Improve json_comment_eater.py performance.

tools/json_comment_eater/json_comment_eater.py

 #!/usr/bin/env python
 # Copyright (c) 2012 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.
 
 '''Utility to remove comments from JSON files so that they can be parsed by
 json.loads.
 '''
 
 import sys
 
 
 def _Rcount(string, chars):
   '''Returns the number of consecutive characters from |chars| that occur at the
   end of |string|.
   '''
   return len(string) - len(string.rstrip(chars))
 
 
 def _FindNextToken(string, tokens, start):
   '''Finds the next token in |tokens| that occurs in |string| from |start|.
   Returns a tuple (index, token key).
   '''
-  min_index, min_key = (-1, None)
-  for k in tokens:
-    index = string.find(k, start)
-    if index != -1 and (min_index == -1 or index < min_index):
-      min_index, min_key = (index, k)
-  return (min_index, min_key)
+  for index, item in enumerate(string, start):
+    for k in tokens:
+      if (string[index:index + len(k)] == k):
+        return (index, k)
 
+  return (-1, None)
 
 def _ReadString(input, start, output):
   output.append('"')
   start_range, end_range = (start, input.find('"', start))
   # \" escapes the ", \\" doesn't, \\\" does, etc.
   while (end_range != -1 and
          _Rcount(input[start_range:end_range], '\\') % 2 == 1):
     start_range, end_range = (end_range, input.find('"', end_range + 1))
   if end_range == -1:
     return start_range + 1
@@ skipping 29 matching lines @@
     if token is None:
       output.append(input[pos:])
       break
     output.append(input[pos:token_index])
     pos = token_actions[token](input, token_index + len(token), output)
   return ''.join(output)
 
 
 if __name__ == '__main__':
     sys.stdout.write(Nom(sys.stdin.read()))