Struct arc_swap::Lease

pub struct Lease<T: RefCnt> { /* fields omitted */ }

A temporary storage of the pointer.

This, unlike Guard, does not block any write operations and is usually faster than loading the full Arc. However, this holds only if each thread keeps only small number of Leases around and if too many are held, the following ones will just fall back to creating the Arc internally.

Methods

impl<T: RefCnt> Lease<T>

pub fn upgrade(lease: &Self) -> T

Loads a full Arc from the lease.

pub fn into_upgrade(lease: Self) -> T

A consuming version of upgrade.

This is a bit faster in certain situations, but consumes the lease.

pub fn get_ref(lease: &Self) -> Option<&T::Base>

Returns access to the data held.

This returns Option even when it can't hold NULL internally, to keep the interface the same. But there's also the Deref trait for the non-NULL cases, which is usually more comfortable.

pub fn is_null(lease: &Self) -> bool

Checks if it contains a null pointer.

Note that for non-NULL T, this always returns false.

impl<T: NonNull> Lease<Option<T>>

pub fn expect(self, msg: &str) -> Lease<T>

Like [unwrap][Lease::unwrap], but with a panic message.

Panics

If the lease contains a NULL pointer.

pub fn unwrap(self) -> Lease<T>

Asserts the lease contains non-NULL content and gets direct access to it.

This is very much like [Option::unwrap].

Panics

If the lease contains a NULL pointer.

pub fn into_option(self) -> Option<Lease<T>>

Transposes the Lease<Option<RefCnt>> into Option<Lease<RefCnt>>.

Examples

let shared = ArcSwapOption::from_pointee(42);
if let Some(ptr) = shared.lease().into_option() {
    println!("It is {}", ptr);
} else {
    println!("Nothing present");
}

Trait Implementations

impl<'a, T: RefCnt> AsRaw<<T as RefCnt>::Base> for &'a Lease<T>

fn as_raw(&self) -> *mut T::Base

Converts the value into a raw pointer.

impl<T: RefCnt> AsRaw<<T as RefCnt>::Base> for Lease<T>

fn as_raw(&self) -> *mut T::Base

Converts the value into a raw pointer.

impl<T> Sync for Lease<T> where
    T: RefCnt + Send + Sync,
    T::Base: Send + Sync, 

impl<T> Send for Lease<T> where
    T: RefCnt + Send + Sync,
    T::Base: Send + Sync, 

impl<T: RefCnt> Drop for Lease<T>

fn drop(&mut self)

Executes the destructor for this type.

impl<T> Display for Lease<T> where
    T: NonNull,
    T::Base: Display, 

fn fmt(&self, formatter: &mut Formatter) -> FmtResult

Formats the value using the given formatter.

impl<T: NonNull> Deref for Lease<T>

type Target = T::Base

The resulting type after dereferencing.

fn deref(&self) -> &T::Base

Dereferences the value.

impl<T> Debug for Lease<T> where
    T: RefCnt,
    T::Base: Debug, 

fn fmt(&self, formatter: &mut Formatter) -> FmtResult

Formats the value using the given formatter.