The Tor Browser / file revision

 # Copyright 2011, Google Inc.

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 #

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 # 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

 # copyright notice, this list of conditions and the following disclaimer

 # in the documentation and/or other materials provided with the

 # distribution.

 #     * Neither the name of Google Inc. nor the names of its

 # contributors may be used to endorse or promote products derived from

 # this software without specific prior written permission.

 #

 # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

 # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

 # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

 # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

 # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

 # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

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 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 """Message related utilities.

 Note: request.connection.write/read are used in this module, even though

 mod_python document says that they should be used only in connection

 handlers. Unfortunately, we have no other options. For example,

 request.write/read are not suitable because they don't allow direct raw

 bytes writing/reading.

 """

 import Queue

 import threading

 # Export Exception symbols from msgutil for backward compatibility

 from mod_pywebsocket._stream_base import ConnectionTerminatedException

 from mod_pywebsocket._stream_base import InvalidFrameException

 from mod_pywebsocket._stream_base import BadOperationException

 from mod_pywebsocket._stream_base import UnsupportedFrameException

 # An API for handler to send/receive WebSocket messages.

 def close_connection(request):

     """Close connection.

     Args:

         request: mod_python request.

     """

     request.ws_stream.close_connection()

 def send_message(request, message, end=True, binary=False):

     """Send message.

     Args:

         request: mod_python request.

         message: unicode text or str binary to send.

         end: False to send message as a fragment. All messages until the

              first call with end=True (inclusive) will be delivered to the

              client in separate frames but as one WebSocket message.

         binary: send message as binary frame.

     Raises:

         BadOperationException: when server already terminated.

     """

     request.ws_stream.send_message(message, end, binary)

 def receive_message(request):

     """Receive a WebSocket frame and return its payload as a text in

     unicode or a binary in str.

     Args:

         request: mod_python request.

     Raises:

         InvalidFrameException:     when client send invalid frame.

         UnsupportedFrameException: when client send unsupported frame e.g. some

                                    of reserved bit is set but no extension can

                                    recognize it.

         InvalidUTF8Exception:      when client send a text frame containing any

                                    invalid UTF-8 string.

         ConnectionTerminatedException: when the connection is closed

                                    unexpectedly.

         BadOperationException:     when client already terminated.

     """

     return request.ws_stream.receive_message()

 def send_ping(request, body=''):

     request.ws_stream.send_ping(body)

 class MessageReceiver(threading.Thread):

     """This class receives messages from the client.

     This class provides three ways to receive messages: blocking,

     non-blocking, and via callback. Callback has the highest precedence.

     Note: This class should not be used with the standalone server for wss

     because pyOpenSSL used by the server raises a fatal error if the socket

     is accessed from multiple threads.

     """

     def __init__(self, request, onmessage=None):

         """Construct an instance.

         Args:

             request: mod_python request.

             onmessage: a function to be called when a message is received.

                        May be None. If not None, the function is called on

                        another thread. In that case, MessageReceiver.receive

                        and MessageReceiver.receive_nowait are useless

                        because they will never return any messages.

         """

         threading.Thread.__init__(self)

         self._request = request

         self._queue = Queue.Queue()

         self._onmessage = onmessage

         self._stop_requested = False

         self.setDaemon(True)

         self.start()

     def run(self):

         try:

             while not self._stop_requested:

                 message = receive_message(self._request)

                 if self._onmessage:

                     self._onmessage(message)

                 else:

                     self._queue.put(message)

         finally:

             close_connection(self._request)

     def receive(self):

         """ Receive a message from the channel, blocking.

         Returns:

             message as a unicode string.

         """

         return self._queue.get()

     def receive_nowait(self):

         """ Receive a message from the channel, non-blocking.

         Returns:

             message as a unicode string if available. None otherwise.

         """

         try:

             message = self._queue.get_nowait()

         except Queue.Empty:

             message = None

         return message

     def stop(self):

         """Request to stop this instance.

         The instance will be stopped after receiving the next message.

         This method may not be very useful, but there is no clean way

         in Python to forcefully stop a running thread.

         """

         self._stop_requested = True

 class MessageSender(threading.Thread):

     """This class sends messages to the client.

     This class provides both synchronous and asynchronous ways to send

     messages.

     Note: This class should not be used with the standalone server for wss

     because pyOpenSSL used by the server raises a fatal error if the socket

     is accessed from multiple threads.

     """

     def __init__(self, request):

         """Construct an instance.

         Args:

             request: mod_python request.

         """

         threading.Thread.__init__(self)

         self._request = request

         self._queue = Queue.Queue()

         self.setDaemon(True)

         self.start()

     def run(self):

         while True:

             message, condition = self._queue.get()

             condition.acquire()

             send_message(self._request, message)

             condition.notify()

             condition.release()

     def send(self, message):

         """Send a message, blocking."""

         condition = threading.Condition()

         condition.acquire()

         self._queue.put((message, condition))

         condition.wait()

     def send_nowait(self, message):

         """Send a message, non-blocking."""

         self._queue.put((message, threading.Condition()))

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