Histograms.xml python script housekeeping

tools/metrics/histograms/update_editor_commands.py

 # Copyright 2014 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 MappedEditingCommands enum in histograms.xml file with values read
  from EditorCommand.cpp.
 
 If the file was pretty-printed, the updated version is pretty-printed too.
 """
 
 import logging
 import os
 import re
 import sys
 
 from xml.dom import minidom
 
-from diffutil import PromptUserToAcceptDiff
+sys.path.append(os.path.join(os.path.dirname(__file__), '..', 'common'))
+from diff_util import PromptUserToAcceptDiff
+import path_util
+
 import print_style
 
-# Import the metrics/common module.
-sys.path.append(os.path.join(os.path.dirname(__file__), '..', 'common'))
-from diff_util import PromptUserToAcceptDiff
-
-HISTOGRAMS_PATH = 'histograms.xml'
+HISTOGRAMS_PATH = path_util.GetHistogramsFile()
 ENUM_NAME = 'MappedEditingCommands'
 
-EXTENSION_FUNCTIONS_HISTOGRAM_VALUE_PATH = \
-  '../../../third_party/WebKit/Source/core/editing/EditorCommand.cpp'
+EDITOR_COMMAND_CPP = 'third_party/WebKit/Source/core/editing/EditorCommand.cpp'
 ENUM_START_MARKER = "^    static const CommandEntry commands\[\] = {"
 ENUM_END_MARKER = "^    };"
 
 
 class UserError(Exception):
   def __init__(self, message):
     Exception.__init__(self, message)
 
   @property
   def message(self):
     return self.args[0]
 
 
 def ReadHistogramValues(filename):
   """Returns a list of pairs (label, value) corresponding to HistogramValue.
 
   Reads the EditorCommand.cpp 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:
+  with open(path_util.GetInputFile(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:
     if inside_enum:
       # Exit condition: we reached last enum value
       if re.match(ENUM_END_MARKER, line):
         inside_enum = False
@@ skipping 28 matching lines @@
         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)
+  comment = ' Generated from {0} '.format(EDITOR_COMMAND_CPP)
   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 histogram enum definition from "%s".' % EDITOR_COMMAND_CPP)
+  histogram_values = ReadHistogramValues(EDITOR_COMMAND_CPP)
 
   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 = print_style.GetPrintStyle().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()