pub struct CurrentGuard<'a, T: Any> { /* private fields */ }Available on crate features
std and unsafe_layout only.Expand description
A guard that temporarily sets a global current pointer for T, restoring the old one on drop.
When dropped, it restores the previous pointer or sets a placeholder if none existed.“
This is useful for tracking the current instance of a type within a thread.
§Vendored
This is adapted work from current.
Implementations§
Source§impl<T: Any> CurrentGuard<'_, T>
impl<T: Any> CurrentGuard<'_, T>
Sourcepub fn new(current: &mut T) -> CurrentGuard<'_, T>
pub fn new(current: &mut T) -> CurrentGuard<'_, T>
Creates a new current guard for the given value.
When this guard is dropped, the previous pointer (if any) will be restored.
§Safety
- This function modifies global state within a thread-local map.
- It ensures that only one mutable reference to a given
Texists at a time. - Improper use may lead to stale pointers if lifetimes are not respected.
§Example
let mut my_value = MyType::new();
let guard = CurrentGuard::new(&mut my_value);Trait Implementations§
Auto Trait Implementations§
impl<'a, T> Freeze for CurrentGuard<'a, T>
impl<'a, T> RefUnwindSafe for CurrentGuard<'a, T>where
T: RefUnwindSafe,
impl<'a, T> !Send for CurrentGuard<'a, T>
impl<'a, T> !Sync for CurrentGuard<'a, T>
impl<'a, T> Unpin for CurrentGuard<'a, T>
impl<'a, T> !UnwindSafe for CurrentGuard<'a, T>
Blanket Implementations§
Source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
Source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
Source§impl<T> ByteSized for T
impl<T> ByteSized for T
Source§const BYTE_ALIGN: usize = _
const BYTE_ALIGN: usize = _
The alignment of this type in bytes.
Source§fn byte_align(&self) -> usize
fn byte_align(&self) -> usize
Returns the alignment of this type in bytes.
Source§fn ptr_size_ratio(&self) -> [usize; 2]
fn ptr_size_ratio(&self) -> [usize; 2]
Source§impl<T, R> Chain<R> for Twhere
T: ?Sized,
impl<T, R> Chain<R> for Twhere
T: ?Sized,
Source§impl<T> ExtAny for T
impl<T> ExtAny for T
Source§fn type_hash_with<H: Hasher>(&self, hasher: H) -> u64
fn type_hash_with<H: Hasher>(&self, hasher: H) -> u64
Returns a deterministic hash of the
TypeId of Self using a custom hasher.Source§fn as_any_mut(&mut self) -> &mut dyn Anywhere
Self: Sized,
fn as_any_mut(&mut self) -> &mut dyn Anywhere
Self: Sized,
Source§impl<T> ExtMem for Twhere
T: ?Sized,
impl<T> ExtMem for Twhere
T: ?Sized,
Source§const NEEDS_DROP: bool = _
const NEEDS_DROP: bool = _
Know whether dropping values of this type matters, in compile-time.
Source§fn mem_align_of<T>() -> usize
fn mem_align_of<T>() -> usize
Returns the minimum alignment of the type in bytes. Read more
Source§fn mem_align_of_val(&self) -> usize
fn mem_align_of_val(&self) -> usize
Returns the alignment of the pointed-to value in bytes. Read more
Source§fn mem_size_of<T>() -> usize
fn mem_size_of<T>() -> usize
Returns the size of a type in bytes. Read more
Source§fn mem_size_of_val(&self) -> usize
fn mem_size_of_val(&self) -> usize
Returns the size of the pointed-to value in bytes. Read more
Source§fn mem_needs_drop(&self) -> bool
fn mem_needs_drop(&self) -> bool
Returns
true if dropping values of this type matters. Read moreSource§fn mem_forget(self)where
Self: Sized,
fn mem_forget(self)where
Self: Sized,
Forgets about
self without running its destructor. Read moreSource§fn mem_replace(&mut self, other: Self) -> Selfwhere
Self: Sized,
fn mem_replace(&mut self, other: Self) -> Selfwhere
Self: Sized,
Source§unsafe fn mem_zeroed<T>() -> T
unsafe fn mem_zeroed<T>() -> T
Available on crate feature
unsafe_layout only.Returns the value of type
T represented by the all-zero byte-pattern. Read moreSource§unsafe fn mem_transmute_copy<Src, Dst>(src: &Src) -> Dst
unsafe fn mem_transmute_copy<Src, Dst>(src: &Src) -> Dst
Available on crate feature
unsafe_layout only.Returns the value of type
T represented by the all-zero byte-pattern. Read moreSource§fn mem_as_bytes(&self) -> &[u8] ⓘ
fn mem_as_bytes(&self) -> &[u8] ⓘ
Available on crate feature
unsafe_slice only.§impl<S> FromSample<S> for S
impl<S> FromSample<S> for S
fn from_sample_(s: S) -> S
Source§impl<T> Hook for T
impl<T> Hook for T
§impl<T> Instrument for T
impl<T> Instrument for T
§fn instrument(self, span: Span) -> Instrumented<Self> ⓘ
fn instrument(self, span: Span) -> Instrumented<Self> ⓘ
§fn in_current_span(self) -> Instrumented<Self> ⓘ
fn in_current_span(self) -> Instrumented<Self> ⓘ
Source§impl<T> IntoEither for T
impl<T> IntoEither for T
Source§fn into_either(self, into_left: bool) -> Either<Self, Self> ⓘ
fn into_either(self, into_left: bool) -> Either<Self, Self> ⓘ
Converts
self into a Left variant of Either<Self, Self>
if into_left is true.
Converts self into a Right variant of Either<Self, Self>
otherwise. Read moreSource§fn into_either_with<F>(self, into_left: F) -> Either<Self, Self> ⓘ
fn into_either_with<F>(self, into_left: F) -> Either<Self, Self> ⓘ
Converts
self into a Left variant of Either<Self, Self>
if into_left(&self) returns true.
Converts self into a Right variant of Either<Self, Self>
otherwise. Read more