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import dbus_bindings
import _dbus
import operator
import traceback
from exceptions import NameExistsException
from exceptions import UnknownMethodException
from decorators import method
from decorators import signal
class BusName(object):
"""A base class for exporting your own Named Services across the Bus
"""
def __new__(cls, name, bus=None):
# get default bus
if bus == None:
bus = _dbus.Bus()
# see if this name is already defined, return it if so
if name in bus._bus_names:
return bus._bus_names[name]
# otherwise register the name
retval = dbus_bindings.bus_request_name(bus.get_connection(), name)
# TODO: more intelligent tracking of bus name states?
if retval == dbus_bindings.REQUEST_NAME_REPLY_PRIMARY_OWNER:
pass
elif retval == dbus_bindings.REQUEST_NAME_REPLY_IN_QUEUE:
# queueing can happen by default, maybe we should
# track this better or let the user know if they're
# queued or not?
pass
elif retval == dbus_bindings.REQUEST_NAME_REPLY_EXISTS:
raise NameExistsException(name)
elif retval == dbus_bindings.REQUEST_NAME_REPLY_ALREADY_OWNER:
# if this is a shared bus which is being used by someone
# else in this process, this can happen legitimately
pass
else:
raise RuntimeError('requesting bus name %s returned unexpected value %s' % (name, retval))
# and create the object
bus_name = object.__new__(cls)
bus_name._bus = bus
bus_name._name = name
# cache instance
bus._bus_names[name] = bus_name
return bus_name
# do nothing because this is called whether or not the bus name
# object was retrieved from the cache or created new
def __init__(self, *args, **keywords):
pass
# we can delete the low-level name here because these objects
# are guaranteed to exist only once for each bus name
def __del__(self):
dbus_bindings.bus_release_name(self._bus.get_connection(), self._name)
pass
def get_bus(self):
"""Get the Bus this Service is on"""
return self._bus
def get_name(self):
"""Get the name of this service"""
return self._name
def __repr__(self):
return '<dbus.service.BusName %s on %r at %#x>' % (self._name, self._bus, id(self))
__str__ = __repr__
def _method_lookup(self, method_name, dbus_interface):
"""Walks the Python MRO of the given class to find the method to invoke.
Returns two methods, the one to call, and the one it inherits from which
defines its D-Bus interface name, signature, and attributes.
"""
parent_method = None
candidate_class = None
successful = False
# split up the cases when we do and don't have an interface because the
# latter is much simpler
if dbus_interface:
# search through the class hierarchy in python MRO order
for cls in self.__class__.__mro__:
# if we haven't got a candidate class yet, and we find a class with a
# suitably named member, save this as a candidate class
if (not candidate_class and method_name in cls.__dict__):
if ("_dbus_is_method" in cls.__dict__[method_name].__dict__
and "_dbus_interface" in cls.__dict__[method_name].__dict__):
# however if it is annotated for a different interface
# than we are looking for, it cannot be a candidate
if cls.__dict__[method_name]._dbus_interface == dbus_interface:
candidate_class = cls
parent_method = cls.__dict__[method_name]
successful = True
break
else:
pass
else:
candidate_class = cls
# if we have a candidate class, carry on checking this and all
# superclasses for a method annoated as a dbus method
# on the correct interface
if (candidate_class and method_name in cls.__dict__
and "_dbus_is_method" in cls.__dict__[method_name].__dict__
and "_dbus_interface" in cls.__dict__[method_name].__dict__
and cls.__dict__[method_name]._dbus_interface == dbus_interface):
# the candidate class has a dbus method on the correct interface,
# or overrides a method that is, success!
parent_method = cls.__dict__[method_name]
successful = True
break
else:
# simpler version of above
for cls in self.__class__.__mro__:
if (not candidate_class and method_name in cls.__dict__):
candidate_class = cls
if (candidate_class and method_name in cls.__dict__
and "_dbus_is_method" in cls.__dict__[method_name].__dict__):
parent_method = cls.__dict__[method_name]
successful = True
break
if successful:
return (candidate_class.__dict__[method_name], parent_method)
else:
if dbus_interface:
raise UnknownMethodException('%s is not a valid method of interface %s' % (method_name, dbus_interface))
else:
raise UnknownMethodException('%s is not a valid method' % method_name)
def _method_reply_return(connection, message, method_name, signature, *retval):
reply = dbus_bindings.MethodReturn(message)
iter = reply.get_iter(append=True)
# do strict adding if an output signature was provided
if signature:
if len(signature) > len(retval):
raise TypeError('output signature %s is longer than the number of values returned by %s' %
(signature, method_name))
elif len(retval) > len(signature):
raise TypeError('output signature %s is shorter than the number of values returned by %s' %
(signature, method_name))
else:
for (value, sig) in zip(retval, signature):
iter.append_strict(value, sig)
# no signature, try and guess the return type by inspection
else:
for value in retval:
iter.append(value)
connection.send(reply)
def _method_reply_error(connection, message, exception):
if '_dbus_error_name' in exception.__dict__:
name = exception._dbus_error_name
elif exception.__module__ == '__main__':
name = 'org.freedesktop.DBus.Python.%s' % exception.__class__.__name__
else:
name = 'org.freedesktop.DBus.Python.%s.%s' % (exception.__module__, exception.__class__.__name__)
contents = traceback.format_exc()
reply = dbus_bindings.Error(message, name, contents)
connection.send(reply)
class InterfaceType(type):
def __init__(cls, name, bases, dct):
# these attributes are shared between all instances of the Interface
# object, so this has to be a dictionary that maps class names to
# the per-class introspection/interface data
class_table = getattr(cls, '_dbus_class_table', {})
cls._dbus_class_table = class_table
interface_table = class_table[cls.__module__ + '.' + name] = {}
# merge all the name -> method tables for all the interfaces
# implemented by our base classes into our own
for b in bases:
base_name = b.__module__ + '.' + b.__name__
if getattr(b, '_dbus_class_table', False):
for (interface, method_table) in class_table[base_name].iteritems():
our_method_table = interface_table.setdefault(interface, {})
our_method_table.update(method_table)
# add in all the name -> method entries for our own methods/signals
for func in dct.values():
if getattr(func, '_dbus_interface', False):
method_table = interface_table.setdefault(func._dbus_interface, {})
method_table[func.__name__] = func
super(InterfaceType, cls).__init__(name, bases, dct)
# methods are different to signals, so we have two functions... :)
def _reflect_on_method(cls, func):
args = func._dbus_args
if func._dbus_in_signature:
# convert signature into a tuple so length refers to number of
# types, not number of characters. the length is checked by
# the decorator to make sure it matches the length of args.
in_sig = tuple(dbus_bindings.Signature(func._dbus_in_signature))
else:
# magic iterator which returns as many v's as we need
in_sig = dbus_bindings.VariantSignature()
if func._dbus_out_signature:
out_sig = dbus_bindings.Signature(func._dbus_out_signature)
else:
# its tempting to default to dbus_bindings.Signature('v'), but
# for methods that return nothing, providing incorrect
# introspection data is worse than providing none at all
out_sig = []
reflection_data = ' <method name="%s">\n' % (func.__name__)
for pair in zip(in_sig, args):
reflection_data += ' <arg direction="in" type="%s" name="%s" />\n' % pair
for type in out_sig:
reflection_data += ' <arg direction="out" type="%s" />\n' % type
reflection_data += ' </method>\n'
return reflection_data
def _reflect_on_signal(cls, func):
args = func._dbus_args
if func._dbus_signature:
# convert signature into a tuple so length refers to number of
# types, not number of characters
sig = tuple(dbus_bindings.Signature(func._dbus_signature))
else:
# magic iterator which returns as many v's as we need
sig = dbus_bindings.VariantSignature()
reflection_data = ' <signal name="%s">\n' % (func.__name__)
for pair in zip(sig, args):
reflection_data = reflection_data + ' <arg type="%s" name="%s" />\n' % pair
reflection_data = reflection_data + ' </signal>\n'
return reflection_data
class Interface(object):
__metaclass__ = InterfaceType
class Object(Interface):
"""A base class for exporting your own Objects across the Bus.
Just inherit from Object and provide a list of methods to share
across the Bus
"""
def __init__(self, bus_name, object_path):
self._object_path = object_path
self._name = bus_name
self._bus = bus_name.get_bus()
self._connection = self._bus.get_connection()
self._connection.register_object_path(object_path, self._unregister_cb, self._message_cb)
def _unregister_cb(self, connection):
print ("Unregister")
def _message_cb(self, connection, message):
try:
# lookup candidate method and parent method
method_name = message.get_member()
interface_name = message.get_interface()
(candidate_method, parent_method) = _method_lookup(self, method_name, interface_name)
# set up method call parameters
args = message.get_args_list()
keywords = {}
# iterate signature into list of complete types
if parent_method._dbus_out_signature:
signature = tuple(dbus_bindings.Signature(parent_method._dbus_out_signature))
else:
signature = None
# set up async callback functions
if parent_method._dbus_async_callbacks:
(return_callback, error_callback) = parent_method._dbus_async_callbacks
keywords[return_callback] = lambda *retval: _method_reply_return(connection, message, method_name, signature, *retval)
keywords[error_callback] = lambda exception: _method_reply_error(connection, message, exception)
# include the sender if desired
if parent_method._dbus_sender_keyword:
keywords[parent_method._dbus_sender_keyword] = message.get_sender()
# call method
retval = candidate_method(self, *args, **keywords)
# we're done - the method has got callback functions to reply with
if parent_method._dbus_async_callbacks:
return
# otherwise we send the return values in a reply. if we have a
# signature, use it to turn the return value into a tuple as
# appropriate
if parent_method._dbus_out_signature:
# if we have zero or one return values we want make a tuple
# for the _method_reply_return function, otherwise we need
# to check we're passing it a sequence
if len(signature) == 0:
if retval == None:
retval = ()
else:
raise TypeError('%s has an empty output signature but did not return None' %
method_name)
elif len(signature) == 1:
retval = (retval,)
else:
if operator.isSequenceType(retval):
# multi-value signature, multi-value return... proceed unchanged
pass
else:
raise TypeError('%s has multiple output values in signature %s but did not return a sequence' %
(method_name, signature))
# no signature, so just turn the return into a tuple and send it as normal
else:
signature = None
if retval == None:
retval = ()
else:
retval = (retval,)
_method_reply_return(connection, message, method_name, signature, *retval)
except Exception, exception:
# send error reply
_method_reply_error(connection, message, exception)
@method('org.freedesktop.DBus.Introspectable', in_signature='', out_signature='s')
def Introspect(self):
reflection_data = '<!DOCTYPE node PUBLIC "-//freedesktop//DTD D-BUS Object Introspection 1.0//EN" "http://www.freedesktop.org/standards/dbus/1.0/introspect.dtd">\n'
reflection_data += '<node name="%s">\n' % (self._object_path)
interfaces = self._dbus_class_table[self.__class__.__module__ + '.' + self.__class__.__name__]
for (name, funcs) in interfaces.iteritems():
reflection_data += ' <interface name="%s">\n' % (name)
for func in funcs.values():
if getattr(func, '_dbus_is_method', False):
reflection_data += self.__class__._reflect_on_method(func)
elif getattr(func, '_dbus_is_signal', False):
reflection_data += self.__class__._reflect_on_signal(func)
reflection_data += ' </interface>\n'
reflection_data += '</node>\n'
return reflection_data
def __repr__(self):
return '<dbus.service.Object %s on %r at %#x>' % (self._object_path, self._name, id(self))
__str__ = __repr__
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