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.
|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).|
Inherited from FileDescriptor:
|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||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||registerProducer||Register to receive data from a producer.|
|Method||unregisterProducer||Stop consuming data from a producer, without disconnecting.|
|Method||stopConsuming||Stop consuming data.|
|Method||stopProducing||Stop producing data.|
|Method||_postLoseConnection||Called after a loseConnection(), when all data has been written.|
|Method||logPrefix||Override this method to insert custom logging behavior. Its return value will be inserted in front of every line. It may be called more times than the number of output lines.|
Reliably write some data.The data is buffered until the underlying file descriptor is ready for writing. If there is more than
self.bufferSizedata in the buffer and this descriptor has a registered streaming producer, its
pauseProducing()method will be called.
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).