Struct zng::update::OnUpdateHandle

pub struct OnUpdateHandle(/* private fields */);

Represents an on_pre_update or on_update handler.

Drop all clones of this handle to drop the binding, or call perm to drop the handle but keep the handler alive for the duration of the app.

Implementations

impl OnUpdateHandle

pub fn dummy() -> OnUpdateHandle

Create a handle to nothing, the handle always in the unsubscribed state.

Note that Option<OnUpdateHandle> takes up the same space as OnUpdateHandle and avoids an allocation.

pub fn perm(self)

Drops the handle but does not unsubscribe.

The handler stays in memory for the duration of the app or until another handle calls unsubscribe

pub fn is_permanent(&self) -> bool

If another handle has called perm.

If true the var binding will stay active until the app exits, unless unsubscribe is called.

pub fn unsubscribe(self)

Drops the handle and forces the handler to drop.

pub fn is_unsubscribed(&self) -> bool

If another handle has called unsubscribe.

The handler is already dropped or will be dropped in the next app update, this is irreversible.

pub fn downgrade(&self) -> WeakOnUpdateHandle

Create a weak handle.

Trait Implementations

impl Clone for OnUpdateHandle

fn clone(&self) -> OnUpdateHandle

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for OnUpdateHandle

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

Formats the value using the given formatter.

impl Hash for OnUpdateHandle

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

where __H: Hasher,

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 PartialEq for OnUpdateHandle

fn eq(&self, other: &OnUpdateHandle) -> 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 Eq for OnUpdateHandle

impl StructuralPartialEq for OnUpdateHandle