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Diffstat (limited to 'services/datastore/dbus_helpers.py')
| -rw-r--r-- | services/datastore/dbus_helpers.py | 222 |
1 files changed, 222 insertions, 0 deletions
diff --git a/services/datastore/dbus_helpers.py b/services/datastore/dbus_helpers.py new file mode 100644 index 0000000..391e201 --- /dev/null +++ b/services/datastore/dbus_helpers.py @@ -0,0 +1,222 @@ +# Copyright (C) 2006, Red Hat, Inc. +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program; if not, write to the Free Software +# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + + +# Mostly taken from dbus-python's service.py + +import dbus +from dbus import service +import inspect + +def method(dbus_interface, in_signature=None, out_signature=None, async_callbacks=None, sender_keyword=None, dbus_message_keyword=None): + dbus._util._validate_interface_or_name(dbus_interface) + + def decorator(func): + args = inspect.getargspec(func)[0] + args.pop(0) + + if async_callbacks: + if type(async_callbacks) != tuple: + raise TypeError('async_callbacks must be a tuple of (keyword for return callback, keyword for error callback)') + if len(async_callbacks) != 2: + raise ValueError('async_callbacks must be a tuple of (keyword for return callback, keyword for error callback)') + args.remove(async_callbacks[0]) + args.remove(async_callbacks[1]) + + if sender_keyword: + args.remove(sender_keyword) + + if dbus_message_keyword: + args.remove(dbus_message_keyword) + + if in_signature: + in_sig = tuple(dbus.dbus_bindings.Signature(in_signature)) + + if len(in_sig) > len(args): + raise ValueError, 'input signature is longer than the number of arguments taken' + elif len(in_sig) < len(args): + raise ValueError, 'input signature is shorter than the number of arguments taken' + + func._dbus_message_keyword = dbus_message_keyword + func._dbus_is_method = True + func._dbus_async_callbacks = async_callbacks + func._dbus_interface = dbus_interface + func._dbus_in_signature = in_signature + func._dbus_out_signature = out_signature + func._dbus_sender_keyword = sender_keyword + func._dbus_args = args + return func + + return decorator + +def fallback_signal(dbus_interface, signature=None, ignore_args=None): + dbus._util._validate_interface_or_name(dbus_interface) + def decorator(func): + def emit_signal(self, *args, **keywords): + obj_path = func(self, *args, **keywords) + message = dbus.dbus_bindings.Signal(obj_path, dbus_interface, func.__name__) + iter = message.get_iter(True) + + if emit_signal._dbus_signature: + signature = tuple(dbus.dbus_bindings.Signature(emit_signal._dbus_signature)) + for (arg, sig) in zip(args, signature): + iter.append_strict(arg, sig) + else: + for arg in args: + iter.append(arg) + + self._connection.send(message) + + temp_args = inspect.getargspec(func)[0] + temp_args.pop(0) + + args = [] + for arg in temp_args: + if arg not in ignore_args: + args.append(arg) + + if signature: + sig = tuple(dbus.dbus_bindings.Signature(signature)) + + if len(sig) > len(args): + raise ValueError, 'signal signature is longer than the number of arguments provided' + elif len(sig) < len(args): + raise ValueError, 'signal signature is shorter than the number of arguments provided' + + emit_signal.__name__ = func.__name__ + emit_signal.__doc__ = func.__doc__ + emit_signal._dbus_is_signal = True + emit_signal._dbus_interface = dbus_interface + emit_signal._dbus_signature = signature + emit_signal._dbus_args = args + return emit_signal + + return decorator + +class FallbackObject(dbus.service.Object): + """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, fallback_object_path): + self._object_path = fallback_object_path + self._name = bus_name + self._bus = bus_name.get_bus() + + self._connection = self._bus.get_connection() + + self._connection.register_fallback(fallback_object_path, self._unregister_cb, self._message_cb) + + 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) = dbus.service._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.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: dbus.service._method_reply_return(connection, message, method_name, signature, *retval) + keywords[error_callback] = lambda exception: dbus.service._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() + + if parent_method._dbus_message_keyword: + keywords[parent_method._dbus_message_keyword] = message + + # 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,) + + dbus.service._method_reply_return(connection, message, method_name, signature, *retval) + except Exception, exception: + # send error reply + dbus.service._method_reply_error(connection, message, exception) + + @method('org.freedesktop.DBus.Introspectable', in_signature='', out_signature='s', dbus_message_keyword="dbus_message") + def Introspect(self, dbus_message=None): + 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' + op = dbus_message.get_path() + reflection_data += '<node name="%s">\n' % (op) + + 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_helpers.FallbackObject %s on %r at %#x>' % (self._fallback_object_path, self._name, id(self)) + __str__ = __repr__ + |