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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 ExtensionFunctions enum in histograms.xml file with values read from
extension_function_histogram_value.h.
If the file was pretty-printed, the updated version is pretty-printed too.
"""
import logging
import re
import sys
from xml.dom import minidom
from diffutil import PromptUserToAcceptDiff
from pretty_print import PrettyPrintNode
HISTOGRAMS_PATH = 'histograms.xml'
ENUM_NAME = 'ExtensionFunctions'
EXTENSION_FUNCTIONS_HISTOGRAM_VALUE_PATH = \
'../../../chrome/browser/extensions/extension_function_histogram_value.h'
ENUM_START_MARKER = "^enum HistogramValue {"
ENUM_END_MARKER = "^ENUM_BOUNDARY"
class UserError(Exception):
def __init__(self, message):
Exception.__init__(self, message)
@property
def message(self):
return self.args[0]
def ExtractRegexGroup(line, regex):
m = re.match(regex, line)
if m:
return m.group(1)
else:
return None
def ReadHistogramValues(filename):
"""Returns a list of pairs (label, value) corresponding to HistogramValue.
Reads the extension_functions_histogram_value.h file, locates the
HistogramValue enum definition and returns a pair for each entry.
"""
# Read the file as a list of lines
with open(filename) as f:
content = f.readlines()
# Locate the enum definition and collect all entries in it
inside_enum = False # We haven't found the enum definition yet
result = []
for line in content:
line = line.strip()
if inside_enum:
# Exit condition: we reached last enum value
if re.match(ENUM_END_MARKER, line):
inside_enum = False
else:
# Inside enum: generate new xml entry
label = ExtractRegexGroup(line.strip(), "^([\w]+)")
if label:
result.append((label, enum_value))
enum_value += 1
else:
if re.match(ENUM_START_MARKER, line):
inside_enum = True
enum_value = 0 # Start at 'UNKNOWN'
return result
def UpdateHistogramDefinitions(histogram_values, document):
"""Sets the children of <enum name="ExtensionFunctions" ...> node in
|document| to values generated from policy ids contained in
|policy_templates|.
Args:
histogram_values: A list of pairs (label, value) defining each extension
function
document: A minidom.Document object representing parsed histogram
definitions XML file.
"""
# Find ExtensionFunctions enum.
for enum_node in document.getElementsByTagName('enum'):
if enum_node.attributes['name'].value == ENUM_NAME:
extension_functions_enum_node = enum_node
break
else:
raise UserError('No policy enum node found')
# Remove existing values.
while extension_functions_enum_node.hasChildNodes():
extension_functions_enum_node.removeChild(
extension_functions_enum_node.lastChild)
# Add a "Generated from (...)" comment
comment = ' Generated from {0} '.format(
EXTENSION_FUNCTIONS_HISTOGRAM_VALUE_PATH)
extension_functions_enum_node.appendChild(document.createComment(comment))
# Add values generated from policy templates.
for (label, value) in histogram_values:
node = document.createElement('int')
node.attributes['value'] = str(value)
node.attributes['label'] = label
extension_functions_enum_node.appendChild(node)
def Log(message):
logging.info(message)
def main():
if len(sys.argv) > 1:
print >>sys.stderr, 'No arguments expected!'
sys.stderr.write(__doc__)
sys.exit(1)
Log('Reading histogram enum definition from "%s".'
% (EXTENSION_FUNCTIONS_HISTOGRAM_VALUE_PATH))
histogram_values = ReadHistogramValues(
EXTENSION_FUNCTIONS_HISTOGRAM_VALUE_PATH)
Log('Reading existing histograms from "%s".' % (HISTOGRAMS_PATH))
with open(HISTOGRAMS_PATH, 'rb') as f:
histograms_doc = minidom.parse(f)
f.seek(0)
xml = f.read()
Log('Comparing histograms enum with new enum definition.')
UpdateHistogramDefinitions(histogram_values, histograms_doc)
Log('Writing out new histograms file.')
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)
Log('Done.')
if __name__ == '__main__':
main()
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