CasperSecurity
# -*- test-case-name: twisted._threads.test -*-
# Copyright (c) Twisted Matrix Laboratories.
# See LICENSE for details.
"""
Interfaces related to threads.
"""
from zope.interface import Interface
class AlreadyQuit(Exception):
"""
This worker worker is dead and cannot execute more instructions.
"""
class IWorker(Interface):
"""
A worker that can perform some work concurrently.
All methods on this interface must be thread-safe.
"""
def do(task):
"""
Perform the given task.
As an interface, this method makes no specific claims about concurrent
execution. An L{IWorker}'s C{do} implementation may defer execution
for later on the same thread, immediately on a different thread, or
some combination of the two. It is valid for a C{do} method to
schedule C{task} in such a way that it may never be executed.
It is important for some implementations to provide specific properties
with respect to where C{task} is executed, of course, and client code
may rely on a more specific implementation of C{do} than L{IWorker}.
@param task: a task to call in a thread or other concurrent context.
@type task: 0-argument callable
@raise AlreadyQuit: if C{quit} has been called.
"""
def quit():
"""
Free any resources associated with this L{IWorker} and cause it to
reject all future work.
@raise AlreadyQuit: if this method has already been called.
"""
class IExclusiveWorker(IWorker):
"""
Like L{IWorker}, but with the additional guarantee that the callables
passed to C{do} will not be called exclusively with each other.
"""