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Viewing changes to vendor/Twisted-10.0.0/twisted/protocols/stateful.py

  • Committer: Jesse Andrews
  • Date: 2010-05-28 06:05:26 UTC
  • Revision ID: git-v1:bf6e6e718cdc7488e2da87b21e258ccc065fe499
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vendor/Twisted-10.0.0/twisted/protocols/stateful.py
 
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# -*- test-case-name: twisted.test.test_stateful -*-
 
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# Copyright (c) 2001-2004 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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