Add presubmit check for correct MessageLoopProxy usage in src/media/.

media/PRESUBMIT.py

Index: media/PRESUBMIT.py
diff --git a/media/PRESUBMIT.py b/media/PRESUBMIT.py
index aafe23a2f9fd19fd482c762d878ebdb48ae43014..de7bc1eabda77376b9829b1b7017f5c0145d18c5 100644
--- a/media/PRESUBMIT.py
+++ b/media/PRESUBMIT.py
@@ -8,15 +8,15 @@ See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
 for more details about the presubmit API built into gcl.
 """
 
+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."""
 
-  def FilterFile(affected_file):
-    """Return true if the file could contain code referencing base::Time."""
-    return affected_file.LocalPath().endswith(
-        ('.h', '.cc', '.cpp', '.cxx', '.mm'))
-
   # Regular expression that should detect any explicit references to the
   # base::Time type (or base::Clock/DefaultClock), whether in using decls,
   # typedefs, or to call static methods.
@@ -45,7 +45,7 @@ def _CheckForUseOfWrongClock(input_api, output_api):
       r'(' + using_base_time_decl_pattern + r')|(' +
       base_time_konstant_pattern + r')')
   problems = []
-  for f in input_api.AffectedSourceFiles(FilterFile):
+  for f in input_api.AffectedSourceFiles(_FilterFile):
     for line_number, line in f.ChangedContents():
       if problem_re.search(line):
         if not exception_re.search(line):
@@ -64,9 +64,35 @@ def _CheckForUseOfWrongClock(input_api, output_api):
     return []
 
 
+def _CheckForMessageLoopProxy(input_api, output_api):
+  """Make sure media code only uses MessageLoopProxy for accessing the current
+  loop."""
+
+  message_loop_proxy_re = r'\bMessageLoopProxy(::current\(\))?'
+
+  bad_files = []
+  for f in input_api.AffectedSourceFiles(_FilterFile):
+    contents = input_api.ReadFile(f, 'rb')

[DaleCurtis, 2014/01/07 20:13:46]

Instead of reading the file you should only need to check f.ChangedContents() as
is done on _CheckForUseOfWrongClock().

[scherkus (not reviewing), 2014/01/07 21:40:22]

Done.

(I initially had it read the whole file to catch instances that weren't included
in the diff, but it looks like my existing CL to fix all instances should do the
trick)

+    for match in input_api.re.finditer(message_loop_proxy_re, contents):
+      if match.lastindex == 1:
+        continue
+
+      # No need to check remaining matches in an offending file.
+      bad_files.append(f)
+      break
+
+  if bad_files:
+    return [output_api.PresubmitError(
+      'These files reference MessageLoopProxy for uses other than accessing '
+      'the current loop:', bad_files)]
+
+  return []
+
+
 def _CheckChange(input_api, output_api):
   results = []
   results.extend(_CheckForUseOfWrongClock(input_api, output_api))
+  results.extend(_CheckForMessageLoopProxy(input_api, output_api))
   return results