53 lines
1.7 KiB
Python
53 lines
1.7 KiB
Python
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# -*- test-case-name: twisted.test.test_stateful -*-
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# Copyright (c) Twisted Matrix Laboratories.
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# See LICENSE for details.
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from twisted.internet import protocol
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try:
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from cStringIO import StringIO
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except ImportError:
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from StringIO import StringIO
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class StatefulProtocol(protocol.Protocol):
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"""A Protocol that stores state for you.
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state is a pair (function, num_bytes). When num_bytes bytes of data arrives
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from the network, function is called. It is expected to return the next
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state or None to keep same state. Initial state is returned by
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getInitialState (override it).
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"""
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_sful_data = None, None, 0
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def makeConnection(self, transport):
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protocol.Protocol.makeConnection(self, transport)
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self._sful_data = self.getInitialState(), StringIO(), 0
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def getInitialState(self):
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raise NotImplementedError
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def dataReceived(self, data):
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state, buffer, offset = self._sful_data
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buffer.seek(0, 2)
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buffer.write(data)
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blen = buffer.tell() # how many bytes total is in the buffer
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buffer.seek(offset)
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while blen - offset >= state[1]:
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d = buffer.read(state[1])
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offset += state[1]
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next = state[0](d)
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if self.transport.disconnecting: # XXX: argh stupid hack borrowed right from LineReceiver
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return # dataReceived won't be called again, so who cares about consistent state
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if next:
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state = next
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if offset != 0:
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b = buffer.read()
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buffer.seek(0)
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buffer.truncate()
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buffer.write(b)
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offset = 0
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self._sful_data = state, buffer, offset
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