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Posted to commits@qpid.apache.org by gs...@apache.org on 2014/11/26 21:06:07 UTC

[20/35] qpid-proton git commit: changed proton.py from a module into a package

http://git-wip-us.apache.org/repos/asf/qpid-proton/blob/6a78d2f7/proton-c/bindings/python/proton/__init__.py
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diff --git a/proton-c/bindings/python/proton/__init__.py b/proton-c/bindings/python/proton/__init__.py
new file mode 100644
index 0000000..fce3255
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+++ b/proton-c/bindings/python/proton/__init__.py
@@ -0,0 +1,3891 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
+"""
+The proton module defines a suite of APIs that implement the AMQP 1.0
+protocol.
+
+The proton APIs consist of the following classes:
+
+ - L{Messenger} -- A messaging endpoint.
+ - L{Message}   -- A class for creating and/or accessing AMQP message content.
+ - L{Data}      -- A class for creating and/or accessing arbitrary AMQP encoded
+                  data.
+
+"""
+
+from cproton import *
+
+import weakref, re, socket
+try:
+  import uuid
+except ImportError:
+  """
+  No 'native' UUID support.  Provide a very basic UUID type that is a compatible subset of the uuid type provided by more modern python releases.
+  """
+  import struct
+  class uuid:
+    class UUID:
+      def __init__(self, hex=None, bytes=None):
+        if [hex, bytes].count(None) != 1:
+          raise TypeError("need one of hex or bytes")
+        if bytes is not None:
+          self.bytes = bytes
+        elif hex is not None:
+          fields=hex.split("-")
+          fields[4:5] = [fields[4][:4], fields[4][4:]]
+          self.bytes = struct.pack("!LHHHHL", *[int(x,16) for x in fields])
+
+      def __cmp__(self, other):
+        if isinstance(other, uuid.UUID):
+          return cmp(self.bytes, other.bytes)
+        else:
+          return -1
+
+      def __str__(self):
+        return "%08x-%04x-%04x-%04x-%04x%08x" % struct.unpack("!LHHHHL", self.bytes)
+
+      def __repr__(self):
+        return "UUID(%r)" % str(self)
+
+      def __hash__(self):
+        return self.bytes.__hash__()
+
+  import os, random, socket, time
+  rand = random.Random()
+  rand.seed((os.getpid(), time.time(), socket.gethostname()))
+  def random_uuid():
+    bytes = [rand.randint(0, 255) for i in xrange(16)]
+
+    # From RFC4122, the version bits are set to 0100
+    bytes[7] &= 0x0F
+    bytes[7] |= 0x40
+
+    # From RFC4122, the top two bits of byte 8 get set to 01
+    bytes[8] &= 0x3F
+    bytes[8] |= 0x80
+    return "".join(map(chr, bytes))
+
+  def uuid4():
+    return uuid.UUID(bytes=random_uuid())
+
+try:
+  bytes()
+except NameError:
+  bytes = str
+
+VERSION_MAJOR = PN_VERSION_MAJOR
+VERSION_MINOR = PN_VERSION_MINOR
+API_LANGUAGE = "C"
+IMPLEMENTATION_LANGUAGE = "C"
+
+class Constant(object):
+
+  def __init__(self, name):
+    self.name = name
+
+  def __repr__(self):
+    return self.name
+
+class ProtonException(Exception):
+  """
+  The root of the proton exception hierarchy. All proton exception
+  classes derive from this exception.
+  """
+  pass
+
+class Timeout(ProtonException):
+  """
+  A timeout exception indicates that a blocking operation has timed
+  out.
+  """
+  pass
+
+class Interrupt(ProtonException):
+  """
+  An interrupt exception indicaes that a blocking operation was interrupted.
+  """
+  pass
+
+class MessengerException(ProtonException):
+  """
+  The root of the messenger exception hierarchy. All exceptions
+  generated by the messenger class derive from this exception.
+  """
+  pass
+
+class MessageException(ProtonException):
+  """
+  The MessageException class is the root of the message exception
+  hierarhcy. All exceptions generated by the Message class derive from
+  this exception.
+  """
+  pass
+
+EXCEPTIONS = {
+  PN_TIMEOUT: Timeout,
+  PN_INTR: Interrupt
+  }
+
+PENDING = Constant("PENDING")
+ACCEPTED = Constant("ACCEPTED")
+REJECTED = Constant("REJECTED")
+RELEASED = Constant("RELEASED")
+ABORTED = Constant("ABORTED")
+SETTLED = Constant("SETTLED")
+
+STATUSES = {
+  PN_STATUS_ABORTED: ABORTED,
+  PN_STATUS_ACCEPTED: ACCEPTED,
+  PN_STATUS_REJECTED: REJECTED,
+  PN_STATUS_RELEASED: RELEASED,
+  PN_STATUS_PENDING: PENDING,
+  PN_STATUS_SETTLED: SETTLED,
+  PN_STATUS_UNKNOWN: None
+  }
+
+AUTOMATIC = Constant("AUTOMATIC")
+MANUAL = Constant("MANUAL")
+
+class Messenger(object):
+  """
+  The L{Messenger} class defines a high level interface for sending
+  and receiving L{Messages<Message>}. Every L{Messenger} contains a
+  single logical queue of incoming messages and a single logical queue
+  of outgoing messages. These messages in these queues may be destined
+  for, or originate from, a variety of addresses.
+
+  The messenger interface is single-threaded.  All methods
+  except one (L{interrupt}) are intended to be used from within
+  the messenger thread.
+
+
+  Address Syntax
+  ==============
+
+  An address has the following form::
+
+    [ amqp[s]:// ] [user[:password]@] domain [/[name]]
+
+  Where domain can be one of::
+
+    host | host:port | ip | ip:port | name
+
+  The following are valid examples of addresses:
+
+   - example.org
+   - example.org:1234
+   - amqp://example.org
+   - amqps://example.org
+   - example.org/incoming
+   - amqps://example.org/outgoing
+   - amqps://fred:trustno1@example.org
+   - 127.0.0.1:1234
+   - amqps://127.0.0.1:1234
+
+  Sending & Receiving Messages
+  ============================
+
+  The L{Messenger} class works in conjuction with the L{Message} class. The
+  L{Message} class is a mutable holder of message content.
+
+  The L{put} method copies its L{Message} to the outgoing queue, and may
+  send queued messages if it can do so without blocking.  The L{send}
+  method blocks until it has sent the requested number of messages,
+  or until a timeout interrupts the attempt.
+
+
+    >>> message = Message()
+    >>> for i in range(3):
+    ...   message.address = "amqp://host/queue"
+    ...   message.subject = "Hello World %i" % i
+    ...   messenger.put(message)
+    >>> messenger.send()
+
+  Similarly, the L{recv} method receives messages into the incoming
+  queue, and may block as it attempts to receive the requested number
+  of messages,  or until timeout is reached. It may receive fewer
+  than the requested number.  The L{get} method pops the
+  eldest L{Message} off the incoming queue and copies it into the L{Message}
+  object that you supply.  It will not block.
+
+
+    >>> message = Message()
+    >>> messenger.recv(10):
+    >>> while messenger.incoming > 0:
+    ...   messenger.get(message)
+    ...   print message.subject
+    Hello World 0
+    Hello World 1
+    Hello World 2
+
+  The blocking flag allows you to turn off blocking behavior entirely,
+  in which case L{send} and L{recv} will do whatever they can without
+  blocking, and then return.  You can then look at the number
+  of incoming and outgoing messages to see how much outstanding work
+  still remains.
+  """
+
+  def __init__(self, name=None):
+    """
+    Construct a new L{Messenger} with the given name. The name has
+    global scope. If a NULL name is supplied, a UUID based name will
+    be chosen.
+
+    @type name: string
+    @param name: the name of the messenger or None
+
+    """
+    self._mng = pn_messenger(name)
+    self._selectables = {}
+
+  def __del__(self):
+    """
+    Destroy the L{Messenger}.  This will close all connections that
+    are managed by the L{Messenger}.  Call the L{stop} method before
+    destroying the L{Messenger}.
+    """
+    if hasattr(self, "_mng"):
+      pn_messenger_free(self._mng)
+      del self._mng
+
+  def _check(self, err):
+    if err < 0:
+      if (err == PN_INPROGRESS):
+        return
+      exc = EXCEPTIONS.get(err, MessengerException)
+      raise exc("[%s]: %s" % (err, pn_error_text(pn_messenger_error(self._mng))))
+    else:
+      return err
+
+  @property
+  def name(self):
+    """
+    The name of the L{Messenger}.
+    """
+    return pn_messenger_name(self._mng)
+
+  def _get_certificate(self):
+    return pn_messenger_get_certificate(self._mng)
+
+  def _set_certificate(self, value):
+    self._check(pn_messenger_set_certificate(self._mng, value))
+
+  certificate = property(_get_certificate, _set_certificate,
+                         doc="""
+Path to a certificate file for the L{Messenger}. This certificate is
+used when the L{Messenger} accepts or establishes SSL/TLS connections.
+This property must be specified for the L{Messenger} to accept
+incoming SSL/TLS connections and to establish client authenticated
+outgoing SSL/TLS connection. Non client authenticated outgoing SSL/TLS
+connections do not require this property.
+""")
+
+  def _get_private_key(self):
+    return pn_messenger_get_private_key(self._mng)
+
+  def _set_private_key(self, value):
+    self._check(pn_messenger_set_private_key(self._mng, value))
+
+  private_key = property(_get_private_key, _set_private_key,
+                         doc="""
+Path to a private key file for the L{Messenger's<Messenger>}
+certificate. This property must be specified for the L{Messenger} to
+accept incoming SSL/TLS connections and to establish client
+authenticated outgoing SSL/TLS connection. Non client authenticated
+SSL/TLS connections do not require this property.
+""")
+
+  def _get_password(self):
+    return pn_messenger_get_password(self._mng)
+
+  def _set_password(self, value):
+    self._check(pn_messenger_set_password(self._mng, value))
+
+  password = property(_get_password, _set_password,
+                      doc="""
+This property contains the password for the L{Messenger.private_key}
+file, or None if the file is not encrypted.
+""")
+
+  def _get_trusted_certificates(self):
+    return pn_messenger_get_trusted_certificates(self._mng)
+
+  def _set_trusted_certificates(self, value):
+    self._check(pn_messenger_set_trusted_certificates(self._mng, value))
+
+  trusted_certificates = property(_get_trusted_certificates,
+                                  _set_trusted_certificates,
+                                  doc="""
+A path to a database of trusted certificates for use in verifying the
+peer on an SSL/TLS connection. If this property is None, then the peer
+will not be verified.
+""")
+
+  def _get_timeout(self):
+    t = pn_messenger_get_timeout(self._mng)
+    if t == -1:
+      return None
+    else:
+      return millis2secs(t)
+
+  def _set_timeout(self, value):
+    if value is None:
+      t = -1
+    else:
+      t = secs2millis(value)
+    self._check(pn_messenger_set_timeout(self._mng, t))
+
+  timeout = property(_get_timeout, _set_timeout,
+                     doc="""
+The timeout property contains the default timeout for blocking
+operations performed by the L{Messenger}.
+""")
+
+  def _is_blocking(self):
+    return pn_messenger_is_blocking(self._mng)
+
+  def _set_blocking(self, b):
+    self._check(pn_messenger_set_blocking(self._mng, b))
+
+  blocking = property(_is_blocking, _set_blocking,
+                      doc="""
+Enable or disable blocking behavior during L{Message} sending
+and receiving.  This affects every blocking call, with the
+exception of L{work}.  Currently, the affected calls are
+L{send}, L{recv}, and L{stop}.
+""")
+
+  def _is_passive(self):
+    return pn_messenger_is_passive(self._mng)
+
+  def _set_passive(self, b):
+    self._check(pn_messenger_set_passive(self._mng, b))
+
+  passive = property(_is_passive, _set_passive,
+                      doc="""
+When passive is set to true, Messenger will not attempt to perform I/O
+internally. In this mode it is necessary to use the selectables API to
+drive any I/O needed to perform requested actions. In this mode
+Messenger will never block.
+""")
+
+  def _get_incoming_window(self):
+    return pn_messenger_get_incoming_window(self._mng)
+
+  def _set_incoming_window(self, window):
+    self._check(pn_messenger_set_incoming_window(self._mng, window))
+
+  incoming_window = property(_get_incoming_window, _set_incoming_window,
+                             doc="""
+The incoming tracking window for the messenger. The messenger will
+track the remote status of this many incoming deliveries after they
+have been accepted or rejected. Defaults to zero.
+
+L{Messages<Message>} enter this window only when you take them into your application
+using L{get}.  If your incoming window size is I{n}, and you get I{n}+1 L{messages<Message>}
+without explicitly accepting or rejecting the oldest message, then the
+message that passes beyond the edge of the incoming window will be assigned
+the default disposition of its link.
+""")
+
+  def _get_outgoing_window(self):
+    return pn_messenger_get_outgoing_window(self._mng)
+
+  def _set_outgoing_window(self, window):
+    self._check(pn_messenger_set_outgoing_window(self._mng, window))
+
+  outgoing_window = property(_get_outgoing_window, _set_outgoing_window,
+                             doc="""
+The outgoing tracking window for the messenger. The messenger will
+track the remote status of this many outgoing deliveries after calling
+send. Defaults to zero.
+
+A L{Message} enters this window when you call the put() method with the
+message.  If your outgoing window size is I{n}, and you call L{put} I{n}+1
+times, status information will no longer be available for the
+first message.
+""")
+
+  def start(self):
+    """
+    Currently a no-op placeholder.
+    For future compatibility, do not L{send} or L{recv} messages
+    before starting the L{Messenger}.
+    """
+    self._check(pn_messenger_start(self._mng))
+
+  def stop(self):
+    """
+    Transitions the L{Messenger} to an inactive state. An inactive
+    L{Messenger} will not send or receive messages from its internal
+    queues. A L{Messenger} should be stopped before being discarded to
+    ensure a clean shutdown handshake occurs on any internally managed
+    connections.
+    """
+    self._check(pn_messenger_stop(self._mng))
+
+  @property
+  def stopped(self):
+    """
+    Returns true iff a L{Messenger} is in the stopped state.
+    This function does not block.
+    """
+    return pn_messenger_stopped(self._mng)
+
+  def subscribe(self, source):
+    """
+    Subscribes the L{Messenger} to messages originating from the
+    specified source. The source is an address as specified in the
+    L{Messenger} introduction with the following addition. If the
+    domain portion of the address begins with the '~' character, the
+    L{Messenger} will interpret the domain as host/port, bind to it,
+    and listen for incoming messages. For example "~0.0.0.0",
+    "amqp://~0.0.0.0", and "amqps://~0.0.0.0" will all bind to any
+    local interface and listen for incoming messages with the last
+    variant only permitting incoming SSL connections.
+
+    @type source: string
+    @param source: the source of messages to subscribe to
+    """
+    sub_impl = pn_messenger_subscribe(self._mng, source)
+    if not sub_impl:
+      self._check(pn_error_code(pn_messenger_error(self._mng)))
+      raise MessengerException("Cannot subscribe to %s"%source)
+    return Subscription(sub_impl)
+
+  def put(self, message):
+    """
+    Places the content contained in the message onto the outgoing
+    queue of the L{Messenger}. This method will never block, however
+    it will send any unblocked L{Messages<Message>} in the outgoing
+    queue immediately and leave any blocked L{Messages<Message>}
+    remaining in the outgoing queue. The L{send} call may be used to
+    block until the outgoing queue is empty. The L{outgoing} property
+    may be used to check the depth of the outgoing queue.
+
+    When the content in a given L{Message} object is copied to the outgoing
+    message queue, you may then modify or discard the L{Message} object
+    without having any impact on the content in the outgoing queue.
+
+    This method returns an outgoing tracker for the L{Message}.  The tracker
+    can be used to determine the delivery status of the L{Message}.
+
+    @type message: Message
+    @param message: the message to place in the outgoing queue
+    @return: a tracker
+    """
+    message._pre_encode()
+    self._check(pn_messenger_put(self._mng, message._msg))
+    return pn_messenger_outgoing_tracker(self._mng)
+
+  def status(self, tracker):
+    """
+    Gets the last known remote state of the delivery associated with
+    the given tracker.
+
+    @type tracker: tracker
+    @param tracker: the tracker whose status is to be retrieved
+
+    @return: one of None, PENDING, REJECTED, or ACCEPTED
+    """
+    disp = pn_messenger_status(self._mng, tracker);
+    return STATUSES.get(disp, disp)
+
+  def buffered(self, tracker):
+    """
+    Checks if the delivery associated with the given tracker is still
+    waiting to be sent.
+
+    @type tracker: tracker
+    @param tracker: the tracker whose status is to be retrieved
+
+    @return: true if delivery is still buffered
+    """
+    return pn_messenger_buffered(self._mng, tracker);
+
+  def settle(self, tracker=None):
+    """
+    Frees a L{Messenger} from tracking the status associated with a given
+    tracker. If you don't supply a tracker, all outgoing L{messages<Message>} up
+    to the most recent will be settled.
+    """
+    if tracker is None:
+      tracker = pn_messenger_outgoing_tracker(self._mng)
+      flags = PN_CUMULATIVE
+    else:
+      flags = 0
+    self._check(pn_messenger_settle(self._mng, tracker, flags))
+
+  def send(self, n=-1):
+    """
+    This call will block until the indicated number of L{messages<Message>}
+    have been sent, or until the operation times out.  If n is -1 this call will
+    block until all outgoing L{messages<Message>} have been sent. If n is 0 then
+    this call will send whatever it can without blocking.
+    """
+    self._check(pn_messenger_send(self._mng, n))
+
+  def recv(self, n=None):
+    """
+    Receives up to I{n} L{messages<Message>} into the incoming queue.  If no value
+    for I{n} is supplied, this call will receive as many L{messages<Message>} as it
+    can buffer internally.  If the L{Messenger} is in blocking mode, this
+    call will block until at least one L{Message} is available in the
+    incoming queue.
+    """
+    if n is None:
+      n = -1
+    self._check(pn_messenger_recv(self._mng, n))
+
+  def work(self, timeout=None):
+    """
+    Sends or receives any outstanding L{messages<Message>} queued for a L{Messenger}.
+    This will block for the indicated timeout.
+    This method may also do I/O work other than sending and receiving
+    L{messages<Message>}.  For example, closing connections after messenger.L{stop}()
+    has been called.
+    """
+    if timeout is None:
+      t = -1
+    else:
+      t = secs2millis(timeout)
+    err = pn_messenger_work(self._mng, t)
+    if (err == PN_TIMEOUT):
+      return False
+    else:
+      self._check(err)
+      return True
+
+  @property
+  def receiving(self):
+    return pn_messenger_receiving(self._mng)
+
+  def interrupt(self):
+    """
+    The L{Messenger} interface is single-threaded.
+    This is the only L{Messenger} function intended to be called
+    from outside of the L{Messenger} thread.
+    Call this from a non-messenger thread to interrupt
+    a L{Messenger} that is blocking.
+    This will cause any in-progress blocking call to throw
+    the L{Interrupt} exception.  If there is no currently blocking
+    call, then the next blocking call will be affected, even if it
+    is within the same thread that interrupt was called from.
+    """
+    self._check(pn_messenger_interrupt(self._mng))
+
+  def get(self, message=None):
+    """
+    Moves the message from the head of the incoming message queue into
+    the supplied message object. Any content in the message will be
+    overwritten.
+
+    A tracker for the incoming L{Message} is returned.  The tracker can
+    later be used to communicate your acceptance or rejection of the
+    L{Message}.
+
+    If None is passed in for the L{Message} object, the L{Message}
+    popped from the head of the queue is discarded.
+
+    @type message: Message
+    @param message: the destination message object
+    @return: a tracker
+    """
+    if message is None:
+      impl = None
+    else:
+      impl = message._msg
+    self._check(pn_messenger_get(self._mng, impl))
+    if message is not None:
+      message._post_decode()
+    return pn_messenger_incoming_tracker(self._mng)
+
+  def accept(self, tracker=None):
+    """
+    Signal the sender that you have acted on the L{Message}
+    pointed to by the tracker.  If no tracker is supplied,
+    then all messages that have been returned by the L{get}
+    method are accepted, except those that have already been
+    auto-settled by passing beyond your incoming window size.
+
+    @type tracker: tracker
+    @param tracker: a tracker as returned by get
+    """
+    if tracker is None:
+      tracker = pn_messenger_incoming_tracker(self._mng)
+      flags = PN_CUMULATIVE
+    else:
+      flags = 0
+    self._check(pn_messenger_accept(self._mng, tracker, flags))
+
+  def reject(self, tracker=None):
+    """
+    Rejects the L{Message} indicated by the tracker.  If no tracker
+    is supplied, all messages that have been returned by the L{get}
+    method are rejected, except those that have already been auto-settled
+    by passing beyond your outgoing window size.
+
+    @type tracker: tracker
+    @param tracker: a tracker as returned by get
+    """
+    if tracker is None:
+      tracker = pn_messenger_incoming_tracker(self._mng)
+      flags = PN_CUMULATIVE
+    else:
+      flags = 0
+    self._check(pn_messenger_reject(self._mng, tracker, flags))
+
+  @property
+  def outgoing(self):
+    """
+    The outgoing queue depth.
+    """
+    return pn_messenger_outgoing(self._mng)
+
+  @property
+  def incoming(self):
+    """
+    The incoming queue depth.
+    """
+    return pn_messenger_incoming(self._mng)
+
+  def route(self, pattern, address):
+    """
+          Adds a routing rule to a L{Messenger's<Messenger>} internal routing table.
+
+          The route procedure may be used to influence how a L{Messenger} will
+          internally treat a given address or class of addresses. Every call
+          to the route procedure will result in L{Messenger} appending a routing
+          rule to its internal routing table.
+
+          Whenever a L{Message} is presented to a L{Messenger} for delivery, it
+          will match the address of this message against the set of routing
+          rules in order. The first rule to match will be triggered, and
+          instead of routing based on the address presented in the message,
+          the L{Messenger} will route based on the address supplied in the rule.
+
+          The pattern matching syntax supports two types of matches, a '%'
+          will match any character except a '/', and a '*' will match any
+          character including a '/'.
+
+          A routing address is specified as a normal AMQP address, however it
+          may additionally use substitution variables from the pattern match
+          that triggered the rule.
+
+          Any message sent to "foo" will be routed to "amqp://foo.com":
+
+             >>> messenger.route("foo", "amqp://foo.com");
+
+          Any message sent to "foobar" will be routed to
+          "amqp://foo.com/bar":
+
+             >>> messenger.route("foobar", "amqp://foo.com/bar");
+
+          Any message sent to bar/<path> will be routed to the corresponding
+          path within the amqp://bar.com domain:
+
+             >>> messenger.route("bar/*", "amqp://bar.com/$1");
+
+          Route all L{messages<Message>} over TLS:
+
+             >>> messenger.route("amqp:*", "amqps:$1")
+
+          Supply credentials for foo.com:
+
+             >>> messenger.route("amqp://foo.com/*", "amqp://user:password@foo.com/$1");
+
+          Supply credentials for all domains:
+
+             >>> messenger.route("amqp://*", "amqp://user:password@$1");
+
+          Route all addresses through a single proxy while preserving the
+          original destination:
+
+             >>> messenger.route("amqp://%/*", "amqp://user:password@proxy/$1/$2");
+
+          Route any address through a single broker:
+
+             >>> messenger.route("*", "amqp://user:password@broker/$1");
+    """
+    self._check(pn_messenger_route(self._mng, pattern, address))
+
+  def rewrite(self, pattern, address):
+    """
+    Similar to route(), except that the destination of
+    the L{Message} is determined before the message address is rewritten.
+
+    The outgoing address is only rewritten after routing has been
+    finalized.  If a message has an outgoing address of
+    "amqp://0.0.0.0:5678", and a rewriting rule that changes its
+    outgoing address to "foo", it will still arrive at the peer that
+    is listening on "amqp://0.0.0.0:5678", but when it arrives there,
+    the receiver will see its outgoing address as "foo".
+
+    The default rewrite rule removes username and password from addresses
+    before they are transmitted.
+    """
+    self._check(pn_messenger_rewrite(self._mng, pattern, address))
+
+  def selectable(self):
+    impl = pn_messenger_selectable(self._mng)
+    if impl:
+      fd = pn_selectable_fd(impl)
+      sel = self._selectables.get(fd, None)
+      if sel is None:
+        sel = Selectable(self, impl)
+        self._selectables[fd] = sel
+      return sel
+    else:
+      return None
+
+  @property
+  def deadline(self):
+    tstamp = pn_messenger_deadline(self._mng)
+    if tstamp:
+      return millis2secs(tstamp)
+    else:
+      return None
+
+class Message(object):
+  """The L{Message} class is a mutable holder of message content.
+
+  @ivar instructions: delivery instructions for the message
+  @type instructions: dict
+  @ivar annotations: infrastructure defined message annotations
+  @type annotations: dict
+  @ivar properties: application defined message properties
+  @type properties: dict
+  @ivar body: message body
+  @type body: bytes | unicode | dict | list | int | long | float | UUID
+  """
+
+  DATA = PN_DATA
+  TEXT = PN_TEXT
+  AMQP = PN_AMQP
+  JSON = PN_JSON
+
+  DEFAULT_PRIORITY = PN_DEFAULT_PRIORITY
+
+  def __init__(self, **kwargs):
+    """
+    @param kwargs: Message property name/value pairs to initialise the Message
+    """
+    self._msg = pn_message()
+    self._id = Data(pn_message_id(self._msg))
+    self._correlation_id = Data(pn_message_correlation_id(self._msg))
+    self.instructions = None
+    self.annotations = None
+    self.properties = None
+    self.body = None
+    for k,v in kwargs.iteritems():
+      getattr(self, k)          # Raise exception if it's not a valid attribute.
+      setattr(self, k, v)
+
+  def __del__(self):
+    if hasattr(self, "_msg"):
+      pn_message_free(self._msg)
+      del self._msg
+
+  def _check(self, err):
+    if err < 0:
+      exc = EXCEPTIONS.get(err, MessageException)
+      raise exc("[%s]: %s" % (err, pn_error_text(pn_message_error(self._msg))))
+    else:
+      return err
+
+  def _pre_encode(self):
+    inst = Data(pn_message_instructions(self._msg))
+    ann = Data(pn_message_annotations(self._msg))
+    props = Data(pn_message_properties(self._msg))
+    body = Data(pn_message_body(self._msg))
+
+    inst.clear()
+    if self.instructions is not None:
+      inst.put_object(self.instructions)
+    ann.clear()
+    if self.annotations is not None:
+      ann.put_object(self.annotations)
+    props.clear()
+    if self.properties is not None:
+      props.put_object(self.properties)
+    body.clear()
+    if self.body is not None:
+      body.put_object(self.body)
+
+  def _post_decode(self):
+    inst = Data(pn_message_instructions(self._msg))
+    ann = Data(pn_message_annotations(self._msg))
+    props = Data(pn_message_properties(self._msg))
+    body = Data(pn_message_body(self._msg))
+
+    if inst.next():
+      self.instructions = inst.get_object()
+    else:
+      self.instructions = None
+    if ann.next():
+      self.annotations = ann.get_object()
+    else:
+      self.annotations = None
+    if props.next():
+      self.properties = props.get_object()
+    else:
+      self.properties = None
+    if body.next():
+      self.body = body.get_object()
+    else:
+      self.body = None
+
+  def clear(self):
+    """
+    Clears the contents of the L{Message}. All fields will be reset to
+    their default values.
+    """
+    pn_message_clear(self._msg)
+    self.instructions = None
+    self.annotations = None
+    self.properties = None
+    self.body = None
+
+  def _is_inferred(self):
+    return pn_message_is_inferred(self._msg)
+
+  def _set_inferred(self, value):
+    self._check(pn_message_set_inferred(self._msg, bool(value)))
+
+  inferred = property(_is_inferred, _set_inferred, doc="""
+The inferred flag for a message indicates how the message content
+is encoded into AMQP sections. If inferred is true then binary and
+list values in the body of the message will be encoded as AMQP DATA
+and AMQP SEQUENCE sections, respectively. If inferred is false,
+then all values in the body of the message will be encoded as AMQP
+VALUE sections regardless of their type.
+""")
+
+  def _is_durable(self):
+    return pn_message_is_durable(self._msg)
+
+  def _set_durable(self, value):
+    self._check(pn_message_set_durable(self._msg, bool(value)))
+
+  durable = property(_is_durable, _set_durable,
+                     doc="""
+The durable property indicates that the message should be held durably
+by any intermediaries taking responsibility for the message.
+""")
+
+  def _get_priority(self):
+    return pn_message_get_priority(self._msg)
+
+  def _set_priority(self, value):
+    self._check(pn_message_set_priority(self._msg, value))
+
+  priority = property(_get_priority, _set_priority,
+                      doc="""
+The priority of the message.
+""")
+
+  def _get_ttl(self):
+    return millis2secs(pn_message_get_ttl(self._msg))
+
+  def _set_ttl(self, value):
+    self._check(pn_message_set_ttl(self._msg, secs2millis(value)))
+
+  ttl = property(_get_ttl, _set_ttl,
+                 doc="""
+The time to live of the message measured in seconds. Expired messages
+may be dropped.
+""")
+
+  def _is_first_acquirer(self):
+    return pn_message_is_first_acquirer(self._msg)
+
+  def _set_first_acquirer(self, value):
+    self._check(pn_message_set_first_acquirer(self._msg, bool(value)))
+
+  first_acquirer = property(_is_first_acquirer, _set_first_acquirer,
+                            doc="""
+True iff the recipient is the first to acquire the message.
+""")
+
+  def _get_delivery_count(self):
+    return pn_message_get_delivery_count(self._msg)
+
+  def _set_delivery_count(self, value):
+    self._check(pn_message_set_delivery_count(self._msg, value))
+
+  delivery_count = property(_get_delivery_count, _set_delivery_count,
+                            doc="""
+The number of delivery attempts made for this message.
+""")
+
+
+  def _get_id(self):
+    return self._id.get_object()
+  def _set_id(self, value):
+    if type(value) in (int, long):
+      value = ulong(value)
+    self._id.rewind()
+    self._id.put_object(value)
+  id = property(_get_id, _set_id,
+                doc="""
+The id of the message.
+""")
+
+  def _get_user_id(self):
+    return pn_message_get_user_id(self._msg)
+
+  def _set_user_id(self, value):
+    self._check(pn_message_set_user_id(self._msg, value))
+
+  user_id = property(_get_user_id, _set_user_id,
+                     doc="""
+The user id of the message creator.
+""")
+
+  def _get_address(self):
+    return pn_message_get_address(self._msg)
+
+  def _set_address(self, value):
+    self._check(pn_message_set_address(self._msg, value))
+
+  address = property(_get_address, _set_address,
+                     doc="""
+The address of the message.
+""")
+
+  def _get_subject(self):
+    return pn_message_get_subject(self._msg)
+
+  def _set_subject(self, value):
+    self._check(pn_message_set_subject(self._msg, value))
+
+  subject = property(_get_subject, _set_subject,
+                     doc="""
+The subject of the message.
+""")
+
+  def _get_reply_to(self):
+    return pn_message_get_reply_to(self._msg)
+
+  def _set_reply_to(self, value):
+    self._check(pn_message_set_reply_to(self._msg, value))
+
+  reply_to = property(_get_reply_to, _set_reply_to,
+                      doc="""
+The reply-to address for the message.
+""")
+
+  def _get_correlation_id(self):
+    return self._correlation_id.get_object()
+  def _set_correlation_id(self, value):
+    if type(value) in (int, long):
+      value = ulong(value)
+    self._correlation_id.rewind()
+    self._correlation_id.put_object(value)
+
+  correlation_id = property(_get_correlation_id, _set_correlation_id,
+                            doc="""
+The correlation-id for the message.
+""")
+
+  def _get_content_type(self):
+    return pn_message_get_content_type(self._msg)
+
+  def _set_content_type(self, value):
+    self._check(pn_message_set_content_type(self._msg, value))
+
+  content_type = property(_get_content_type, _set_content_type,
+                          doc="""
+The content-type of the message.
+""")
+
+  def _get_content_encoding(self):
+    return pn_message_get_content_encoding(self._msg)
+
+  def _set_content_encoding(self, value):
+    self._check(pn_message_set_content_encoding(self._msg, value))
+
+  content_encoding = property(_get_content_encoding, _set_content_encoding,
+                              doc="""
+The content-encoding of the message.
+""")
+
+  def _get_expiry_time(self):
+    return millis2secs(pn_message_get_expiry_time(self._msg))
+
+  def _set_expiry_time(self, value):
+    self._check(pn_message_set_expiry_time(self._msg, secs2millis(value)))
+
+  expiry_time = property(_get_expiry_time, _set_expiry_time,
+                         doc="""
+The expiry time of the message.
+""")
+
+  def _get_creation_time(self):
+    return millis2secs(pn_message_get_creation_time(self._msg))
+
+  def _set_creation_time(self, value):
+    self._check(pn_message_set_creation_time(self._msg, secs2millis(value)))
+
+  creation_time = property(_get_creation_time, _set_creation_time,
+                           doc="""
+The creation time of the message.
+""")
+
+  def _get_group_id(self):
+    return pn_message_get_group_id(self._msg)
+
+  def _set_group_id(self, value):
+    self._check(pn_message_set_group_id(self._msg, value))
+
+  group_id = property(_get_group_id, _set_group_id,
+                      doc="""
+The group id of the message.
+""")
+
+  def _get_group_sequence(self):
+    return pn_message_get_group_sequence(self._msg)
+
+  def _set_group_sequence(self, value):
+    self._check(pn_message_set_group_sequence(self._msg, value))
+
+  group_sequence = property(_get_group_sequence, _set_group_sequence,
+                            doc="""
+The sequence of the message within its group.
+""")
+
+  def _get_reply_to_group_id(self):
+    return pn_message_get_reply_to_group_id(self._msg)
+
+  def _set_reply_to_group_id(self, value):
+    self._check(pn_message_set_reply_to_group_id(self._msg, value))
+
+  reply_to_group_id = property(_get_reply_to_group_id, _set_reply_to_group_id,
+                               doc="""
+The group-id for any replies.
+""")
+
+  # XXX
+  def _get_format(self):
+    return pn_message_get_format(self._msg)
+
+  def _set_format(self, value):
+    self._check(pn_message_set_format(self._msg, value))
+
+  format = property(_get_format, _set_format,
+                    doc="""
+The format of the message.
+""")
+
+  def encode(self):
+    self._pre_encode()
+    sz = 16
+    while True:
+      err, data = pn_message_encode(self._msg, sz)
+      if err == PN_OVERFLOW:
+        sz *= 2
+        continue
+      else:
+        self._check(err)
+        return data
+
+  def decode(self, data):
+    self._check(pn_message_decode(self._msg, data, len(data)))
+    self._post_decode()
+
+  def load(self, data):
+    self._check(pn_message_load(self._msg, data))
+
+  def save(self):
+    sz = 16
+    while True:
+      err, data = pn_message_save(self._msg, sz)
+      if err == PN_OVERFLOW:
+        sz *= 2
+        continue
+      else:
+        self._check(err)
+        return data
+
+  def __repr2__(self):
+    props = []
+    for attr in ("inferred", "address", "reply_to", "durable", "ttl",
+                 "priority", "first_acquirer", "delivery_count", "id",
+                 "correlation_id", "user_id", "group_id", "group_sequence",
+                 "reply_to_group_id", "instructions", "annotations",
+                 "properties", "body"):
+      value = getattr(self, attr)
+      if value: props.append("%s=%r" % (attr, value))
+    return "Message(%s)" % ", ".join(props)
+
+  def __repr__(self):
+    tmp = pn_string(None)
+    err = pn_inspect(self._msg, tmp)
+    result = pn_string_get(tmp)
+    pn_free(tmp)
+    self._check(err)
+    return result
+
+class Subscription(object):
+
+  def __init__(self, impl):
+    self._impl = impl
+
+  @property
+  def address(self):
+    return pn_subscription_address(self._impl)
+
+class Selectable(object):
+
+  def __init__(self, messenger, impl):
+    self.messenger = messenger
+    self._impl = impl
+
+  def fileno(self):
+    if not self._impl: raise ValueError("selectable freed")
+    return pn_selectable_fd(self._impl)
+
+  @property
+  def capacity(self):
+    if not self._impl: raise ValueError("selectable freed")
+    return pn_selectable_capacity(self._impl)
+
+  @property
+  def pending(self):
+    if not self._impl: raise ValueError("selectable freed")
+    return pn_selectable_pending(self._impl)
+
+  @property
+  def deadline(self):
+    if not self._impl: raise ValueError("selectable freed")
+    tstamp = pn_selectable_deadline(self._impl)
+    if tstamp:
+      return millis2secs(tstamp)
+    else:
+      return None
+
+  def readable(self):
+    if not self._impl: raise ValueError("selectable freed")
+    pn_selectable_readable(self._impl)
+
+  def writable(self):
+    if not self._impl: raise ValueError("selectable freed")
+    pn_selectable_writable(self._impl)
+
+  def expired(self):
+    if not self._impl: raise ValueError("selectable freed")
+    pn_selectable_expired(self._impl)
+
+  def _is_registered(self):
+    if not self._impl: raise ValueError("selectable freed")
+    return pn_selectable_is_registered(self._impl)
+
+  def _set_registered(self, registered):
+    if not self._impl: raise ValueError("selectable freed")
+    pn_selectable_set_registered(self._impl, registered)
+
+  registered = property(_is_registered, _set_registered,
+                    doc="""
+The registered property may be get/set by an I/O polling system to
+indicate whether the fd has been registered or not.
+""")
+
+  @property
+  def is_terminal(self):
+    if not self._impl: return True
+    return pn_selectable_is_terminal(self._impl)
+
+  def free(self):
+    if self._impl:
+      del self.messenger._selectables[self.fileno()]
+      pn_selectable_free(self._impl)
+      self._impl = None
+
+  def __del__(self):
+    self.free()
+
+class DataException(ProtonException):
+  """
+  The DataException class is the root of the Data exception hierarchy.
+  All exceptions raised by the Data class extend this exception.
+  """
+  pass
+
+class UnmappedType:
+
+  def __init__(self, msg):
+    self.msg = msg
+
+  def __repr__(self):
+    return "UnmappedType(%s)" % self.msg
+
+class ulong(long):
+
+  def __repr__(self):
+    return "ulong(%s)" % long.__repr__(self)
+
+class timestamp(long):
+
+  def __repr__(self):
+    return "timestamp(%s)" % long.__repr__(self)
+
+class symbol(unicode):
+
+  def __repr__(self):
+    return "symbol(%s)" % unicode.__repr__(self)
+
+class char(unicode):
+
+  def __repr__(self):
+    return "char(%s)" % unicode.__repr__(self)
+
+class Described(object):
+
+  def __init__(self, descriptor, value):
+    self.descriptor = descriptor
+    self.value = value
+
+  def __repr__(self):
+    return "Described(%r, %r)" % (self.descriptor, self.value)
+
+  def __eq__(self, o):
+    if isinstance(o, Described):
+      return self.descriptor == o.descriptor and self.value == o.value
+    else:
+      return False
+
+UNDESCRIBED = Constant("UNDESCRIBED")
+
+class Array(object):
+
+  def __init__(self, descriptor, type, *elements):
+    self.descriptor = descriptor
+    self.type = type
+    self.elements = elements
+
+  def __repr__(self):
+    if self.elements:
+      els = ", %s"  % (", ".join(map(repr, self.elements)))
+    else:
+      els = ""
+    return "Array(%r, %r%s)" % (self.descriptor, self.type, els)
+
+  def __eq__(self, o):
+    if isinstance(o, Array):
+      return self.descriptor == o.descriptor and \
+          self.type == o.type and self.elements == o.elements
+    else:
+      return False
+
+class Data:
+  """
+  The L{Data} class provides an interface for decoding, extracting,
+  creating, and encoding arbitrary AMQP data. A L{Data} object
+  contains a tree of AMQP values. Leaf nodes in this tree correspond
+  to scalars in the AMQP type system such as L{ints<INT>} or
+  L{strings<STRING>}. Non-leaf nodes in this tree correspond to
+  compound values in the AMQP type system such as L{lists<LIST>},
+  L{maps<MAP>}, L{arrays<ARRAY>}, or L{described values<DESCRIBED>}.
+  The root node of the tree is the L{Data} object itself and can have
+  an arbitrary number of children.
+
+  A L{Data} object maintains the notion of the current sibling node
+  and a current parent node. Siblings are ordered within their parent.
+  Values are accessed and/or added by using the L{next}, L{prev},
+  L{enter}, and L{exit} methods to navigate to the desired location in
+  the tree and using the supplied variety of put_*/get_* methods to
+  access or add a value of the desired type.
+
+  The put_* methods will always add a value I{after} the current node
+  in the tree. If the current node has a next sibling the put_* method
+  will overwrite the value on this node. If there is no current node
+  or the current node has no next sibling then one will be added. The
+  put_* methods always set the added/modified node to the current
+  node. The get_* methods read the value of the current node and do
+  not change which node is current.
+
+  The following types of scalar values are supported:
+
+   - L{NULL}
+   - L{BOOL}
+   - L{UBYTE}
+   - L{USHORT}
+   - L{SHORT}
+   - L{UINT}
+   - L{INT}
+   - L{ULONG}
+   - L{LONG}
+   - L{FLOAT}
+   - L{DOUBLE}
+   - L{BINARY}
+   - L{STRING}
+   - L{SYMBOL}
+
+  The following types of compound values are supported:
+
+   - L{DESCRIBED}
+   - L{ARRAY}
+   - L{LIST}
+   - L{MAP}
+  """
+
+  NULL = PN_NULL; "A null value."
+  BOOL = PN_BOOL; "A boolean value."
+  UBYTE = PN_UBYTE; "An unsigned byte value."
+  BYTE = PN_BYTE; "A signed byte value."
+  USHORT = PN_USHORT; "An unsigned short value."
+  SHORT = PN_SHORT; "A short value."
+  UINT = PN_UINT; "An unsigned int value."
+  INT = PN_INT; "A signed int value."
+  CHAR = PN_CHAR; "A character value."
+  ULONG = PN_ULONG; "An unsigned long value."
+  LONG = PN_LONG; "A signed long value."
+  TIMESTAMP = PN_TIMESTAMP; "A timestamp value."
+  FLOAT = PN_FLOAT; "A float value."
+  DOUBLE = PN_DOUBLE; "A double value."
+  DECIMAL32 = PN_DECIMAL32; "A DECIMAL32 value."
+  DECIMAL64 = PN_DECIMAL64; "A DECIMAL64 value."
+  DECIMAL128 = PN_DECIMAL128; "A DECIMAL128 value."
+  UUID = PN_UUID; "A UUID value."
+  BINARY = PN_BINARY; "A binary string."
+  STRING = PN_STRING; "A unicode string."
+  SYMBOL = PN_SYMBOL; "A symbolic string."
+  DESCRIBED = PN_DESCRIBED; "A described value."
+  ARRAY = PN_ARRAY; "An array value."
+  LIST = PN_LIST; "A list value."
+  MAP = PN_MAP; "A map value."
+
+  type_names = {
+    NULL: "null",
+    BOOL: "bool",
+    BYTE: "byte",
+    UBYTE: "ubyte",
+    SHORT: "short",
+    USHORT: "ushort",
+    INT: "int",
+    UINT: "uint",
+    CHAR: "char",
+    LONG: "long",
+    ULONG: "ulong",
+    TIMESTAMP: "timestamp",
+    FLOAT: "float",
+    DOUBLE: "double",
+    DECIMAL32: "decimal32",
+    DECIMAL64: "decimal64",
+    DECIMAL128: "decimal128",
+    UUID: "uuid",
+    BINARY: "binary",
+    STRING: "string",
+    SYMBOL: "symbol",
+    DESCRIBED: "described",
+    ARRAY: "array",
+    LIST: "list",
+    MAP: "map"
+    }
+
+  @classmethod
+  def type_name(type): return Data.type_names[type]
+
+  def __init__(self, capacity=16):
+    if type(capacity) in (int, long):
+      self._data = pn_data(capacity)
+      self._free = True
+    else:
+      self._data = capacity
+      self._free = False
+
+  def __del__(self):
+    if self._free and hasattr(self, "_data"):
+      pn_data_free(self._data)
+      del self._data
+
+  def _check(self, err):
+    if err < 0:
+      exc = EXCEPTIONS.get(err, DataException)
+      raise exc("[%s]: %s" % (err, pn_error_text(pn_data_error(self._data))))
+    else:
+      return err
+
+  def clear(self):
+    """
+    Clears the data object.
+    """
+    pn_data_clear(self._data)
+
+  def rewind(self):
+    """
+    Clears current node and sets the parent to the root node.  Clearing the
+    current node sets it _before_ the first node, calling next() will advance to
+    the first node.
+    """
+    assert self._data is not None
+    pn_data_rewind(self._data)
+
+  def next(self):
+    """
+    Advances the current node to its next sibling and returns its
+    type. If there is no next sibling the current node remains
+    unchanged and None is returned.
+    """
+    found = pn_data_next(self._data)
+    if found:
+      return self.type()
+    else:
+      return None
+
+  def prev(self):
+    """
+    Advances the current node to its previous sibling and returns its
+    type. If there is no previous sibling the current node remains
+    unchanged and None is returned.
+    """
+    found = pn_data_prev(self._data)
+    if found:
+      return self.type()
+    else:
+      return None
+
+  def enter(self):
+    """
+    Sets the parent node to the current node and clears the current node.
+    Clearing the current node sets it _before_ the first child,
+    call next() advances to the first child.
+    """
+    return pn_data_enter(self._data)
+
+  def exit(self):
+    """
+    Sets the current node to the parent node and the parent node to
+    its own parent.
+    """
+    return pn_data_exit(self._data)
+
+  def lookup(self, name):
+    return pn_data_lookup(self._data, name)
+
+  def narrow(self):
+    pn_data_narrow(self._data)
+
+  def widen(self):
+    pn_data_widen(self._data)
+
+  def type(self):
+    """
+    Returns the type of the current node.
+    """
+    dtype = pn_data_type(self._data)
+    if dtype == -1:
+      return None
+    else:
+      return dtype
+
+  def encode(self):
+    """
+    Returns a representation of the data encoded in AMQP format.
+    """
+    size = 1024
+    while True:
+      cd, enc = pn_data_encode(self._data, size)
+      if cd == PN_OVERFLOW:
+        size *= 2
+      elif cd >= 0:
+        return enc
+      else:
+        self._check(cd)
+
+  def decode(self, encoded):
+    """
+    Decodes the first value from supplied AMQP data and returns the
+    number of bytes consumed.
+
+    @type encoded: binary
+    @param encoded: AMQP encoded binary data
+    """
+    return self._check(pn_data_decode(self._data, encoded))
+
+  def put_list(self):
+    """
+    Puts a list value. Elements may be filled by entering the list
+    node and putting element values.
+
+      >>> data = Data()
+      >>> data.put_list()
+      >>> data.enter()
+      >>> data.put_int(1)
+      >>> data.put_int(2)
+      >>> data.put_int(3)
+      >>> data.exit()
+    """
+    self._check(pn_data_put_list(self._data))
+
+  def put_map(self):
+    """
+    Puts a map value. Elements may be filled by entering the map node
+    and putting alternating key value pairs.
+
+      >>> data = Data()
+      >>> data.put_map()
+      >>> data.enter()
+      >>> data.put_string("key")
+      >>> data.put_string("value")
+      >>> data.exit()
+    """
+    self._check(pn_data_put_map(self._data))
+
+  def put_array(self, described, element_type):
+    """
+    Puts an array value. Elements may be filled by entering the array
+    node and putting the element values. The values must all be of the
+    specified array element type. If an array is described then the
+    first child value of the array is the descriptor and may be of any
+    type.
+
+      >>> data = Data()
+      >>>
+      >>> data.put_array(False, Data.INT)
+      >>> data.enter()
+      >>> data.put_int(1)
+      >>> data.put_int(2)
+      >>> data.put_int(3)
+      >>> data.exit()
+      >>>
+      >>> data.put_array(True, Data.DOUBLE)
+      >>> data.enter()
+      >>> data.put_symbol("array-descriptor")
+      >>> data.put_double(1.1)
+      >>> data.put_double(1.2)
+      >>> data.put_double(1.3)
+      >>> data.exit()
+
+    @type described: bool
+    @param described: specifies whether the array is described
+    @type element_type: int
+    @param element_type: the type of the array elements
+    """
+    self._check(pn_data_put_array(self._data, described, element_type))
+
+  def put_described(self):
+    """
+    Puts a described value. A described node has two children, the
+    descriptor and the value. These are specified by entering the node
+    and putting the desired values.
+
+      >>> data = Data()
+      >>> data.put_described()
+      >>> data.enter()
+      >>> data.put_symbol("value-descriptor")
+      >>> data.put_string("the value")
+      >>> data.exit()
+    """
+    self._check(pn_data_put_described(self._data))
+
+  def put_null(self):
+    """
+    Puts a null value.
+    """
+    self._check(pn_data_put_null(self._data))
+
+  def put_bool(self, b):
+    """
+    Puts a boolean value.
+
+    @param b: a boolean value
+    """
+    self._check(pn_data_put_bool(self._data, b))
+
+  def put_ubyte(self, ub):
+    """
+    Puts an unsigned byte value.
+
+    @param ub: an integral value
+    """
+    self._check(pn_data_put_ubyte(self._data, ub))
+
+  def put_byte(self, b):
+    """
+    Puts a signed byte value.
+
+    @param b: an integral value
+    """
+    self._check(pn_data_put_byte(self._data, b))
+
+  def put_ushort(self, us):
+    """
+    Puts an unsigned short value.
+
+    @param us: an integral value.
+    """
+    self._check(pn_data_put_ushort(self._data, us))
+
+  def put_short(self, s):
+    """
+    Puts a signed short value.
+
+    @param s: an integral value
+    """
+    self._check(pn_data_put_short(self._data, s))
+
+  def put_uint(self, ui):
+    """
+    Puts an unsigned int value.
+
+    @param ui: an integral value
+    """
+    self._check(pn_data_put_uint(self._data, ui))
+
+  def put_int(self, i):
+    """
+    Puts a signed int value.
+
+    @param i: an integral value
+    """
+    self._check(pn_data_put_int(self._data, i))
+
+  def put_char(self, c):
+    """
+    Puts a char value.
+
+    @param c: a single character
+    """
+    self._check(pn_data_put_char(self._data, ord(c)))
+
+  def put_ulong(self, ul):
+    """
+    Puts an unsigned long value.
+
+    @param ul: an integral value
+    """
+    self._check(pn_data_put_ulong(self._data, ul))
+
+  def put_long(self, l):
+    """
+    Puts a signed long value.
+
+    @param l: an integral value
+    """
+    self._check(pn_data_put_long(self._data, l))
+
+  def put_timestamp(self, t):
+    """
+    Puts a timestamp value.
+
+    @param t: an integral value
+    """
+    self._check(pn_data_put_timestamp(self._data, t))
+
+  def put_float(self, f):
+    """
+    Puts a float value.
+
+    @param f: a floating point value
+    """
+    self._check(pn_data_put_float(self._data, f))
+
+  def put_double(self, d):
+    """
+    Puts a double value.
+
+    @param d: a floating point value.
+    """
+    self._check(pn_data_put_double(self._data, d))
+
+  def put_decimal32(self, d):
+    """
+    Puts a decimal32 value.
+
+    @param d: a decimal32 value
+    """
+    self._check(pn_data_put_decimal32(self._data, d))
+
+  def put_decimal64(self, d):
+    """
+    Puts a decimal64 value.
+
+    @param d: a decimal64 value
+    """
+    self._check(pn_data_put_decimal64(self._data, d))
+
+  def put_decimal128(self, d):
+    """
+    Puts a decimal128 value.
+
+    @param d: a decimal128 value
+    """
+    self._check(pn_data_put_decimal128(self._data, d))
+
+  def put_uuid(self, u):
+    """
+    Puts a UUID value.
+
+    @param u: a uuid value
+    """
+    self._check(pn_data_put_uuid(self._data, u.bytes))
+
+  def put_binary(self, b):
+    """
+    Puts a binary value.
+
+    @type b: binary
+    @param b: a binary value
+    """
+    self._check(pn_data_put_binary(self._data, b))
+
+  def put_string(self, s):
+    """
+    Puts a unicode value.
+
+    @type s: unicode
+    @param s: a unicode value
+    """
+    self._check(pn_data_put_string(self._data, s.encode("utf8")))
+
+  def put_symbol(self, s):
+    """
+    Puts a symbolic value.
+
+    @type s: string
+    @param s: the symbol name
+    """
+    self._check(pn_data_put_symbol(self._data, s))
+
+  def get_list(self):
+    """
+    If the current node is a list, return the number of elements,
+    otherwise return zero. List elements can be accessed by entering
+    the list.
+
+      >>> count = data.get_list()
+      >>> data.enter()
+      >>> for i in range(count):
+      ...   type = data.next()
+      ...   if type == Data.STRING:
+      ...     print data.get_string()
+      ...   elif type == ...:
+      ...     ...
+      >>> data.exit()
+    """
+    return pn_data_get_list(self._data)
+
+  def get_map(self):
+    """
+    If the current node is a map, return the number of child elements,
+    otherwise return zero. Key value pairs can be accessed by entering
+    the map.
+
+      >>> count = data.get_map()
+      >>> data.enter()
+      >>> for i in range(count/2):
+      ...   type = data.next()
+      ...   if type == Data.STRING:
+      ...     print data.get_string()
+      ...   elif type == ...:
+      ...     ...
+      >>> data.exit()
+    """
+    return pn_data_get_map(self._data)
+
+  def get_array(self):
+    """
+    If the current node is an array, return a tuple of the element
+    count, a boolean indicating whether the array is described, and
+    the type of each element, otherwise return (0, False, None). Array
+    data can be accessed by entering the array.
+
+      >>> # read an array of strings with a symbolic descriptor
+      >>> count, described, type = data.get_array()
+      >>> data.enter()
+      >>> data.next()
+      >>> print "Descriptor:", data.get_symbol()
+      >>> for i in range(count):
+      ...    data.next()
+      ...    print "Element:", data.get_string()
+      >>> data.exit()
+    """
+    count = pn_data_get_array(self._data)
+    described = pn_data_is_array_described(self._data)
+    type = pn_data_get_array_type(self._data)
+    if type == -1:
+      type = None
+    return count, described, type
+
+  def is_described(self):
+    """
+    Checks if the current node is a described value. The descriptor
+    and value may be accessed by entering the described value.
+
+      >>> # read a symbolically described string
+      >>> assert data.is_described() # will error if the current node is not described
+      >>> data.enter()
+      >>> print data.get_symbol()
+      >>> print data.get_string()
+      >>> data.exit()
+    """
+    return pn_data_is_described(self._data)
+
+  def is_null(self):
+    """
+    Checks if the current node is a null.
+    """
+    return pn_data_is_null(self._data)
+
+  def get_bool(self):
+    """
+    If the current node is a boolean, returns its value, returns False
+    otherwise.
+    """
+    return pn_data_get_bool(self._data)
+
+  def get_ubyte(self):
+    """
+    If the current node is an unsigned byte, returns its value,
+    returns 0 otherwise.
+    """
+    return pn_data_get_ubyte(self._data)
+
+  def get_byte(self):
+    """
+    If the current node is a signed byte, returns its value, returns 0
+    otherwise.
+    """
+    return pn_data_get_byte(self._data)
+
+  def get_ushort(self):
+    """
+    If the current node is an unsigned short, returns its value,
+    returns 0 otherwise.
+    """
+    return pn_data_get_ushort(self._data)
+
+  def get_short(self):
+    """
+    If the current node is a signed short, returns its value, returns
+    0 otherwise.
+    """
+    return pn_data_get_short(self._data)
+
+  def get_uint(self):
+    """
+    If the current node is an unsigned int, returns its value, returns
+    0 otherwise.
+    """
+    return pn_data_get_uint(self._data)
+
+  def get_int(self):
+    """
+    If the current node is a signed int, returns its value, returns 0
+    otherwise.
+    """
+    return pn_data_get_int(self._data)
+
+  def get_char(self):
+    """
+    If the current node is a char, returns its value, returns 0
+    otherwise.
+    """
+    return char(unichr(pn_data_get_char(self._data)))
+
+  def get_ulong(self):
+    """
+    If the current node is an unsigned long, returns its value,
+    returns 0 otherwise.
+    """
+    return ulong(pn_data_get_ulong(self._data))
+
+  def get_long(self):
+    """
+    If the current node is an signed long, returns its value, returns
+    0 otherwise.
+    """
+    return pn_data_get_long(self._data)
+
+  def get_timestamp(self):
+    """
+    If the current node is a timestamp, returns its value, returns 0
+    otherwise.
+    """
+    return timestamp(pn_data_get_timestamp(self._data))
+
+  def get_float(self):
+    """
+    If the current node is a float, returns its value, raises 0
+    otherwise.
+    """
+    return pn_data_get_float(self._data)
+
+  def get_double(self):
+    """
+    If the current node is a double, returns its value, returns 0
+    otherwise.
+    """
+    return pn_data_get_double(self._data)
+
+  # XXX: need to convert
+  def get_decimal32(self):
+    """
+    If the current node is a decimal32, returns its value, returns 0
+    otherwise.
+    """
+    return pn_data_get_decimal32(self._data)
+
+  # XXX: need to convert
+  def get_decimal64(self):
+    """
+    If the current node is a decimal64, returns its value, returns 0
+    otherwise.
+    """
+    return pn_data_get_decimal64(self._data)
+
+  # XXX: need to convert
+  def get_decimal128(self):
+    """
+    If the current node is a decimal128, returns its value, returns 0
+    otherwise.
+    """
+    return pn_data_get_decimal128(self._data)
+
+  def get_uuid(self):
+    """
+    If the current node is a UUID, returns its value, returns None
+    otherwise.
+    """
+    if pn_data_type(self._data) == Data.UUID:
+      return uuid.UUID(bytes=pn_data_get_uuid(self._data))
+    else:
+      return None
+
+  def get_binary(self):
+    """
+    If the current node is binary, returns its value, returns ""
+    otherwise.
+    """
+    return pn_data_get_binary(self._data)
+
+  def get_string(self):
+    """
+    If the current node is a string, returns its value, returns ""
+    otherwise.
+    """
+    return pn_data_get_string(self._data).decode("utf8")
+
+  def get_symbol(self):
+    """
+    If the current node is a symbol, returns its value, returns ""
+    otherwise.
+    """
+    return symbol(pn_data_get_symbol(self._data))
+
+  def copy(self, src):
+    self._check(pn_data_copy(self._data, src._data))
+
+  def format(self):
+    sz = 16
+    while True:
+      err, result = pn_data_format(self._data, sz)
+      if err == PN_OVERFLOW:
+        sz *= 2
+        continue
+      else:
+        self._check(err)
+        return result
+
+  def dump(self):
+    pn_data_dump(self._data)
+
+  def put_dict(self, d):
+    self.put_map()
+    self.enter()
+    try:
+      for k, v in d.items():
+        self.put_object(k)
+        self.put_object(v)
+    finally:
+      self.exit()
+
+  def get_dict(self):
+    if self.enter():
+      try:
+        result = {}
+        while self.next():
+          k = self.get_object()
+          if self.next():
+            v = self.get_object()
+          else:
+            v = None
+          result[k] = v
+      finally:
+        self.exit()
+      return result
+
+  def put_sequence(self, s):
+    self.put_list()
+    self.enter()
+    try:
+      for o in s:
+        self.put_object(o)
+    finally:
+      self.exit()
+
+  def get_sequence(self):
+    if self.enter():
+      try:
+        result = []
+        while self.next():
+          result.append(self.get_object())
+      finally:
+        self.exit()
+      return result
+
+  def get_py_described(self):
+    if self.enter():
+      try:
+        self.next()
+        descriptor = self.get_object()
+        self.next()
+        value = self.get_object()
+      finally:
+        self.exit()
+      return Described(descriptor, value)
+
+  def put_py_described(self, d):
+    self.put_described()
+    self.enter()
+    try:
+      self.put_object(d.descriptor)
+      self.put_object(d.value)
+    finally:
+      self.exit()
+
+  def get_py_array(self):
+    """
+    If the current node is an array, return an Array object
+    representing the array and its contents. Otherwise return None.
+    This is a convenience wrapper around get_array, enter, etc.
+    """
+
+    count, described, type = self.get_array()
+    if type is None: return None
+    if self.enter():
+      try:
+        if described:
+          self.next()
+          descriptor = self.get_object()
+        else:
+          descriptor = UNDESCRIBED
+        elements = []
+        while self.next():
+          elements.append(self.get_object())
+      finally:
+        self.exit()
+      return Array(descriptor, type, *elements)
+
+  def put_py_array(self, a):
+    described = a.descriptor != UNDESCRIBED
+    self.put_array(described, a.type)
+    self.enter()
+    try:
+      if described:
+        self.put_object(a.descriptor)
+      for e in a.elements:
+        self.put_object(e)
+    finally:
+      self.exit()
+
+  put_mappings = {
+    None.__class__: lambda s, _: s.put_null(),
+    bool: put_bool,
+    dict: put_dict,
+    list: put_sequence,
+    tuple: put_sequence,
+    unicode: put_string,
+    bytes: put_binary,
+    symbol: put_symbol,
+    int: put_long,
+    char: put_char,
+    long: put_long,
+    ulong: put_ulong,
+    timestamp: put_timestamp,
+    float: put_double,
+    uuid.UUID: put_uuid,
+    Described: put_py_described,
+    Array: put_py_array
+    }
+  get_mappings = {
+    NULL: lambda s: None,
+    BOOL: get_bool,
+    BYTE: get_byte,
+    UBYTE: get_ubyte,
+    SHORT: get_short,
+    USHORT: get_ushort,
+    INT: get_int,
+    UINT: get_uint,
+    CHAR: get_char,
+    LONG: get_long,
+    ULONG: get_ulong,
+    TIMESTAMP: get_timestamp,
+    FLOAT: get_float,
+    DOUBLE: get_double,
+    DECIMAL32: get_decimal32,
+    DECIMAL64: get_decimal64,
+    DECIMAL128: get_decimal128,
+    UUID: get_uuid,
+    BINARY: get_binary,
+    STRING: get_string,
+    SYMBOL: get_symbol,
+    DESCRIBED: get_py_described,
+    ARRAY: get_py_array,
+    LIST: get_sequence,
+    MAP: get_dict
+    }
+
+
+  def put_object(self, obj):
+    putter = self.put_mappings[obj.__class__]
+    putter(self, obj)
+
+  def get_object(self):
+    type = self.type()
+    if type is None: return None
+    getter = self.get_mappings.get(type)
+    if getter:
+      return getter(self)
+    else:
+      return UnmappedType(str(type))
+
+class ConnectionException(ProtonException):
+  pass
+
+class Endpoint(object):
+
+  LOCAL_UNINIT = PN_LOCAL_UNINIT
+  REMOTE_UNINIT = PN_REMOTE_UNINIT
+  LOCAL_ACTIVE = PN_LOCAL_ACTIVE
+  REMOTE_ACTIVE = PN_REMOTE_ACTIVE
+  LOCAL_CLOSED = PN_LOCAL_CLOSED
+  REMOTE_CLOSED  = PN_REMOTE_CLOSED
+
+  def __init__(self):
+    self.condition = None
+    self._release_invoked = False
+
+  def _release(self):
+    """Release the underlying C Engine resource."""
+    if not self._release_invoked:
+      for c in self._children:
+        c._release()
+      self._free_resource()
+      self.connection._releasing(self)
+      self._release_invoked = True
+
+  def _update_cond(self):
+    obj2cond(self.condition, self._get_cond_impl())
+
+  @property
+  def remote_condition(self):
+    return cond2obj(self._get_remote_cond_impl())
+
+  # the following must be provided by subclasses
+  def _get_cond_impl(self):
+      assert False, "Subclass must override this!"
+
+  def _get_remote_cond_impl(self):
+      assert False, "Subclass must override this!"
+
+class Condition:
+
+  def __init__(self, name, description=None, info=None):
+    self.name = name
+    self.description = description
+    self.info = info
+
+  def __repr__(self):
+    return "Condition(%s)" % ", ".join([repr(x) for x in
+                                        (self.name, self.description, self.info)
+                                        if x])
+
+  def __eq__(self, o):
+    if not isinstance(o, Condition): return False
+    return self.name == o.name and \
+        self.description == o.description and \
+        self.info == o.info
+
+def obj2cond(obj, cond):
+  pn_condition_clear(cond)
+  if obj:
+    pn_condition_set_name(cond, str(obj.name))
+    pn_condition_set_description(cond, obj.description)
+    info = Data(pn_condition_info(cond))
+    if obj.info:
+      info.put_object(obj.info)
+
+def cond2obj(cond):
+  if pn_condition_is_set(cond):
+    return Condition(pn_condition_get_name(cond),
+                     pn_condition_get_description(cond),
+                     dat2obj(pn_condition_info(cond)))
+  else:
+    return None
+
+def dat2obj(dimpl):
+  if dimpl:
+    d = Data(dimpl)
+    d.rewind()
+    d.next()
+    obj = d.get_object()
+    d.rewind()
+    return obj
+
+def obj2dat(obj, dimpl):
+  if obj is not None:
+    d = Data(dimpl)
+    d.put_object(obj)
+
+def secs2millis(secs):
+  return long(secs*1000)
+
+def millis2secs(millis):
+  return float(millis)/1000.0
+
+class Connection(Endpoint):
+
+  @staticmethod
+  def _wrap_connection(c_conn):
+    """Maintain only a single instance of this class for each Connection
+    object that exists in the the C Engine.  This is done by storing a (weak)
+    reference to the python instance in the context field of the C object.
+    """
+    if not c_conn: return None
+    py_conn = pn_void2py(pn_connection_get_context(c_conn))
+    if py_conn: return py_conn
+    wrapper = Connection(_conn=c_conn)
+    return wrapper
+
+  def __init__(self, _conn=None):
+    Endpoint.__init__(self)
+    if _conn:
+      self._conn = _conn
+    else:
+      self._conn = pn_connection()
+    pn_connection_set_context(self._conn, pn_py2void(self))
+    self.offered_capabilities = None
+    self.desired_capabilities = None
+    self.properties = None
+    self._sessions = set()
+
+  def __del__(self):
+    if hasattr(self, "_conn") and self._conn:
+      self._release()
+
+  def free(self):
+    self._release()
+
+  @property
+  def _children(self):
+    return self._sessions
+
+  @property
+  def connection(self):
+    return self
+
+  def _free_resource(self):
+    pn_connection_free(self._conn)
+
+  def _released(self):
+    self._conn = None
+
+  def _releasing(self, child):
+    coll = getattr(self, "_collector", None)
+    if coll: coll = coll()
+    if coll:
+      coll._contexts.add(child)
+    else:
+      child._released()
+
+  def _check(self, err):
+    if err < 0:
+      exc = EXCEPTIONS.get(err, ConnectionException)
+      raise exc("[%s]: %s" % (err, pn_connection_error(self._conn)))
+    else:
+      return err
+
+  def _get_cond_impl(self):
+    return pn_connection_condition(self._conn)
+
+  def _get_remote_cond_impl(self):
+    return pn_connection_remote_condition(self._conn)
+
+  def collect(self, collector):
+    if collector is None:
+      pn_connection_collect(self._conn, None)
+    else:
+      pn_connection_collect(self._conn, collector._impl)
+    self._collector = weakref.ref(collector)
+
+  def _get_container(self):
+    return pn_connection_get_container(self._conn)
+  def _set_container(self, name):
+    return pn_connection_set_container(self._conn, name)
+
+  container = property(_get_container, _set_container)
+
+  def _get_hostname(self):
+    return pn_connection_get_hostname(self._conn)
+  def _set_hostname(self, name):
+    return pn_connection_set_hostname(self._conn, name)
+
+  hostname = property(_get_hostname, _set_hostname)
+
+  @property
+  def remote_container(self):
+    return pn_connection_remote_container(self._conn)
+
+  @property
+  def remote_hostname(self):
+    return pn_connection_remote_hostname(self._conn)
+
+  @property
+  def remote_offered_capabilities(self):
+    return dat2obj(pn_connection_remote_offered_capabilities(self._conn))
+
+  @property
+  def remote_desired_capabilities(self):
+    return dat2obj(pn_connection_remote_desired_capabilities(self._conn))
+
+  @property
+  def remote_properties(self):
+    return dat2obj(pn_connection_remote_properties(self._conn))
+
+  def open(self):
+    obj2dat(self.offered_capabilities,
+            pn_connection_offered_capabilities(self._conn))
+    obj2dat(self.desired_capabilities,
+            pn_connection_desired_capabilities(self._conn))
+    obj2dat(self.properties, pn_connection_properties(self._conn))
+    pn_connection_open(self._conn)
+
+  def close(self):
+    self._update_cond()
+    pn_connection_close(self._conn)
+
+  @property
+  def state(self):
+    return pn_connection_state(self._conn)
+
+  def session(self):
+    return Session._wrap_session(pn_session(self._conn))
+
+  def session_head(self, mask):
+    return Session._wrap_session(pn_session_head(self._conn, mask))
+
+  def link_head(self, mask):
+    return Link._wrap_link(pn_link_head(self._conn, mask))
+
+  @property
+  def work_head(self):
+    return Delivery._wrap_delivery(pn_work_head(self._conn))
+
+  @property
+  def error(self):
+    return pn_error_code(pn_connection_error(self._conn))
+
+class SessionException(ProtonException):
+  pass
+
+class Session(Endpoint):
+
+  @staticmethod
+  def _wrap_session(c_ssn):
+    """Maintain only a single instance of this class for each Session object that
+    exists in the C Engine.
+    """
+    if c_ssn is None: return None
+    py_ssn = pn_void2py(pn_session_get_context(c_ssn))
+    if py_ssn: return py_ssn
+    wrapper = Session(c_ssn)
+    return wrapper
+
+  def __init__(self, ssn):
+    Endpoint.__init__(self)
+    self._ssn = ssn
+    pn_session_set_context(self._ssn, pn_py2void(self))
+    self._links = set()
+    self.connection._sessions.add(self)
+
+  @property
+  def _children(self):
+    return self._links
+
+  def _free_resource(self):
+    pn_session_free(self._ssn)
+
+  def _released(self):
+    self._ssn = None
+
+  def free(self):
+    """Release the Session, freeing its resources.
+
+    Call this when you no longer need the session.  This will allow the
+    session's resources to be reclaimed.  Once called, you should no longer
+    reference the session.
+
+    """
+    self.connection._sessions.remove(self)
+    self._release()
+
+  def _get_cond_impl(self):
+    return pn_session_condition(self._ssn)
+
+  def _get_remote_cond_impl(self):
+    return pn_session_remote_condition(self._ssn)
+
+  def _get_incoming_capacity(self):
+    return pn_session_get_incoming_capacity(self._ssn)
+
+  def _set_incoming_capacity(self, capacity):
+    pn_session_set_incoming_capacity(self._ssn, capacity)
+
+  incoming_capacity = property(_get_incoming_capacity, _set_incoming_capacity)
+
+  @property
+  def outgoing_bytes(self):
+    return pn_session_outgoing_bytes(self._ssn)
+
+  @property
+  def incoming_bytes(self):
+    return pn_session_incoming_bytes(self._ssn)
+
+  def open(self):
+    pn_session_open(self._ssn)
+
+  def close(self):
+    self._update_cond()
+    pn_session_close(self._ssn)
+
+  def next(self, mask):
+    return Session._wrap_session(pn_session_next(self._ssn, mask))
+
+  @property
+  def state(self):
+    return pn_session_state(self._ssn)
+
+  @property
+  def connection(self):
+    return Connection._wrap_connection(pn_session_connection(self._ssn))
+
+  def sender(self, name):
+    return Link._wrap_link(pn_sender(self._ssn, name))
+
+  def receiver(self, name):
+    return Link._wrap_link(pn_receiver(self._ssn, name))
+
+class LinkException(ProtonException):
+  pass
+
+class Link(Endpoint):
+
+  SND_UNSETTLED = PN_SND_UNSETTLED
+  SND_SETTLED = PN_SND_SETTLED
+  SND_MIXED = PN_SND_MIXED
+
+  RCV_FIRST = PN_RCV_FIRST
+  RCV_SECOND = PN_RCV_SECOND
+
+  @staticmethod
+  def _wrap_link(c_link):
+    """Maintain only a single instance of this class for each Session object that
+    exists in the C Engine.
+    """
+    if c_link is None: return None
+    py_link = pn_void2py(pn_link_get_context(c_link))
+    if py_link: return py_link
+    if pn_link_is_sender(c_link):
+      wrapper = Sender(c_link)
+    else:
+      wrapper = Receiver(c_link)
+    return wrapper
+
+  def __init__(self, c_link):
+    Endpoint.__init__(self)
+    self._link = c_link
+    pn_link_set_context(self._link, pn_py2void(self))
+    self._deliveries = set()
+    self.session._links.add(self)
+
+  @property
+  def _children(self):
+    return self._deliveries
+
+  def _free_resource(self):
+    pn_link_free(self._link)
+
+  def _released(self):
+    self._link = None
+
+  def free(self):
+    """Release the Link, freeing its resources"""
+    self.session._links.remove(self)
+    self._release()
+
+  def _check(self, err):
+    if err < 0:
+      exc = EXCEPTIONS.get(err, LinkException)
+      raise exc("[%s]: %s" % (err, pn_link_error(self._link)))
+    else:
+      return err
+
+  def _get_cond_impl(self):
+    return pn_link_condition(self._link)
+
+  def _get_remote_cond_impl(self):
+    return pn_link_remote_condition(self._link)
+
+  def open(self):
+    pn_link_open(self._link)
+
+  def close(self):
+    self._update_cond()
+    pn_link_close(self._link)
+
+  @property
+  def state(self):
+    return pn_link_state(self._link)
+
+  @property
+  def source(self):
+    return Terminus(pn_link_source(self._link))
+
+  @property
+  def target(self):
+    return Terminus(pn_link_target(self._link))
+
+  @property
+  def remote_source(self):
+    return Terminus(pn_link_remote_source(self._link))
+  @property
+  def remote_target(self):
+    return Terminus(pn_link_remote_target(self._link))
+
+  @property
+  def session(self):
+    return Session._wrap_session(pn_link_session(self._link))
+
+  @property
+  def connection(self):
+    return self.session.connection
+
+  def delivery(self, tag):
+    return Delivery._wrap_delivery(pn_delivery(self._link, tag))
+
+  @property
+  def current(self):
+    return Delivery._wrap_delivery(pn_link_current(self._link))
+
+  def advance(self):
+    return pn_link_advance(self._link)
+
+  @property
+  def unsettled(self):
+    return pn_link_unsettled(self._link)
+
+  @property
+  def credit(self):
+    return pn_link_credit(self._link)
+
+  @property
+  def available(self):
+    return pn_link_available(self._link)
+
+  @property
+  def queued(self):
+    return pn_link_queued(self._link)
+
+  def next(self, mask):
+    return Link._wrap_link(pn_link_next(self._link, mask))
+
+  @property
+  def name(self):
+      return pn_link_name(self._link)
+
+  @property
+  def is_sender(self):
+    return pn_link_is_sender(self._link)
+
+  @property
+  def is_receiver(self):
+    return pn_link_is_receiver(self._link)
+
+  @property
+  def remote_snd_settle_mode(self):
+    return pn_link_remote_snd_settle_mode(self._link)
+
+  @property
+  def remote_rcv_settle_mode(self):
+    return pn_link_remote_rcv_settle_mode(self._link)
+
+  def _get_snd_settle_mode(self):
+    return pn_link_snd_settle_mode(self._link)
+  def _set_snd_settle_mode(self, mode):
+    pn_link_set_snd_settle_mode(self._link, mode)
+  snd_settle_mode = property(_get_snd_settle_mode, _set_snd_settle_mode)
+
+  def _get_rcv_settle_mode(self):
+    return pn_link_rcv_settle_mode(self._link)
+  def _set_rcv_settle_mode(self, mode):
+    pn_link_set_rcv_settle_mode(self._link, mode)
+  rcv_settle_mode = property(_get_rcv_settle_mode, _set_rcv_settle_mode)
+
+  def drained(self):
+    return pn_link_drained(self._link)
+
+  def detach(self):
+    return pn_link_detach(self._link)
+
+class Terminus(object):
+
+  UNSPECIFIED = PN_UNSPECIFIED
+  SOURCE = PN_SOURCE
+  TARGET = PN_TARGET
+  COORDINATOR = PN_COORDINATOR
+
+  NONDURABLE = PN_NONDURABLE
+  CONFIGURATION = PN_CONFIGURATION
+  DELIVERIES = PN_DELIVERIES
+
+  DIST_MODE_UNSPECIFIED = PN_DIST_MODE_UNSPECIFIED
+  DIST_MODE_COPY = PN_DIST_MODE_COPY
+  DIST_MODE_MOVE = PN_DIST_MODE_MOVE
+
+  def __init__(self, impl):
+    self._impl = impl
+
+  def _check(self, err):
+    if err < 0:
+      exc = EXCEPTIONS.get(err, LinkException)
+      raise exc("[%s]" % err)
+    else:
+      return err
+
+  def _get_type(self):
+    return pn_terminus_get_type(self._impl)
+  def _set_type(self, type):
+    self._check(pn_terminus_set_type(self._impl, type))
+  type = property(_get_type, _set_type)
+
+  def _get_address(self):
+    return pn_terminus_get_address(self._impl)
+  def _set_address(self, address):
+    self._check(pn_terminus_set_address(self._impl, address))
+  address = property(_get_address, _set_address)
+
+  def _get_durability(self):
+    return pn_terminus_get_durability(self._impl)
+  def _set_durability(self, seconds):
+    self._check(pn_terminus_set_durability(self._impl, seconds))
+  durability = property(_get_durability, _set_durability)
+
+  def _get_expiry_policy(self):
+    return pn_terminus_get_expiry_policy(self._impl)
+  def _set_expiry_policy(self, seconds):
+    self._check(pn_terminus_set_expiry_policy(self._impl, seconds))
+  expiry_policy = property(_get_expiry_policy, _set_expiry_policy)
+
+  def _get_timeout(self):
+    return pn_terminus_get_timeout(self._impl)
+  def _set_timeout(self, seconds):
+    self._check(pn_terminus_set_timeout(self._impl, seconds))
+  timeout = property(_get_timeout, _set_timeout)
+
+  def _is_dynamic(self):
+    return pn_terminus_is_dynamic(self._impl)
+  def _set_dynamic(self, dynamic):
+    self._check(pn_terminus_set_dynamic(self._impl, dynamic))
+  dynamic = property(_is_dynamic, _set_dynamic)
+
+  def _get_distribution_mode(self):
+    return pn_terminus_get_distribution_mode(self._impl)
+  def _set_distribution_mode(self, mode):
+    self._check(pn_terminus_set_distribution_mode(self._impl, mode))
+  distribution_mode = property(_get_distribution_mode, _set_distribution_mode)
+
+  @property
+  def properties(self):
+    return Data(pn_terminus_properties(self._impl))
+
+  @property
+  def capabilities(self):
+    return Data(pn_terminus_capabilities(self._impl))
+
+  @property
+  def outcomes(self):
+    return Data(pn_terminus_outcomes(self._impl))
+
+  @property
+  def filter(self):
+    return Data(pn_terminus_filter(self._impl))
+
+  def copy(self, src):
+    self._check(pn_terminus_copy(self._impl, src._impl))
+
+class Sender(Link):
+
+  def __init__(self, c_link):
+    super(Sender, self).__init__(c_link)
+
+  def offered(self, n):
+    pn_link_offered(self._link, n)
+
+  def send(self, bytes):
+    return self._check(pn_link_send(self._link, bytes))
+
+class Receiver(Link):
+
+  def __init__(self, c_link):
+    super(Receiver, self).__init__(c_link)
+
+  def flow(self, n):
+    pn_link_flow(self._link, n)
+
+  def recv(self, limit):
+    n, bytes = pn_link_recv(self._link, limit)
+    if n == PN_EOS:
+      return None
+    else:
+      self._check(n)
+      return bytes
+
+  def drain(self, n):
+    pn_link_drain(self._link, n)
+
+  def draining(self):
+    return pn_link_draining(self._link)
+
+class NamedInt(int):
+
+  values = {}
+
+  def __new__(cls, i, name):
+    ni = super(NamedInt, cls).__new__(cls, i)
+    cls.values[i] = ni
+    return ni
+
+  def __init__(self, i, name):
+    self.name = name
+
+  def __repr__(self):
+    return self.name
+
+  def __str__(self):
+    return self.name
+
+  @classmethod
+  def get(cls, i):
+    return cls.values.get(i, i)
+
+class DispositionType(NamedInt):
+  values = {}
+
+class Disposition(object):
+
+  RECEIVED = DispositionType(PN_RECEIVED, "RECEIVED")
+  ACCEPTED = DispositionType(PN_ACCEPTED, "ACCEPTED")
+  REJECTED = DispositionType(PN_REJECTED, "REJECTED")
+  RELEASED = DispositionType(PN_RELEASED, "RELEASED")
+  MODIFIED = DispositionType(PN_MODIFIED, "MODIFIED")
+
+  def __init__(self, impl, local):
+    self._impl = impl
+    self.local = local
+    self._data = None
+    self._condition = None
+    self._annotations = None
+
+  @property
+  def type(self):
+    return DispositionType.get(pn_disposition_type(self._impl))
+
+  def _get_section_number(self):
+    return pn_disposition_get_section_number(self._impl)
+  def _set_section_number(self, n):
+    pn_disposition_set_section_number(self._impl, n)
+  section_number = property(_get_section_number, _set_section_number)
+
+  def _get_section_offset(self):
+    return pn_disposition_get_section_offset(self._impl)
+  def _set_section_offset(self, n):
+    pn_disposition_set_section_offset(self._impl, n)
+  section_offset = property(_get_section_offset, _set_section_offset)
+
+  def _get_failed(self):
+    return pn_disposition_is_failed(self._impl)
+  def _set_failed(self, b):
+    pn_disposition_set_failed(self._impl, b)
+  failed = property(_get_failed, _set_failed)
+
+  def _get_undeliverable(self):
+    return pn_disposition_is_undeliverable(self._impl)
+  def _set_undeliverable(self, b):
+    pn_disposition_set_undeliverable(self._impl, b)
+  undeliverable = property(_get_undeliverable, _set_undeliverable)
+
+  def _get_data(self):
+    if self.local:
+      return self._data
+    else:
+      return dat2obj(pn_disposition_data(self._impl))
+  def _set_data(self, obj):
+    if self.local:
+      self._data = obj
+    else:
+      raise AttributeError("data attribute is read-only")
+  data = property(_get_data, _set_data)
+
+  def _get_annotations(self):
+    if self.local:
+      return self._annotations
+    else:
+      return dat2obj(pn_disposition_annotations(self._impl))
+  def _set_annotations(self, obj):
+    if self.local:
+      self._annotations = obj
+    else:
+      raise AttributeError("annotations attribute is read-only")
+  annotations = property(_get_annotations, _set_annotations)
+
+  def _get_condition(self):
+    if self.local:
+      return self._condition
+    else:
+      return cond2obj(pn_disposition_condition(self._impl))
+  def _set_condition(self, obj):
+    if self.local:
+      self._condition = obj
+    else:
+      raise AttributeError("condition attribute is read-only")
+  condition = property(_get_condition, _set_condition)
+
+class Delivery(object):
+
+  RECEIVED = Disposition.RECEIVED
+  ACCEPTED = Disposition.ACCEPTED
+  REJECTED = Disposition.REJECTED
+  RELEASED = Disposition.RELEASED
+  MODIFIED = Disposition.MODIFIED
+
+  @staticmethod
+  def _wrap_delivery(c_dlv):
+    """Maintain only a single instance of this class for each Delivery object that
+    exists in the C Engine.
+    """
+    if not c_dlv: return None
+    py_dlv = pn_void2py(pn_delivery_get_context(c_dlv))
+    if py_dlv: return py_dlv
+    wrapper = Delivery(c_dlv)
+    return wrapper
+
+  def __init__(self, dlv):
+    self._dlv = dlv
+    pn_delivery_set_context(self._dlv, pn_py2void(self))
+    self.local = Disposition(pn_delivery_local(self._dlv), True)
+    self.remote = Disposition(pn_delivery_remote(self._dlv), False)
+    self.link._deliveries.add(self)
+
+  def __del__(self):
+    self._release()
+
+  def _release(self):
+    """Release the underlying C Engine resource."""
+    if self._dlv:
+      pn_delivery_set_context(self._dlv, pn_py2void(None))
+      pn_delivery_settle(self._dlv)
+      self._dlv = None
+
+  @property
+  def released(self):
+    return self._dlv is None
+
+  @property
+  def tag(self):
+    return pn_delivery_tag(self._dlv)
+
+  @property
+  def writable(self):
+    return pn_delivery_writable(self._dlv)
+
+  @property
+  def readable(self):
+    return pn_delivery_readable(self._dlv)
+
+  @property
+  def updated(self):
+    return pn_delivery_updated(self._dlv)
+
+  def update(self, state):
+    obj2dat(self.local._data, pn_disposition_data(self.local._impl))
+    obj2dat(self.local._annotations, pn_disposition_annotations(self.local._impl))
+    obj2cond(self.local._condition, pn_disposition_condition(self.local._impl))
+    pn_delivery_update(self._dlv, state)
+
+  @property
+  def pending(self):
+    return pn_delivery_pending(self._dlv)
+
+  @property
+  def partial(self):
+    return pn_delivery_partial(self._dlv)
+
+  @property
+  def local_state(self):
+    return DispositionType.get(pn_delivery_local_state(self._dlv))
+
+  @property
+  def remote_state(self):
+    return DispositionType.get(pn_delivery_remote_state(self._dlv))
+
+  @property
+  def settled(self):
+    return pn_delivery_settled(self._dlv)
+
+  def settle(self):
+    """Release the delivery"""
+    self.link._deliveries.remove(self)
+    self._release()
+
+  @property
+  def work_next(self):
+    return Delivery._wrap_delivery(pn_work_next(self._dlv))
+
+  @property
+  def link(self):
+    return Link._wrap_link(pn_delivery_link(self._dlv))
+
+class TransportException(ProtonException):
+  pass
+
+class Transport(object):
+
+  TRACE_OFF = PN_TRACE_OFF
+  TRACE_DRV = PN_TRACE_DRV
+  TRACE_FRM = PN_TRACE_FRM
+  TRACE_RAW = PN_TRACE_RAW
+
+  CLIENT = 1
+  SERVER = 2
+
+  @staticmethod
+  def _wrap_transport(c_trans):
+    if not c_trans: return None
+    wrapper = Transport(_trans=c_trans)
+    return wrapper
+
+  def __init__(self, mode=None, _trans=None):
+    if not mode and not _trans:
+      self._trans = pn_transport()
+    elif not mode:
+      self._shared_trans = True
+      self._trans = _trans
+    elif mode==Transport.CLIENT:
+      self._trans = pn_transport()
+    elif mode==Transport.SERVER:
+      self._trans = pn_transport()
+      pn_transport_set_server(self._trans)
+    else:
+      raise TransportException("Cannot initialise Transport from mode: %s" % str(mode))
+    self._sasl = None
+    self._ssl = None
+
+  def __del__(self):
+    if hasattr(self, "_trans"):
+      if not hasattr(self, "_shared_trans"):
+        pn_transport_free(self._trans)
+        if hasattr(self, "_sasl") and self._sasl:
+            # pn_transport_free deallocs the C sasl associated with the
+            # transport, so erase the reference if a SASL object was used.
+            self._sasl._sasl = None
+            self._sasl = None
+        if hasattr(self, "_ssl") and self._ssl:
+            # ditto the owned c SSL object
+            self._ssl._ssl = None
+            self._ssl = None
+      del self._trans
+
+  def _check(self, err):
+    if err < 0:
+      exc = EXCEPTIONS.get(err, TransportException)
+      raise exc("[%s]: %s" % (err, pn_error_text(pn_transport_error(self._trans))))
+    else:
+      return err
+
+  def bind(self, connection):
+    """Assign a connection to the transport"""
+    self._check(pn_transport_bind(self._trans, connection._conn))
+    # keep python connection from being garbage collected:
+    self._connection = connection
+
+  def unbind(self):
+    """Release the connection"""
+    self._check(pn_transport_unbind(self._trans))
+    self._connection = None
+
+  def trace(self, n):
+    pn_transport_trace(self._trans, n)
+
+  def tick(self, now):
+    """Process any timed events (like heartbeat generation).
+    now = seconds since epoch (float).
+    """
+    return millis2secs(pn_transport_tick(self._trans, secs2millis(now)))
+
+  def capacity(self):
+    c = pn_transport_capacity(self._trans)
+    if c >= PN_EOS:
+      return c
+    else:
+      return self._check(c)
+
+  def push(self, bytes):
+    n = self._check(pn_transport_push(self._trans, bytes))
+    if n != len(bytes):
+      raise OverflowError("unable to process all bytes")
+
+  def close_tail(self):
+    self._check(pn_transport_close_tail(self._trans))
+
+  def pending(self):
+    p = pn_transport_pending(self._trans)
+    if p >= PN_EOS:
+      return p
+    else:
+      return self._check(p)
+
+  def peek(self, size):
+    cd, out = pn_transport_peek(self._trans, size)
+    if cd == PN_EOS:
+      return None
+    else:
+      self._check(cd)
+      return out
+
+  def pop(self, size):
+    pn_transport_pop(self._trans, size)
+
+  def close_head(self):
+    self._check(pn_transport_close_head(self._trans))
+
+  @property
+  def closed(self):
+    return pn_transport_closed(self._trans)
+
+  # AMQP 1.0 max-frame-size
+  def _get_max_frame_size(self):
+    return pn_transport_get_max_frame(self._tra

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