1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147

/*! Python `attribute` descriptor class. (PyGetSet)

*/
use super::PyType;
use crate::{
    class::PyClassImpl,
    function::{IntoPyGetterFunc, IntoPySetterFunc, PyGetterFunc, PySetterFunc, PySetterValue},
    types::{Constructor, GetDescriptor, Unconstructible},
    AsObject, Context, Py, PyObject, PyObjectRef, PyPayload, PyResult, VirtualMachine,
};

#[pyclass(module = false, name = "getset_descriptor")]
pub struct PyGetSet {
    name: String,
    class: &'static Py<PyType>,
    getter: Option<PyGetterFunc>,
    setter: Option<PySetterFunc>,
    // doc: Option<String>,
}

impl std::fmt::Debug for PyGetSet {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(
            f,
            "PyGetSet {{ name: {}, getter: {}, setter: {} }}",
            self.name,
            if self.getter.is_some() {
                "Some"
            } else {
                "None"
            },
            if self.setter.is_some() {
                "Some"
            } else {
                "None"
            },
        )
    }
}

impl PyPayload for PyGetSet {
    fn class(ctx: &Context) -> &'static Py<PyType> {
        ctx.types.getset_type
    }
}

impl GetDescriptor for PyGetSet {
    fn descr_get(
        zelf: PyObjectRef,
        obj: Option<PyObjectRef>,
        _cls: Option<PyObjectRef>,
        vm: &VirtualMachine,
    ) -> PyResult {
        let (zelf, obj) = match Self::_check(&zelf, obj, vm) {
            Some(obj) => obj,
            None => return Ok(zelf),
        };
        if let Some(ref f) = zelf.getter {
            f(vm, obj)
        } else {
            Err(vm.new_attribute_error(format!(
                "attribute '{}' of '{}' objects is not readable",
                zelf.name,
                Self::class(&vm.ctx).name()
            )))
        }
    }
}

impl PyGetSet {
    pub fn new(name: String, class: &'static Py<PyType>) -> Self {
        Self {
            name,
            class,
            getter: None,
            setter: None,
        }
    }

    pub fn with_get<G, X>(mut self, getter: G) -> Self
    where
        G: IntoPyGetterFunc<X>,
    {
        self.getter = Some(getter.into_getter());
        self
    }

    pub fn with_set<S, X>(mut self, setter: S) -> Self
    where
        S: IntoPySetterFunc<X>,
    {
        self.setter = Some(setter.into_setter());
        self
    }
}

#[pyclass(with(GetDescriptor, Constructor))]
impl PyGetSet {
    // Descriptor methods

    #[pyslot]
    fn descr_set(
        zelf: &PyObject,
        obj: PyObjectRef,
        value: PySetterValue<PyObjectRef>,
        vm: &VirtualMachine,
    ) -> PyResult<()> {
        let zelf = zelf.try_to_ref::<Self>(vm)?;
        if let Some(ref f) = zelf.setter {
            f(vm, obj, value)
        } else {
            Err(vm.new_attribute_error(format!(
                "attribute '{}' of '{}' objects is not writable",
                zelf.name,
                obj.class().name()
            )))
        }
    }
    #[pymethod]
    fn __set__(
        zelf: PyObjectRef,
        obj: PyObjectRef,
        value: PyObjectRef,
        vm: &VirtualMachine,
    ) -> PyResult<()> {
        Self::descr_set(&zelf, obj, PySetterValue::Assign(value), vm)
    }
    #[pymethod]
    fn __delete__(zelf: PyObjectRef, obj: PyObjectRef, vm: &VirtualMachine) -> PyResult<()> {
        Self::descr_set(&zelf, obj, PySetterValue::Delete, vm)
    }

    #[pygetset(magic)]
    fn name(&self) -> String {
        self.name.clone()
    }

    #[pygetset(magic)]
    fn qualname(&self) -> String {
        format!("{}.{}", self.class.slot_name(), self.name.clone())
    }
}
impl Unconstructible for PyGetSet {}

pub(crate) fn init(context: &Context) {
    PyGetSet::extend_class(context, context.types.getset_type);
}