# ``twisted`.`protocols`.`amp`.`_DescriptorExchanger``

class documentation

`class _DescriptorExchanger: (source)`

Known subclasses: `twisted.protocols.amp.BinaryBoxProtocol`

Implements interfaces: `twisted.internet.interfaces.IFileDescriptorReceiver`

View In Hierarchy

`_DescriptorExchanger` is a mixin for `BinaryBoxProtocol` which adds support for receiving file descriptors, a feature offered by `IUNIXTransport`.

Method | `__init__` | Undocumented
Method | `fileDescriptorReceived` | Collect received file descriptors to be claimed later by `Descriptor`.
Method | `_sendFileDescriptor` | Assign and return the next ordinal to the given descriptor after sending the descriptor over this protocol's transport.
Instance Variable | `_descriptors` | Temporary storage for all file descriptors received. Values in this dictionary are the file descriptors (as integers). Keys in this dictionary are ordinals giving the order in which each descriptor was received. The ordering information is used to allow `Descriptor` to determine which is the correct descriptor for any particular usage of that argument type.
Instance Variable | `_getDescriptor` | Undocumented
Instance Variable | `_receivingDescriptorCounter` | A no-argument callable which returns the ordinals, starting from 0. This is used to construct values for `fileDescriptorReceived`.
Instance Variable | `_sendingDescriptorCounter` | A no-argument callable which returns the ordinals, starting from 0. This is used to construct values for `_sendFileDescriptor`.

def __init__(self): (source)
overridden in `twisted.protocols.amp.BinaryBoxProtocol`

Undocumented

def fileDescriptorReceived(self, descriptor): (source)
from `twisted.internet.interfaces.IFileDescriptorReceiver`
Collect received file descriptors to be claimed later by `Descriptor`.

Parameters
descriptor:`int` | The received file descriptor.

def _sendFileDescriptor(self, descriptor): (source)
Assign and return the next ordinal to the given descriptor after sending the descriptor over this protocol's transport.
_descriptors: `dict` = (source)
Temporary storage for all file descriptors received. Values in this dictionary are the file descriptors (as integers). Keys in this dictionary are ordinals giving the order in which each descriptor was received. The ordering information is used to allow `Descriptor` to determine which is the correct descriptor for any particular usage of that argument type.
_getDescriptor = (source)

Undocumented

_receivingDescriptorCounter = (source)
A no-argument callable which returns the ordinals, starting from 0. This is used to construct values for `fileDescriptorReceived`.
_sendingDescriptorCounter = (source)
A no-argument callable which returns the ordinals, starting from 0. This is used to construct values for `_sendFileDescriptor`.