Skip to main content

OwnedProtect

miniextendr_api::gc_protect

Struct OwnedProtect

pub struct OwnedProtect {
    sexp: SEXP,
    armed: bool,
    _nosend: PhantomData<Rc<()>>,
}

Expand description

A single-object RAII guard: PROTECT on create, UNPROTECT(1) on drop.

Use this for simple cases where you’re protecting a single value and don’t need the batching benefits of ProtectScope.

§Example

unsafe fn allocate_and_fill() -> SEXP {
    let guard = OwnedProtect::new(Rf_allocVector(REALSXP, 10));
    fill_vector(guard.get());
    // Return the SEXP - guard drops and unprotects on this line.
    // This is safe because no GC can occur between unprotect and return.
    guard.get()
}

§Warning: Stack Ordering

OwnedProtect uses UNPROTECT(1), which removes the top of the protection stack. If you have nested protections from other sources, the drop order matters!

For complex scenarios, prefer ProtectScope which unprotects all its values at once when dropped.

Fields§

§sexp: SEXP§armed: bool§_nosend: PhantomData<Rc<()>>

Implementations§

impl OwnedProtect

pub unsafe fn new(x: SEXP) -> Self

Create a new protection guard for x.

Calls Rf_protect(x) immediately.

§Safety

Must be called from the R main thread
x must be a valid SEXP

pub fn get(&self) -> SEXP

Get the protected SEXP.

pub unsafe fn forget(self)

Escape hatch: do not UNPROTECT(1) on drop.

§Safety

Leaks one protection entry unless unprotected elsewhere.

Trait Implementations§

impl Deref for OwnedProtect

type Target = SEXP

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl Drop for OwnedProtect

fn drop(&mut self)

Executes the destructor for this type. Read more

fn pin_drop(self: Pin<&mut Self>)

🔬This is a nightly-only experimental API. (pin_ergonomics)

Execute the destructor for this type, but different to Drop::drop, it requires self to be pinned. Read more

Auto Trait Implementations§

impl Freeze for OwnedProtect

impl RefUnwindSafe for OwnedProtect

impl !Send for OwnedProtect

impl !Sync for OwnedProtect

impl Unpin for OwnedProtect

impl UnsafeUnpin for OwnedProtect

impl UnwindSafe for OwnedProtect

Blanket Implementations§

impl<T> Any for T
where T: 'static + ?Sized,

fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more

impl<T> Borrow<T> for T
where T: ?Sized,

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more

impl<T> BorrowMut<T> for T
where T: ?Sized,

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more

impl<T> From<T> for T

fn from(t: T) -> T

Returns the argument unchanged.

impl<T, U> Into<U> for T
where U: From<T>,

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

impl<P, T> Receiver for P
where P: Deref<Target = T> + ?Sized, T: ?Sized,

type Target = T

🔬This is a nightly-only experimental API. (arbitrary_self_types)

The target type on which the method may be called.

impl<T> SizeEq<Cell<T>> for T
where T: ?Sized,

type CastFrom = CastFromWrapper

impl<T> SizeEq<ManuallyDrop<T>> for T
where T: ?Sized,

type CastFrom = CastFromWrapper

impl<T> SizeEq<MaybeUninit<T>> for T

type CastFrom = CastSizedExact

impl<T> SizeEq<ReadOnly<T>> for T
where T: ?Sized,

type CastFrom = CastFromReadOnly

impl<T> SizeEq<T> for T
where T: ?Sized,

type CastFrom = IdCast

impl<T> SizeEq<Unalign<T>> for T

type CastFrom = CastFromWrapper

impl<T> SizeEq<UnsafeCell<T>> for T
where T: ?Sized,

type CastFrom = CastFromWrapper

impl<T> SizeEq<Wrapping<T>> for T

type CastFrom = CastFromWrapper

impl<T> SizedTypeProperties for T

#[doc(hidden)]
const SIZE: usize = _

🔬This is a nightly-only experimental API. (sized_type_properties)

#[doc(hidden)]
const ALIGN: usize = _

🔬This is a nightly-only experimental API. (sized_type_properties)

#[doc(hidden)]
const ALIGNMENT: Alignment = _

🔬This is a nightly-only experimental API. (ptr_alignment_type)

#[doc(hidden)]
const IS_ZST: bool = _

🔬This is a nightly-only experimental API. (sized_type_properties)

true if this type requires no storage. false if its size is greater than zero. Read more

#[doc(hidden)]
const LAYOUT: Layout = _

🔬This is a nightly-only experimental API. (sized_type_properties)

#[doc(hidden)]
const MAX_SLICE_LEN: usize = _

🔬This is a nightly-only experimental API. (sized_type_properties)

The largest safe length for a [Self]. Read more

impl<T, U> TryFrom<U> for T
where U: Into<T>,

type Error = Infallible

The type returned in the event of a conversion error.

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.

impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.

fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.

impl<ST, DT> CastableFrom<ST, Initialized, Initialized> for DT
where ST: ?Sized, DT: ?Sized,

impl<ST, DT> CastableFrom<ST, Uninit, Uninit> for DT
where ST: ?Sized, DT: ?Sized,

impl<T> InvariantsEq<ManuallyDrop<T>> for T
where T: ?Sized,

impl<T> InvariantsEq<T> for T
where T: ?Sized,

impl<T> InvariantsEq<Unalign<T>> for T

impl<T> InvariantsEq<Wrapping<T>> for T

impl<Src, Dst, A, SV, DV, R> MutationCompatible<Src, A, SV, DV, (BecauseRead, R)> for Dst
where A: Aliasing, SV: Validity, DV: Validity, Src: Read<A, R> + ?Sized, Dst: Read<A, R> + ?Sized,

impl<Src, Dst, A, SV, DV> MutationCompatible<Src, A, SV, DV, BecauseInvariantsEq> for Dst
where A: Aliasing, SV: Validity, DV: Validity, Src: TransmuteFrom<Dst, DV, SV> + ?Sized, Dst: TransmuteFrom<Src, SV, DV> + InvariantsEq<Src> + ?Sized,

impl<T> Read<Exclusive, BecauseExclusive> for T
where T: ?Sized,

impl<T> TransmuteFrom<Cell<T>, Valid, Valid> for T
where T: ?Sized,

impl<T> TransmuteFrom<ManuallyDrop<T>, Valid, Valid> for T
where T: ?Sized,

impl<T> TransmuteFrom<ReadOnly<T>, Valid, Valid> for T
where T: ?Sized,

impl<Src, Dst> TransmuteFrom<Src, Initialized, Initialized> for Dst
where Src: ?Sized, Dst: ?Sized,

impl<Src, Dst, V> TransmuteFrom<Src, V, Uninit> for Dst
where V: Validity, Src: ?Sized, Dst: ?Sized,

impl<Src, Dst> TransmuteFrom<Src, Valid, Initialized> for Dst
where Src: IntoBytes + ?Sized, Dst: ?Sized,

impl<T> TransmuteFrom<Unalign<T>, Valid, Valid> for T

impl<T> TransmuteFrom<UnsafeCell<T>, Valid, Valid> for T
where T: ?Sized,

impl<T> TransmuteFrom<Wrapping<T>, Valid, Valid> for T

impl<Src, Dst, A, SV, DV, C, R> TransmuteFromPtr<Src, A, SV, DV, C, R> for Dst
where A: Aliasing, SV: Validity, DV: Validity, C: CastExact<Src, Dst>, Dst: TransmuteFrom<Src, SV, DV> + TryTransmuteFromPtr<Src, A, SV, DV, C, R> + ?Sized, Src: ?Sized,

impl<Src, Dst, SV, DV, A, C, R> TryTransmuteFromPtr<Src, A, SV, DV, C, (BecauseMutationCompatible, R)> for Dst
where A: Aliasing, SV: Validity, DV: Validity, Src: TransmuteFrom<Dst, DV, SV> + ?Sized, Dst: MutationCompatible<Src, A, SV, DV, R> + ?Sized, C: CastExact<Src, Dst>,

Layout§

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 16 bytes