15222427616

Committed 24 May 2025 02:17AM UTC coverage: 57.627% (-0.02%) from 57.643%

Build # 15222427616

Build Type

Pull #673

github

Committed by

web-flow

Commit Message

Merge 484c5ddbc into 950e6a37a

Pull Request Pull Request #673: Add `Shape.type_identifier` to access type name in const contexts

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4 existing lines in 3 files now uncovered.

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65.9

/facet-core/src/impls_alloc/rc.rs

use crate::{
    Def, Facet, KnownSmartPointer, PtrConst, PtrMut, PtrUninit, Shape, SmartPointerDef,
    SmartPointerFlags, SmartPointerVTable, TryBorrowInnerError, TryFromError, TryIntoInnerError,
    Type, UserType, ValueVTable, value_vtable,
};

unsafe impl<'a, T: Facet<'a>> Facet<'a> for alloc::rc::Rc<T> {
    const VTABLE: &'static ValueVTable = &const {
        // Define the functions for transparent conversion between Rc<T> and T
        unsafe fn try_from<'a, 'shape, 'src, 'dst, T: Facet<'a>>(
            src_ptr: PtrConst<'src>,
            src_shape: &'shape Shape<'shape>,
            dst: PtrUninit<'dst>,
        ) -> Result<PtrMut<'dst>, TryFromError<'shape>> {
            if src_shape.id != T::SHAPE.id {
                return Err(TryFromError::UnsupportedSourceShape {
                    src_shape,
                    expected: &[T::SHAPE],
                });
            }
            let t = unsafe { src_ptr.read::<T>() };
            let rc = alloc::rc::Rc::new(t);
            Ok(unsafe { dst.put(rc) })
        }

        unsafe fn try_into_inner<'a, 'src, 'dst, T: Facet<'a>>(
            src_ptr: PtrMut<'src>,
            dst: PtrUninit<'dst>,
        ) -> Result<PtrMut<'dst>, TryIntoInnerError> {
            let rc = unsafe { src_ptr.get::<alloc::rc::Rc<T>>() };
            match alloc::rc::Rc::try_unwrap(rc.clone()) {
                Ok(t) => Ok(unsafe { dst.put(t) }),
                Err(_) => Err(TryIntoInnerError::Unavailable),
            }
        }

        unsafe fn try_borrow_inner<'a, 'src, T: Facet<'a>>(
            src_ptr: PtrConst<'src>,
        ) -> Result<PtrConst<'src>, TryBorrowInnerError> {
            let rc = unsafe { src_ptr.get::<alloc::rc::Rc<T>>() };
            Ok(PtrConst::new(&**rc))
        }

        let mut vtable = value_vtable!(alloc::rc::Rc<T>, |f, opts| {
            write!(f, "{}", Self::SHAPE.type_identifier)?;
            if let Some(opts) = opts.for_children() {
                write!(f, "<")?;
                (T::SHAPE.vtable.type_name)(f, opts)?;
                write!(f, ">")?;
            } else {
                write!(f, "<…>")?;
            }
            Ok(())
        });
        vtable.try_from = || Some(try_from::<T>);
        vtable.try_into_inner = || Some(try_into_inner::<T>);
        vtable.try_borrow_inner = || Some(try_borrow_inner::<T>);
        vtable
    };

    const SHAPE: &'static crate::Shape<'static> = &const {
        // Function to return inner type's shape
        fn inner_shape<'a, T: Facet<'a>>() -> &'static Shape<'static> {
            T::SHAPE
        }

        crate::Shape::builder_for_sized::<Self>()
            .type_identifier("Rc")
            .type_params(&[crate::TypeParam {
                name: "T",
                shape: || T::SHAPE,
            }])
            .ty(Type::User(UserType::Opaque))
            .def(Def::SmartPointer(
                SmartPointerDef::builder()
                    .pointee(|| T::SHAPE)
                    .flags(SmartPointerFlags::EMPTY)
                    .known(KnownSmartPointer::Rc)
                    .weak(|| <alloc::rc::Weak<T> as Facet>::SHAPE)
                    .vtable(
                        &const {
                            SmartPointerVTable::builder()
                                .borrow_fn(|this| {
                                    let ptr = Self::as_ptr(unsafe { this.get() });
                                    PtrConst::new(ptr)
                                })
                                .new_into_fn(|this, ptr| {
                                    let t = unsafe { ptr.read::<T>() };
                                    let rc = alloc::rc::Rc::new(t);
                                    unsafe { this.put(rc) }
                                })
                                .downgrade_into_fn(|strong, weak| unsafe {
                                    weak.put(alloc::rc::Rc::downgrade(strong.get::<Self>()))
                                })
                                .build()
                        },
                    )
                    .build(),
            ))
            .inner(inner_shape::<T>)
            .build()
    };
}

unsafe impl<'a, T: Facet<'a>> Facet<'a> for alloc::rc::Weak<T> {
    const VTABLE: &'static ValueVTable = &const {
        value_vtable!(alloc::rc::Weak<T>, |f, opts| {
            write!(f, "{}", Self::SHAPE.type_identifier)?;
            if let Some(opts) = opts.for_children() {
                write!(f, "<")?;
                (T::SHAPE.vtable.type_name)(f, opts)?;
                write!(f, ">")?;
            } else {
                write!(f, "<…>")?;
            }
            Ok(())
        })
    };

    const SHAPE: &'static crate::Shape<'static> = &const {
        // Function to return inner type's shape
        fn inner_shape<'a, T: Facet<'a>>() -> &'static Shape<'static> {
            T::SHAPE
        }

        crate::Shape::builder_for_sized::<Self>()
            .type_identifier("Weak")
            .type_params(&[crate::TypeParam {
                name: "T",
                shape: || T::SHAPE,
            }])
            .ty(Type::User(UserType::Opaque))
            .def(Def::SmartPointer(
                SmartPointerDef::builder()
                    .pointee(|| T::SHAPE)
                    .flags(SmartPointerFlags::WEAK)
                    .known(KnownSmartPointer::RcWeak)
                    .strong(|| <alloc::rc::Rc<T> as Facet>::SHAPE)
                    .vtable(
                        &const {
                            SmartPointerVTable::builder()
                                .upgrade_into_fn(|weak, strong| unsafe {
                                    Some(strong.put(weak.get::<Self>().upgrade()?))
                                })
                                .build()
                        },
                    )
                    .build(),
            ))
            .inner(inner_shape::<T>)
            .build()
    };
}

#[cfg(test)]
mod tests {
    use alloc::rc::{Rc, Weak as RcWeak};
    use alloc::string::String;

    use super::*;

    #[test]
    fn test_rc_type_params() {
        let [type_param_1] = <Rc<i32>>::SHAPE.type_params else {
            panic!("Rc<T> should only have 1 type param")
        };
        assert_eq!(type_param_1.shape(), i32::SHAPE);
    }

    #[test]
    fn test_rc_vtable_1_new_borrow_drop() -> eyre::Result<()> {
        facet_testhelpers::setup();

        let rc_shape = <Rc<String>>::SHAPE;
        let rc_def = rc_shape
            .def
            .into_smart_pointer()
            .expect("Rc<T> should have a smart pointer definition");

        // Allocate memory for the Rc
        let rc_uninit_ptr = rc_shape.allocate()?;

        // Get the function pointer for creating a new Rc from a value
        let new_into_fn = rc_def
            .vtable
            .new_into_fn
            .expect("Rc<T> should have new_into_fn");

        // Create the value and initialize the Rc
        let mut value = String::from("example");
        let rc_ptr = unsafe { new_into_fn(rc_uninit_ptr, PtrMut::new(&raw mut value)) };
        // The value now belongs to the Rc, prevent its drop
        core::mem::forget(value);

        // Get the function pointer for borrowing the inner value
        let borrow_fn = rc_def
            .vtable
            .borrow_fn
            .expect("Rc<T> should have borrow_fn");

        // Borrow the inner value and check it
        let borrowed_ptr = unsafe { borrow_fn(rc_ptr.as_const()) };
        // SAFETY: borrowed_ptr points to a valid String within the Rc
        assert_eq!(unsafe { borrowed_ptr.get::<String>() }, "example");

        // Get the function pointer for dropping the Rc
        let drop_fn = (rc_shape.vtable.drop_in_place)().expect("Rc<T> should have drop_in_place");

        // Drop the Rc in place
        // SAFETY: rc_ptr points to a valid Rc<String>
        unsafe { drop_fn(rc_ptr) };

        // Deallocate the memory
        // SAFETY: rc_ptr was allocated by rc_shape and is now dropped (but memory is still valid)
        unsafe { rc_shape.deallocate_mut(rc_ptr)? };

        Ok(())
    }

    #[test]
    fn test_rc_vtable_2_downgrade_upgrade_drop() -> eyre::Result<()> {
        facet_testhelpers::setup();

        let rc_shape = <Rc<String>>::SHAPE;
        let rc_def = rc_shape
            .def
            .into_smart_pointer()
            .expect("Rc<T> should have a smart pointer definition");

        let weak_shape = <RcWeak<String>>::SHAPE;
        let weak_def = weak_shape
            .def
            .into_smart_pointer()
            .expect("RcWeak<T> should have a smart pointer definition");

        // 1. Create the first Rc (rc1)
        let rc1_uninit_ptr = rc_shape.allocate()?;
        let new_into_fn = rc_def.vtable.new_into_fn.unwrap();
        let mut value = String::from("example");
        let rc1_ptr = unsafe { new_into_fn(rc1_uninit_ptr, PtrMut::new(&raw mut value)) };
        core::mem::forget(value); // Value now owned by rc1

        // 2. Downgrade rc1 to create a weak pointer (weak1)
        let weak1_uninit_ptr = weak_shape.allocate()?;
        let downgrade_into_fn = rc_def.vtable.downgrade_into_fn.unwrap();
        // SAFETY: rc1_ptr points to a valid Rc, weak1_uninit_ptr is allocated for a Weak
        let weak1_ptr = unsafe { downgrade_into_fn(rc1_ptr, weak1_uninit_ptr) };

        // 3. Upgrade weak1 to create a second Rc (rc2)
        let rc2_uninit_ptr = rc_shape.allocate()?;
        let upgrade_into_fn = weak_def.vtable.upgrade_into_fn.unwrap();
        // SAFETY: weak1_ptr points to a valid Weak, rc2_uninit_ptr is allocated for an Rc.
        // Upgrade should succeed as rc1 still exists.
        let rc2_ptr = unsafe { upgrade_into_fn(weak1_ptr, rc2_uninit_ptr) }
            .expect("Upgrade should succeed while original Rc exists");

        // Check the content of the upgraded Rc
        let borrow_fn = rc_def.vtable.borrow_fn.unwrap();
        // SAFETY: rc2_ptr points to a valid Rc<String>
        let borrowed_ptr = unsafe { borrow_fn(rc2_ptr.as_const()) };
        // SAFETY: borrowed_ptr points to a valid String
        assert_eq!(unsafe { borrowed_ptr.get::<String>() }, "example");

        // 4. Drop everything and free memory
        let rc_drop_fn = (rc_shape.vtable.drop_in_place)().unwrap();
        let weak_drop_fn = (weak_shape.vtable.drop_in_place)().unwrap();

        unsafe {
            // Drop Rcs
            rc_drop_fn(rc1_ptr);
            rc_shape.deallocate_mut(rc1_ptr)?;
            rc_drop_fn(rc2_ptr);
            rc_shape.deallocate_mut(rc2_ptr)?;

            // Drop Weak
            weak_drop_fn(weak1_ptr);
            weak_shape.deallocate_mut(weak1_ptr)?;
        }

        Ok(())
    }

    #[test]
    fn test_rc_vtable_3_downgrade_drop_try_upgrade() -> eyre::Result<()> {
        facet_testhelpers::setup();

        let rc_shape = <Rc<String>>::SHAPE;
        let rc_def = rc_shape
            .def
            .into_smart_pointer()
            .expect("Rc<T> should have a smart pointer definition");

        let weak_shape = <RcWeak<String>>::SHAPE;
        let weak_def = weak_shape
            .def
            .into_smart_pointer()
            .expect("RcWeak<T> should have a smart pointer definition");

        // 1. Create the strong Rc (rc1)
        let rc1_uninit_ptr = rc_shape.allocate()?;
        let new_into_fn = rc_def.vtable.new_into_fn.unwrap();
        let mut value = String::from("example");
        let rc1_ptr = unsafe { new_into_fn(rc1_uninit_ptr, PtrMut::new(&raw mut value)) };
        core::mem::forget(value);

        // 2. Downgrade rc1 to create a weak pointer (weak1)
        let weak1_uninit_ptr = weak_shape.allocate()?;
        let downgrade_into_fn = rc_def.vtable.downgrade_into_fn.unwrap();
        // SAFETY: rc1_ptr is valid, weak1_uninit_ptr is allocated for Weak
        let weak1_ptr = unsafe { downgrade_into_fn(rc1_ptr, weak1_uninit_ptr) };

        // 3. Drop and free the strong pointer (rc1)
        let rc_drop_fn = (rc_shape.vtable.drop_in_place)().unwrap();
        unsafe {
            rc_drop_fn(rc1_ptr);
            rc_shape.deallocate_mut(rc1_ptr)?;
        }

        // 4. Attempt to upgrade the weak pointer (weak1)
        let upgrade_into_fn = weak_def.vtable.upgrade_into_fn.unwrap();
        let rc2_uninit_ptr = rc_shape.allocate()?;
        // SAFETY: weak1_ptr is valid (though points to dropped data), rc2_uninit_ptr is allocated for Rc
        let upgrade_result = unsafe { upgrade_into_fn(weak1_ptr, rc2_uninit_ptr) };

        // Assert that the upgrade failed
        assert!(
            upgrade_result.is_none(),
            "Upgrade should fail after the strong Rc is dropped"
        );

        // 5. Clean up: Deallocate the memory intended for the failed upgrade and drop/deallocate the weak pointer
        let weak_drop_fn = (weak_shape.vtable.drop_in_place)().unwrap();
        unsafe {
            // Deallocate the *uninitialized* memory allocated for the failed upgrade attempt
            rc_shape.deallocate_uninit(rc2_uninit_ptr)?;

            // Drop and deallocate the weak pointer
            weak_drop_fn(weak1_ptr);
            weak_shape.deallocate_mut(weak1_ptr)?;
        }

        Ok(())
    }
}

1	use crate::{
2	Def, Facet, KnownSmartPointer, PtrConst, PtrMut, PtrUninit, Shape, SmartPointerDef,
3	SmartPointerFlags, SmartPointerVTable, TryBorrowInnerError, TryFromError, TryIntoInnerError,
4	Type, UserType, ValueVTable, value_vtable,
5	};
6
7	unsafe impl<'a, T: Facet<'a>> Facet<'a> for alloc::rc::Rc<T> {
8	const VTABLE: &'static ValueVTable = &const {
9	// Define the functions for transparent conversion between Rc<T> and T
10	unsafe fn try_from<'a, 'shape, 'src, 'dst, T: Facet<'a>>(	×
11	src_ptr: PtrConst<'src>,	×
12	src_shape: &'shape Shape<'shape>,	×
13	dst: PtrUninit<'dst>,	×
14	) -> Result<PtrMut<'dst>, TryFromError<'shape>> {	×
15	if src_shape.id != T::SHAPE.id {	×
16	return Err(TryFromError::UnsupportedSourceShape {	×
17	src_shape,	×
18	expected: &[T::SHAPE],	×
19	});	×
20	}	×
21	let t = unsafe { src_ptr.read::<T>() };	×
22	let rc = alloc::rc::Rc::new(t);	×
23	Ok(unsafe { dst.put(rc) })	×
24	}	×
25
26	unsafe fn try_into_inner<'a, 'src, 'dst, T: Facet<'a>>(	×
27	src_ptr: PtrMut<'src>,	×
28	dst: PtrUninit<'dst>,	×
29	) -> Result<PtrMut<'dst>, TryIntoInnerError> {	×
30	let rc = unsafe { src_ptr.get::<alloc::rc::Rc<T>>() };	×
31	match alloc::rc::Rc::try_unwrap(rc.clone()) {	×
32	Ok(t) => Ok(unsafe { dst.put(t) }),	×
33	Err(_) => Err(TryIntoInnerError::Unavailable),	×
34	}
35	}	×
36
37	unsafe fn try_borrow_inner<'a, 'src, T: Facet<'a>>(	×
38	src_ptr: PtrConst<'src>,	×
39	) -> Result<PtrConst<'src>, TryBorrowInnerError> {	×
40	let rc = unsafe { src_ptr.get::<alloc::rc::Rc<T>>() };	×
41	Ok(PtrConst::new(&**rc))	×
42	}	×
43
44	let mut vtable = value_vtable!(alloc::rc::Rc<T>, \|f, opts\| {	×
NEW 45	write!(f, "{}", Self::SHAPE.type_identifier)?;	×
46	if let Some(opts) = opts.for_children() {	×
47	write!(f, "<")?;	×
48	(T::SHAPE.vtable.type_name)(f, opts)?;	×
49	write!(f, ">")?;	×
50	} else {
51	write!(f, "<…>")?;	×
52	}
53	Ok(())	×
54	});	×
55	vtable.try_from = \|\| Some(try_from::<T>);	×
56	vtable.try_into_inner = \|\| Some(try_into_inner::<T>);	×
57	vtable.try_borrow_inner = \|\| Some(try_borrow_inner::<T>);	×
58	vtable
59	};
60
61	const SHAPE: &'static crate::Shape<'static> = &const {
62	// Function to return inner type's shape
63	fn inner_shape<'a, T: Facet<'a>>() -> &'static Shape<'static> {	×
64	T::SHAPE	×
65	}	×
66
67	crate::Shape::builder_for_sized::<Self>()
68	.type_identifier("Rc")
69	.type_params(&[crate::TypeParam {
70	name: "T",
71	shape: \|\| T::SHAPE,
72	}])
73	.ty(Type::User(UserType::Opaque))
74	.def(Def::SmartPointer(
75	SmartPointerDef::builder()
76	.pointee(\|\| T::SHAPE)
77	.flags(SmartPointerFlags::EMPTY)
78	.known(KnownSmartPointer::Rc)
79	.weak(\|\| <alloc::rc::Weak<T> as Facet>::SHAPE)
80	.vtable(
81	&const {
82	SmartPointerVTable::builder()
83	.borrow_fn(\|this\| {	2✔
84	let ptr = Self::as_ptr(unsafe { this.get() });	2✔
85	PtrConst::new(ptr)	2✔
86	})	2✔
87	.new_into_fn(\|this, ptr\| {	3✔
88	let t = unsafe { ptr.read::<T>() };	3✔
89	let rc = alloc::rc::Rc::new(t);	3✔
90	unsafe { this.put(rc) }	3✔
91	})	3✔
92	.downgrade_into_fn(\|strong, weak\| unsafe {
93	weak.put(alloc::rc::Rc::downgrade(strong.get::<Self>()))	2✔
94	})	2✔
95	.build()
96	},
97	)
98	.build(),
99	))
100	.inner(inner_shape::<T>)
101	.build()
102	};
103	}
104
105	unsafe impl<'a, T: Facet<'a>> Facet<'a> for alloc::rc::Weak<T> {
106	const VTABLE: &'static ValueVTable = &const {
107	value_vtable!(alloc::rc::Weak<T>, \|f, opts\| {	×
NEW 108	write!(f, "{}", Self::SHAPE.type_identifier)?;	×
109	if let Some(opts) = opts.for_children() {	×
110	write!(f, "<")?;	×
111	(T::SHAPE.vtable.type_name)(f, opts)?;	×
112	write!(f, ">")?;	×
113	} else {
114	write!(f, "<…>")?;	×
115	}
116	Ok(())	×
117	})	×
118	};
119
120	const SHAPE: &'static crate::Shape<'static> = &const {
121	// Function to return inner type's shape
122	fn inner_shape<'a, T: Facet<'a>>() -> &'static Shape<'static> {	×
123	T::SHAPE	×
124	}	×
125
126	crate::Shape::builder_for_sized::<Self>()
127	.type_identifier("Weak")
128	.type_params(&[crate::TypeParam {
129	name: "T",
130	shape: \|\| T::SHAPE,
131	}])
132	.ty(Type::User(UserType::Opaque))
133	.def(Def::SmartPointer(
134	SmartPointerDef::builder()
135	.pointee(\|\| T::SHAPE)
136	.flags(SmartPointerFlags::WEAK)
137	.known(KnownSmartPointer::RcWeak)
138	.strong(\|\| <alloc::rc::Rc<T> as Facet>::SHAPE)
139	.vtable(
140	&const {
141	SmartPointerVTable::builder()
142	.upgrade_into_fn(\|weak, strong\| unsafe {
143	Some(strong.put(weak.get::<Self>().upgrade()?))	2✔
144	})	2✔
145	.build()
146	},
147	)
148	.build(),
149	))
150	.inner(inner_shape::<T>)
151	.build()
152	};
153	}
154
155	#[cfg(test)]
156	mod tests {
157	use alloc::rc::{Rc, Weak as RcWeak};
158	use alloc::string::String;
159
160	use super::*;
161
162	#[test]
163	fn test_rc_type_params() {	1✔
164	let [type_param_1] = <Rc<i32>>::SHAPE.type_params else {	1✔
165	panic!("Rc<T> should only have 1 type param")	×
166	};
167	assert_eq!(type_param_1.shape(), i32::SHAPE);	1✔
168	}	1✔
169
170	#[test]
171	fn test_rc_vtable_1_new_borrow_drop() -> eyre::Result<()> {	1✔
172	facet_testhelpers::setup();	1✔
173
174	let rc_shape = <Rc<String>>::SHAPE;	1✔
175	let rc_def = rc_shape	1✔
176	.def	1✔
177	.into_smart_pointer()	1✔
178	.expect("Rc<T> should have a smart pointer definition");	1✔
179
180	// Allocate memory for the Rc
181	let rc_uninit_ptr = rc_shape.allocate()?;	1✔
182
183	// Get the function pointer for creating a new Rc from a value
184	let new_into_fn = rc_def	1✔
185	.vtable	1✔
186	.new_into_fn	1✔
187	.expect("Rc<T> should have new_into_fn");	1✔
188
189	// Create the value and initialize the Rc
190	let mut value = String::from("example");	1✔
191	let rc_ptr = unsafe { new_into_fn(rc_uninit_ptr, PtrMut::new(&raw mut value)) };	1✔
192	// The value now belongs to the Rc, prevent its drop
193	core::mem::forget(value);	1✔
194
195	// Get the function pointer for borrowing the inner value
196	let borrow_fn = rc_def	1✔
197	.vtable	1✔
198	.borrow_fn	1✔
199	.expect("Rc<T> should have borrow_fn");	1✔
200
201	// Borrow the inner value and check it
202	let borrowed_ptr = unsafe { borrow_fn(rc_ptr.as_const()) };	1✔
203	// SAFETY: borrowed_ptr points to a valid String within the Rc
204	assert_eq!(unsafe { borrowed_ptr.get::<String>() }, "example");	1✔
205
206	// Get the function pointer for dropping the Rc
207	let drop_fn = (rc_shape.vtable.drop_in_place)().expect("Rc<T> should have drop_in_place");	1✔
208
209	// Drop the Rc in place
210	// SAFETY: rc_ptr points to a valid Rc<String>
211	unsafe { drop_fn(rc_ptr) };	1✔
212
213	// Deallocate the memory
214	// SAFETY: rc_ptr was allocated by rc_shape and is now dropped (but memory is still valid)
215	unsafe { rc_shape.deallocate_mut(rc_ptr)? };	1✔
216
217	Ok(())	1✔
218	}	1✔
219
220	#[test]
221	fn test_rc_vtable_2_downgrade_upgrade_drop() -> eyre::Result<()> {	1✔
222	facet_testhelpers::setup();	1✔
223
224	let rc_shape = <Rc<String>>::SHAPE;	1✔
225	let rc_def = rc_shape	1✔
226	.def	1✔
227	.into_smart_pointer()	1✔
228	.expect("Rc<T> should have a smart pointer definition");	1✔
229
230	let weak_shape = <RcWeak<String>>::SHAPE;	1✔
231	let weak_def = weak_shape	1✔
232	.def	1✔
233	.into_smart_pointer()	1✔
234	.expect("RcWeak<T> should have a smart pointer definition");	1✔
235
236	// 1. Create the first Rc (rc1)
237	let rc1_uninit_ptr = rc_shape.allocate()?;	1✔
238	let new_into_fn = rc_def.vtable.new_into_fn.unwrap();	1✔
239	let mut value = String::from("example");	1✔
240	let rc1_ptr = unsafe { new_into_fn(rc1_uninit_ptr, PtrMut::new(&raw mut value)) };	1✔
241	core::mem::forget(value); // Value now owned by rc1	1✔
242
243	// 2. Downgrade rc1 to create a weak pointer (weak1)
244	let weak1_uninit_ptr = weak_shape.allocate()?;	1✔
245	let downgrade_into_fn = rc_def.vtable.downgrade_into_fn.unwrap();	1✔
246	// SAFETY: rc1_ptr points to a valid Rc, weak1_uninit_ptr is allocated for a Weak
247	let weak1_ptr = unsafe { downgrade_into_fn(rc1_ptr, weak1_uninit_ptr) };	1✔
248
249	// 3. Upgrade weak1 to create a second Rc (rc2)
250	let rc2_uninit_ptr = rc_shape.allocate()?;	1✔
251	let upgrade_into_fn = weak_def.vtable.upgrade_into_fn.unwrap();	1✔
252	// SAFETY: weak1_ptr points to a valid Weak, rc2_uninit_ptr is allocated for an Rc.
253	// Upgrade should succeed as rc1 still exists.
254	let rc2_ptr = unsafe { upgrade_into_fn(weak1_ptr, rc2_uninit_ptr) }	1✔
255	.expect("Upgrade should succeed while original Rc exists");	1✔
256
257	// Check the content of the upgraded Rc
258	let borrow_fn = rc_def.vtable.borrow_fn.unwrap();	1✔
259	// SAFETY: rc2_ptr points to a valid Rc<String>
260	let borrowed_ptr = unsafe { borrow_fn(rc2_ptr.as_const()) };	1✔
261	// SAFETY: borrowed_ptr points to a valid String
262	assert_eq!(unsafe { borrowed_ptr.get::<String>() }, "example");	1✔
263
264	// 4. Drop everything and free memory
265	let rc_drop_fn = (rc_shape.vtable.drop_in_place)().unwrap();	1✔
266	let weak_drop_fn = (weak_shape.vtable.drop_in_place)().unwrap();	1✔
267
268	unsafe {
269	// Drop Rcs
270	rc_drop_fn(rc1_ptr);	1✔
271	rc_shape.deallocate_mut(rc1_ptr)?;	1✔
272	rc_drop_fn(rc2_ptr);	1✔
273	rc_shape.deallocate_mut(rc2_ptr)?;	1✔
274
275	// Drop Weak
276	weak_drop_fn(weak1_ptr);	1✔
277	weak_shape.deallocate_mut(weak1_ptr)?;	1✔
278	}
279
280	Ok(())	1✔
281	}	1✔
282
283	#[test]
284	fn test_rc_vtable_3_downgrade_drop_try_upgrade() -> eyre::Result<()> {	1✔
285	facet_testhelpers::setup();	1✔
286
287	let rc_shape = <Rc<String>>::SHAPE;	1✔
288	let rc_def = rc_shape	1✔
289	.def	1✔
290	.into_smart_pointer()	1✔
291	.expect("Rc<T> should have a smart pointer definition");	1✔
292
293	let weak_shape = <RcWeak<String>>::SHAPE;	1✔
294	let weak_def = weak_shape	1✔
295	.def	1✔
296	.into_smart_pointer()	1✔
297	.expect("RcWeak<T> should have a smart pointer definition");	1✔
298
299	// 1. Create the strong Rc (rc1)
300	let rc1_uninit_ptr = rc_shape.allocate()?;	1✔
301	let new_into_fn = rc_def.vtable.new_into_fn.unwrap();	1✔
302	let mut value = String::from("example");	1✔
303	let rc1_ptr = unsafe { new_into_fn(rc1_uninit_ptr, PtrMut::new(&raw mut value)) };	1✔
304	core::mem::forget(value);	1✔
305
306	// 2. Downgrade rc1 to create a weak pointer (weak1)
307	let weak1_uninit_ptr = weak_shape.allocate()?;	1✔
308	let downgrade_into_fn = rc_def.vtable.downgrade_into_fn.unwrap();	1✔
309	// SAFETY: rc1_ptr is valid, weak1_uninit_ptr is allocated for Weak
310	let weak1_ptr = unsafe { downgrade_into_fn(rc1_ptr, weak1_uninit_ptr) };	1✔
311
312	// 3. Drop and free the strong pointer (rc1)
313	let rc_drop_fn = (rc_shape.vtable.drop_in_place)().unwrap();	1✔
314	unsafe {
315	rc_drop_fn(rc1_ptr);	1✔
316	rc_shape.deallocate_mut(rc1_ptr)?;	1✔
317	}
318
319	// 4. Attempt to upgrade the weak pointer (weak1)
320	let upgrade_into_fn = weak_def.vtable.upgrade_into_fn.unwrap();	1✔
321	let rc2_uninit_ptr = rc_shape.allocate()?;	1✔
322	// SAFETY: weak1_ptr is valid (though points to dropped data), rc2_uninit_ptr is allocated for Rc
323	let upgrade_result = unsafe { upgrade_into_fn(weak1_ptr, rc2_uninit_ptr) };	1✔
324
325	// Assert that the upgrade failed
326	assert!(	1✔
327	upgrade_result.is_none(),	1✔
328	"Upgrade should fail after the strong Rc is dropped"	×
329	);
330
331	// 5. Clean up: Deallocate the memory intended for the failed upgrade and drop/deallocate the weak pointer
332	let weak_drop_fn = (weak_shape.vtable.drop_in_place)().unwrap();	1✔
333	unsafe {
334	// Deallocate the uninitialized memory allocated for the failed upgrade attempt
335	rc_shape.deallocate_uninit(rc2_uninit_ptr)?;	1✔
336
337	// Drop and deallocate the weak pointer
338	weak_drop_fn(weak1_ptr);	1✔
339	weak_shape.deallocate_mut(weak1_ptr)?;	1✔
340	}
341
342	Ok(())	1✔
343	}	1✔
344	}

facet-rs / facet / 15222427616

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