Add a check to presubmit.py linting python and SCons files for trailing white...

tools/presubmit.py

 #!/usr/bin/env python
 #
 # Copyright 2008 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
@@ skipping 119 matching lines @@
   """
 
   def IsRelevant(self, name):
     return name.endswith('.cc') or name.endswith('.h')
 
   def IgnoreDir(self, name):
     return (super(CppLintProcessor, self).IgnoreDir(name)
               or (name == 'third_party'))
 
   IGNORE_LINT = ['flag-definitions.h']
-  
+
   def IgnoreFile(self, name):
     return (super(CppLintProcessor, self).IgnoreFile(name)
               or (name in CppLintProcessor.IGNORE_LINT))
 
   def GetPathsToSearch(self):
     return ['src', 'public', 'samples', join('test', 'cctest')]
 
   def ProcessFiles(self, files):
     filt = '-,' + ",".join(['+' + n for n in ENABLED_LINT_RULES])
     command = ['cpplint.py', '--filter', filt] + join(files)
@@ skipping 22 matching lines @@
 
   def IgnoreDir(self, name):
     return (super(SourceProcessor, self).IgnoreDir(name)
               or (name == 'third_party')
               or (name == 'obj'))
 
   IGNORE_COPYRIGHTS = ['earley-boyer.js', 'raytrace.js', 'crypto.js',
       'libraries.cc', 'libraries-empty.cc', 'jsmin.py', 'regexp-pcre.js']
   IGNORE_TABS = IGNORE_COPYRIGHTS + ['unicode-test.js',
       'html-comments.js']
+  NO_TRAILING_WHITESPACE_EXTENSIONS = ['py', 'SConscript', 'SConstruct']
 
   def ProcessContents(self, name, contents):
     result = True
     base = basename(name)
+    extension = base.split('.').pop()
     if not base in SourceProcessor.IGNORE_TABS:
       if '\t' in contents:
         print "%s contains tabs" % name
         result = False
     if not base in SourceProcessor.IGNORE_COPYRIGHTS:
       if not COPYRIGHT_HEADER_PATTERN.search(contents):
         print "%s is missing a correct copyright header." % name
         result = False
+    if extension in SourceProcessor.NO_TRAILING_WHITESPACE_EXTENSIONS:
+      if ' \n' in contents or contents.endswith(' '):
+        print "%s has trailing whitespace." % name
+        result = False
     return result
 
   def ProcessFiles(self, files):
     success = True
     for file in files:
       try:
         handle = open(file)
         contents = handle.read()
         success = self.ProcessContents(file, contents) and success
       finally:
@@ skipping 17 matching lines @@
     success = CppLintProcessor().Run(workspace) and success
   success = SourceProcessor().Run(workspace) and success
   if success:
     return 0
   else:
     return 1
 
 
 if __name__ == '__main__':
   sys.exit(Main())