PySetResult and IntoPySetResult

RustPython · youknowone · Feb 2, 2020 · Feb 2, 2020 · Feb 3, 2020 · Feb 3, 2020
commit a5c7a699f0df94ea344af580a4e7b35f56df54b6
diff --git a/vm/src/obj/objgetset.rs b/vm/src/obj/objgetset.rs
@@ -4,13 +4,14 @@
 use super::objtype::PyClassRef;
 use crate::function::{OptionalArg, OwnedParam, RefParam};
 use crate::pyobject::{
-    IntoPyObject, PyClassImpl, PyContext, PyObjectRef, PyRef, PyResult, PyValue, TryFromObject,
+    IntoPyObject, IntoPySetResult, PyClassImpl, PyContext, PyObjectRef, PyRef, PyResult,
+    PySetResult, PyValue, TryFromObject,
 };
 use crate::slots::PyBuiltinDescriptor;
 use crate::vm::VirtualMachine;
 
 pub type PyGetterFunc = Box<dyn Fn(&VirtualMachine, PyObjectRef) -> PyResult>;
-pub type PySetterFunc = Box<dyn Fn(&VirtualMachine, PyObjectRef, PyObjectRef) -> PyResult<()>>;
+pub type PySetterFunc = Box<dyn Fn(&VirtualMachine, PyObjectRef, PyObjectRef) -> PySetResult>;
 
 pub trait IntoPyGetterFunc<T, R> {
     fn into_getter(self) -> PyGetterFunc;
@@ -44,36 +45,41 @@ where
     }
 }
 
-pub trait IntoPySetterFunc<T, V> {
+pub trait IntoPySetterFunc<T, V, R>
+where
+    R: IntoPySetResult,
+{
     fn into_setter(self) -> PySetterFunc;
 }
 
-impl<F, T, V> IntoPySetterFunc<OwnedParam<T>, V> for F
+impl<F, T, V, R> IntoPySetterFunc<OwnedParam<T>, V, R> for F
 where
-    F: Fn(T, V, &VirtualMachine) -> PyResult<()> + 'static,
+    F: Fn(T, V, &VirtualMachine) -> R + 'static,
     T: TryFromObject,
     V: TryFromObject,
+    R: IntoPySetResult,
 {
     fn into_setter(self) -> PySetterFunc {
         Box::new(move |vm, obj, value| {
             let obj = T::try_from_object(vm, obj)?;
             let value = V::try_from_object(vm, value)?;
-            (self)(obj, value, vm)
+            (self)(obj, value, vm).into_pysetresult()
         })
     }
 }
 
-impl<F, S, V> IntoPySetterFunc<RefParam<S>, V> for F
+impl<F, S, V, R> IntoPySetterFunc<RefParam<S>, V, R> for F
 where
-    F: Fn(&S, V, &VirtualMachine) -> PyResult<()> + 'static,
+    F: Fn(&S, V, &VirtualMachine) -> R + 'static,
     S: PyValue,
     V: TryFromObject,
+    R: IntoPySetResult,
 {
     fn into_setter(self) -> PySetterFunc {
         Box::new(move |vm, obj, value| {
             let zelf = PyRef::<S>::try_from_object(vm, obj)?;
             let value = V::try_from_object(vm, value)?;
-            (self)(&zelf, value, vm)
+            (self)(&zelf, value, vm).into_pysetresult()
         })
     }
 }
@@ -145,10 +151,11 @@ impl PyGetSet {
         }
     }
 
-    pub fn with_get_set<G, S, GT, GR, ST, SV>(name: String, getter: G, setter: S) -> Self
+    pub fn with_get_set<G, S, GT, GR, ST, SV, SR>(name: String, getter: G, setter: S) -> Self
     where
         G: IntoPyGetterFunc<GT, GR>,
-        S: IntoPySetterFunc<ST, SV>,
+        S: IntoPySetterFunc<ST, SV, SR>,
+        SR: IntoPySetResult,
     {
         Self {
             name,
@@ -163,7 +170,7 @@ impl PyGetSet {
     // Descriptor methods
 
     #[pymethod(magic)]
-    fn set(&self, obj: PyObjectRef, value: PyObjectRef, vm: &VirtualMachine) -> PyResult<()> {
+    fn set(&self, obj: PyObjectRef, value: PyObjectRef, vm: &VirtualMachine) -> PySetResult {
         if let Some(ref f) = self.setter {
             f(vm, obj, value)
         } else {

diff --git a/vm/src/obj/objobject.rs b/vm/src/obj/objobject.rs
@@ -7,7 +7,7 @@ use crate::function::{OptionalArg, PyFuncArgs};
 use crate::pyhash;
 use crate::pyobject::{
     IdProtocol, ItemProtocol, PyArithmaticValue::*, PyAttributes, PyClassImpl, PyComparisonValue,
-    PyContext, PyObject, PyObjectRef, PyResult, PyValue, TryFromObject, TypeProtocol,
+    PyContext, PyObject, PyObjectRef, PyResult, PySetResult, PyValue, TryFromObject, TypeProtocol,
 };
 use crate::vm::VirtualMachine;
 
@@ -180,7 +180,7 @@ impl PyBaseObject {
     }
 
     #[pyproperty(name = "__class__", setter)]
-    fn set_class(instance: PyObjectRef, _value: PyObjectRef, vm: &VirtualMachine) -> PyResult<()> {
+    fn set_class(instance: PyObjectRef, _value: PyObjectRef, vm: &VirtualMachine) -> PySetResult {
         let type_repr = vm.to_pystr(&instance.class())?;
         Err(vm.new_type_error(format!("can't change class of type '{}'", type_repr)))
     }
@@ -237,7 +237,7 @@ pub(crate) fn setattr(
     attr_name: PyStringRef,
     value: PyObjectRef,
     vm: &VirtualMachine,
-) -> PyResult<()> {
+) -> PySetResult {
     vm_trace!("object.__setattr__({:?}, {}, {:?})", obj, attr_name, value);
     let cls = obj.class();
 

diff --git a/vm/src/obj/objproperty.rs b/vm/src/obj/objproperty.rs
@@ -6,8 +6,8 @@ use std::cell::RefCell;
 use super::objtype::PyClassRef;
 use crate::function::{IntoPyNativeFunc, OptionalArg};
 use crate::pyobject::{
-    IdProtocol, PyClassImpl, PyContext, PyObject, PyObjectRef, PyRef, PyResult, PyValue,
-    TypeProtocol,
+    IdProtocol, IntoPySetResult, PyClassImpl, PyContext, PyObject, PyObjectRef, PyRef, PyResult,
+    PyValue, TypeProtocol,
 };
 use crate::slots::PyBuiltinDescriptor;
 use crate::vm::VirtualMachine;
@@ -259,11 +259,6 @@ pub struct PropertyBuilder<'a> {
     setter: Option<PyObjectRef>,
 }
 
-pub trait PropertySetterResult {}
-
-impl PropertySetterResult for PyResult<()> {}
-impl PropertySetterResult for () {}
-
 impl<'a> PropertyBuilder<'a> {
     pub fn new(ctx: &'a PyContext) -> Self {
         Self {
@@ -282,7 +277,7 @@ impl<'a> PropertyBuilder<'a> {
         }
     }
 
-    pub fn add_setter<I, V, VM, F: IntoPyNativeFunc<(I, V), impl PropertySetterResult, VM>>(
+    pub fn add_setter<I, V, VM, F: IntoPyNativeFunc<(I, V), impl IntoPySetResult, VM>>(
         self,
         func: F,
     ) -> Self {

diff --git a/vm/src/pyobject.rs b/vm/src/pyobject.rs
@@ -67,6 +67,9 @@ pub type PyObjectRef = Rc<PyObject<dyn PyObjectPayload>>;
 /// since exceptions are also python objects.
 pub type PyResult<T = PyObjectRef> = Result<T, PyBaseExceptionRef>; // A valid value, or an exception
 
+/// Use this type for functions which return None or an exception.
+pub type PySetResult = PyResult<()>; // None, or an exception
+
 /// For attributes we do not use a dict, but a hashmap. This is probably
 /// faster, unordered, and only supports strings as keys.
 /// TODO: class attributes should maintain insertion order (use IndexMap here)
@@ -1054,6 +1057,22 @@ where
     }
 }
 
+pub trait IntoPySetResult {
+    fn into_pysetresult(self) -> PySetResult;
+}
+
+impl IntoPySetResult for () {
+    fn into_pysetresult(self) -> PySetResult {
+        Ok(())
+    }
+}
+
+impl IntoPySetResult for PySetResult {
+    fn into_pysetresult(self) -> PySetResult {
+        self
+    }
+}
+
 impl<T> PyObject<T>
 where
     T: Sized + PyObjectPayload,