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

tools/metrics/histograms/update_policies.py

Index: tools/metrics/histograms/update_policies.py
diff --git a/tools/metrics/histograms/update_policies.py b/tools/metrics/histograms/update_policies.py
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index 0000000000000000000000000000000000000000..dd0447fb9019cc07f3365536a40652ee00a1681a
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+++ b/tools/metrics/histograms/update_policies.py
@@ -0,0 +1,132 @@
+# 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 EnterprisePolicies enum in histograms.xml file with policy
+definitions read from policy_templates.json.
+
+If the file was pretty-printed, the updated version is pretty-printed too.
+"""
+
+import re
+import sys
+
+from ast import literal_eval
+from optparse import OptionParser
+from xml.dom import minidom
+
+from diffutil import PromptUserToAcceptDiff
+from pretty_print import PrettyPrintNode
+
+HISTOGRAMS_PATH = 'histograms.xml'
+POLICY_TEMPLATES_PATH = '../../../chrome/app/policy/policy_templates.json'
+ENUM_NAME = 'EnterprisePolicies'
+
+class UserError(Exception):
+  def __init__(self, message):
+    Exception.__init__(self, message)
+
+  @property
+  def message(self):
+    return self.args[0]
+
+
+def FlattenPolicies(policy_definitions, policy_list):
+  """Appends a list of policies defined in |policy_definitions| to
+  |policy_list|, flattening subgroups.
+
+  Args:
+    policy_definitions: A list of policy definitions and groups, as in
+                        policy_templates.json file.
+    policy_list: A list that has policy definitions appended to it.
+  """
+  for policy in policy_definitions:
+    if policy['type'] == 'group':
+      FlattenPolicies(policy['policies'], policy_list)
+    else:
+      policy_list.append(policy)
+
+
+def ParsePlaceholders(text):
+  """Parse placeholders in |text|, making it more human-readable. The format of
+  |text| is exactly the same as in captions in policy_templates.json: it can
+  contain XML tags (ph, ex) and $1-like substitutions. Note that this function
+  does only a very simple parsing that is not fully correct, but should be
+  enough for all practical situations.
+
+  Args:
+    text: A string containing placeholders.
+
+  Returns:
+    |text| with placeholders removed or replaced by readable text.
+  """
+  text = re.sub(r'\$\d+', '', text)    # Remove $1-like substitutions.
+  text = re.sub(r'<[^>]+>', '', text)  # Remove XML tags.
+  return text
+
+
+def UpdateHistogramDefinitions(policy_templates, doc):
+  """Sets the children of <enum name="EnterprisePolicies" ...> node in |doc| to
+  values generated from policy ids contained in |policy_templates|.
+
+  Args:
+    policy_templates: A list of dictionaries, defining policies or policy
+                      groups. The format is exactly the same as in
+                      policy_templates.json file.
+    doc: A minidom.Document object representing parsed histogram definitions
+         XML file.
+  """
+  # Find EnterprisePolicies enum.
+  for enum_node in doc.getElementsByTagName('enum'):
+    if enum_node.attributes['name'].value == ENUM_NAME:
+        policy_enum_node = enum_node
+        break
+  else:
+    raise UserError('No policy enum node found')
+
+  # Remove existing values.
+  while policy_enum_node.hasChildNodes():
+    policy_enum_node.removeChild(policy_enum_node.lastChild)
+
+  # Add a "Generated from (...)" comment
+  comment = ' Generated from {0} '.format(POLICY_TEMPLATES_PATH)
+  policy_enum_node.appendChild(doc.createComment(comment))
+
+  # Add values generated from policy templates.
+  ordered_policies = []
+  FlattenPolicies(policy_templates['policy_definitions'], ordered_policies)
+  ordered_policies.sort(key=lambda policy: policy['id'])
+  for policy in ordered_policies:
+    node = doc.createElement('int')
+    node.attributes['value'] = str(policy['id'])
+    node.attributes['label'] = ParsePlaceholders(policy['caption'])
+    policy_enum_node.appendChild(node)
+
+
+def main():
+  if len(sys.argv) > 1:
+    print >>sys.stderr, 'No arguments expected!'
+    sys.stderr.write(__doc__)
+    sys.exit(1)
+
+  with open(POLICY_TEMPLATES_PATH, 'rb') as f:
+    policy_templates = literal_eval(f.read())
+  with open(HISTOGRAMS_PATH, 'rb') as f:
+    histograms_doc = minidom.parse(f)
+    f.seek(0)
+    xml = f.read()
+
+  UpdateHistogramDefinitions(policy_templates, histograms_doc)
+
+  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)
+
+
+if __name__ == '__main__':
+  try:
+    main()
+  except UserError as e:
+    print >>sys.stderr, e.message
+    sys.exit(1)