84 lines
2.0 KiB
Python
84 lines
2.0 KiB
Python
# -*- test-case-name: twisted.test.test_application -*-
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# Copyright (c) 2006-2007 Twisted Matrix Laboratories.
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# See LICENSE for details.
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"""
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Plugin-based system for enumerating available reactors and installing one of
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them.
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"""
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from zope.interface import Interface, Attribute, implements
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from twisted.plugin import IPlugin, getPlugins
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from twisted.python.reflect import namedAny
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class IReactorInstaller(Interface):
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"""
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Definition of a reactor which can probably be installed.
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"""
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shortName = Attribute("""
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A brief string giving the user-facing name of this reactor.
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""")
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description = Attribute("""
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A longer string giving a user-facing description of this reactor.
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""")
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def install():
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"""
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Install this reactor.
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"""
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# TODO - A method which provides a best-guess as to whether this reactor
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# can actually be used in the execution environment.
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class NoSuchReactor(KeyError):
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"""
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Raised when an attempt is made to install a reactor which cannot be found.
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"""
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class Reactor(object):
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"""
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@ivar moduleName: The fully-qualified Python name of the module of which
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the install callable is an attribute.
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"""
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implements(IPlugin, IReactorInstaller)
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def __init__(self, shortName, moduleName, description):
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self.shortName = shortName
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self.moduleName = moduleName
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self.description = description
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def install(self):
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namedAny(self.moduleName).install()
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def getReactorTypes():
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"""
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Return an iterator of L{IReactorInstaller} plugins.
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"""
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return getPlugins(IReactorInstaller)
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def installReactor(shortName):
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"""
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Install the reactor with the given C{shortName} attribute.
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@raise NoSuchReactor: If no reactor is found with a matching C{shortName}.
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@raise: anything that the specified reactor can raise when installed.
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"""
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for installer in getReactorTypes():
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if installer.shortName == shortName:
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return installer.install()
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raise NoSuchReactor(shortName)
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