples = _GetResourceListFromString(resources_content) 137 138 collisions = _CheckForHashCollisions(hashed_tuples) 139 if collisions: 140 error_message = "\n".join( 141 ["hash: %i, name: %s" % (i[0], i[1]) for i in sorted(collisions)]) 142 error_message = ("\nThe following names had hash collisions " 143 "(sorted by the hash value):\n%s\n" %(error_message)) 144 raise HashCollisionError(error_message) 145 146 hashes_array = _GenDataArray( 147 hashed_tuples, " %iU, // %s", 'kResourceHashes', 'uint32_t', 148 operator.attrgetter('hash')) 149 indices_array = _GenDataArray( 150 hashed_tuples, " %s, // %s", 'kResourceIndices', 'int', 151 operator.attrgetter('index')) 152 153 return ( 154 "// This file was generated by generate_resources_map.py. Do not edit.\n" 155 "\n\n" 156 "#include " 157 "\"chrome/browser/metrics/variations/generated_resources_map.h\"\n\n" 158 "namespace chrome_variations {\n\n" 159 "%s" 160 "\n" 161 "%s" 162 "\n" 163 "} // namespace chrome_variations\n") % (hashes_array, indices_array) 164 165 166 def main(resources_file, map_file): 167 generated_resources_h = "" 168 with open(resources_file, "r") as resources: 169 generated_resources_h = resources.read() 170 171 if len(generated_resources_h) == 0: 172 raise Error("No content loaded for %s." % (resources_file)) 173 174 file_content = _GenerateFileContent(generated_resources_h) 175 176 with open(map_file, "w") as generated_file: 177 generated_file.write(file_content) 178 179 180 if __name__ == '__main__': 181 sys.exit(main(sys.argv[1], sys.argv[2])) 182
