Add pretty printing for rappor.xml

tools/metrics/common/presubmit_util.py

Index: tools/metrics/common/presubmit_util.py
diff --git a/tools/metrics/common/presubmit_util.py b/tools/metrics/common/presubmit_util.py
new file mode 100644
index 0000000000000000000000000000000000000000..235bdda0b3fb522409e1baea83f8133772a6e020
--- /dev/null
+++ b/tools/metrics/common/presubmit_util.py
@@ -0,0 +1,60 @@
+# Copyright (c) 2015 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.
+
+import os
+import sys
+import logging
+import shutil
+
+import diff_util
+
+sys.path.insert(1, os.path.join(sys.path[0], '..', '..', 'python'))
+from google import path_utils
+
+def DoPresubmitMain(argv, original_filename, backup_filename, script_name,
+                    prettyFn):
+  """Execute presubmit/pretty printing for the target file.
+
+  Args:
+    argv: command line arguments
+    original_filename: The filename to read from.
+    backup_filename: When pretty printing, move the old file contents here.
+    script_name: The name of the script to run for pretty printing.
+    prettyFn: A function which takes the original xml content and produces
+        pretty printed xml.
+
+  Returns:
+    An exit status.  Non-zero indicates errors.
+  """
+  presubmit = ('--presubmit' in argv)
+  xml_path = os.path.join(path_utils.ScriptDir(), original_filename)
+
+  # Save the original file content.
+  with open(xml_path, 'rb') as f:
+    original_xml = f.read()
+
+  pretty = prettyFn(original_xml)
+
+  if original_xml == pretty:
+    print '%s is correctly pretty-printed.' % original_filename
+    return 0
+  if presubmit:
+    logging.info('%s is not formatted correctly; run %s to fix.' % (
+        original_filename, script_name))
+    return 1
+
+  # Prompt user to consent on the change.
+  if not diff_util.PromptUserToAcceptDiff(
+      original_xml, pretty, 'Is the new version acceptable?'):
+    logging.error('Aborting')
+    return 1
+
+  print 'Creating backup file: %s' % backup_filename
+  shutil.move(xml_path, backup_filename)
+
+  with open(xml_path, 'wb') as f:
+    f.write(pretty)
+  print ('Updated %s. Don\'t forget to add it to your changelist' %
+         xml_path)
+  return 0