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 from diffutil import PromptUserToAcceptDiff
  19 import print_style
  20
  21 # Import the metrics/common module.
  22 sys.path.append(os.path.join(os.path.dirname(__file__), '..', 'common'))
  23 from diff_util import PromptUserToAcceptDiff
  24
  25 HISTOGRAMS_PATH = 'histograms.xml'
  26 ENUM_NAME = 'MappedEditingCommands'
  27
  28 EXTENSION_FUNCTIONS_HISTOGRAM_VALUE_PATH = \
  29   '../../../third_party/WebKit/Source/core/editing/EditorCommand.cpp'
  30 ENUM_START_MARKER = "^    static const CommandEntry commands\[\] = {"
  31 ENUM_END_MARKER = "^    };"
  32
  33
  34 class UserError(Exception):
  35   def __init__(self, message):
  36     Exception.__init__(self, message)
  37
  38   @property
  39   def message(self):
  40     return self.args[0]
  41
  42
  43 def ReadHistogramValues(filename):
  44   """Returns a list of pairs (label, value) corresponding to HistogramValue.
  45
  46   Reads the EditorCommand.cpp file, locates the
  47   HistogramValue enum definition and returns a pair for each entry.
  48   """
  49
  50   # Read the file as a list of lines
  51   with open(filename) as f:
  52     content = f.readlines()
  53
  54   # Locate the enum definition and collect all entries in it
  55   inside_enum = False # We haven't found the enum definition yet
  56   result = []
  57   for line in content:
  58     if inside_enum:
  59       # Exit condition: we reached last enum value
  60       if re.match(ENUM_END_MARKER, line):
  61         inside_enum = False
  62       else:
  63           # Inside enum: generate new xml entry
  64         m = re.match("^{ \"([\w]+)\", \{([\w]+)", line.strip())
  65         if m:
  66           result.append((m.group(1), int(m.group(2))))
  67     else:
  68       if re.match(ENUM_START_MARKER, line):
  69         inside_enum = True
  70         enum_value = 0 # Start at 'UNKNOWN'
  71   return sorted(result, key=lambda pair: pair[1])
  72
  73
  74 def UpdateHistogramDefinitions(histogram_values, document):
  75   """Sets the children of <enum name="ExtensionFunctions" ...> node in
  76   |document| to values generated from policy ids contained in
  77   |policy_templates|.
  78
  79   Args:
  80     histogram_values: A list of pairs (label, value) defining each extension
  81                       function
  82     document: A minidom.Document object representing parsed histogram
  83               definitions XML file.
  84
  85   """
  86   # Find ExtensionFunctions enum.
  87   for enum_node in document.getElementsByTagName('enum'):
  88     if enum_node.attributes['name'].value == ENUM_NAME:
  89         extension_functions_enum_node = enum_node
  90         break
  91   else:
  92     raise UserError('No policy enum node found')
  93
  94   # Remove existing values.
  95   while extension_functions_enum_node.hasChildNodes():
  96     extension_functions_enum_node.removeChild(
  97       extension_functions_enum_node.lastChild)
  98
  99   # Add a "Generated from (...)" comment
 100   comment = ' Generated from {0} '.format(
 101     EXTENSION_FUNCTIONS_HISTOGRAM_VALUE_PATH)
 102   extension_functions_enum_node.appendChild(document.createComment(comment))
 103
 104   # Add values generated from policy templates.
 105   for (label, value) in histogram_values:
 106     node = document.createElement('int')
 107     node.attributes['value'] = str(value)
 108     node.attributes['label'] = label
 109     extension_functions_enum_node.appendChild(node)
 110
 111 def Log(message):
 112   logging.info(message)
 113
 114 def main():
 115   if len(sys.argv) > 1:
 116     print >>sys.stderr, 'No arguments expected!'
 117     sys.stderr.write(__doc__)
 118     sys.exit(1)
 119
 120   Log('Reading histogram enum definition from "%s".'
 121       % (EXTENSION_FUNCTIONS_HISTOGRAM_VALUE_PATH))
 122   histogram_values = ReadHistogramValues(
 123     EXTENSION_FUNCTIONS_HISTOGRAM_VALUE_PATH)
 124
 125   Log('Reading existing histograms from "%s".' % (HISTOGRAMS_PATH))
 126   with open(HISTOGRAMS_PATH, 'rb') as f:
 127     histograms_doc = minidom.parse(f)
 128     f.seek(0)
 129     xml = f.read()
 130
 131   Log('Comparing histograms enum with new enum definition.')
 132   UpdateHistogramDefinitions(histogram_values, histograms_doc)
 133
 134   Log('Writing out new histograms file.')
 135   new_xml = print_style.GetPrintStyle().PrettyPrintNode(histograms_doc)
 136   if PromptUserToAcceptDiff(xml, new_xml, 'Is the updated version acceptable?'):
 137     with open(HISTOGRAMS_PATH, 'wb') as f:
 138       f.write(new_xml)
 139
 140   Log('Done.')
 141
 142
 143 if __name__ == '__main__':
 144   main()