t.i.p.ProcessWriter(abstract.FileDescriptor) : class documentation

Part of twisted.internet.process View Source View In Hierarchy

(Internal) Helper class to write into a Process's input pipe.

I am a helper which describes a selectable asynchronous writer to a process's input pipe, including stdin.
Instance VariablesenableReadHackA flag which determines how readability on this write descriptor will be handled. If True, then readability may indicate the reader for this write descriptor has been closed (ie, the connection has been lost). If False, then readability events are ignored.
Method __init__ Initialize, specifying a Process instance to connect to.
Method fileno Return the fileno() of my process's stdin.
Method writeSomeData Write some data to the open process.
Method write Reliably write some data.
Method doRead The only way a write pipe can become "readable" is at EOF, because the child has closed it, and we're using a reactor which doesn't distinguish between readable and closed (such as the select reactor).
Method connectionLost See abstract.FileDescriptor.connectionLost.

Inherited from FileDescriptor:

Method logPrefix Returns the default log prefix
Method doWrite Called when data can be written.
Method writeConnectionLost Indicates write connection was lost.
Method readConnectionLost Indicates read connection was lost.
Method writeSequence Reliably write a sequence of data.
Method loseConnection Close the connection at the next available opportunity.
Method loseWriteConnection Undocumented
Method stopReading Stop waiting for read availability.
Method stopWriting Stop waiting for write availability.
Method startReading Start waiting for read availability.
Method startWriting Start waiting for write availability.
Method stopConsuming Stop consuming data.
Method resumeProducing Undocumented
Method pauseProducing Undocumented
Method stopProducing Stop producing data.
Method _postLoseConnection Called after a loseConnection(), when all data has been written.
Method _closeWriteConnection Undocumented

Inherited from _ConsumerMixin (via FileDescriptor):

Method registerProducer Register to receive data from a producer.
Method unregisterProducer Stop consuming data from a producer, without disconnecting.
def __init__(self, reactor, proc, name, fileno, forceReadHack=False): (source)
Initialize, specifying a Process instance to connect to.
def fileno(self): (source)
Return the fileno() of my process's stdin.
def writeSomeData(self, data): (source)
Write some data to the open process.
def write(self, data): (source)

Reliably write some data.

The data is buffered until the underlying file descriptor is ready for writing. If there is more than self.bufferSize data in the buffer and this descriptor has a registered streaming producer, its pauseProducing() method will be called.
def doRead(self): (source)

The only way a write pipe can become "readable" is at EOF, because the child has closed it, and we're using a reactor which doesn't distinguish between readable and closed (such as the select reactor).

Except that's not true on linux < 2.6.11. It has the following characteristics: write pipe is completely empty => POLLOUT (writable in select), write pipe is not completely empty => POLLIN (readable in select), write pipe's reader closed => POLLIN|POLLERR (readable and writable in select)

That's what this funky code is for. If linux was not broken, this function could be simply "return CONNECTION_LOST".

BUG: We call select no matter what the reactor. If the reactor is pollreactor, and the fd is > 1024, this will fail. (only occurs on broken versions of linux, though).
def connectionLost(self, reason): (source)
See abstract.FileDescriptor.connectionLost.
API Documentation for Twisted, generated by pydoctor at 2011-10-27 16:27:37.