Struct ScopeGuard 

pub struct ScopeGuard { /* private fields */ }

A scope that a value owns, which closes when the guard is dropped.

nested and nested_or_detached return this guard. Keep the guard with the value that the scope’s children serve, so that they stop when that value is dropped.

Implementations

impl ScopeGuard

pub fn spawn<T>(&mut self, child: T) -> Option<ChildId>

where T: Into<ChildSpecification<WorkerSpec>>,

Spawns a child into the scope.

Returns the child’s ChildId, or None if the guard is detached and the child started as a detached task. A detached child receives a shutdown signal that fires when the guard is dropped. It has no other supervision: nothing restarts it, and nothing waits for it.

pub fn enter_sync<R>(&self, f: impl FnOnce() -> R) -> R

Runs f with the scope of this guard as the current scope.

Each spawn into the current scope inside f goes into this scope instead. This includes each scope that f creates with nested_or_detached. Thus, a value that builds other values can also own their background tasks. For example, a resolver builds its caches inside its own scope. The tasks of the caches then appear below the resolver, and they stop when the resolver is dropped.

A detached guard has no scope, so it runs f with no change. The values that f builds then also run their tasks detached.

pub fn is_detached(&self) -> bool

Returns true if the guard acts as a scope outside supervision and runs its children as detached tasks.

Trait Implementations

impl Debug for ScopeGuard

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

Formats the value using the given formatter.