facet_core/impls/alloc/
rc.rs

1use core::ptr::NonNull;
2
3use alloc::boxed::Box;
4use alloc::rc::{Rc, Weak};
5use alloc::vec::Vec;
6
7use crate::{
8    Def, Facet, KnownPointer, OxPtrConst, OxPtrMut, PointerDef, PointerFlags, PointerVTable,
9    PtrConst, PtrMut, PtrUninit, Shape, ShapeBuilder, SliceBuilderVTable, Type, TypeNameOpts,
10    TypeOpsIndirect, UserType, VTableIndirect,
11};
12
13//////////////////////////////////////////////////////////////////////
14// Rc<T>
15//////////////////////////////////////////////////////////////////////
16
17/// Type name formatter for `Rc<T>`
18fn rc_type_name<'a, T: Facet<'a>>(
19    _shape: &'static Shape,
20    f: &mut core::fmt::Formatter<'_>,
21    opts: TypeNameOpts,
22) -> core::fmt::Result {
23    write!(f, "Rc")?;
24    if let Some(opts) = opts.for_children() {
25        write!(f, "<")?;
26        T::SHAPE.write_type_name(f, opts)?;
27        write!(f, ">")?;
28    } else {
29        write!(f, "<…>")?;
30    }
31    Ok(())
32}
33
34/// Drop function for `Rc<T>`
35unsafe fn rc_drop<T>(ox: OxPtrMut) {
36    unsafe {
37        core::ptr::drop_in_place(ox.ptr().as_ptr::<Rc<T>>() as *mut Rc<T>);
38    }
39}
40
41/// Debug function for `Rc<T>`
42unsafe fn rc_debug<'a, T: Facet<'a>>(
43    ox: OxPtrConst,
44    f: &mut core::fmt::Formatter<'_>,
45) -> Option<core::fmt::Result> {
46    let rc = unsafe { ox.get::<Rc<T>>() };
47
48    // Try to debug the inner value if T has debug
49    let inner_ptr = PtrConst::new(NonNull::from(&**rc).as_ptr());
50    if let Some(result) = unsafe { T::SHAPE.call_debug(inner_ptr, f) } {
51        return Some(result);
52    }
53
54    // Fallback: just show it's an Rc
55    Some(write!(f, "Rc(...)"))
56}
57
58/// Borrow function for PointerVTable
59unsafe fn rc_borrow_fn<T>(this: PtrConst) -> PtrConst {
60    let ptr = unsafe { Rc::<T>::as_ptr(this.get()) };
61    PtrConst::new(ptr)
62}
63
64/// New into function for PointerVTable
65unsafe fn rc_new_into_fn<'a, 'ptr, T: Facet<'a>>(this: PtrUninit, ptr: PtrMut) -> PtrMut {
66    let t = unsafe { ptr.read::<T>() };
67    let rc = Rc::new(t);
68    unsafe { this.put(rc) }
69}
70
71/// Downgrade into function for PointerVTable
72unsafe fn rc_downgrade_into_fn<'a, 'ptr, T: Facet<'a>>(strong: PtrMut, weak: PtrUninit) -> PtrMut {
73    unsafe { weak.put(Rc::downgrade(strong.get::<Rc<T>>())) }
74}
75
76unsafe impl<'a, T: Facet<'a>> Facet<'a> for Rc<T> {
77    const SHAPE: &'static Shape = &const {
78        ShapeBuilder::for_sized::<Rc<T>>("Rc")
79            .type_name(rc_type_name::<T>)
80            .ty(Type::User(UserType::Opaque))
81            .def(Def::Pointer(PointerDef {
82                vtable: &const {
83                    PointerVTable {
84                        borrow_fn: Some(rc_borrow_fn::<T>),
85                        new_into_fn: Some(rc_new_into_fn::<T>),
86                        downgrade_into_fn: Some(|strong, weak| unsafe {
87                            rc_downgrade_into_fn::<T>(strong, weak)
88                        }),
89                        ..PointerVTable::new()
90                    }
91                },
92                pointee: Some(T::SHAPE),
93                weak: Some(|| <Weak<T> as Facet>::SHAPE),
94                strong: None,
95                flags: PointerFlags::EMPTY,
96                known: Some(KnownPointer::Rc),
97            }))
98            .type_params(&[crate::TypeParam {
99                name: "T",
100                shape: T::SHAPE,
101            }])
102            .inner(T::SHAPE)
103            .vtable_indirect(
104                &const {
105                    VTableIndirect {
106                        debug: Some(rc_debug::<T>),
107                        display: None,
108                        hash: None,
109                        invariants: None,
110                        parse: None,
111                        try_from: None,
112                        try_into_inner: None,
113                        try_borrow_inner: None,
114                        partial_eq: None,
115                        partial_cmp: None,
116                        cmp: None,
117                    }
118                },
119            )
120            .type_ops_indirect(
121                &const {
122                    TypeOpsIndirect {
123                        drop_in_place: rc_drop::<T>,
124                        default_in_place: None,
125                        clone_into: None,
126                        is_truthy: None,
127                    }
128                },
129            )
130            .build()
131    };
132}
133
134//////////////////////////////////////////////////////////////////////
135// Rc<str>
136//////////////////////////////////////////////////////////////////////
137
138/// Type name formatter for `Rc<str>`
139fn rc_str_type_name(
140    _shape: &'static Shape,
141    f: &mut core::fmt::Formatter<'_>,
142    opts: TypeNameOpts,
143) -> core::fmt::Result {
144    write!(f, "Rc")?;
145    if let Some(opts) = opts.for_children() {
146        write!(f, "<")?;
147        str::SHAPE.write_type_name(f, opts)?;
148        write!(f, ">")?;
149    } else {
150        write!(f, "<…>")?;
151    }
152    Ok(())
153}
154
155/// Drop function for `Rc<str>`
156unsafe fn rc_str_drop(ox: OxPtrMut) {
157    unsafe {
158        core::ptr::drop_in_place(ox.ptr().as_ptr::<Rc<str>>() as *mut Rc<str>);
159    }
160}
161
162/// Clone function for `Rc<str>`
163unsafe fn rc_str_clone(src: OxPtrConst, dst: OxPtrMut) {
164    unsafe {
165        let value = src.get::<Rc<str>>().clone();
166        (dst.ptr().as_ptr::<Rc<str>>() as *mut Rc<str>).write(value);
167    }
168}
169
170/// Debug function for `Rc<str>`
171unsafe fn rc_str_debug(
172    ox: OxPtrConst,
173    f: &mut core::fmt::Formatter<'_>,
174) -> Option<core::fmt::Result> {
175    let rc = unsafe { ox.get::<Rc<str>>() };
176    let s: &str = rc;
177    Some(write!(f, "Rc({s:?})"))
178}
179
180/// Borrow function for `Rc<str>`
181unsafe fn rc_str_borrow_fn(this: PtrConst) -> PtrConst {
182    unsafe {
183        let concrete = this.get::<Rc<str>>();
184        let s: &str = concrete;
185        PtrConst::new(NonNull::from(s).as_ptr())
186    }
187}
188
189/// Downgrade into function for `Rc<str>`
190unsafe fn rc_str_downgrade_into_fn(strong: PtrMut, weak: PtrUninit) -> PtrMut {
191    unsafe { weak.put(Rc::downgrade(strong.get::<Rc<str>>())) }
192}
193
194unsafe impl<'a> Facet<'a> for Rc<str> {
195    const SHAPE: &'static Shape = &const {
196        const VTABLE: VTableIndirect = VTableIndirect {
197            debug: Some(rc_str_debug),
198            display: None,
199            hash: None,
200            invariants: None,
201            parse: None,
202            try_from: None,
203            try_into_inner: None,
204            try_borrow_inner: None,
205            partial_eq: None,
206            partial_cmp: None,
207            cmp: None,
208        };
209
210        const TYPE_OPS: TypeOpsIndirect = TypeOpsIndirect {
211            drop_in_place: rc_str_drop,
212            default_in_place: None,
213            clone_into: Some(rc_str_clone),
214            is_truthy: None,
215        };
216
217        ShapeBuilder::for_sized::<Rc<str>>("Rc")
218            .type_name(rc_str_type_name)
219            .ty(Type::User(UserType::Opaque))
220            .def(Def::Pointer(PointerDef {
221                vtable: &const {
222                    PointerVTable {
223                        borrow_fn: Some(rc_str_borrow_fn),
224                        downgrade_into_fn: Some(|strong, weak| unsafe {
225                            rc_str_downgrade_into_fn(strong, weak)
226                        }),
227                        ..PointerVTable::new()
228                    }
229                },
230                pointee: Some(str::SHAPE),
231                weak: Some(|| <Weak<str> as Facet>::SHAPE),
232                strong: None,
233                flags: PointerFlags::EMPTY,
234                known: Some(KnownPointer::Rc),
235            }))
236            .type_params(&[crate::TypeParam {
237                name: "T",
238                shape: str::SHAPE,
239            }])
240            .inner(str::SHAPE)
241            .vtable_indirect(&VTABLE)
242            .type_ops_indirect(&TYPE_OPS)
243            .build()
244    };
245}
246
247//////////////////////////////////////////////////////////////////////
248// Rc<[U]>
249//////////////////////////////////////////////////////////////////////
250
251fn slice_builder_new<'a, U: Facet<'a>>() -> PtrMut {
252    let v = Box::new(Vec::<U>::new());
253    let raw = Box::into_raw(v);
254    PtrMut::new(unsafe { NonNull::new_unchecked(raw as *mut u8) }.as_ptr())
255}
256
257fn slice_builder_push<'a, U: Facet<'a>>(builder: PtrMut, item: PtrMut) {
258    unsafe {
259        let vec = builder.as_mut::<Vec<U>>();
260        let value = item.read::<U>();
261        vec.push(value);
262    }
263}
264
265fn slice_builder_convert<'a, U: Facet<'a>>(builder: PtrMut) -> PtrConst {
266    unsafe {
267        let vec_box = Box::from_raw(builder.as_ptr::<Vec<U>>() as *mut Vec<U>);
268        let rc: Rc<[U]> = (*vec_box).into();
269        let rc_box = Box::new(rc);
270        PtrConst::new(NonNull::new_unchecked(Box::into_raw(rc_box) as *mut u8).as_ptr())
271    }
272}
273
274fn slice_builder_free<'a, U: Facet<'a>>(builder: PtrMut) {
275    unsafe {
276        let _ = Box::from_raw(builder.as_ptr::<Vec<U>>() as *mut Vec<U>);
277    }
278}
279
280/// Type name formatter for `Rc<[U]>`
281fn rc_slice_type_name<'a, U: Facet<'a>>(
282    _shape: &'static Shape,
283    f: &mut core::fmt::Formatter<'_>,
284    opts: TypeNameOpts,
285) -> core::fmt::Result {
286    write!(f, "Rc")?;
287    if let Some(opts) = opts.for_children() {
288        write!(f, "<")?;
289        <[U]>::SHAPE.write_type_name(f, opts)?;
290        write!(f, ">")?;
291    } else {
292        write!(f, "<…>")?;
293    }
294    Ok(())
295}
296
297/// Drop function for `Rc<[U]>`
298unsafe fn rc_slice_drop<U>(ox: OxPtrMut) {
299    unsafe {
300        core::ptr::drop_in_place(ox.ptr().as_ptr::<Rc<[U]>>() as *mut Rc<[U]>);
301    }
302}
303
304/// Debug function for `Rc<[U]>`
305unsafe fn rc_slice_debug<'a, U: Facet<'a>>(
306    ox: OxPtrConst,
307    f: &mut core::fmt::Formatter<'_>,
308) -> Option<core::fmt::Result> {
309    let rc = unsafe { ox.get::<Rc<[U]>>() };
310    let slice: &[U] = rc;
311
312    // Try to debug the slice if U has debug
313    let slice_ptr = PtrConst::new(NonNull::from(slice).as_ptr());
314    if let Some(result) = unsafe { <[U]>::SHAPE.call_debug(slice_ptr, f) } {
315        return Some(result);
316    }
317
318    Some(write!(f, "Rc([...])"))
319}
320
321/// Borrow function for `Rc<[U]>`
322unsafe fn rc_slice_borrow_fn<U>(this: PtrConst) -> PtrConst {
323    unsafe {
324        let concrete = this.get::<Rc<[U]>>();
325        let s: &[U] = concrete;
326        PtrConst::new(NonNull::from(s).as_ptr())
327    }
328}
329
330/// Downgrade into function for `Rc<[U]>`
331unsafe fn rc_slice_downgrade_into_fn<'a, 'ptr, U: Facet<'a>>(
332    strong: PtrMut,
333    weak: PtrUninit,
334) -> PtrMut {
335    unsafe { weak.put(Rc::downgrade(strong.get::<Rc<[U]>>())) }
336}
337
338unsafe impl<'a, U: Facet<'a>> Facet<'a> for Rc<[U]> {
339    const SHAPE: &'static Shape = &const {
340        ShapeBuilder::for_sized::<Rc<[U]>>("Rc")
341            .type_name(rc_slice_type_name::<U>)
342            .ty(Type::User(UserType::Opaque))
343            .def(Def::Pointer(PointerDef {
344                vtable: &const {
345                    PointerVTable {
346                        borrow_fn: Some(rc_slice_borrow_fn::<U>),
347                        downgrade_into_fn: Some(|strong, weak| unsafe {
348                            rc_slice_downgrade_into_fn::<U>(strong, weak)
349                        }),
350                        slice_builder_vtable: Some(
351                            &const {
352                                SliceBuilderVTable::new(
353                                    slice_builder_new::<U>,
354                                    slice_builder_push::<U>,
355                                    slice_builder_convert::<U>,
356                                    slice_builder_free::<U>,
357                                )
358                            },
359                        ),
360                        ..PointerVTable::new()
361                    }
362                },
363                pointee: Some(<[U]>::SHAPE),
364                weak: Some(|| <Weak<[U]> as Facet>::SHAPE),
365                strong: None,
366                flags: PointerFlags::EMPTY,
367                known: Some(KnownPointer::Rc),
368            }))
369            .type_params(&[crate::TypeParam {
370                name: "T",
371                shape: <[U]>::SHAPE,
372            }])
373            .inner(<[U]>::SHAPE)
374            .vtable_indirect(
375                &const {
376                    VTableIndirect {
377                        debug: Some(rc_slice_debug::<U>),
378                        display: None,
379                        hash: None,
380                        invariants: None,
381                        parse: None,
382                        try_from: None,
383                        try_into_inner: None,
384                        try_borrow_inner: None,
385                        partial_eq: None,
386                        partial_cmp: None,
387                        cmp: None,
388                    }
389                },
390            )
391            .type_ops_indirect(
392                &const {
393                    TypeOpsIndirect {
394                        drop_in_place: rc_slice_drop::<U>,
395                        default_in_place: None,
396                        clone_into: None,
397                        is_truthy: None,
398                    }
399                },
400            )
401            .build()
402    };
403}
404
405//////////////////////////////////////////////////////////////////////
406// Weak<T>
407//////////////////////////////////////////////////////////////////////
408
409/// Type name formatter for `Weak<T>`
410fn weak_type_name<'a, T: Facet<'a>>(
411    _shape: &'static Shape,
412    f: &mut core::fmt::Formatter<'_>,
413    opts: TypeNameOpts,
414) -> core::fmt::Result {
415    write!(f, "Weak")?;
416    if let Some(opts) = opts.for_children() {
417        write!(f, "<")?;
418        T::SHAPE.write_type_name(f, opts)?;
419        write!(f, ">")?;
420    } else {
421        write!(f, "<…>")?;
422    }
423    Ok(())
424}
425
426/// Drop function for `Weak<T>`
427unsafe fn weak_drop<T>(ox: OxPtrMut) {
428    unsafe {
429        core::ptr::drop_in_place(ox.ptr().as_ptr::<Weak<T>>() as *mut Weak<T>);
430    }
431}
432
433/// Default function for `Weak<T>`
434unsafe fn weak_default<T>(ox: OxPtrMut) {
435    unsafe {
436        (ox.ptr().as_ptr::<Weak<T>>() as *mut Weak<T>).write(Weak::<T>::new());
437    }
438}
439
440/// Clone function for `Weak<T>`
441unsafe fn weak_clone<T>(src: OxPtrConst, dst: OxPtrMut) {
442    unsafe {
443        let value = src.get::<Weak<T>>().clone();
444        (dst.ptr().as_ptr::<Weak<T>>() as *mut Weak<T>).write(value);
445    }
446}
447
448/// Debug function for `Weak<T>`
449unsafe fn weak_debug(
450    _ox: OxPtrConst,
451    f: &mut core::fmt::Formatter<'_>,
452) -> Option<core::fmt::Result> {
453    Some(write!(f, "(Weak)"))
454}
455
456/// Upgrade into function for `Weak<T>`
457unsafe fn weak_upgrade_into_fn<'a, 'ptr, T: Facet<'a>>(
458    weak: PtrMut,
459    strong: PtrUninit,
460) -> Option<PtrMut> {
461    unsafe { Some(strong.put(weak.get::<Weak<T>>().upgrade()?)) }
462}
463
464unsafe impl<'a, T: Facet<'a>> Facet<'a> for Weak<T> {
465    const SHAPE: &'static Shape = &const {
466        ShapeBuilder::for_sized::<Weak<T>>("Weak")
467            .type_name(weak_type_name::<T>)
468            .ty(Type::User(UserType::Opaque))
469            .def(Def::Pointer(PointerDef {
470                vtable: &const {
471                    PointerVTable {
472                        upgrade_into_fn: Some(|weak, strong| unsafe {
473                            weak_upgrade_into_fn::<T>(weak, strong)
474                        }),
475                        ..PointerVTable::new()
476                    }
477                },
478                pointee: Some(T::SHAPE),
479                weak: None,
480                strong: Some(<Rc<T> as Facet>::SHAPE),
481                flags: PointerFlags::WEAK,
482                known: Some(KnownPointer::RcWeak),
483            }))
484            .type_params(&[crate::TypeParam {
485                name: "T",
486                shape: T::SHAPE,
487            }])
488            .inner(T::SHAPE)
489            .vtable_indirect(
490                &const {
491                    VTableIndirect {
492                        debug: Some(weak_debug),
493                        display: None,
494                        hash: None,
495                        invariants: None,
496                        parse: None,
497                        try_from: None,
498                        try_into_inner: None,
499                        try_borrow_inner: None,
500                        partial_eq: None,
501                        partial_cmp: None,
502                        cmp: None,
503                    }
504                },
505            )
506            .type_ops_indirect(
507                &const {
508                    TypeOpsIndirect {
509                        drop_in_place: weak_drop::<T>,
510                        default_in_place: Some(weak_default::<T>),
511                        clone_into: Some(weak_clone::<T>),
512                        is_truthy: None,
513                    }
514                },
515            )
516            .build()
517    };
518}
519
520//////////////////////////////////////////////////////////////////////
521// Weak<str>
522//////////////////////////////////////////////////////////////////////
523
524/// Type name formatter for `Weak<str>`
525fn weak_str_type_name(
526    _shape: &'static Shape,
527    f: &mut core::fmt::Formatter<'_>,
528    opts: TypeNameOpts,
529) -> core::fmt::Result {
530    write!(f, "Weak")?;
531    if let Some(opts) = opts.for_children() {
532        write!(f, "<")?;
533        str::SHAPE.write_type_name(f, opts)?;
534        write!(f, ">")?;
535    } else {
536        write!(f, "<…>")?;
537    }
538    Ok(())
539}
540
541/// Drop function for `Weak<str>`
542unsafe fn weak_str_drop(ox: OxPtrMut) {
543    unsafe {
544        core::ptr::drop_in_place(ox.ptr().as_ptr::<Weak<str>>() as *mut Weak<str>);
545    }
546}
547
548/// Clone function for `Weak<str>`
549unsafe fn weak_str_clone(src: OxPtrConst, dst: OxPtrMut) {
550    unsafe {
551        let value = src.get::<Weak<str>>().clone();
552        (dst.ptr().as_ptr::<Weak<str>>() as *mut Weak<str>).write(value);
553    }
554}
555
556/// Upgrade into function for `Weak<str>`
557unsafe fn weak_str_upgrade_into_fn(weak: PtrMut, strong: PtrUninit) -> Option<PtrMut> {
558    unsafe { Some(strong.put(weak.get::<Weak<str>>().upgrade()?)) }
559}
560
561unsafe impl<'a> Facet<'a> for Weak<str> {
562    const SHAPE: &'static Shape = &const {
563        const VTABLE: VTableIndirect = VTableIndirect {
564            debug: Some(weak_debug),
565            display: None,
566            hash: None,
567            invariants: None,
568            parse: None,
569            try_from: None,
570            try_into_inner: None,
571            try_borrow_inner: None,
572            partial_eq: None,
573            partial_cmp: None,
574            cmp: None,
575        };
576
577        const TYPE_OPS: TypeOpsIndirect = TypeOpsIndirect {
578            drop_in_place: weak_str_drop,
579            default_in_place: None,
580            clone_into: Some(weak_str_clone),
581            is_truthy: None,
582        };
583
584        ShapeBuilder::for_sized::<Weak<str>>("Weak")
585            .type_name(weak_str_type_name)
586            .ty(Type::User(UserType::Opaque))
587            .def(Def::Pointer(PointerDef {
588                vtable: &const {
589                    PointerVTable {
590                        upgrade_into_fn: Some(|weak, strong| unsafe {
591                            weak_str_upgrade_into_fn(weak, strong)
592                        }),
593                        ..PointerVTable::new()
594                    }
595                },
596                pointee: Some(str::SHAPE),
597                weak: None,
598                strong: Some(<Rc<str> as Facet>::SHAPE),
599                flags: PointerFlags::WEAK,
600                known: Some(KnownPointer::RcWeak),
601            }))
602            .type_params(&[crate::TypeParam {
603                name: "T",
604                shape: str::SHAPE,
605            }])
606            .inner(str::SHAPE)
607            .vtable_indirect(&VTABLE)
608            .type_ops_indirect(&TYPE_OPS)
609            .build()
610    };
611}
612
613//////////////////////////////////////////////////////////////////////
614// Weak<[U]>
615//////////////////////////////////////////////////////////////////////
616
617/// Type name formatter for `Weak<[U]>`
618fn weak_slice_type_name<'a, U: Facet<'a>>(
619    _shape: &'static Shape,
620    f: &mut core::fmt::Formatter<'_>,
621    opts: TypeNameOpts,
622) -> core::fmt::Result {
623    write!(f, "Weak")?;
624    if let Some(opts) = opts.for_children() {
625        write!(f, "<")?;
626        <[U]>::SHAPE.write_type_name(f, opts)?;
627        write!(f, ">")?;
628    } else {
629        write!(f, "<…>")?;
630    }
631    Ok(())
632}
633
634/// Drop function for `Weak<[U]>`
635unsafe fn weak_slice_drop<U>(ox: OxPtrMut) {
636    unsafe {
637        core::ptr::drop_in_place(ox.ptr().as_ptr::<Weak<[U]>>() as *mut Weak<[U]>);
638    }
639}
640
641/// Clone function for `Weak<[U]>`
642unsafe fn weak_slice_clone<U>(src: OxPtrConst, dst: OxPtrMut) {
643    unsafe {
644        let value = src.get::<Weak<[U]>>().clone();
645        (dst.ptr().as_ptr::<Weak<[U]>>() as *mut Weak<[U]>).write(value);
646    }
647}
648
649/// Upgrade into function for `Weak<[U]>`
650unsafe fn weak_slice_upgrade_into_fn<'a, 'ptr, U: Facet<'a>>(
651    weak: PtrMut,
652    strong: PtrUninit,
653) -> Option<PtrMut> {
654    unsafe { Some(strong.put(weak.get::<Weak<[U]>>().upgrade()?)) }
655}
656
657unsafe impl<'a, U: Facet<'a>> Facet<'a> for Weak<[U]> {
658    const SHAPE: &'static Shape = &const {
659        ShapeBuilder::for_sized::<Weak<[U]>>("Weak")
660            .type_name(weak_slice_type_name::<U>)
661            .ty(Type::User(UserType::Opaque))
662            .def(Def::Pointer(PointerDef {
663                vtable: &const {
664                    PointerVTable {
665                        upgrade_into_fn: Some(|weak, strong| unsafe {
666                            weak_slice_upgrade_into_fn::<U>(weak, strong)
667                        }),
668                        ..PointerVTable::new()
669                    }
670                },
671                pointee: Some(<[U]>::SHAPE),
672                weak: None,
673                strong: Some(<Rc<[U]> as Facet>::SHAPE),
674                flags: PointerFlags::WEAK,
675                known: Some(KnownPointer::RcWeak),
676            }))
677            .type_params(&[crate::TypeParam {
678                name: "T",
679                shape: <[U]>::SHAPE,
680            }])
681            .inner(<[U]>::SHAPE)
682            .vtable_indirect(
683                &const {
684                    VTableIndirect {
685                        debug: Some(weak_debug),
686                        display: None,
687                        hash: None,
688                        invariants: None,
689                        parse: None,
690                        try_from: None,
691                        try_into_inner: None,
692                        try_borrow_inner: None,
693                        partial_eq: None,
694                        partial_cmp: None,
695                        cmp: None,
696                    }
697                },
698            )
699            .type_ops_indirect(
700                &const {
701                    TypeOpsIndirect {
702                        drop_in_place: weak_slice_drop::<U>,
703                        default_in_place: None,
704                        clone_into: Some(weak_slice_clone::<U>),
705                        is_truthy: None,
706                    }
707                },
708            )
709            .build()
710    };
711}
712
713#[cfg(test)]
714mod tests {
715    use core::mem::ManuallyDrop;
716
717    use alloc::rc::{Rc, Weak as RcWeak};
718    use alloc::string::String;
719
720    use super::*;
721
722    #[test]
723    fn test_rc_type_params() {
724        let [type_param_1] = <Rc<i32>>::SHAPE.type_params else {
725            panic!("Rc<T> should only have 1 type param")
726        };
727        assert_eq!(type_param_1.shape(), i32::SHAPE);
728    }
729
730    #[test]
731    fn test_rc_vtable_1_new_borrow_drop() {
732        facet_testhelpers::setup();
733
734        let rc_shape = <Rc<String>>::SHAPE;
735        let rc_def = rc_shape
736            .def
737            .into_pointer()
738            .expect("Rc<T> should have a smart pointer definition");
739
740        // Allocate memory for the Rc
741        let rc_uninit_ptr = rc_shape.allocate().unwrap();
742
743        // Get the function pointer for creating a new Rc from a value
744        let new_into_fn = rc_def
745            .vtable
746            .new_into_fn
747            .expect("Rc<T> should have new_into_fn");
748
749        // Create the value and initialize the Rc
750        let mut value = ManuallyDrop::new(String::from("example"));
751        let rc_ptr = unsafe {
752            new_into_fn(
753                rc_uninit_ptr,
754                PtrMut::new(NonNull::from(&mut value).as_ptr()),
755            )
756        };
757
758        // Get the function pointer for borrowing the inner value
759        let borrow_fn = rc_def
760            .vtable
761            .borrow_fn
762            .expect("Rc<T> should have borrow_fn");
763
764        // Borrow the inner value and check it
765        let borrowed_ptr = unsafe { borrow_fn(rc_ptr.as_const()) };
766        // SAFETY: borrowed_ptr points to a valid String within the Rc
767        assert_eq!(unsafe { borrowed_ptr.get::<String>() }, "example");
768
769        // Drop the Rc in place
770        // SAFETY: rc_ptr points to a valid Rc<String>
771        unsafe {
772            rc_shape
773                .call_drop_in_place(rc_ptr)
774                .expect("Rc<T> should have drop_in_place");
775        }
776
777        // Deallocate the memory
778        // SAFETY: rc_ptr was allocated by rc_shape and is now dropped (but memory is still valid)
779        unsafe { rc_shape.deallocate_mut(rc_ptr).unwrap() };
780    }
781
782    #[test]
783    fn test_rc_vtable_2_downgrade_upgrade_drop() {
784        facet_testhelpers::setup();
785
786        let rc_shape = <Rc<String>>::SHAPE;
787        let rc_def = rc_shape
788            .def
789            .into_pointer()
790            .expect("Rc<T> should have a smart pointer definition");
791
792        let weak_shape = <RcWeak<String>>::SHAPE;
793        let weak_def = weak_shape
794            .def
795            .into_pointer()
796            .expect("RcWeak<T> should have a smart pointer definition");
797
798        // 1. Create the first Rc (rc1)
799        let rc1_uninit_ptr = rc_shape.allocate().unwrap();
800        let new_into_fn = rc_def.vtable.new_into_fn.unwrap();
801        let mut value = ManuallyDrop::new(String::from("example"));
802        let rc1_ptr = unsafe {
803            new_into_fn(
804                rc1_uninit_ptr,
805                PtrMut::new(NonNull::from(&mut value).as_ptr()),
806            )
807        };
808
809        // 2. Downgrade rc1 to create a weak pointer (weak1)
810        let weak1_uninit_ptr = weak_shape.allocate().unwrap();
811        let downgrade_into_fn = rc_def.vtable.downgrade_into_fn.unwrap();
812        // SAFETY: rc1_ptr points to a valid Rc, weak1_uninit_ptr is allocated for a Weak
813        let weak1_ptr = unsafe { downgrade_into_fn(rc1_ptr, weak1_uninit_ptr) };
814
815        // 3. Upgrade weak1 to create a second Rc (rc2)
816        let rc2_uninit_ptr = rc_shape.allocate().unwrap();
817        let upgrade_into_fn = weak_def.vtable.upgrade_into_fn.unwrap();
818        // SAFETY: weak1_ptr points to a valid Weak, rc2_uninit_ptr is allocated for an Rc.
819        // Upgrade should succeed as rc1 still exists.
820        let rc2_ptr = unsafe { upgrade_into_fn(weak1_ptr, rc2_uninit_ptr) }
821            .expect("Upgrade should succeed while original Rc exists");
822
823        // Check the content of the upgraded Rc
824        let borrow_fn = rc_def.vtable.borrow_fn.unwrap();
825        // SAFETY: rc2_ptr points to a valid Rc<String>
826        let borrowed_ptr = unsafe { borrow_fn(rc2_ptr.as_const()) };
827        // SAFETY: borrowed_ptr points to a valid String
828        assert_eq!(unsafe { borrowed_ptr.get::<String>() }, "example");
829
830        // 4. Drop everything and free memory
831        unsafe {
832            // Drop Rcs
833            rc_shape.call_drop_in_place(rc1_ptr).unwrap();
834            rc_shape.deallocate_mut(rc1_ptr).unwrap();
835
836            rc_shape.call_drop_in_place(rc2_ptr).unwrap();
837            rc_shape.deallocate_mut(rc2_ptr).unwrap();
838
839            // Drop Weak
840            weak_shape.call_drop_in_place(weak1_ptr).unwrap();
841            weak_shape.deallocate_mut(weak1_ptr).unwrap();
842        }
843    }
844
845    #[test]
846    fn test_rc_vtable_3_downgrade_drop_try_upgrade() {
847        facet_testhelpers::setup();
848
849        let rc_shape = <Rc<String>>::SHAPE;
850        let rc_def = rc_shape
851            .def
852            .into_pointer()
853            .expect("Rc<T> should have a smart pointer definition");
854
855        let weak_shape = <RcWeak<String>>::SHAPE;
856        let weak_def = weak_shape
857            .def
858            .into_pointer()
859            .expect("RcWeak<T> should have a smart pointer definition");
860
861        // 1. Create the strong Rc (rc1)
862        let rc1_uninit_ptr = rc_shape.allocate().unwrap();
863        let new_into_fn = rc_def.vtable.new_into_fn.unwrap();
864        let mut value = ManuallyDrop::new(String::from("example"));
865        let rc1_ptr = unsafe {
866            new_into_fn(
867                rc1_uninit_ptr,
868                PtrMut::new(NonNull::from(&mut value).as_ptr()),
869            )
870        };
871
872        // 2. Downgrade rc1 to create a weak pointer (weak1)
873        let weak1_uninit_ptr = weak_shape.allocate().unwrap();
874        let downgrade_into_fn = rc_def.vtable.downgrade_into_fn.unwrap();
875        // SAFETY: rc1_ptr is valid, weak1_uninit_ptr is allocated for Weak
876        let weak1_ptr = unsafe { downgrade_into_fn(rc1_ptr, weak1_uninit_ptr) };
877
878        // 3. Drop and free the strong pointer (rc1)
879        unsafe {
880            rc_shape.call_drop_in_place(rc1_ptr).unwrap();
881            rc_shape.deallocate_mut(rc1_ptr).unwrap();
882        }
883
884        // 4. Attempt to upgrade the weak pointer (weak1)
885        let upgrade_into_fn = weak_def.vtable.upgrade_into_fn.unwrap();
886        let rc2_uninit_ptr = rc_shape.allocate().unwrap();
887        // SAFETY: weak1_ptr is valid (though points to dropped data), rc2_uninit_ptr is allocated for Rc
888        let upgrade_result = unsafe { upgrade_into_fn(weak1_ptr, rc2_uninit_ptr) };
889
890        // Assert that the upgrade failed
891        assert!(
892            upgrade_result.is_none(),
893            "Upgrade should fail after the strong Rc is dropped"
894        );
895
896        // 5. Clean up: Deallocate the memory intended for the failed upgrade and drop/deallocate the weak pointer
897        unsafe {
898            // Deallocate the *uninitialized* memory allocated for the failed upgrade attempt
899            rc_shape.deallocate_uninit(rc2_uninit_ptr).unwrap();
900
901            // Drop and deallocate the weak pointer
902            weak_shape.call_drop_in_place(weak1_ptr).unwrap();
903            weak_shape.deallocate_mut(weak1_ptr).unwrap();
904        }
905    }
906}
facet_core/impls/alloc/rc.rs

facet_core/impls/alloc/
rc.rs
