bevy_utils

Enum CowArc

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pub enum CowArc<'a, T: ?Sized + 'static> {
    Borrowed(&'a T),
    Static(&'static T),
    Owned(Arc<T>),
}
Expand description

Much like a Cow, but owned values are Arc-ed to make clones cheap. This should be used for values that are cloned for use across threads and change rarely (if ever).

This also makes an opinionated tradeoff by adding a CowArc::Static and implementing [From<&'static T>] instead of [From<'a T>]. This preserves the static context and prevents conversion to CowArc::Owned in cases where a reference is known to be static. This is an optimization that prevents allocations and atomic ref-counting.

This means that static references should prefer From::from or CowArc::Static and non-static references must use CowArc::Borrowed.

Variants§

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Borrowed(&'a T)

A borrowed value

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Static(&'static T)

A static value reference. This exists to avoid conversion to CowArc::Owned in cases where a reference is known to be static. This is an optimization that prevents allocations and atomic ref-counting.

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Owned(Arc<T>)

An owned Arc-ed value

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impl<'a, T: ?Sized> CowArc<'a, T>
where &'a T: Into<Arc<T>>,

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pub fn into_owned(self) -> CowArc<'static, T>

Converts this into an “owned” value. If internally a value is borrowed, it will be cloned into an “owned Arc”. If it is already a CowArc::Owned or a CowArc::Static, it will remain unchanged.

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pub fn clone_owned(&self) -> CowArc<'static, T>

Clones into an owned [CowArc<'static>]. If internally a value is borrowed, it will be cloned into an “owned Arc”. If it is already a CowArc::Owned or CowArc::Static, the value will be cloned. This is equivalent to .clone().into_owned().

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impl<'a, T: ?Sized> AsRef<T> for CowArc<'a, T>

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fn as_ref(&self) -> &T

Converts this type into a shared reference of the (usually inferred) input type.
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impl<'a, T: ?Sized> Borrow<T> for CowArc<'a, T>

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<'a, T: ?Sized> Clone for CowArc<'a, T>

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fn clone(&self) -> Self

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl<'a, T: Debug + ?Sized> Debug for CowArc<'a, T>

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

Formats the value using the given formatter. Read more
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impl Default for CowArc<'static, Path>

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fn default() -> Self

Returns the “default value” for a type. Read more
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impl Default for CowArc<'static, str>

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fn default() -> Self

Returns the “default value” for a type. Read more
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impl<'a, T: ?Sized> Deref for CowArc<'a, T>

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type Target = T

The resulting type after dereferencing.
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fn deref(&self) -> &Self::Target

Dereferences the value.
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impl<'a, T: Display + ?Sized> Display for CowArc<'a, T>

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

Formats the value using the given formatter. Read more
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impl<'a> From<&'a String> for CowArc<'a, str>

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fn from(value: &'a String) -> Self

Converts to this type from the input type.
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impl<T: ?Sized> From<&'static T> for CowArc<'static, T>

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fn from(value: &'static T) -> Self

Converts to this type from the input type.
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impl From<&'static str> for CowArc<'static, Path>

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fn from(value: &'static str) -> Self

Converts to this type from the input type.
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impl From<PathBuf> for CowArc<'static, Path>

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fn from(value: PathBuf) -> Self

Converts to this type from the input type.
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impl From<String> for CowArc<'static, str>

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fn from(value: String) -> Self

Converts to this type from the input type.
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impl<'a, T: Hash + ?Sized> Hash for CowArc<'a, T>

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

Feeds this value into the given Hasher. Read more
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fn hash_slice<H>(data: &[Self], state: &mut H)
where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher. Read more
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impl<'a, T: Ord + ?Sized> Ord for CowArc<'a, T>

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

This method returns an Ordering between self and other. Read more
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fn max(self, other: Self) -> Self
where Self: Sized,

Compares and returns the maximum of two values. Read more
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fn min(self, other: Self) -> Self
where Self: Sized,

Compares and returns the minimum of two values. Read more
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fn clamp(self, min: Self, max: Self) -> Self
where Self: Sized,

Restrict a value to a certain interval. Read more
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impl<'a, T: PartialEq + ?Sized> PartialEq for CowArc<'a, T>

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

Tests for self and other values to be equal, and is used by ==.
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fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl<'a, T: PartialOrd + ?Sized> PartialOrd for CowArc<'a, T>

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

This method returns an ordering between self and other values if one exists. Read more
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fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator. Read more
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fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator. Read more
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fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator. Read more
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fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator. Read more
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impl<'a, T: PartialEq + ?Sized> Eq for CowArc<'a, T>

Auto Trait Implementations§

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impl<'a, T> Freeze for CowArc<'a, T>
where T: ?Sized,

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impl<'a, T> RefUnwindSafe for CowArc<'a, T>
where T: RefUnwindSafe + ?Sized,

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impl<'a, T> Send for CowArc<'a, T>
where T: Sync + Send + ?Sized,

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impl<'a, T> Sync for CowArc<'a, T>
where T: Sync + Send + ?Sized,

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impl<'a, T> Unpin for CowArc<'a, T>
where T: ?Sized,

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impl<'a, T> UnwindSafe for CowArc<'a, T>
where T: RefUnwindSafe + ?Sized,

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

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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

Mutably borrows from an owned value. Read more
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impl<T> CloneToUninit for T
where T: Clone,

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unsafe fn clone_to_uninit(&self, dst: *mut T)

🔬This is a nightly-only experimental API. (clone_to_uninit)
Performs copy-assignment from self to dst. Read more
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impl<Q, K> Equivalent<K> for Q
where Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

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fn equivalent(&self, key: &K) -> bool

Checks if this value is equivalent to the given key. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T> Instrument for T

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fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
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fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

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

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impl<T> ToOwned for T
where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T> ToString for T
where T: Display + ?Sized,

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default fn to_string(&self) -> String

Converts the given value to a String. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<T> WithSubscriber for T

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fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
where S: Into<Dispatch>,

Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more
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fn with_current_subscriber(self) -> WithDispatch<Self>

Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more
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impl<T> ConditionalSend for T
where T: Send,