tools/metrics/histograms/update_editor_commands.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 """Updates MappedEditingCommands enum in histograms.xml file with values read
   6  from EditorCommand.cpp.
   7
   8 If the file was pretty-printed, the updated version is pretty-printed too.
   9 """
  10
  11 import logging
  12 import os
  13 import re
  14 import sys
  15
  16 from xml.dom import minidom
  17
  18 sys.path.append(os.path.join(os.path.dirname(__file__), '..', 'common'))
  19 from diff_util import PromptUserToAcceptDiff
  20 import path_util
  21
  22 import print_style
  23
  24 HISTOGRAMS_PATH = path_util.GetHistogramsFile()
  25 ENUM_NAME = 'MappedEditingCommands'
  26
  27 EDITOR_COMMAND_CPP = 'third_party/WebKit/Source/core/editing/EditorCommand.cpp'
  28 ENUM_START_MARKER = "^    static const CommandEntry commands\[\] = {"
  29 ENUM_END_MARKER = "^    };"
  30
  31
  32 class UserError(Exception):
  33   def __init__(self, message):
  34     Exception.__init__(self, message)
  35
  36   @property
  37   def message(self):
  38     return self.args[0]
  39
  40
  41 def ReadHistogramValues(filename):
  42   """Returns a list of pairs (label, value) corresponding to HistogramValue.
  43
  44   Reads the EditorCommand.cpp file, locates the
  45   HistogramValue enum definition and returns a pair for each entry.
  46   """
  47
  48   # Read the file as a list of lines
  49   with open(path_util.GetInputFile(filename)) as f:
  50     content = f.readlines()
  51
  52   # Locate the enum definition and collect all entries in it
  53   inside_enum = False # We haven't found the enum definition yet
  54   result = []
  55   for line in content:
  56     if inside_enum:
  57       # Exit condition: we reached last enum value
  58       if re.match(ENUM_END_MARKER, line):
  59         inside_enum = False
  60       else:
  61           # Inside enum: generate new xml entry
  62         m = re.match("^{ \"([\w]+)\", \{([\w]+)", line.strip())
  63         if m:
  64           result.append((m.group(1), int(m.group(2))))
  65     else:
  66       if re.match(ENUM_START_MARKER, line):
  67         inside_enum = True
  68         enum_value = 0 # Start at 'UNKNOWN'
  69   return sorted(result, key=lambda pair: pair[1])
  70
  71
  72 def UpdateHistogramDefinitions(histogram_values, document):
  73   """Sets the children of <enum name="ExtensionFunctions" ...> node in
  74   |document| to values generated from policy ids contained in
  75   |policy_templates|.
  76
  77   Args:
  78     histogram_values: A list of pairs (label, value) defining each extension
  79                       function
  80     document: A minidom.Document object representing parsed histogram
  81               definitions XML file.
  82
  83   """
  84   # Find ExtensionFunctions enum.
  85   for enum_node in document.getElementsByTagName('enum'):
  86     if enum_node.attributes['name'].value == ENUM_NAME:
  87         extension_functions_enum_node = enum_node
  88         break
  89   else:
  90     raise UserError('No policy enum node found')
  91
  92   # Remove existing values.
  93   while extension_functions_enum_node.hasChildNodes():
  94     extension_functions_enum_node.removeChild(
  95       extension_functions_enum_node.lastChild)
  96
  97   # Add a "Generated from (...)" comment
  98   comment = ' Generated from {0} '.format(EDITOR_COMMAND_CPP)
  99   extension_functions_enum_node.appendChild(document.createComment(comment))
 100
 101   # Add values generated from policy templates.
 102   for (label, value) in histogram_values:
 103     node = document.createElement('int')
 104     node.attributes['value'] = str(value)
 105     node.attributes['label'] = label
 106     extension_functions_enum_node.appendChild(node)
 107
 108
 109 def Log(message):
 110   logging.info(message)
 111
 112
 113 def main():
 114   if len(sys.argv) > 1:
 115     print >>sys.stderr, 'No arguments expected!'
 116     sys.stderr.write(__doc__)
 117     sys.exit(1)
 118
 119   Log('Reading histogram enum definition from "%s".' % EDITOR_COMMAND_CPP)
 120   histogram_values = ReadHistogramValues(EDITOR_COMMAND_CPP)
 121
 122   Log('Reading existing histograms from "%s".' % (HISTOGRAMS_PATH))
 123   with open(HISTOGRAMS_PATH, 'rb') as f:
 124     histograms_doc = minidom.parse(f)
 125     f.seek(0)
 126     xml = f.read()
 127
 128   Log('Comparing histograms enum with new enum definition.')
 129   UpdateHistogramDefinitions(histogram_values, histograms_doc)
 130
 131   Log('Writing out new histograms file.')
 132   new_xml = print_style.GetPrintStyle().PrettyPrintNode(histograms_doc)
 133   if PromptUserToAcceptDiff(xml, new_xml, 'Is the updated version acceptable?'):
 134     with open(HISTOGRAMS_PATH, 'wb') as f:
 135       f.write(new_xml)
 136
 137   Log('Done.')
 138
 139
 140 if __name__ == '__main__':
 141   main()