class twisted.internet.process.ProcessWriter(abstract.FileDescriptor): (source)
(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 Variable | enableReadHack | A 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. |
| Class Variable | connected | Undocumented |
| Class Variable | ic | Undocumented |
| Method | __init__ | Initialize, specifying a Process instance to connect to. |
| Instance Variable | proc | Undocumented |
| Instance Variable | name | Undocumented |
| Instance Variable | fd | Undocumented |
| 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:
| Instance Variable | disconnected | Undocumented |
| Instance Variable | disconnecting | Undocumented |
| Instance Variable | dataBuffer | Undocumented |
| Instance Variable | offset | Undocumented |
| Class Variable | SEND_LIMIT | Undocumented |
| Instance Variable | reactor | Undocumented |
| Instance Variable | producer | Undocumented |
| Method | doWrite | Called when data can be written. |
| Instance Variable | producerPaused | Undocumented |
| Method | writeConnectionLost | Undocumented |
| Method | readConnectionLost | Undocumented |
| Method | getHost | Undocumented |
| Method | getPeer | Undocumented |
| 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. |
| Class Variable | bufferSize | Undocumented |
| Method | stopConsuming | Stop consuming data. |
| Method | resumeProducing | Undocumented |
| Method | pauseProducing | Undocumented |
| Method | stopProducing | Undocumented |
| Instance Variable | _writeDisconnecting | Undocumented |
| Instance Variable | _writeDisconnected | Undocumented |
| Instance Variable | _tempDataBuffer | Undocumented |
| Instance Variable | _tempDataLen | Undocumented |
| Method | _postLoseConnection | Called after a loseConnection(), when all data has been written. |
| Method | _closeWriteConnection | Undocumented |
| Method | _isSendBufferFull | Determine whether the user-space send buffer for this transport is full or not. |
| Method | _maybePauseProducer | Possibly pause a producer, if there is one and the send buffer is full. |
Inherited from _ConsumerMixin (via FileDescriptor):
| Instance Variable | streamingProducer | bool or int |
| Method | registerProducer | Register to receive data from a producer. |
| Method | unregisterProducer | Stop consuming data from a producer, without disconnecting. |
Inherited from _LogOwner (via FileDescriptor):
| 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. |
| Method | _getLogPrefix | Determine the log prefix to use for messages related to applicationObject, which may or may not be an interfaces.ILoggingContext provider. |
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.bool)
Initialize, specifying a Process instance to connect to.
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.
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".