1 # -*- Mode: Python; py-indent-offset: 4 -*-
2 # pygobject - Python bindings for the GObject library
3 # Copyright (C) 2012 Simon Feltman
5 # gi/_signalhelper.py: GObject signal binding decorator object
7 # This library is free software; you can redistribute it and/or
8 # modify it under the terms of the GNU Lesser General Public
9 # License as published by the Free Software Foundation; either
10 # version 2.1 of the License, or (at your option) any later version.
12 # This library is distributed in the hope that it will be useful,
13 # but WITHOUT ANY WARRANTY; without even the implied warranty of
14 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 # Lesser General Public License for more details.
17 # You should have received a copy of the GNU Lesser General Public
18 # License along with this library; if not, see <http://www.gnu.org/licenses/>.
24 """Object which gives a nice API for creating and binding signals.
27 Name of signal or callable closure when used as a decorator.
28 :type name: str or callable
30 Callable closure method.
31 :param GObject.SignalFlags flags:
32 Flags specifying when to run closure.
33 :param type return_type:
34 Return type of the Signal.
35 :param list arg_types:
36 List of argument types specifying the signals function signature
38 Documentation of signal object.
39 :param callable accumulator:
40 Accumulator method with the signature:
41 func(ihint, return_accu, handler_return, accu_data) -> boolean
42 :param object accu_data:
43 User data passed to the accumulator.
47 .. code-block:: python
49 class Spam(GObject.Object):
56 @GObject.Signal(flags=GObject.SignalFlags.RUN_LAST)
60 stomped = GObject.Signal('stomped', arg_types=(int,))
63 def annotated_signal(self, a:int, b:str):
64 "Python3 annotation support for parameter types.
70 spam.pushed.connect(on_pushed)
73 class BoundSignal(str):
75 Temporary binding object which can be used for connecting signals
76 without specifying the signal name string to connect.
78 def __new__(cls
, name
, *args
, **kargs
):
79 return str.__new
__(cls
, name
)
81 def __init__(self
, signal
, gobj
):
87 return 'BoundSignal("%s")' % self
89 def __call__(self
, *args
, **kargs
):
90 """Call the signals closure."""
91 return self
.signal
.func(self
.gobj
, *args
, **kargs
)
93 def connect(self
, callback
, *args
, **kargs
):
94 """Same as GObject.Object.connect except there is no need to specify
96 return self
.gobj
.connect(self
, callback
, *args
, **kargs
)
98 def connect_detailed(self
, callback
, detail
, *args
, **kargs
):
99 """Same as GObject.Object.connect except there is no need to specify
100 the signal name. In addition concats "::<detail>" to the signal name
101 when connecting; for use with notifications like "notify" when a property
104 return self
.gobj
.connect(self
+ '::' + detail
, callback
, *args
, **kargs
)
106 def disconnect(self
, handler_id
):
107 """Same as GObject.Object.disconnect."""
108 self
.gobj
.disconnect(handler_id
)
110 def emit(self
, *args
, **kargs
):
111 """Same as GObject.Object.emit except there is no need to specify
113 return self
.gobj
.emit(str(self
), *args
, **kargs
)
115 def __new__(cls
, name
='', *args
, **kargs
):
118 return str.__new
__(cls
, name
)
120 def __init__(self
, name
='', func
=None, flags
=_gi
.SIGNAL_RUN_FIRST
,
121 return_type
=None, arg_types
=None, doc
='', accumulator
=None, accu_data
=None):
122 if func
is None and callable(name
):
130 if func
and not (return_type
or arg_types
):
131 return_type
, arg_types
= get_signal_annotations(func
)
132 if arg_types
is None:
137 self
.return_type
= return_type
138 self
.arg_types
= arg_types
140 self
.accumulator
= accumulator
141 self
.accu_data
= accu_data
143 def __get__(self
, instance
, owner
=None):
144 """Returns a BoundSignal when accessed on an object instance."""
147 return self
.BoundSignal(self
, instance
)
149 def __call__(self
, obj
, *args
, **kargs
):
150 """Allows for instantiated Signals to be used as a decorator or calling
151 of the underlying signal method."""
153 # If obj is a GObject, than we call this signal as a closure otherwise
154 # it is used as a re-application of a decorator.
155 if isinstance(obj
, _gi
.GObject
):
156 self
.func(obj
, *args
, **kargs
)
158 # If self is already an allocated name, use it otherwise create a new named
159 # signal using the closure name as the name.
164 # Return a new value of this type since it is based on an immutable string.
165 return type(self
)(name
=name
, func
=obj
, flags
=self
.flags
,
166 return_type
=self
.return_type
, arg_types
=self
.arg_types
,
167 doc
=self
.__doc
__, accumulator
=self
.accumulator
, accu_data
=self
.accu_data
)
169 def copy(self
, newName
=None):
170 """Returns a renamed copy of the Signal."""
172 return type(self
)(name
=newName
, func
=self
.func
, flags
=self
.flags
,
173 return_type
=self
.return_type
, arg_types
=self
.arg_types
,
174 doc
=self
.__doc
__, accumulator
=self
.accumulator
, accu_data
=self
.accu_data
)
176 def get_signal_args(self
):
177 """Returns a tuple of: (flags, return_type, arg_types, accumulator, accu_data)"""
178 return (self
.flags
, self
.return_type
, self
.arg_types
, self
.accumulator
, self
.accu_data
)
181 class SignalOverride(Signal
):
182 """Specialized sub-class of Signal which can be used as a decorator for overriding
183 existing signals on GObjects.
187 .. code-block:: python
189 class MyWidget(Gtk.Widget):
190 @GObject.SignalOverride
191 def configure_event(self):
194 def get_signal_args(self
):
195 """Returns the string 'override'."""
199 def get_signal_annotations(func
):
200 """Attempt pulling python 3 function annotations off of 'func' for
201 use as a signals type information. Returns an ordered nested tuple
202 of (return_type, (arg_type1, arg_type2, ...)). If the given function
203 does not have annotations then (None, tuple()) is returned.
208 if hasattr(func
, '__annotations__'):
209 # import inspect only when needed because it takes ~10 msec to load
211 spec
= inspect
.getfullargspec(func
)
212 arg_types
= tuple(spec
.annotations
[arg
] for arg
in spec
.args
213 if arg
in spec
.annotations
)
214 if 'return' in spec
.annotations
:
215 return_type
= spec
.annotations
['return']
217 return return_type
, arg_types
220 def install_signals(cls
):
221 """Adds Signal instances on a GObject derived class into the '__gsignals__'
222 dictionary to be picked up and registered as real GObject signals.
224 gsignals
= cls
.__dict
__.get('__gsignals__', {})
226 for name
, signal
in cls
.__dict
__.items():
227 if isinstance(signal
, Signal
):
228 signalName
= str(signal
)
229 # Fixup a signal which is unnamed by using the class variable name.
230 # Since Signal is based on string which immutable,
231 # we must copy and replace the class variable.
234 signal
= signal
.copy(name
)
235 setattr(cls
, name
, signal
)
236 if signalName
in gsignals
:
237 raise ValueError('Signal "%s" has already been registered.' % name
)
238 newsignals
[signalName
] = signal
239 gsignals
[signalName
] = signal
.get_signal_args()
241 cls
.__gsignals
__ = gsignals
243 # Setup signal closures by adding the specially named
244 # method to the class in the form of "do_<signal_name>".
245 for name
, signal
in newsignals
.items():
246 if signal
.func
is not None:
247 funcName
= 'do_' + name
.replace('-', '_')
248 if not hasattr(cls
, funcName
):
249 setattr(cls
, funcName
, signal
.func
)