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+#!/usr/bin/env python
+
+#
+# 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.
+#
+
+"""
+Support for amqp 'reference' content (as opposed to inline content)
+"""
+
+import threading
+from queue import Queue, Closed
+
+class NotOpened(Exception): pass
+
+class AlreadyOpened(Exception): pass
+
+"""
+A representation of a reference id; can be passed wherever amqp
+content is required in place of inline data
+"""
+class ReferenceId:
+
+ def __init__(self, id):
+ self.id = id
+
+"""
+Holds content received through 'reference api'. Instances of this
+class will be placed in the consumers queue on receiving a transfer
+(assuming the reference has been opened). Data can be retrieved in
+chunks (as append calls are received) or in full (after reference has
+been closed signalling data s complete).
+"""
+
+class Reference:
+
+ def __init__(self, id):
+ self.id = id
+ self.chunks = Queue(0)
+
+ def close(self):
+ self.chunks.close()
+
+ def append(self, bytes):
+ self.chunks.put(bytes)
+
+ def get_chunk(self):
+ return self.chunks.get()
+
+ def get_complete(self):
+ data = ""
+ for chunk in self:
+ data += chunk
+ return data
+
+ def next(self):
+ try:
+ return self.get_chunk()
+ except Closed, e:
+ raise StopIteration
+
+ def __iter__(self):
+ return self
+
+"""
+Manages a set of opened references. New references can be opened and
+existing references can be retrieved or closed.
+"""
+class References:
+
+ def __init__(self):
+ self.map = {}
+ self.lock = threading.Lock()
+
+ def get(self, id):
+ self.lock.acquire()
+ try:
+ try:
+ ref = self.map[id]
+ except KeyError:
+ raise NotOpened()
+ finally:
+ self.lock.release()
+ return ref
+
+ def open(self, id):
+ self.lock.acquire()
+ try:
+ if id in self.map: raise AlreadyOpened()
+ self.map[id] = Reference(id)
+ finally:
+ self.lock.release()
+
+
+ def close(self, id):
+ self.get(id).close()
+ self.lock.acquire()
+ try:
+ self.map.pop(id)
+ finally:
+ self.lock.release()
+