# Copyright (c) 2001-2004 Twisted Matrix Laboratories. # See LICENSE for details. """Support for generic select()able objects. API Stability: stable Maintainer: U{Itamar Shtull-Trauring} """ # System Imports import types, string from zope.interface import implements # Twisted Imports from twisted.python import log, reflect, components, failure from twisted.persisted import styles # Sibling Imports import interfaces, main class FileDescriptor(log.Logger, styles.Ephemeral, object): """An object which can be operated on by select(). This is an abstract superclass of all objects which may be notified when they are readable or writable; e.g. they have a file-descriptor that is valid to be passed to select(2). """ connected = 0 producerPaused = 0 streamingProducer = 0 producer = None disconnected = 0 disconnecting = 0 _writeDisconnecting = False _writeDisconnected = False dataBuffer = "" offset = 0 SEND_LIMIT = 128*1024 implements(interfaces.IProducer, interfaces.IReadWriteDescriptor, interfaces.IConsumer, interfaces.ITransport, interfaces.IHalfCloseableDescriptor) def __init__(self, reactor=None): if not reactor: from twisted.internet import reactor self.reactor = reactor self._tempDataBuffer = [] # will be added to dataBuffer in doWrite self._tempDataLen = 0 def connectionLost(self, reason): """The connection was lost. This is called when the connection on a selectable object has been lost. It will be called whether the connection was closed explicitly, an exception occurred in an event handler, or the other end of the connection closed it first. Clean up state here, but make sure to call back up to FileDescriptor. """ self.disconnected = 1 self.connected = 0 if self.producer is not None: self.producer.stopProducing() self.producer = None self.stopReading() self.stopWriting() def writeSomeData(self, data): """Write as much as possible of the given data, immediately. This is called to invoke the lower-level writing functionality, such as a socket's send() method, or a file's write(); this method returns an integer. If positive, it is the number of bytes written; if negative, it indicates the connection was lost. """ raise NotImplementedError("%s does not implement writeSomeData" % reflect.qual(self.__class__)) def doRead(self): raise NotImplementedError("%s does not implement doRead" % reflect.qual(self.__class__)) def doWrite(self): """Called when data is available for writing. A result that is true (which will be a negative number) implies the connection was lost. A false result implies the connection is still there; a result of 0 implies no write was done, and a result of None indicates that a write was done. """ if len(self.dataBuffer) - self.offset < self.SEND_LIMIT: # If there is currently less than SEND_LIMIT bytes left to send # in the string, extend it with the array data. self.dataBuffer = buffer(self.dataBuffer, self.offset) + "".join(self._tempDataBuffer) self.offset = 0 self._tempDataBuffer = [] self._tempDataLen = 0 # Send as much data as you can. if self.offset: l = self.writeSomeData(buffer(self.dataBuffer, self.offset)) else: l = self.writeSomeData(self.dataBuffer) if l < 0 or isinstance(l, Exception): return l if l == 0 and self.dataBuffer: result = 0 else: result = None self.offset += l # If there is nothing left to send, if self.offset == len(self.dataBuffer) and not self._tempDataLen: self.dataBuffer = "" self.offset = 0 # stop writing. self.stopWriting() # If I've got a producer who is supposed to supply me with data, if self.producer is not None and ((not self.streamingProducer) or self.producerPaused): # tell them to supply some more. self.producerPaused = 0 self.producer.resumeProducing() elif self.disconnecting: # But if I was previously asked to let the connection die, do # so. return self._postLoseConnection() elif self._writeDisconnecting: # I was previously asked to to half-close the connection. result = self._closeWriteConnection() self._writeDisconnected = True return result return result def _postLoseConnection(self): """Called after a loseConnection(), when all data has been written. Whatever this returns is then returned by doWrite. """ # default implementation, telling reactor we're finished return main.CONNECTION_DONE def _closeWriteConnection(self): # override in subclasses pass def writeConnectionLost(self, reason): # in current code should never be called self.connectionLost(reason) def readConnectionLost(self, reason): # override in subclasses self.connectionLost(reason) def write(self, data): """Reliably write some data. If there is no buffered data this tries to write this data immediately, otherwise this adds data to be written the next time this file descriptor is ready for writing. """ if isinstance(data, unicode): # no, really, I mean it raise TypeError("Data must not be unicode") if not self.connected or self._writeDisconnected: return if data: self._tempDataBuffer.append(data) self._tempDataLen += len(data) if self.producer is not None: if len(self.dataBuffer) + self._tempDataLen > self.bufferSize: self.producerPaused = 1 self.producer.pauseProducing() self.startWriting() def writeSequence(self, iovec): if not self.connected or not iovec or self._writeDisconnected: return self._tempDataBuffer.extend(iovec) for i in iovec: self._tempDataLen += len(i) if self.producer is not None: if len(self.dataBuffer) + self._tempDataLen > self.bufferSize: self.producerPaused = 1 self.producer.pauseProducing() self.startWriting() def loseConnection(self, _connDone=failure.Failure(main.CONNECTION_DONE)): """Close the connection at the next available opportunity. Call this to cause this FileDescriptor to lose its connection. It will first write any data that it has buffered. If there is data buffered yet to be written, this method will cause the transport to lose its connection as soon as it's done flushing its write buffer. If you have a producer registered, the connection won't be closed until the producer is finished. Therefore, make sure you unregister your producer when it's finished, or the connection will never close. """ if self.connected and not self.disconnecting: if self._writeDisconnected: # doWrite won't trigger the connection close anymore self.stopReading() self.stopWriting() self.connectionLost(_connDone) else: self.stopReading() self.startWriting() self.disconnecting = 1 def loseWriteConnection(self): self._writeDisconnecting = True self.startWriting() def stopReading(self): """Stop waiting for read availability. Call this to remove this selectable from being notified when it is ready for reading. """ self.reactor.removeReader(self) def stopWriting(self): """Stop waiting for write availability. Call this to remove this selectable from being notified when it is ready for writing. """ self.reactor.removeWriter(self) def startReading(self): """Start waiting for read availability. """ self.reactor.addReader(self) def startWriting(self): """Start waiting for write availability. Call this to have this FileDescriptor be notified whenever it is ready for writing. """ self.reactor.addWriter(self) # Producer/consumer implementation # first, the consumer stuff. This requires no additional work, as # any object you can write to can be a consumer, really. producer = None bufferSize = 2**2**2**2 def registerProducer(self, producer, streaming): """Register to receive data from a producer. This sets this selectable to be a consumer for a producer. When this selectable runs out of data on a write() call, it will ask the producer to resumeProducing(). A producer should implement the IProducer interface. FileDescriptor provides some infrastructure for producer methods. """ if self.producer is not None: raise RuntimeError("Cannot register producer %s, because producer %s was never unregistered." % (producer, self.producer)) if self.disconnected: producer.stopProducing() else: self.producer = producer self.streamingProducer = streaming if not streaming: producer.resumeProducing() def unregisterProducer(self): """Stop consuming data from a producer, without disconnecting. """ self.producer = None def stopConsuming(self): """Stop consuming data. This is called when a producer has lost its connection, to tell the consumer to go lose its connection (and break potential circular references). """ self.unregisterProducer() self.loseConnection() # producer interface implementation def resumeProducing(self): assert self.connected and not self.disconnecting self.startReading() def pauseProducing(self): self.stopReading() def stopProducing(self): self.loseConnection() def fileno(self): """File Descriptor number for select(). This method must be overridden or assigned in subclasses to indicate a valid file descriptor for the operating system. """ return -1 components.backwardsCompatImplements(FileDescriptor) def isIPAddress(addr): parts = string.split(addr, '.') if len(parts) == 4: try: for part in map(int, parts): if not (0<=part<256): break else: return 1 except ValueError: pass return 0 __all__ = ["FileDescriptor"]