Struct ScopeCell 

pub struct ScopeCell { /* private fields */ }

A scope whose scheduler binding owns one shared lease while active.

Scheduler hooks acquire the lease before publishing the pinned pointer and release it after clearing that pointer. Scope-local hot reads therefore need no per-access lock. Every contended operation returns ScopeCellBusy without waiting in a non-preemptible context.

Implementations

impl ScopeCell

pub fn new() -> Self

Creates a managed scope with no active scheduler binding.

pub fn from_scope(scope: Scope) -> Self

Wraps an existing scope with a managed scheduler binding.

pub fn try_read(&self) -> Result<ScopeCellReadGuard<'_>, ScopeCellBusy>

Attempts to acquire an ordinary shared scope reference while preventing migration. It returns immediately when an exclusive lease is active.

pub fn try_write(&self) -> Result<ScopeCellWriteGuard<'_>, ScopeCellBusy>

Attempts to acquire an ordinary exclusive scope reference while preventing migration. It returns immediately while any lease is live.

pub unsafe fn try_activate_pinned( &self, pin: &CpuPin<'_>, ) -> Result<(), ScopeActivationError>

Attempts to install this scope for the pinned CPU and retain its sole scheduler lease.

This operation does not enter a new IRQ or preemption context, so it is suitable for a scheduler switch-in hook that already owns its CPU-local baton.

Safety

Only one CPU may activate a cell at a time. On success, the caller must keep this ScopeCell alive, retain the current CPU pin, and invoke deactivate_pinned exactly once before another scope is installed or the cell can be dropped. The scheduler must run both hooks while holding its switch baton.

pub unsafe fn deactivate_pinned(&self, pin: &CpuPin<'_>)

Clears this scope from the pinned CPU and retires its active identity.

Safety

The current CPU must own exactly one activation previously established by try_activate_pinned for this cell.

pub unsafe fn try_with_active_mut_pinned<R>( &self, pin: &CpuPin<'_>, operation: impl for<'scope> FnOnce(&'scope mut ScopeCellWriteGuard<'_>) -> R, ) -> Result<R, ScopeCellBusy>

Mutates the calling task’s active scope.

The active shared lease is atomically upgraded to the writer state and restored before this function returns. A remote reader or a second CPU activation returns ScopeCellBusy instead of making the caller spin.

Safety

This cell must have exactly one activation, owned by the current CPU, and pin must remain valid for the complete call. The caller must prevent reentrant scope-local access while operation runs.

Trait Implementations

impl Default for ScopeCell

fn default() -> Self

Returns the “default value” for a type.

impl Drop for ScopeCell

fn drop(&mut self)

Executes the destructor for this type.

fn pin_drop(self: Pin<&mut Self>)

🔬This is a nightly-only experimental API. (pin_ergonomics)

Execute the destructor for this type, but different to Drop::drop, it requires self to be pinned.