gin/fingerprint/fingerprint_v8_snapshot.py

   1 #!/usr/bin/env python
   2 #
   3 # Copyright 2015 The Chromium Authors. All rights reserved.
   4 # Use of this source code is governed by a BSD-style license that can be
   5 # found in the LICENSE file.
   6
   7 """Fingerprints the V8 snapshot blob files.
   8
   9 Constructs a SHA256 fingerprint of the V8 natives and snapshot blob files and
  10 creates a .cc file which includes these fingerprint as variables.
  11 """
  12
  13 import hashlib
  14 import optparse
  15 import os
  16 import sys
  17
  18 _HEADER = """// Copyright 2015 The Chromium Authors. All rights reserved.
  19 // Use of this source code is governed by a BSD-style license that can be
  20 // found in the LICENSE file.
  21
  22 // This file was generated by fingerprint_v8_snapshot.py.
  23
  24 namespace gin {
  25 """
  26
  27 _FOOTER = """
  28 }  // namespace gin
  29 """
  30
  31
  32 def FingerprintFile(file_path):
  33   input_file = open(file_path, 'rb')
  34   sha256 = hashlib.sha256()
  35   while True:
  36     block = input_file.read(sha256.block_size)
  37     if not block:
  38       break
  39     sha256.update(block)
  40   return sha256.digest()
  41
  42
  43 def WriteFingerprint(output_file, variable_name, fingerprint):
  44   output_file.write('\nextern const unsigned char %s[] = { ' % variable_name)
  45   for byte in fingerprint:
  46     output_file.write(str(ord(byte)) + ', ')
  47   output_file.write('};\n')
  48
  49
  50 def WriteOutputFile(natives_fingerprint,
  51                     snapshot_fingerprint,
  52                     output_file_path):
  53   output_dir_path = os.path.dirname(output_file_path)
  54   if not os.path.exists(output_dir_path):
  55     os.makedirs(output_dir_path)
  56   output_file = open(output_file_path, 'w')
  57
  58   output_file.write(_HEADER)
  59   WriteFingerprint(output_file, 'g_natives_fingerprint', natives_fingerprint)
  60   output_file.write('\n')
  61   WriteFingerprint(output_file, 'g_snapshot_fingerprint', snapshot_fingerprint)
  62   output_file.write(_FOOTER)
  63
  64
  65 def main():
  66   parser = optparse.OptionParser()
  67
  68   parser.add_option('--snapshot_file',
  69                     help='The input V8 snapshot blob file path.')
  70   parser.add_option('--natives_file',
  71                     help='The input V8 natives blob file path.')
  72   parser.add_option('--output_file',
  73                     help='The path for the output cc file which will be write.')
  74
  75   options, _ = parser.parse_args()
  76
  77   natives_fingerprint = FingerprintFile(options.natives_file)
  78   snapshot_fingerprint = FingerprintFile(options.snapshot_file)
  79   WriteOutputFile(
  80       natives_fingerprint, snapshot_fingerprint, options.output_file)
  81
  82   return 0
  83
  84
  85 if __name__ == '__main__':
  86   sys.exit(main())