media/PRESUBMIT.py: adding CheckPassByValue for base::Time and derived classes

media/PRESUBMIT.py

 # 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.
 
 """Top-level presubmit script for Chromium media component.
 
 See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
 for more details about the presubmit API built into depot_tools.
 """
 
+import re
+import string
+
+# Well-defined simple classes containing only <= 4 ints, or <= 2 floats.
+BASE_TIME_TYPES = [
+    'base::Time',
+    'base::TimeDelta',
+    'base::TimeTicks',
+]
+
+PASS_BY_VALUE_RE = re.compile(r'\bconst (%s)&' %

[sandersd (OOO until July 31), 2015/10/20 21:01:03]

This should be BASE_TIME_TYPES_RE to match.

[mcasas, 2016/04/01 21:34:39]

Done.

+                              string.join(BASE_TIME_TYPES, '|'))
+
 def _FilterFile(affected_file):
   """Return true if the file could contain code requiring a presubmit check."""
   return affected_file.LocalPath().endswith(
       ('.h', '.cc', '.cpp', '.cxx', '.mm'))
 
 
 def _CheckForUseOfWrongClock(input_api, output_api):
   """Make sure new lines of media code don't use a clock susceptible to skew."""
 
   # Regular expression that should detect any explicit references to the
@@ skipping 131 matching lines @@
       'UMA_HISTOGRAM_ENUMERATION reports in src/media/ are expected to adhere\n'
       'to the following guidelines:\n'
       ' - The max value (3rd argument) should be an enum value equal to the\n'
       '   last valid value, e.g. FOO_MAX = LAST_VALID_FOO.\n'
       ' - 1 must be added to that max value.\n'
       'Contact rileya@chromium.org if you have questions.' , problems)]
 
   return []
 
 
+def _CheckPassByValue(input_api, output_api):
+  """Check that base::Time and derived classes are passed by value, and not by
+  const reference """
+
+  problems = []
+
+  for f in input_api.AffectedSourceFiles(_FilterFile):
+    for line_number, line in f.ChangedContents():
+      if PASS_BY_VALUE_RE.search(line):
+        problems.append('%s:%d' % (f, line_number))
+
+  if problems:
+    return [output_api.PresubmitError(
+      'base::Time and derived classes should be passed by value and not by\n'
+      'const ref, see base/time/time.h for more information.', problems)]
+  return []
+
+
 def _CheckChange(input_api, output_api):
   results = []
   results.extend(_CheckForUseOfWrongClock(input_api, output_api))
   results.extend(_CheckForMessageLoopProxy(input_api, output_api))
+  results.extend(_CheckPassByValue(input_api, output_api))
   results.extend(_CheckForHistogramOffByOne(input_api, output_api))
   return results
 
 
 def CheckChangeOnUpload(input_api, output_api):
   return _CheckChange(input_api, output_api)
 
 
 def CheckChangeOnCommit(input_api, output_api):
   return _CheckChange(input_api, output_api)