Open-source histograms.xml, starting with Autofill histograms.

tools/metrics/histograms/update_extension_functions.py

Index: tools/metrics/histograms/update_extension_functions.py
diff --git a/tools/metrics/histograms/update_extension_functions.py b/tools/metrics/histograms/update_extension_functions.py
new file mode 100644
index 0000000000000000000000000000000000000000..1925c6e4e4ea7d707f5cbe53202c790ff206a4bf
--- /dev/null
+++ b/tools/metrics/histograms/update_extension_functions.py
@@ -0,0 +1,148 @@
+# 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()