Fix some low hanging inefficiencies in the docs server

chrome/common/extensions/docs/server2/preview.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.
 
 # This helps you preview the apps and extensions docs.
 #
 #    ./preview.py --help
 #
 # There are two modes: server- and render- mode. The default is server, in which
@@ skipping 16 matching lines @@
 # Note: absolute paths into static content (e.g. /static/css/site.css) will be
 # relative paths (e.g. static/css/site.css) for convenient sandboxing.
 
 from BaseHTTPServer import BaseHTTPRequestHandler, HTTPServer
 import logging
 import optparse
 import os
 import shutil
 from StringIO import StringIO
 import sys
+import time
 import urlparse
 
 import build_server
 # Copy all the files necessary to run the server. These are cleaned up when the
 # server quits.
 build_server.main()
 
 from fake_fetchers import ConfigureFakeFetchers
 
 class _Response(object):
@@ skipping 42 matching lines @@
   parser.add_option('-p', '--port', default='8000',
       help='port to run the server on')
   parser.add_option('-d', '--directory', default=_GetLocalPath(),
       help='extensions directory to serve from - '
            'should be chrome/common/extensions within a Chromium checkout')
   parser.add_option('-r', '--render', default='',
       help='statically render a page and print to stdout rather than starting '
            'the server, e.g. apps/storage.html. The path may optionally end '
            'with #n where n is the number of times to render the page before '
            'printing it, e.g. apps/storage.html#50, to use for profiling.')
+  parser.add_option('-t', '--time', action='store_true',
+      help='Print the time taken rendering rather than the result.')
 
   (opts, argv) = parser.parse_args()
 
   if (not os.path.isdir(opts.directory) or
       not os.path.isdir(os.path.join(opts.directory, 'docs')) or
       not os.path.isdir(os.path.join(opts.directory, 'api'))):
     print('Specified directory does not exist or does not contain extension '
           'docs.')
     exit()
 
   ConfigureFakeFetchers(os.path.join(opts.directory, 'docs'))
   from handler import Handler
 
   if opts.render:
     if opts.render.find('#') >= 0:
       (path, iterations) = opts.render.rsplit('#', 1)
       extra_iterations = int(iterations) - 1
     else:
       path = opts.render
       extra_iterations = 0
 
+    if opts.time:
+      start_time = time.time()
+
     content, status, headers = _Render(path)
     if status in [301, 302]:
       # Handle a single level of redirection.
       redirect_path = headers['Location'].lstrip('/')
       sys.stderr.write('<!-- Redirected %s to %s -->\n' % (path, redirect_path))
       content, status, headers = _Render(redirect_path)
     if status != 200:
       print('Error status: %s' % status)
       exit(1)
 
     for _ in range(extra_iterations):
       _Render(path)
 
-    # Static paths will show up as /stable/static/foo but this only makes sense
-    # from a webserver.
-    print(content.replace('/stable/static', 'static'))
+    if opts.time:
+      print('Took %s seconds' % (time.time() - start_time))
+    else:
+      # Static paths will show up as /stable/static/foo but this only makes
+      # sense from a webserver.
+      print(content.replace('/stable/static', 'static'))
     exit()
 
   print('Starting previewserver on port %s' % opts.port)
   print('')
   print('The extension documentation can be found at:')
   print('')
   print('  http://localhost:%s/extensions/' % opts.port)
   print('')
   print('The apps documentation can be found at:')
   print('')
   print('  http://localhost:%s/apps/' % opts.port)
   print('')
 
   logging.getLogger().setLevel(logging.INFO)
   server = HTTPServer(('', int(opts.port)), RequestHandler)
   try:
     server.serve_forever()
   finally:
     server.socket.close()