Struct ScopedRefGuard 

pub struct ScopedRefGuard<'a, T: 'static> { /* private fields */ }

A reference with lifetime 'a that can be lifted to a reference with a 'static lifetime (ScopedRef). Runtime checks are used to ensure that no derived ScopedRef exists when this ScopedRefGuard is dropped.

use scoped_static::ScopedRefGuard;

#[tokio::main]
async fn main() {
    let concrete_value = Box::new(1.0);
    let ref_value = &concrete_value;
    let guard = unsafe { ScopedRefGuard::new(ref_value) };
    let lifted = guard.lift();
    tokio::spawn(async move {
        // Lifted is 'static so it can be moved into this closure that needs 'static
        let value = **lifted + 1.0;
        assert_eq!(value, 2.0);
        // `lifted` is dropped here
    })
    .await
    .unwrap();
   // `guard` is dropped here
}

If a ScopedRefGuard is dropped while any derived ScopedRef exist, then it will abort the whole program (instead of panic). This is because ScopedRef could exist on another thread and be unaffected by the panic or the panic could be recovered from. This could lead to undefined behavior.

UNDEFINED BEHAVIOR: It may cause undefined behavior to leak/forget this value (e.g. std::mem::forget, std::mem::ManuallyDrop, or Rc cycles, etc.)

• the Drop code must run to prevent undefined behavior.

See scoped_static macro for a safe way to create.

Implementations

impl<'a, T: 'static> ScopedRefGuard<'a, T>

pub unsafe fn new(value: &'a T) -> Self

Creates a new ScopeGuard. See scoped_static for a safe way to create

pub fn lift(&self) -> ScopedRef<T>

Lifts this reference with lifetime 'a into 'static and relies on runtime checks to ensure safety.

Trait Implementations

impl<'a, T: Debug + 'static> Debug for ScopedRefGuard<'a, T>

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

Formats the value using the given formatter.

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

type Target = T

The resulting type after dereferencing.

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

Dereferences the value.

impl<'a, T: 'static> Drop for ScopedRefGuard<'a, T>

fn drop(&mut self)

Executes the destructor for this type.

impl<'a, T: Hash + 'static> Hash for ScopedRefGuard<'a, T>

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

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

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<'a, T: Ord + 'static> Ord for ScopedRefGuard<'a, T>

fn cmp(&self, other: &ScopedRefGuard<'a, T>) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl<'a, T: PartialEq + 'static> PartialEq for ScopedRefGuard<'a, T>

fn eq(&self, other: &ScopedRefGuard<'a, T>) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<'a, T: PartialOrd + 'static> PartialOrd for ScopedRefGuard<'a, T>

fn partial_cmp(&self, other: &ScopedRefGuard<'a, T>) -> Option<Ordering>

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

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

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

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

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

impl<'a, T: Eq + 'static> Eq for ScopedRefGuard<'a, T>

impl<'a, T: 'static> StructuralPartialEq for ScopedRefGuard<'a, T>