"""Service-side D-Bus decorators."""

# Copyright (C) 2003, 2004, 2005, 2006 Red Hat Inc. <http://www.redhat.com/>

# Copyright (C) 2003 David Zeuthen

# Copyright (C) 2004 Rob Taylor

# Copyright (C) 2005, 2006 Collabora Ltd. <http://www.collabora.co.uk/>

#

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__all__ = ('method', 'signal')

__docformat__ = 'restructuredtext'

import inspect

from dbus import validate_interface_name, Signature, validate_member_name

from dbus.lowlevel import SignalMessage

from dbus.exceptions import DBusException

from dbus._compat import is_py2

def method(dbus_interface, in_signature=None, out_signature=None,

           async_callbacks=None,

           sender_keyword=None, path_keyword=None, destination_keyword=None,

           message_keyword=None, connection_keyword=None,

           byte_arrays=False,

           rel_path_keyword=None, **kwargs):

    """Factory for decorators used to mark methods of a `dbus.service.Object`

    to be exported on the D-Bus.

    The decorated method will be exported over D-Bus as the method of the

    same name on the given D-Bus interface.

    :Parameters:

        `dbus_interface` : str

            Name of a D-Bus interface

        `in_signature` : str or None

            If not None, the signature of the method parameters in the usual

            D-Bus notation

        `out_signature` : str or None

            If not None, the signature of the return value in the usual

            D-Bus notation

        `async_callbacks` : tuple containing (str,str), or None

            If None (default) the decorated method is expected to return

            values matching the `out_signature` as usual, or raise

            an exception on error. If not None, the following applies:

            `async_callbacks` contains the names of two keyword arguments to

            the decorated function, which will be used to provide a success

            callback and an error callback (in that order).

            When the decorated method is called via the D-Bus, its normal

            return value will be ignored; instead, a pair of callbacks are

            passed as keyword arguments, and the decorated method is

            expected to arrange for one of them to be called.

            On success the success callback must be called, passing the

            results of this method as positional parameters in the format

            given by the `out_signature`.

            On error the decorated method may either raise an exception

            before it returns, or arrange for the error callback to be

            called with an Exception instance as parameter.

        `sender_keyword` : str or None

            If not None, contains the name of a keyword argument to the

            decorated function, conventionally ``'sender'``. When the

            method is called, the sender's unique name will be passed as

            this keyword argument.

        `path_keyword` : str or None

            If not None (the default), the decorated method will receive

            the destination object path as a keyword argument with this

            name. Normally you already know the object path, but in the

            case of "fallback paths" you'll usually want to use the object

            path in the method's implementation.

            For fallback objects, `rel_path_keyword` (new in 0.82.2) is

            likely to be more useful.

            :Since: 0.80.0?

        `rel_path_keyword` : str or None

            If not None (the default), the decorated method will receive

            the destination object path, relative to the path at which the

            object was exported, as a keyword argument with this

            name. For non-fallback objects the relative path will always be

            '/'.

            :Since: 0.82.2

        `destination_keyword` : str or None

            If not None (the default), the decorated method will receive

            the destination bus name as a keyword argument with this name.

            Included for completeness - you shouldn't need this.

            :Since: 0.80.0?

        `message_keyword` : str or None

            If not None (the default), the decorated method will receive

            the `dbus.lowlevel.MethodCallMessage` as a keyword argument

            with this name.

            :Since: 0.80.0?

        `connection_keyword` : str or None

            If not None (the default), the decorated method will receive

            the `dbus.connection.Connection` as a keyword argument

            with this name. This is generally only useful for objects

            that are available on more than one connection.

            :Since: 0.82.0

        `utf8_strings` : bool

            If False (default), D-Bus strings are passed to the decorated

            method as objects of class dbus.String, a unicode subclass.

            If True, D-Bus strings are passed to the decorated method

            as objects of class dbus.UTF8String, a str subclass guaranteed

            to be encoded in UTF-8.

            This option does not affect object-paths and signatures, which

            are always 8-bit strings (str subclass) encoded in ASCII.

            :Since: 0.80.0

        `byte_arrays` : bool

            If False (default), a byte array will be passed to the decorated

            method as an `Array` (a list subclass) of `Byte` objects.

            If True, a byte array will be passed to the decorated method as

            a `ByteArray`, a str subclass. This is usually what you want,

            but is switched off by default to keep dbus-python's API

            consistent.

            :Since: 0.80.0

    """

    validate_interface_name(dbus_interface)

    def decorator(func):

        if hasattr(inspect, 'Signature'):

            args = []

            for arg in inspect.signature(func).parameters.values():

                if arg.kind in (inspect.Parameter.POSITIONAL_ONLY,

                        inspect.Parameter.POSITIONAL_OR_KEYWORD):

                    args.append(arg.name)

        else:

            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 rel_path_keyword:

            args.remove(rel_path_keyword)

        if path_keyword:

            args.remove(path_keyword)

        if destination_keyword:

            args.remove(destination_keyword)

        if message_keyword:

            args.remove(message_keyword)

        if connection_keyword:

            args.remove(connection_keyword)

        if in_signature:

            in_sig = tuple(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_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_path_keyword = path_keyword

        func._dbus_rel_path_keyword = rel_path_keyword

        func._dbus_destination_keyword = destination_keyword

        func._dbus_message_keyword = message_keyword

        func._dbus_connection_keyword = connection_keyword

        func._dbus_args = args

        func._dbus_get_args_options = dict(byte_arrays=byte_arrays)

        if is_py2:

            func._dbus_get_args_options['utf8_strings'] = kwargs.get(

                'utf8_strings', False)

        elif 'utf8_strings' in kwargs:

            raise TypeError("unexpected keyword argument 'utf8_strings'")

        return func

    return decorator

def signal(dbus_interface, signature=None, path_keyword=None,

           rel_path_keyword=None):

    """Factory for decorators used to mark methods of a `dbus.service.Object`

    to emit signals on the D-Bus.

    Whenever the decorated method is called in Python, after the method

    body is executed, a signal with the same name as the decorated method,

    with the given D-Bus interface, will be emitted from this object.

    :Parameters:

        `dbus_interface` : str

            The D-Bus interface whose signal is emitted

        `signature` : str

            The signature of the signal in the usual D-Bus notation

        `path_keyword` : str or None

            A keyword argument to the decorated method. If not None,

            that argument will not be emitted as an argument of

            the signal, and when the signal is emitted, it will appear

            to come from the object path given by the keyword argument.

            Note that when calling the decorated method, you must always

            pass in the object path as a keyword argument, not as a

            positional argument.

            This keyword argument cannot be used on objects where

            the class attribute ``SUPPORTS_MULTIPLE_OBJECT_PATHS`` is true.

            :Deprecated: since 0.82.0. Use `rel_path_keyword` instead.

        `rel_path_keyword` : str or None

            A keyword argument to the decorated method. If not None,

            that argument will not be emitted as an argument of

            the signal.

            When the signal is emitted, if the named keyword argument is given,

            the signal will appear to come from the object path obtained by

            appending the keyword argument to the object's object path.

            This is useful to implement "fallback objects" (objects which

            own an entire subtree of the object-path tree).

            If the object is available at more than one object-path on the

            same or different connections, the signal will be emitted at

            an appropriate object-path on each connection - for instance,

            if the object is exported at /abc on connection 1 and at

            /def and /x/y/z on connection 2, and the keyword argument is

            /foo, then signals will be emitted from /abc/foo and /def/foo

            on connection 1, and /x/y/z/foo on connection 2.

            :Since: 0.82.0

    """

    validate_interface_name(dbus_interface)

    if path_keyword is not None:

        from warnings import warn

        warn(DeprecationWarning('dbus.service.signal::path_keyword has been '

                                'deprecated since dbus-python 0.82.0, and '

                                'will not work on objects that support '

                                'multiple object paths'),

             DeprecationWarning, stacklevel=2)

        if rel_path_keyword is not None:

            raise TypeError('dbus.service.signal::path_keyword and '

                            'rel_path_keyword cannot both be used')

    def decorator(func):

        member_name = func.__name__

        validate_member_name(member_name)

        def emit_signal(self, *args, **keywords):

            abs_path = None

            if path_keyword is not None:

                if self.SUPPORTS_MULTIPLE_OBJECT_PATHS:

                    raise TypeError('path_keyword cannot be used on the '

                                    'signals of an object that supports '

                                    'multiple object paths')

                abs_path = keywords.pop(path_keyword, None)

                if (abs_path != self.__dbus_object_path__ and

                    not self.__dbus_object_path__.startswith(abs_path + '/')):

                    raise ValueError('Path %r is not below %r', abs_path,

                                     self.__dbus_object_path__)

            rel_path = None

            if rel_path_keyword is not None:

                rel_path = keywords.pop(rel_path_keyword, None)

            func(self, *args, **keywords)

            for location in self.locations:

                if abs_path is None:

                    # non-deprecated case

                    if rel_path is None or rel_path in ('/', ''):

                        object_path = location[1]

                    else:

                        # will be validated by SignalMessage ctor in a moment

                        object_path = location[1] + rel_path

                else:

                    object_path = abs_path

                message = SignalMessage(object_path,

                                                       dbus_interface,

                                                       member_name)

                message.append(signature=signature, *args)

                location[0].send_message(message)

        # end emit_signal

        args = inspect.getargspec(func)[0]

        args.pop(0)

        for keyword in rel_path_keyword, path_keyword:

            if keyword is not None:

                try:

                    args.remove(keyword)

                except ValueError:

                    raise ValueError('function has no argument "%s"' % keyword)

        if signature:

            sig = tuple(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