update_policies.py

# Copyright 2013 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""Updates EnterprisePolicies enum in histograms.xml file with policy
definitions read from policy_templates.json.

If the file was pretty-printed, the updated version is pretty-printed too.
"""

from __future__ import print_function

import os
import re
import sys

from ast import literal_eval
from optparse import OptionParser
from xml.dom import minidom

sys.path.append(os.path.join(os.path.dirname(__file__), '..', 'common'))
from diff_util import PromptUserToAcceptDiff
import path_util

import histogram_paths
import histogram_configuration_model

ENUMS_PATH = histogram_paths.ENUMS_XML
POLICY_TEMPLATES_PATH = 'components/policy/resources/policy_templates.json'
POLICIES_ENUM_NAME = 'EnterprisePolicies'
POLICY_ATOMIC_GROUPS_ENUM_NAME = 'PolicyAtomicGroups'

class UserError(Exception):
  def __init__(self, message):
    Exception.__init__(self, message)

  @property
  def message(self):
    return self.args[0]


def UpdatePoliciesHistogramDefinitions(policy_templates, doc):
  """Sets the children of <enum name="EnterprisePolicies" ...> node in |doc| to
  values generated from policy ids contained in |policy_templates|.

  Args:
    policy_templates: A list of dictionaries, defining policies or policy
                      groups. The format is exactly the same as in
                      policy_templates.json file.
    doc: A minidom.Document object representing parsed histogram definitions
         XML file.
  """
  # Find EnterprisePolicies enum.
  for enum_node in doc.getElementsByTagName('enum'):
    if enum_node.attributes['name'].value == POLICIES_ENUM_NAME:
      policy_enum_node = enum_node
      break
  else:
    raise UserError('No policy enum node found')

  # Remove existing values.
  while policy_enum_node.hasChildNodes():
    policy_enum_node.removeChild(policy_enum_node.lastChild)

  # Add a "Generated from (...)" comment
  comment = ' Generated from {0} '.format(POLICY_TEMPLATES_PATH)
  policy_enum_node.appendChild(doc.createComment(comment))

  # Add values generated from policy templates.
  ordered_policies = [x for x in policy_templates['policy_definitions']
                      if x['type'] != 'group']
  ordered_policies.sort(key=lambda policy: policy['id'])
  for policy in ordered_policies:
    node = doc.createElement('int')
    node.attributes['value'] = str(policy['id'])
    node.attributes['label'] = policy['name']
    policy_enum_node.appendChild(node)


def UpdateAtomicGroupsHistogramDefinitions(policy_templates, doc):
  """Sets the children of <enum name="PolicyAtomicGroups" ...> node in |doc| to
  values generated from policy ids contained in |policy_templates|.

  Args:
    policy_templates: A list of dictionaries, defining policy atomic
                      groups. The format is exactly the same as in
                      policy_templates.json file.
    doc: A minidom.Document object representing parsed histogram definitions
         XML file.
  """
  # Find EnterprisePolicies enum.
  for enum_node in doc.getElementsByTagName('enum'):
    if enum_node.attributes['name'].value == POLICY_ATOMIC_GROUPS_ENUM_NAME:
      atomic_group_enum_node = enum_node
      break
  else:
    raise UserError('No policy atomic group enum node found')

  # Remove existing values.
  while atomic_group_enum_node.hasChildNodes():
    atomic_group_enum_node.removeChild(atomic_group_enum_node.lastChild)

  # Add a "Generated from (...)" comment
  comment = ' Generated from {0} '.format(POLICY_TEMPLATES_PATH)
  atomic_group_enum_node.appendChild(doc.createComment(comment))

  # Add values generated from policy templates.
  ordered_atomic_groups = [
    x for x in policy_templates['policy_atomic_group_definitions']
  ]
  ordered_atomic_groups.sort(key=lambda policy: policy['id'])
  for group in ordered_atomic_groups:
    node = doc.createElement('int')
    node.attributes['value'] = str(group['id'])
    node.attributes['label'] = group['name']
    atomic_group_enum_node.appendChild(node)

def main():
  if len(sys.argv) > 1:
    print('No arguments expected!', file=sys.stderr)
    sys.stderr.write(__doc__)
    sys.exit(1)

  with open(path_util.GetInputFile(POLICY_TEMPLATES_PATH), 'rb') as f:
    policy_templates = literal_eval(f.read())

  with open(ENUMS_PATH, 'rb') as f:
    histograms_doc = minidom.parse(f)
    f.seek(0)
    xml = f.read()

  UpdatePoliciesHistogramDefinitions(policy_templates, histograms_doc)
  UpdateAtomicGroupsHistogramDefinitions(policy_templates, histograms_doc)
  new_xml = histogram_configuration_model.PrettifyTree(histograms_doc)
  if PromptUserToAcceptDiff(xml, new_xml, 'Is the updated version acceptable?'):
    with open(ENUMS_PATH, 'wb') as f:
      f.write(new_xml)


if __name__ == '__main__':
  try:
    main()
  except UserError as e:
    print(e.message, file=sys.stderr)
    sys.exit(1)