Struct abi_stable::sabi_types::RRef

#[repr(transparent)]pub struct RRef<'a, T> { /* fields omitted */ }

Equivalent to &'a T, defined as a workaround to allow casting from &T to &U inside a const fn in stable Rust.

Implementations

impl<'a, T> RRef<'a, T>

pub const unsafe fn from_raw(ref_: *const T) -> Self where
    T: 'a, 

Constructs this RRef from a raw pointer.

Safety

You must ensure that the raw pointer is valid for the 'a lifetime.

Example

use abi_stable::sabi_types::RRef;

struct GetPtr<'a,T>(&'a T);

impl<'a,T:'a> GetPtr<'a,T>{
    const PTR:*const Option<T>=&None;

    const STATIC:RRef<'a,Option<T>>=unsafe{
        RRef::from_raw(Self::PTR)
    };
}

pub const fn new(ref_: &'a T) -> Self

Constructs this RRef from a reference.

Example

use abi_stable::sabi_types::RRef;

struct GetPtr<'a,T>(&'a T);

impl<'a,T:'a> GetPtr<'a,T>{
    const REF:&'a Option<T>=&None;

    const STATIC:RRef<'a,Option<T>>=
        RRef::new(Self::REF);
}

pub fn get(self) -> &'a T

Gets access to the reference.

Use this to get a &'a T, instead of a reference borrowing from the pointer.

Example

use abi_stable::sabi_types::RRef;

struct GetPtr<'a,T>(&'a T);

impl<'a,T:'a> GetPtr<'a,T>{
    const NONE_REF:&'a Option<T>=&None;

    const REFERENCE:RRef<'a,Option<T>>=RRef::new(Self::NONE_REF);

    // This returns a reference that lives as long as T does
    fn returns_ref()->&'a Option<String>{
        let reference=GetPtr::<String>::REFERENCE;
        reference.get()
    }

    // This doesn't work,it borrows the reference `variable`.
    // fn returns_ref_2()->&'a Option<String>{
    //     let reference=GetPtr::<String>::REFERENCE;
    //     &*reference
    // }
}

pub const fn get_raw(self) -> *const T

Gets access to the referenced value,as a raw pointer.

Example

use abi_stable::sabi_types::RRef;
use std::convert::Infallible;

struct GetPtr<'a,T>(&'a T);

impl<'a,T:'a> GetPtr<'a,T>{
    const NONE_REF:&'a Option<T>=&None;

    const STATIC:RRef<'a,Option<T>>=
        RRef::new(Self::NONE_REF);
}

let reference:*const Option<Infallible>=
    GetPtr::<Infallible>::STATIC.get_raw();

pub const fn cast_into_raw<U>(self) -> *const U

Accesses the referenced value as a casted raw pointer.

pub const unsafe fn transmute<'b, U>(self) -> RRef<'b, U> where
    U: 'b, 

Transmutes this RRef<'a,T> to a RRef<'b,U>.

Safety

This has the same safety problems that transmuting &'a T to &'b U has.

Example

use abi_stable::sabi_types::RRef;

struct GetPtr<'a,T>(&'a T);

impl<'a,T:'a> GetPtr<'a,T>{
    const PTR:*const Option<T>=&None;

    const STATIC:RRef<'a,Option<T>>=unsafe{
        RRef::from_raw(Self::PTR)
    };
}

let reference:RRef<'static,Option<[();0xFFF_FFFF]>>=unsafe{
    GetPtr::<()>::STATIC
        .transmute::<'static,Option<[();0xFFF_FFFF]>>()
};

pub const unsafe fn transmute_ref<U>(self) -> RRef<'a, U> where
    U: 'a, 

Transmutes this RRef<'a,T> to a RRef<'a,U>.

This is equivalent to calling transmute, except that it doesn't change the lifetime parameter of RRef.

Safety

This has the same safety problems that transmuting &'a T to &'a U has.

Example

use abi_stable::sabi_types::RRef;

struct GetPtr<'a,T>(&'a T);

impl<'a,T:'a> GetPtr<'a,T>{
    const PTR:*const Option<T>=&None;

    const STATIC:RRef<'a,Option<T>>=unsafe{
        RRef::from_raw(Self::PTR)
    };
}

let reference:RRef<'static,[();0xFFF_FFFF]>=unsafe{
    GetPtr::<'static,()>::STATIC
        .transmute_ref::<[();0xFFF_FFFF]>()
};

Trait Implementations

impl<'a, T, U> CanTransmuteElement<U> for RRef<'a, T> where
    U: 'a, 

type TransmutedPtr = RRef<'a, U>

The type of the pointer after it's element type has been changed.

impl<'a, T> Clone for RRef<'a, T>

pub fn clone(&self) -> Self

Returns a copy of the value.

pub fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<'a, T> Copy for RRef<'a, T>

impl<'a, T> Debug for RRef<'a, T> where
    T: Debug, 

pub fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'a, T> Deref for RRef<'a, T>

type Target = T

The resulting type after dereferencing.

pub fn deref(&self) -> &T

Dereferences the value.

impl<'a, T> Display for RRef<'a, T> where
    T: Display, 

pub fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'a, T> Eq for RRef<'a, T> where
    T: Eq, 

impl<'a, T> GetPointerKind for RRef<'a, T>

type Kind = PK_Reference

The kind of the pointer.

pub const KIND: PointerKind

The kind of the pointer.

impl<'a, T> GetStaticEquivalent_ for RRef<'a, T> where
    T: __StableAbi,
    T: 'a, 

type StaticEquivalent = _static_RRef<'static, __GetStaticEquivalent<T>>

impl<'a, T> Hash for RRef<'a, T> where
    T: Hash, 

pub fn hash<H>(&self, state: &mut H) where
    H: Hasher, 

Feeds this value into the given Hasher.

pub fn hash_slice<H>(data: &[Self], state: &mut H) where
    H: Hasher, 

Feeds a slice of this type into the given Hasher.

impl<'a, T> Ord for RRef<'a, T> where
    T: Ord, 

pub fn cmp(&self, other: &Self) -> Ordering

This method returns an Ordering between self and other.

#[must_use]pub fn max(self, other: Self) -> Self

Compares and returns the maximum of two values.

#[must_use]pub fn min(self, other: Self) -> Self

Compares and returns the minimum of two values.

#[must_use]pub fn clamp(self, min: Self, max: Self) -> Self

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

Restrict a value to a certain interval.

impl<'a, T> PartialEq<RRef<'a, T>> for RRef<'a, T> where
    T: PartialEq, 

pub fn eq(&self, other: &Self) -> bool

This method tests for self and other values to be equal, and is used by ==.

#[must_use]pub fn ne(&self, other: &Rhs) -> bool

This method tests for !=.

impl<'a, T> PartialOrd<RRef<'a, T>> for RRef<'a, T> where
    T: PartialOrd, 

pub fn partial_cmp(&self, other: &Self) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

#[must_use]pub fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator.

#[must_use]pub fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

#[must_use]pub fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator.

#[must_use]pub fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl<'a, T> Send for RRef<'a, T> where
    &'a T: Send, 

impl<'a, T> StableAbi for RRef<'a, T> where
    T: __StableAbi,
    T: 'a, 

type IsNonZeroType = <NonNull<T> as __StableAbi>::IsNonZeroType

Whether this type has a single invalid bit-pattern.

pub const LAYOUT: &'static TypeLayout

The layout of the type provided by implementors.

pub const ABI_CONSTS: AbiConsts

const-equivalents of the associated types.

impl<'a, T> Sync for RRef<'a, T> where
    &'a T: Sync,