Made testserver communicate to parent process with JSON

net/tools/testserver/testserver.py

 #!/usr/bin/python2.4
 # Copyright (c) 2006-2010 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 is a simple HTTP server used for testing Chrome.
 
 It supports several test URLs, as specified by the handlers in TestPageHandler.
 By default, it listens on an ephemeral port and sends the port number back to
 the originating process over a pipe. The originating process can specify an
@@ skipping 31 matching lines @@
   import md5
   _new_md5 = md5.new
 
 if sys.platform == 'win32':
   import msvcrt
 
 SERVER_HTTP = 0
 SERVER_FTP = 1
 SERVER_SYNC = 2
 
+# Using debug() seems to cause hangs on XP: see http://crbug.com/64515 .
 debug_output = sys.stderr
 def debug(str):
   debug_output.write(str + "\n")
   debug_output.flush()
 
 class StoppableHTTPServer(BaseHTTPServer.HTTPServer):
   """This is a specialization of of BaseHTTPServer to allow it
   to be exited cleanly (by setting its "stop" member to True)."""
 
   def serve_forever(self):
@@ skipping 1257 matching lines @@
     listen_port = server.socket.getsockname()[1]
     print 'FTP server started on port %d...' % listen_port
 
   # Notify the parent that we've started. (BaseServer subclasses
   # bind their sockets on construction.)
   if options.startup_pipe is not None:
     server_data = {
       'port': listen_port
     }
     server_data_json = simplejson.dumps(server_data)
+    server_data_len = len(server_data_json)
+    print 'sending server_data: %s (%d bytes)' % (
+      server_data_json, server_data_len)
     if sys.platform == 'win32':
       fd = msvcrt.open_osfhandle(options.startup_pipe, 0)
     else:
       fd = options.startup_pipe
     startup_pipe = os.fdopen(fd, "w")
-    # Write the listening port as a 2 byte value. This is _not_ using
-    # network byte ordering since the other end of the pipe is on the same
-    # machine.
-    startup_pipe.write(struct.pack('@H', listen_port))
+    # First write the data length as an unsigned 4-byte value.  This
+    # is _not_ using network byte ordering since the other end of the
+    # pipe is on the same machine.
+    startup_pipe.write(struct.pack('=L', server_data_len))
+    startup_pipe.write(server_data_json)
     startup_pipe.close()
 
   try:
     server.serve_forever()
   except KeyboardInterrupt:
     print 'shutting down server'
     server.stop = True
 
 if __name__ == '__main__':
   option_parser = optparse.OptionParser()
@@ skipping 31 matching lines @@
                            'option may appear multiple times, indicating '
                            'multiple algorithms should be enabled.');
   option_parser.add_option('', '--file-root-url', default='/files/',
                            help='Specify a root URL for files served.')
   option_parser.add_option('', '--startup-pipe', type='int',
                            dest='startup_pipe',
                            help='File handle of pipe to parent process')
   options, args = option_parser.parse_args()
 
   sys.exit(main(options, args))