# *****************************************************************************
# * Copyright (c) 2011, 2013-2014 Wind River Systems, Inc. and others.
# * All rights reserved. This program and the accompanying materials
# * are made available under the terms of the Eclipse Public License v1.0
# * which accompanies this distribution, and is available at
# * http://www.eclipse.org/legal/epl-v10.html
# *
# * Contributors:
# * Wind River Systems - initial API and implementation
# *****************************************************************************
import collections
import threading
from .. import protocol
_providers = []
_lock = threading.RLock()
class ServiceProvider(object):
"""Clients can implement this abstract class if they want to provide
implementation of a local service or remote service proxy.
"""
def getLocalService(self, channel):
pass
def getServiceProxy(self, channel, service_name):
pass
def addServiceProvider(provider):
with _lock:
_providers.append(provider)
def removeServiceProvider(provider):
with _lock:
_providers.remove(provider)
def onChannelCreated(channel, services_by_name):
with _lock:
# TODO ZeroCopy support is incomplete
# zero_copy = ZeroCopy()
# services_by_name[zero_copy.getName()] = zero_copy
for provider in _providers:
try:
arr = provider.getLocalService(channel)
if not arr:
continue
for service in arr:
if service.getName() in services_by_name:
continue
services_by_name[service.getName()] = service
except Exception as x:
protocol.log("Error calling TCF service provider", x)
def onChannelOpened(channel, service_names, services_by_name):
with _lock:
for name in service_names:
for provider in _providers:
try:
service = provider.getServiceProxy(channel, name)
if not service:
continue
services_by_name[name] = service
break
except Exception as x:
protocol.log("Error calling TCF service provider", x)
if name in services_by_name:
continue
services_by_name[name] = GenericProxy(channel, name)
def getServiceManagerID():
# In current implementation ServiceManager is a singleton,
# so its ID is same as agent ID.
return protocol.getAgentID()
class GenericCallback(object):
def __init__(self, callback):
self.callback = callback
def __getattr__(self, attr):
if attr.startswith("done"):
return self.callback
class Service(object):
"""TCF service base class."""
def getName(self):
"""Abstract method to get the service name.
:returns: This service name
"""
raise NotImplementedError("Abstract method")
def __str__(self):
"""TCF service string representation.
:returns: The name of the service.
"""
return self.getName()
def _makeCallback(self, done):
"""Turn *done* into a callable.
If *done* is already a :class:`collections.Callable`, it is returned
as is, else, it is made callable, and returned.
:param done: The item to make callable.
:returns: The callable value of *done*
"""
if isinstance(done, collections.Callable):
return GenericCallback(done)
return done
class ZeroCopy(Service):
def getName(self):
return "ZeroCopy"
class GenericProxy(Service):
"""Objects of GenericProxy class represent remote services, which don't
have a proxy class defined for them.
Clients still can use such services, but framework will not provide
service specific utility methods for message formatting and parsing.
"""
def __init__(self, channel, name):
self.__channel = channel
self.name = name
def getName(self):
return self.name
def getChannel(self):
return self.__channel
class DefaultServiceProvider(ServiceProvider):
package_base = str(__package__) + ".remote"
def getLocalService(self, channel):
# TODO DiagnosticsService
# return [DiagnosticsService(channel)]
return []
def getServiceProxy(self, channel, service_name):
service = None
try:
clsName = service_name + "Proxy"
package = self.package_base + "." + clsName
clsModule = __import__(package, fromlist=[clsName],
globals=globals())
cls = clsModule.__dict__.get(clsName)
service = cls(channel)
assert service_name == service.getName()
except ImportError:
pass
except Exception as x:
protocol.log("Cannot instantiate service proxy for " +
service_name, x)
return service
addServiceProvider(DefaultServiceProvider())
