Method generic_getattr_opt

crates/vm/src/protocol/object.rs:226–271

CPython _PyObject_GenericGetAttrWithDict

(
        &self,
        name_str: &Py<PyStr>,
        dict: Option<PyDictRef>,
        vm: &VirtualMachine,
    )

    /// CPython _PyObject_GenericGetAttrWithDict
    pub fn generic_getattr_opt(
        &self,
        name_str: &Py<PyStr>,
        dict: Option<PyDictRef>,
        vm: &VirtualMachine,
    ) -> PyResult<Option<PyObjectRef>> {
        let name = name_str.as_wtf8();
        let obj_cls = self.class();
        let cls_attr_name = vm.ctx.interned_str(name_str);
        let cls_attr = match cls_attr_name.and_then(|name| obj_cls.get_attr(name)) {
            Some(descr) => {
                let descr_cls = descr.class();
                let descr_get = descr_cls.slots.descr_get.load();
                if let Some(descr_get) = descr_get
                    && descr_cls.slots.descr_set.load().is_some()
                {
                    let cls = obj_cls.to_owned().into();
                    return descr_get(descr, Some(self.to_owned()), Some(cls), vm).map(Some);
                }
                Some((descr, descr_get))
            }
            None => None,
        };

        let dict = dict.or_else(|| self.dict());

        let attr = if let Some(dict) = dict {
            dict.get_item_opt(name, vm)?
        } else {
            None
        };

        if let Some(obj_attr) = attr {
            Ok(Some(obj_attr))
        } else if let Some((attr, descr_get)) = cls_attr {
            match descr_get {
                Some(descr_get) => {
                    let cls = obj_cls.to_owned().into();
                    descr_get(attr, Some(self.to_owned()), Some(cls), vm).map(Some)
                }
                None => Ok(Some(attr)),
            }
        } else {
            Ok(None)
        }
    }

    pub fn del_attr<'a>(&self, attr_name: impl AsPyStr<'a>, vm: &VirtualMachine) -> PyResult<()> {
        let attr_name = attr_name.as_pystr(&vm.ctx);