JezK

Edit File: proxies.py

# Copyright (C) 2003-2007 Red Hat Inc. <http://www.redhat.com/> # Copyright (C) 2003 David Zeuthen # Copyright (C) 2004 Rob Taylor # Copyright (C) 2005-2007 Collabora Ltd. <http://www.collabora.co.uk/> # # SPDX-License-Identifier: MIT # # Permission is hereby granted, free of charge, to any person # obtaining a copy of this software and associated documentation # files (the "Software"), to deal in the Software without # restriction, including without limitation the rights to use, copy, # modify, merge, publish, distribute, sublicense, and/or sell copies # of the Software, and to permit persons to whom the Software is # furnished to do so, subject to the following conditions: # # The above copyright notice and this permission notice shall be # included in all copies or substantial portions of the Software. # # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, # EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF # MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND # NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT # HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, # WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER # DEALINGS IN THE SOFTWARE. import logging try: from threading import RLock except ImportError: from dummy_threading import RLock import _dbus_bindings from dbus._expat_introspect_parser import process_introspection_data from dbus.exceptions import ( DBusException, IntrospectionParserException, MissingErrorHandlerException, MissingReplyHandlerException) __docformat__ = 'restructuredtext' _logger = logging.getLogger('dbus.proxies') from _dbus_bindings import ( BUS_DAEMON_IFACE, BUS_DAEMON_NAME, BUS_DAEMON_PATH, INTROSPECTABLE_IFACE, LOCAL_PATH) from dbus._compat import is_py2 class _DeferredMethod: """A proxy method which will only get called once we have its introspection reply. """ def __init__(self, proxy_method, append, block): self._proxy_method = proxy_method # the test suite relies on the existence of this property self._method_name = proxy_method._method_name self._append = append self._block = block def __call__(self, *args, **keywords): if ('reply_handler' in keywords or keywords.get('ignore_reply', False)): # defer the async call til introspection finishes self._append(self._proxy_method, args, keywords) return None else: # we're being synchronous, so block self._block() return self._proxy_method(*args, **keywords) def call_async(self, *args, **keywords): self._append(self._proxy_method, args, keywords) class _ProxyMethod: """A proxy method. Typically a member of a ProxyObject. Calls to the method produce messages that travel over the Bus and are routed to a specific named Service. """ def __init__(self, proxy, connection, bus_name, object_path, method_name, iface): if object_path == LOCAL_PATH: raise DBusException('Methods may not be called on the reserved ' 'path %s' % LOCAL_PATH) # trust that the proxy, and the properties it had, are OK self._proxy = proxy self._connection = connection self._named_service = bus_name self._object_path = object_path # fail early if the method name is bad _dbus_bindings.validate_member_name(method_name) # the test suite relies on the existence of this property self._method_name = method_name # fail early if the interface name is bad if iface is not None: _dbus_bindings.validate_interface_name(iface) self._dbus_interface = iface def __call__(self, *args, **keywords): reply_handler = keywords.pop('reply_handler', None) error_handler = keywords.pop('error_handler', None) ignore_reply = keywords.pop('ignore_reply', False) signature = keywords.pop('signature', None) if reply_handler is not None or error_handler is not None: if reply_handler is None: raise MissingReplyHandlerException() elif error_handler is None: raise MissingErrorHandlerException() elif ignore_reply: raise TypeError('ignore_reply and reply_handler cannot be ' 'used together') dbus_interface = keywords.pop('dbus_interface', self._dbus_interface) if signature is None: if dbus_interface is None: key = self._method_name else: key = dbus_interface + '.' + self._method_name signature = self._proxy._introspect_method_map.get(key, None) if ignore_reply or reply_handler is not None: self._connection.call_async(self._named_service, self._object_path, dbus_interface, self._method_name, signature, args, reply_handler, error_handler, **keywords) else: return self._connection.call_blocking(self._named_service, self._object_path, dbus_interface, self._method_name, signature, args, **keywords) def call_async(self, *args, **keywords): reply_handler = keywords.pop('reply_handler', None) error_handler = keywords.pop('error_handler', None) signature = keywords.pop('signature', None) dbus_interface = keywords.pop('dbus_interface', self._dbus_interface) if signature is None: if dbus_interface: key = dbus_interface + '.' + self._method_name else: key = self._method_name signature = self._proxy._introspect_method_map.get(key, None) self._connection.call_async(self._named_service, self._object_path, dbus_interface, self._method_name, signature, args, reply_handler, error_handler, **keywords) class ProxyObject(object): """A proxy to the remote Object. A ProxyObject is provided by the Bus. ProxyObjects have member functions, and can be called like normal Python objects. """ ProxyMethodClass = _ProxyMethod DeferredMethodClass = _DeferredMethod INTROSPECT_STATE_DONT_INTROSPECT = 0 INTROSPECT_STATE_INTROSPECT_IN_PROGRESS = 1 INTROSPECT_STATE_INTROSPECT_DONE = 2 def __init__(self, conn=None, bus_name=None, object_path=None, introspect=True, follow_name_owner_changes=False, **kwargs): """Initialize the proxy object. :Parameters: `conn` : `dbus.connection.Connection` The bus or connection on which to find this object. The keyword argument `bus` is a deprecated alias for this. `bus_name` : str A bus name for the application owning the object, to be used as the destination for method calls and the sender for signal matches. The keyword argument ``named_service`` is a deprecated alias for this. `object_path` : str The object path at which the application exports the object `introspect` : bool If true (default), attempt to introspect the remote object to find out supported methods and their signatures `follow_name_owner_changes` : bool If true (default is false) and the `bus_name` is a well-known name, follow ownership changes for that name """ bus = kwargs.pop('bus', None) if bus is not None: if conn is not None: raise TypeError('conn and bus cannot both be specified') conn = bus from warnings import warn warn('Passing the bus parameter to ProxyObject by name is ' 'deprecated: please use positional parameters', DeprecationWarning, stacklevel=2) named_service = kwargs.pop('named_service', None) if named_service is not None: if bus_name is not None: raise TypeError('bus_name and named_service cannot both be ' 'specified') bus_name = named_service from warnings import warn warn('Passing the named_service parameter to ProxyObject by name ' 'is deprecated: please use positional parameters', DeprecationWarning, stacklevel=2) if kwargs: raise TypeError('ProxyObject.__init__ does not take these ' 'keyword arguments: %s' % ', '.join(kwargs.keys())) if follow_name_owner_changes: # we don't get the signals unless the Bus has a main loop # XXX: using Bus internals conn._require_main_loop() self._bus = conn if bus_name is not None: _dbus_bindings.validate_bus_name(bus_name) # the attribute is still called _named_service for the moment, # for the benefit of telepathy-python self._named_service = self._requested_bus_name = bus_name _dbus_bindings.validate_object_path(object_path) self.__dbus_object_path__ = object_path if not follow_name_owner_changes: self._named_service = conn.activate_name_owner(bus_name) #PendingCall object for Introspect call self._pending_introspect = None #queue of async calls waiting on the Introspect to return self._pending_introspect_queue = [] #dictionary mapping method names to their input signatures self._introspect_method_map = {} # must be a recursive lock because block() is called while locked, # and calls the callback which re-takes the lock self._introspect_lock = RLock() if not introspect or self.__dbus_object_path__ == LOCAL_PATH: self._introspect_state = self.INTROSPECT_STATE_DONT_INTROSPECT else: self._introspect_state = self.INTROSPECT_STATE_INTROSPECT_IN_PROGRESS self._pending_introspect = self._Introspect() bus_name = property(lambda self: self._named_service, None, None, """The bus name to which this proxy is bound. (Read-only, may change.) If the proxy was instantiated using a unique name, this property is that unique name. If the proxy was instantiated with a well-known name and with ``follow_name_owner_changes`` set false (the default), this property is the unique name of the connection that owned that well-known name when the proxy was instantiated, which might not actually own the requested well-known name any more. If the proxy was instantiated with a well-known name and with ``follow_name_owner_changes`` set true, this property is that well-known name. """) requested_bus_name = property(lambda self: self._requested_bus_name, None, None, """The bus name which was requested when this proxy was instantiated. """) object_path = property(lambda self: self.__dbus_object_path__, None, None, """The object-path of this proxy.""") # XXX: We don't currently support this because it's the signal receiver # that's responsible for tracking name owner changes, but it # seems a natural thing to add in future. #unique_bus_name = property(lambda self: something, None, None, # """The unique name of the connection to which this proxy is # currently bound. (Read-only, may change.) # """) def connect_to_signal(self, signal_name, handler_function, dbus_interface=None, **keywords): """Arrange for the given function to be called when the given signal is received. :Parameters: `signal_name` : str The name of the signal `handler_function` : callable A function to be called when the signal is emitted by the remote object. Its positional arguments will be the arguments of the signal; optionally, it may be given keyword arguments as described below. `dbus_interface` : str Optional interface with which to qualify the signal name. If None (the default) the handler will be called whenever a signal of the given member name is received, whatever its interface. :Keywords: `utf8_strings` : bool If True, the handler function will receive any string arguments as dbus.UTF8String objects (a subclass of str guaranteed to be UTF-8). If False (default) it will receive any string arguments as dbus.String objects (a subclass of unicode). `byte_arrays` : bool If True, the handler function will receive any byte-array arguments as dbus.ByteArray objects (a subclass of str). If False (default) it will receive any byte-array arguments as a dbus.Array of dbus.Byte (subclasses of: a list of ints). `sender_keyword` : str If not None (the default), the handler function will receive the unique name of the sending endpoint as a keyword argument with this name `destination_keyword` : str If not None (the default), the handler function will receive the bus name of the destination (or None if the signal is a broadcast, as is usual) as a keyword argument with this name. `interface_keyword` : str If not None (the default), the handler function will receive the signal interface as a keyword argument with this name. `member_keyword` : str If not None (the default), the handler function will receive the signal name as a keyword argument with this name. `path_keyword` : str If not None (the default), the handler function will receive the object-path of the sending object as a keyword argument with this name `message_keyword` : str If not None (the default), the handler function will receive the `dbus.lowlevel.SignalMessage` as a keyword argument with this name. `arg...` : unicode or UTF-8 str If there are additional keyword parameters of the form ``arg``\ *n*, match only signals where the *n*\ th argument is the value given for that keyword parameter. As of this time only string arguments can be matched (in particular, object paths and signatures can't). """ return \ self._bus.add_signal_receiver(handler_function, signal_name=signal_name, dbus_interface=dbus_interface, bus_name=self._named_service, path=self.__dbus_object_path__, **keywords) def _Introspect(self): kwargs = {} if is_py2: kwargs['utf8_strings'] = True return self._bus.call_async(self._named_service, self.__dbus_object_path__, INTROSPECTABLE_IFACE, 'Introspect', '', (), self._introspect_reply_handler, self._introspect_error_handler, require_main_loop=False, **kwargs) def _introspect_execute_queue(self): # FIXME: potential to flood the bus # We should make sure mainloops all have idle handlers # and do one message per idle for (proxy_method, args, keywords) in self._pending_introspect_queue: proxy_method(*args, **keywords) self._pending_introspect_queue = [] def _introspect_reply_handler(self, data): self._introspect_lock.acquire() try: try: self._introspect_method_map = process_introspection_data(data) except IntrospectionParserException as e: self._introspect_error_handler(e) return self._introspect_state = self.INTROSPECT_STATE_INTROSPECT_DONE self._pending_introspect = None self._introspect_execute_queue() finally: self._introspect_lock.release() def _introspect_error_handler(self, error): logging.basicConfig() _logger.error("Introspect error on %s:%s: %s.%s: %s", self._named_service, self.__dbus_object_path__, error.__class__.__module__, error.__class__.__name__, error) self._introspect_lock.acquire() try: _logger.debug('Executing introspect queue due to error') self._introspect_state = self.INTROSPECT_STATE_DONT_INTROSPECT self._pending_introspect = None self._introspect_execute_queue() finally: self._introspect_lock.release() def _introspect_block(self): self._introspect_lock.acquire() try: if self._pending_introspect is not None: self._pending_introspect.block() # else someone still has a _DeferredMethod from before we # finished introspection: no need to do anything special any more finally: self._introspect_lock.release() def _introspect_add_to_queue(self, callback, args, kwargs): self._introspect_lock.acquire() try: if self._introspect_state == self.INTROSPECT_STATE_INTROSPECT_IN_PROGRESS: self._pending_introspect_queue.append((callback, args, kwargs)) else: # someone still has a _DeferredMethod from before we # finished introspection callback(*args, **kwargs) finally: self._introspect_lock.release() def __getattr__(self, member): if member.startswith('__') and member.endswith('__'): raise AttributeError(member) else: return self.get_dbus_method(member) def get_dbus_method(self, member, dbus_interface=None): """Return a proxy method representing the given D-Bus method. The returned proxy method can be called in the usual way. For instance, :: proxy.get_dbus_method("Foo", dbus_interface='com.example.Bar')(123) is equivalent to:: proxy.Foo(123, dbus_interface='com.example.Bar') or even:: getattr(proxy, "Foo")(123, dbus_interface='com.example.Bar') However, using `get_dbus_method` is the only way to call D-Bus methods with certain awkward names - if the author of a service implements a method called ``connect_to_signal`` or even ``__getattr__``, you'll need to use `get_dbus_method` to call them. For services which follow the D-Bus convention of CamelCaseMethodNames this won't be a problem. """ ret = self.ProxyMethodClass(self, self._bus, self._named_service, self.__dbus_object_path__, member, dbus_interface) # this can be done without taking the lock - the worst that can # happen is that we accidentally return a _DeferredMethod just after # finishing introspection, in which case _introspect_add_to_queue and # _introspect_block will do the right thing anyway if self._introspect_state == self.INTROSPECT_STATE_INTROSPECT_IN_PROGRESS: ret = self.DeferredMethodClass(ret, self._introspect_add_to_queue, self._introspect_block) return ret def __repr__(self): return '<ProxyObject wrapping %s %s %s at %#x>'%( self._bus, self._named_service, self.__dbus_object_path__, id(self)) __str__ = __repr__ class Interface(object): """An interface into a remote object. An Interface can be used to wrap ProxyObjects so that calls can be routed to their correct D-Bus interface. """ def __init__(self, object, dbus_interface): """Construct a proxy for the given interface on the given object. :Parameters: `object` : `dbus.proxies.ProxyObject` or `dbus.Interface` The remote object or another of its interfaces `dbus_interface` : str An interface the `object` implements """ if isinstance(object, Interface): self._obj = object.proxy_object else: self._obj = object self._dbus_interface = dbus_interface object_path = property (lambda self: self._obj.object_path, None, None, "The D-Bus object path of the underlying object") __dbus_object_path__ = object_path bus_name = property (lambda self: self._obj.bus_name, None, None, "The bus name to which the underlying proxy object " "is bound") requested_bus_name = property (lambda self: self._obj.requested_bus_name, None, None, "The bus name which was requested when the " "underlying object was created") proxy_object = property (lambda self: self._obj, None, None, """The underlying proxy object""") dbus_interface = property (lambda self: self._dbus_interface, None, None, """The D-Bus interface represented""") def connect_to_signal(self, signal_name, handler_function, dbus_interface=None, **keywords): """Arrange for a function to be called when the given signal is emitted. The parameters and keyword arguments are the same as for `dbus.proxies.ProxyObject.connect_to_signal`, except that if `dbus_interface` is None (the default), the D-Bus interface that was passed to the `Interface` constructor is used. """ if not dbus_interface: dbus_interface = self._dbus_interface return self._obj.connect_to_signal(signal_name, handler_function, dbus_interface, **keywords) def __getattr__(self, member): if member.startswith('__') and member.endswith('__'): raise AttributeError(member) else: return self._obj.get_dbus_method(member, self._dbus_interface) def get_dbus_method(self, member, dbus_interface=None): """Return a proxy method representing the given D-Bus method. This is the same as `dbus.proxies.ProxyObject.get_dbus_method` except that if `dbus_interface` is None (the default), the D-Bus interface that was passed to the `Interface` constructor is used. """ if dbus_interface is None: dbus_interface = self._dbus_interface return self._obj.get_dbus_method(member, dbus_interface) def __repr__(self): return '<Interface %r implementing %r at %#x>'%( self._obj, self._dbus_interface, id(self)) __str__ = __repr__