Struct WeakInstance 

pub struct WeakInstance { /* private fields */ }

Weak reference to an Instance.

This is a weak handle that does not prevent the Instance from being dropped. Dependent objects (Database, Sync, BackgroundSync) hold weak references to avoid circular reference cycles that would leak memory.

Use upgrade() to convert to a strong Instance reference.

Implementations

impl WeakInstance

pub fn upgrade(&self) -> Option<Instance>

Upgrade to a strong reference.

Attempts to upgrade this weak reference to a strong Instance reference. Returns None if the Instance has already been dropped.

Returns

Some(Instance) if the Instance still exists, None otherwise.

Example

let instance = Instance::open(Box::new(InMemory::new()))?;
let weak = instance.downgrade();

// Upgrade works while instance exists
assert!(weak.upgrade().is_some());

drop(instance);
// Upgrade fails after instance is dropped
assert!(weak.upgrade().is_none());

Trait Implementations

impl Clone for WeakInstance

fn clone(&self) -> WeakInstance

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for WeakInstance

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

Formats the value using the given formatter.

impl Handle for WeakInstance

fn handle(&self) -> Self

Creates a new handle to the same underlying resource.