src/third_party/skia/bin/fetch-gn

#!/usr/bin/env python

# Copyright 2016 Google Inc.
#
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

import hashlib
import os
import shutil
import stat
import sys
import urllib2

os.chdir(os.path.join(os.path.dirname(__file__), os.pardir))

gn_path = 'buildtools/linux64/gn' if 'linux'  in sys.platform else \
          'buildtools/mac/gn'     if 'darwin' in sys.platform else \
          'buildtools/win/gn.exe'

sha1 = open(gn_path + '.sha1').read().strip()

def sha1_of_file(path):
  h = hashlib.sha1()
  if os.path.isfile(path):
    with open(path, 'rb') as f:
      h.update(f.read())
  return h.hexdigest()

if sha1_of_file(gn_path) != sha1:
  with open(gn_path, 'wb') as f:
    f.write(urllib2.urlopen('https://chromium-gn.storage-download.googleapis.com/' + sha1).read())

  os.chmod(gn_path, stat.S_IRUSR | stat.S_IWUSR | stat.S_IXUSR |
                    stat.S_IRGRP                | stat.S_IXGRP |
                    stat.S_IROTH                | stat.S_IXOTH )

gn_copy_path = os.path.join('bin', os.path.basename(gn_path))
if sha1_of_file(gn_copy_path) != sha1:
  shutil.copy(gn_path, gn_copy_path)