Keep two empty lines between declarations for cpp files

tools/presubmit.py

 #!/usr/bin/env python
 #
 # Copyright 2012 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 313 matching lines @@
                        'earley-boyer.js',
                        'raytrace.js',
                        'crypto.js',
                        'libraries.cc',
                        'libraries-empty.cc',
                        'jsmin.py',
                        'regexp-pcre.js',
                        'gnuplot-4.6.3-emscripten.js']
   IGNORE_TABS = IGNORE_COPYRIGHTS + ['unicode-test.js', 'html-comments.js']
 
+  def EndOfDeclaration(self, line):
+    return line == "}" or line == "};"
+
+  def StartOfDeclaration(self, line):
+    return line.find("//") == 0 or \
+           line.find("/*") == 0 or \
+           line.find(") {") != -1
+
   def ProcessContents(self, name, contents):
     result = True
     base = basename(name)
     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
-    ext = base.split('.').pop()
     if ' \n' in contents or contents.endswith(' '):
       line = 0
       lines = []
       parts = contents.split(' \n')
       if not contents.endswith(' '):
         parts.pop()
       for part in parts:
         line += part.count('\n') + 1
         lines.append(str(line))
       linenumbers = ', '.join(lines)
       if len(lines) > 1:
         print "%s has trailing whitespaces in lines %s." % (name, linenumbers)
       else:
         print "%s has trailing whitespaces in line %s." % (name, linenumbers)
       result = False
+    # Check two empty lines between declarations.
+    if name.endswith(".cc"):
+      line = 0
+      lines = []
+      parts = contents.split('\n')
+      while line < len(parts) - 2:
+        if self.EndOfDeclaration(parts[line]):
+          if self.StartOfDeclaration(parts[line + 1]):
+            lines.append(str(line + 1))
+            line += 1
+          elif parts[line + 1] == "" and \
+               self.StartOfDeclaration(parts[line + 2]):
+            lines.append(str(line + 1))
+            line += 2
+        line += 1
+      if len(lines) >= 1:
+        linenumbers = ', '.join(lines)
+        if len(lines) > 1:
+          print "%s does not have two empty lines between declarations " \
+                "in lines %s." % (name, linenumbers)
+        else:
+          print "%s does not have two empty lines between declarations " \
+                "in line %s." % (name, linenumbers)
+        result = False
     return result
 
   def ProcessFiles(self, files, path):
     success = True
     violations = 0
     for file in files:
       try:
         handle = open(file)
         contents = handle.read()
         if not self.ProcessContents(file, contents):
@@ skipping 13 matching lines @@
 
 
 def Main():
   workspace = abspath(join(dirname(sys.argv[0]), '..'))
   parser = GetOptions()
   (options, args) = parser.parse_args()
   success = True
   print "Running C++ lint check..."
   if not options.no_lint:
     success = CppLintProcessor().Run(workspace) and success
-  print "Running copyright header and trailing whitespaces check..."
+  print "Running copyright header, trailing whitespaces and " \
+        "two empty lines between declarations check..."
   success = SourceProcessor().Run(workspace) and success
   if success:
     return 0
   else:
     return 1
 
 
 if __name__ == '__main__':
   sys.exit(Main())