shaka-packager/tools/metrics/histograms/update_policies.py

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# 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.
"""
import re
import sys
from ast import literal_eval
from optparse import OptionParser
from xml.dom import minidom
from diffutil import PromptUserToAcceptDiff
from pretty_print import PrettyPrintNode
HISTOGRAMS_PATH = 'histograms.xml'
POLICY_TEMPLATES_PATH = '../../../chrome/app/policy/policy_templates.json'
ENUM_NAME = 'EnterprisePolicies'
class UserError(Exception):
def __init__(self, message):
Exception.__init__(self, message)
@property
def message(self):
return self.args[0]
def FlattenPolicies(policy_definitions, policy_list):
"""Appends a list of policies defined in |policy_definitions| to
|policy_list|, flattening subgroups.
Args:
policy_definitions: A list of policy definitions and groups, as in
policy_templates.json file.
policy_list: A list that has policy definitions appended to it.
"""
for policy in policy_definitions:
if policy['type'] == 'group':
FlattenPolicies(policy['policies'], policy_list)
else:
policy_list.append(policy)
def ParsePlaceholders(text):
"""Parse placeholders in |text|, making it more human-readable. The format of
|text| is exactly the same as in captions in policy_templates.json: it can
contain XML tags (ph, ex) and $1-like substitutions. Note that this function
does only a very simple parsing that is not fully correct, but should be
enough for all practical situations.
Args:
text: A string containing placeholders.
Returns:
|text| with placeholders removed or replaced by readable text.
"""
text = re.sub(r'\$\d+', '', text) # Remove $1-like substitutions.
text = re.sub(r'<[^>]+>', '', text) # Remove XML tags.
return text
def UpdateHistogramDefinitions(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 == 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 = []
FlattenPolicies(policy_templates['policy_definitions'], ordered_policies)
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'] = ParsePlaceholders(policy['caption'])
policy_enum_node.appendChild(node)
def main():
if len(sys.argv) > 1:
print >>sys.stderr, 'No arguments expected!'
sys.stderr.write(__doc__)
sys.exit(1)
with open(POLICY_TEMPLATES_PATH, 'rb') as f:
policy_templates = literal_eval(f.read())
with open(HISTOGRAMS_PATH, 'rb') as f:
histograms_doc = minidom.parse(f)
f.seek(0)
xml = f.read()
UpdateHistogramDefinitions(policy_templates, histograms_doc)
new_xml = PrettyPrintNode(histograms_doc)
if PromptUserToAcceptDiff(xml, new_xml, 'Is the updated version acceptable?'):
with open(HISTOGRAMS_PATH, 'wb') as f:
f.write(new_xml)
if __name__ == '__main__':
try:
main()
except UserError as e:
print >>sys.stderr, e.message
sys.exit(1)