Connet set attribute to signal (alternate)

psygnal/_signal.py

@@ -17,18 +17,33 @@
     List,
     NoReturn,
     Optional,
+    Protocol,
     Tuple,
     Type,
     Union,
     cast,
     overload,
+    runtime_checkable,
 )
 
 from typing_extensions import Literal, get_args, get_origin, get_type_hints
 
+
+@runtime_checkable
+class CallbackBase(Protocol):
+    def alive(self) -> bool:
+        ...
+
+    def __eq__(self, other: Any) -> bool:
+        ...
+
+    def __call__(self, *args: Any, **kwargs: Any) -> Any:
+        ...
+
+
 MethodRef = Tuple["weakref.ReferenceType[object]", Union[Callable, str]]
-NormedCallback = Union[MethodRef, Callable]
-StoredSlot = Tuple[NormedCallback, Optional[int]]
+NormedCallback = Union[MethodRef, Callable, CallbackBase]
+StoredSlot = Tuple[CallbackBase, Optional[int]]
 AnyType = Type[Any]
 ReducerFunc = Callable[[tuple, tuple], tuple]
 _NULL = object()
@@ -411,6 +426,28 @@ def _wrapper(slot: Callable) -> Callable:
 
         return _wrapper(slot) if slot else _wrapper
 
+    def connect_property(
+        self, obj: Any, name: str, maxargs: Optional[int] = None
+    ) -> None:
+        """
+        Connect property by name.
+
+        Parameters
+        ----------
+        obj : Any
+            object which property should be set
+        name: str
+            name of property
+        maxargs: int, optional
+            numer of arguments to be added
+        """
+        with self._lock:
+            self._slots.append(
+                (PropertyWeakrefCallback(obj, name), maxargs)  # type: ignore
+            )
+            # mypy does not see that PropertyWeakrefCallback
+            # implements CallbackBase protocol
+
     def _check_nargs(
         self, slot: Callable, spec: Signature
     ) -> Tuple[Optional[Signature], Optional[int]]:
@@ -444,14 +481,24 @@ def _raise_connection_error(self, slot: Callable, extra: str = "") -> NoReturn:
         msg += f"\n\nAccepted signature: {self.signature}"
         raise ValueError(msg)
 
-    def _normalize_slot(self, slot: NormedCallback) -> NormedCallback:
+    def _normalize_slot(self, slot: NormedCallback) -> CallbackBase:
+        if isinstance(slot, CallbackBase):
+            return slot
         if isinstance(slot, MethodType):
-            return _get_proper_name(slot)
+            return MethodWeakrefCallback(slot)
         if isinstance(slot, PartialMethod):
-            return _partial_weakref(slot)
-        if isinstance(slot, tuple) and not isinstance(slot[0], weakref.ref):
-            return (weakref.ref(slot[0]), slot[1])
-        return slot
+            return PartialWeakrefCallback(slot)
+        if isinstance(slot, tuple):
+            if isinstance(slot[1], str):
+                target = (
+                    getattr(slot[0](), slot[1])
+                    if isinstance(slot[0], weakref.ref)
+                    else getattr(slot[0], slot[1])
+                )
+            else:
+                target = slot[1]
+            return MethodWeakrefCallback(target)
+        return FunctionCallback(slot)
 
     def _slot_index(self, slot: NormedCallback) -> int:
         """Get index of `slot` in `self._slots`.  Return -1 if not connected."""
@@ -493,6 +540,33 @@ def disconnect(
             elif not missing_ok:
                 raise ValueError(f"slot is not connected: {slot}")
 
+    def disconnect_property(self, obj: Any, name: str, missing_ok: bool = True) -> None:
+        """Disconnect slot from signal.
+
+        Parameters
+        ----------
+        obj : Any
+            object which property should be set
+        name: str
+            name of property
+        missing_ok : bool, optional
+            If `False` and the provided `slot` is not connected, raises `ValueError.
+            by default `True`
+
+        Raises
+        ------
+        ValueError
+            If `slot` is not connected and `missing_ok` is False.
+        """
+        with self._lock:
+            slot = PropertyWeakrefCallback(obj, name)
+
+            idx = self._slot_index(slot)
+            if idx != -1:
+                self._slots.pop(idx)
+            elif not missing_ok:
+                raise ValueError(f"slot is not connected: {slot}")
+
     def __contains__(self, slot: NormedCallback) -> bool:
         """Return `True` if slot is connected."""
         return self._slot_index(slot) >= 0
@@ -626,29 +700,16 @@ def __call__(
         )
 
     def _run_emit_loop(self, args: Tuple[Any, ...]) -> None:
-        rem: List[NormedCallback] = []
+        rem: List[CallbackBase] = []
         # allow receiver to query sender with Signal.current_emitter()
         with self._lock:
             with Signal._emitting(self):
                 for (slot, max_args) in self._slots:
-                    if isinstance(slot, tuple):
-                        _ref, method = slot
-                        obj = _ref()
-                        if obj is None:
-                            rem.append(slot)  # add dead weakref
-                            continue
-                        if callable(method):
-                            cb = method
-                        else:
-                            cb = getattr(obj, method, None)
-                            if cb is None:  # pragma: no cover
-                                rem.append(slot)  # object has changed?
-                                continue
-                    else:
-                        cb = slot
-
+                    if not slot.alive():
+                        rem.append(slot)
+                        continue
                     # TODO: add better exception handling
-                    cb(*args[:max_args])
+                    slot(*args[:max_args])
 
             for slot in rem:
                 self.disconnect(slot)
@@ -940,6 +1001,89 @@ def wrap(*args: Any, **kwargs: Any) -> Any:
     return (ref, wrap)
 
 
+class FunctionCallback:
+    def __init__(self, func: Callable):
+        self.func = func
+
+    def alive(self) -> bool:
+        return True
+
+    def __call__(self, *args: Any, **kwargs: Any) -> Any:
+        self.func(*args, **kwargs)
+
+    def __eq__(self, other: Any) -> bool:
+        return isinstance(other, FunctionCallback) and self.func == other.func
+
+
+class MethodWeakrefCallback:
+    def __init__(self, slot: MethodType):
+        self.obj, self.name = _get_proper_name(slot)
+
+    def alive(self) -> bool:
+        return self.obj() is not None
+
+    def __call__(self, *args: Any, **kwargs: Any) -> Any:
+        return getattr(self.obj(), self.name)(*args, **kwargs)
+
+    def __eq__(self, other: Any) -> bool:
+        return (
+            isinstance(other, MethodWeakrefCallback)
+            and self.name == other.name
+            and self.obj() == other.obj()
+        )
+
+
+class PartialWeakrefCallback:
+    def __init__(self, slot_partial: PartialMethod):
+        self.obj, self.name = _get_proper_name(slot_partial.func)
+        self.args = slot_partial.args
+        self.kwargs = slot_partial.keywords
+
+    def alive(self) -> bool:
+        return self.obj() is not None
+
+    def __call__(self, *args: Any, **kwargs: Any) -> Any:
+        return getattr(self.obj(), self.name)(
+            *self.args, *args, **self.kwargs, **kwargs
+        )
+
+    def __eq__(self, other: Any) -> bool:
+        try:
+            return (
+                isinstance(other, PartialWeakrefCallback)
+                and self.name == other.name
+                and self.obj() == other.obj()
+                and self.args == other.args
+                and self.kwargs == other.kwargs
+            )
+        except:  # noqa: E722
+            return False
+
+
+class PropertyWeakrefCallback:
+    def __init__(self, obj: Union[weakref.ref, object], name: str):
+        if not isinstance(obj, weakref.ref):
+            obj = weakref.ref(obj)
+        self.obj = obj
+        self.name = name
+
+    def alive(self) -> bool:
+        return self.obj() is not None
+
+    def __call__(self, *args: Any) -> None:
+        if len(args) == 1:
+            setattr(self.obj(), self.name, args[0])
+        else:
+            setattr(self.obj(), self.name, args)
+
+    def __eq__(self, other: Any) -> bool:
+        return (
+            isinstance(other, PropertyWeakrefCallback)
+            and self.name == other.name
+            and self.obj() == other.obj()
+        )
+
+
 def _get_proper_name(slot: MethodType) -> Tuple[weakref.ref, str]:
     obj = slot.__self__
     # some decorators will alter method.__name__, so that obj.method

tests/test_psygnal.py

@@ -3,14 +3,13 @@
 import weakref
 from functools import partial, wraps
 from inspect import Signature
-from types import FunctionType
 from typing import Optional
 from unittest.mock import MagicMock, call
 
 import pytest
 
 from psygnal import Signal, SignalInstance
-from psygnal._signal import _get_proper_name
+from psygnal._signal import FunctionCallback, MethodWeakrefCallback, _get_proper_name
 
 
 def stupid_decorator(fun):
@@ -216,14 +215,13 @@ def test_slot_types():
     # connecting same function twice is (currently) OK
     emitter.one_int.connect(f_int)
     assert len(emitter.one_int._slots) == 3
-    assert isinstance(emitter.one_int._slots[-1][0], FunctionType)
+    assert isinstance(emitter.one_int._slots[-1][0], FunctionCallback)
 
     # bound methods
     obj = MyObj()
     emitter.one_int.connect(obj.f_int)
     assert len(emitter.one_int._slots) == 4
-    assert isinstance(emitter.one_int._slots[-1][0], tuple)
-    assert isinstance(emitter.one_int._slots[-1][0][0], weakref.ref)
+    assert isinstance(emitter.one_int._slots[-1][0], MethodWeakrefCallback)
 
     with pytest.raises(TypeError):
         emitter.one_int.connect("not a callable")  # type: ignore
@@ -317,6 +315,36 @@ def test_weakref(slot):
     assert len(emitter.one_int) == 0
 
 
+def test_property_connect():
+    class A:
+        def __init__(self):
+            self.li = []
+
+        @property
+        def x(self):
+            return self.li
+
+        @x.setter
+        def x(self, value):
+            self.li.append(value)
+
+    a = A()
+    emitter = Emitter()
+    emitter.one_int.connect_property(a, "x")
+    assert len(emitter.one_int) == 1
+    emitter.two_int.connect_property(a, "x")
+    assert len(emitter.two_int) == 1
+    emitter.one_int.emit(1)
+    assert a.li == [1]
+    emitter.two_int.emit(1, 1)
+    assert a.li == [1, (1, 1)]
+    emitter.two_int.disconnect_property(a, "x")
+    assert len(emitter.two_int) == 0
+    emitter.two_int.connect_property(a, "x", maxargs=1)
+    emitter.two_int.emit(2, 3)
+    assert a.li == [1, (1, 1), 2]
+
+
 def test_norm_slot():
     e = Emitter()
     r = MyObj()
@@ -325,10 +353,11 @@ def test_norm_slot():
     normed2 = e.one_int._normalize_slot(normed1)
     normed3 = e.one_int._normalize_slot((r, "f_any"))
     normed3 = e.one_int._normalize_slot((weakref.ref(r), "f_any"))
-    assert normed1 == (weakref.ref(r), "f_any")
+    assert isinstance(normed1, MethodWeakrefCallback)
+    assert (normed1.obj, normed1.name) == (weakref.ref(r), "f_any")
     assert normed1 == normed2 == normed3
 
-    assert e.one_int._normalize_slot(f_any) == f_any
+    assert e.one_int._normalize_slot(f_any) == FunctionCallback(f_any)
 
 
 ALL = {n for n, f in locals().items() if callable(f) and n.startswith("f_")}
@@ -550,7 +579,19 @@ def test_pause():
     emitter.one_int.emit(3)
     mock.assert_not_called()
     emitter.one_int.resume()
-    mock.assert_has_calls([call(1), call(2), call(3)])
+    mock.assert_has_calls(
+        [
+            call.alive(),
+            call.alive().__bool__(),
+            call(1),
+            call.alive(),
+            call.alive().__bool__(),
+            call(2),
+            call.alive(),
+            call.alive().__bool__(),
+            call(3),
+        ]
+    )
 
     mock.reset_mock()
     with emitter.one_int.paused(lambda a, b: (a[0].union(set(b)),), (set(),)):