| #!/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() |
| |