From 9f5cd17f2bc296ddf97c4e8311000234f8222d43 Mon Sep 17 00:00:00 2001
From: Jeong YunWon <jeong@youknowone.org>
Date: Sun, 2 Feb 2020 21:43:24 +0900
Subject: [PATCH] Add getset_descriptor

---
 vm/src/obj/mod.rs       |  1 +
 vm/src/obj/objgetset.rs | 71 +++++++++++++++++++++++++++++++++++++++++
 vm/src/obj/objobject.rs |  4 +--
 vm/src/pyobject.rs      |  4 +++
 vm/src/types.rs         |  5 +++
 5 files changed, 83 insertions(+), 2 deletions(-)
 create mode 100644 vm/src/obj/objgetset.rs

diff --git a/vm/src/obj/mod.rs b/vm/src/obj/mod.rs
index 57233025d..af5d531d1 100644
--- a/vm/src/obj/mod.rs
+++ b/vm/src/obj/mod.rs
@@ -17,6 +17,7 @@ pub mod objfloat;
 pub mod objframe;
 pub mod objfunction;
 pub mod objgenerator;
+pub mod objgetset;
 pub mod objint;
 pub mod objiter;
 pub mod objlist;
diff --git a/vm/src/obj/objgetset.rs b/vm/src/obj/objgetset.rs
new file mode 100644
index 000000000..e8ee40b67
--- /dev/null
+++ b/vm/src/obj/objgetset.rs
@@ -0,0 +1,71 @@
+/*! Python `attribute` descriptor class. (PyGetSet)
+
+*/
+use super::objtype::PyClassRef;
+use crate::function::OptionalArg;
+use crate::pyobject::{PyClassImpl, PyContext, PyObjectRef, PyRef, PyResult, PyValue};
+use crate::slots::PyBuiltinDescriptor;
+use crate::vm::VirtualMachine;
+
+pub type PyGetter = dyn Fn(PyObjectRef, &VirtualMachine) -> PyResult;
+pub type PySetter = dyn Fn(PyObjectRef, PyObjectRef, &VirtualMachine) -> PyResult<()>;
+
+#[pyclass]
+pub struct PyGetSet {
+    // name: String,
+    getter: Box<PyGetter>,
+    setter: Box<PySetter>,
+    // doc: Option<String>,
+}
+
+impl std::fmt::Debug for PyGetSet {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(
+            f,
+            "PyGetSet {{ getter: {:p}, setter: {:p} }}",
+            self.getter, self.setter
+        )
+    }
+}
+
+impl PyValue for PyGetSet {
+    fn class(vm: &VirtualMachine) -> PyClassRef {
+        vm.ctx.getset_type()
+    }
+}
+
+pub type PyGetSetRef = PyRef<PyGetSet>;
+
+impl PyBuiltinDescriptor for PyGetSet {
+    fn get(
+        zelf: PyRef<Self>,
+        obj: PyObjectRef,
+        _cls: OptionalArg<PyObjectRef>,
+        vm: &VirtualMachine,
+    ) -> PyResult {
+        (zelf.getter)(obj, vm)
+    }
+}
+
+impl PyGetSet {
+    pub fn new(getter: &'static PyGetter, setter: &'static PySetter) -> Self {
+        Self {
+            getter: Box::new(getter),
+            setter: Box::new(setter),
+        }
+    }
+}
+
+#[pyimpl(with(PyBuiltinDescriptor))]
+impl PyGetSet {
+    // Descriptor methods
+
+    #[pymethod(magic)]
+    fn set(&self, obj: PyObjectRef, value: PyObjectRef, vm: &VirtualMachine) -> PyResult<()> {
+        (self.setter)(obj, value, vm)
+    }
+}
+
+pub(crate) fn init(context: &PyContext) {
+    PyGetSet::extend_class(context, &context.types.getset_type);
+}
diff --git a/vm/src/obj/objobject.rs b/vm/src/obj/objobject.rs
index 671dcd9e6..bafec4abb 100644
--- a/vm/src/obj/objobject.rs
+++ b/vm/src/obj/objobject.rs
@@ -175,12 +175,12 @@ impl PyBaseObject {
     }
 
     #[pyproperty(name = "__class__")]
-    fn _class(obj: PyObjectRef, _vm: &VirtualMachine) -> PyObjectRef {
+    fn get_class(obj: PyObjectRef, _vm: &VirtualMachine) -> PyObjectRef {
         obj.class().into_object()
     }
 
     #[pyproperty(name = "__class__", setter)]
-    fn _set_class(instance: PyObjectRef, _value: PyObjectRef, vm: &VirtualMachine) -> PyResult<()> {
+    fn set_class(instance: PyObjectRef, _value: PyObjectRef, vm: &VirtualMachine) -> PyResult<()> {
         let type_repr = vm.to_pystr(&instance.class())?;
         Err(vm.new_type_error(format!("can't change class of type '{}'", type_repr)))
     }
diff --git a/vm/src/pyobject.rs b/vm/src/pyobject.rs
index db0df14a1..555d480bd 100644
--- a/vm/src/pyobject.rs
+++ b/vm/src/pyobject.rs
@@ -330,6 +330,10 @@ impl PyContext {
         self.types.readonly_property_type.clone()
     }
 
+    pub fn getset_type(&self) -> PyClassRef {
+        self.types.getset_type.clone()
+    }
+
     pub fn classmethod_type(&self) -> PyClassRef {
         self.types.classmethod_type.clone()
     }
diff --git a/vm/src/types.rs b/vm/src/types.rs
index 2c9d94026..a81755a01 100644
--- a/vm/src/types.rs
+++ b/vm/src/types.rs
@@ -14,6 +14,7 @@ use crate::obj::objfloat;
 use crate::obj::objframe;
 use crate::obj::objfunction;
 use crate::obj::objgenerator;
+use crate::obj::objgetset;
 use crate::obj::objint;
 use crate::obj::objiter;
 use crate::obj::objlist;
@@ -94,6 +95,7 @@ pub struct TypeZoo {
     pub method_descriptor_type: PyClassRef,
     pub property_type: PyClassRef,
     pub readonly_property_type: PyClassRef,
+    pub getset_type: PyClassRef,
     pub module_type: PyClassRef,
     pub namespace_type: PyClassRef,
     pub bound_method_type: PyClassRef,
@@ -125,6 +127,7 @@ impl TypeZoo {
         let method_descriptor_type = create_type("method_descriptor", &type_type, &object_type);
         let property_type = create_type("property", &type_type, &object_type);
         let readonly_property_type = create_type("readonly_property", &type_type, &object_type);
+        let getset_type = create_type("getset_descriptor", &type_type, &object_type);
         let super_type = create_type("super", &type_type, &object_type);
         let weakref_type = create_type("ref", &type_type, &object_type);
         let weakproxy_type = create_type("weakproxy", &type_type, &object_type);
@@ -220,6 +223,7 @@ impl TypeZoo {
             mappingproxy_type,
             property_type,
             readonly_property_type,
+            getset_type,
             generator_type,
             module_type,
             namespace_type,
@@ -381,6 +385,7 @@ pub fn initialize_types(context: &PyContext) {
     objbytes::init(&context);
     objbytearray::init(&context);
     objproperty::init(&context);
+    objgetset::init(&context);
     objmemory::init(&context);
     objstr::init(&context);
     objrange::init(&context);