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      1 #!/usr/bin/python
      2 # Copyright 2013 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 # This script can either source a file and dump the enironment changes done by
      7 # it, or just simply dump the current environment as JSON into a file.
      8 
      9 import json
     10 import optparse
     11 import os
     12 import pipes
     13 import subprocess
     14 import sys
     15 
     16 
     17 def main():
     18   parser = optparse.OptionParser()
     19   parser.add_option('-f', '--output-json',
     20                     help='File to dump the environment as JSON into.')
     21   parser.add_option(
     22       '-d', '--dump-mode', action='store_true',
     23       help='Dump the environment to sys.stdout and exit immediately.')
     24 
     25   parser.disable_interspersed_args()
     26   options, args = parser.parse_args()
     27   if options.dump_mode:
     28     if args or options.output_json:
     29       parser.error('Cannot specify args or --output-json with --dump-mode.')
     30     json.dump(dict(os.environ), sys.stdout)
     31   else:
     32     if not options.output_json:
     33       parser.error('Requires --output-json option.')
     34 
     35     envsetup_cmd = ' '.join(map(pipes.quote, args))
     36     full_cmd = [
     37         'bash', '-c',
     38         '. %s > /dev/null; %s -d' % (envsetup_cmd, os.path.abspath(__file__))
     39     ]
     40     try:
     41       output = subprocess.check_output(full_cmd)
     42     except Exception as e:
     43       sys.exit('Error running %s and dumping environment.' % envsetup_cmd)
     44 
     45     env_diff = {}
     46     new_env = json.loads(output)
     47     for k, val in new_env.items():
     48       if k == '_' or (k in os.environ and os.environ[k] == val):
     49         continue
     50       env_diff[k] = val
     51     with open(options.output_json, 'w') as f:
     52       json.dump(env_diff, f)
     53 
     54 
     55 if __name__ == '__main__':
     56   sys.exit(main())
     57