build/gn_helpers.py

   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 """Helper functions useful when writing scripts that are run from GN's
   6 exec_script function."""
   7
   8 class GNException(Exception):
   9   pass
  10
  11
  12 def ToGNString(value, allow_dicts = True):
  13   """Prints the given value to stdout.
  14
  15   allow_dicts indicates if this function will allow converting dictionaries
  16   to GN scopes. This is only possible at the top level, you can't nest a
  17   GN scope in a list, so this should be set to False for recursive calls."""
  18   if isinstance(value, str):
  19     if value.find('\n') >= 0:
  20       raise GNException("Trying to print a string with a newline in it.")
  21     return '"' + value.replace('"', '\\"') + '"'
  22
  23   if isinstance(value, list):
  24     return '[ %s ]' % ', '.join(ToGNString(v) for v in value)
  25
  26   if isinstance(value, dict):
  27     if not allow_dicts:
  28       raise GNException("Attempting to recursively print a dictionary.")
  29     result = ""
  30     for key in value:
  31       if not isinstance(key, str):
  32         raise GNException("Dictionary key is not a string.")
  33       result += "%s = %s\n" % (key, ToGNString(value[key], False))
  34     return result
  35
  36   if isinstance(value, int):
  37     return str(value)
  38
  39   raise GNException("Unsupported type when printing to GN.")