Trait PlatformTimer 

pub trait PlatformTimer {
    type TimerHandle: Send + Sync + 'static;

    // Provided methods
    fn create_periodic(
        _period_us: u32,
        _callback: extern "C" fn(*mut c_void),
        _user_data: *mut c_void,
    ) -> Result<Self::TimerHandle, TimerError> { ... }
    fn destroy(_handle: Self::TimerHandle) { ... }
    fn create_oneshot(
        _timeout_us: u32,
        _callback: extern "C" fn(*mut c_void),
        _user_data: *mut c_void,
    ) -> Result<Self::TimerHandle, TimerError> { ... }
    fn cancel(_handle: &mut Self::TimerHandle) -> bool { ... }
}

Periodic timer for ISR-driven sporadic-server budget refill (Phase 110.E.b). The trait factors out the per-platform timer surface so the executor (nros-node) can register an atomic refill callback without becoming generic over the platform — see docs/design/0017-platform-timer.md.

Default create_periodic returns TimerError::Unsupported so platforms without a timer surface inherit safe behavior; destroy is a no-op default for the same reason.

Required Associated Types

type TimerHandle: Send + Sync + 'static

Opaque per-platform handle (FreeRTOS TimerHandle_t, Zephyr *mut k_timer, ThreadX *mut TX_TIMER, POSIX timer_t). Must be Send + Sync + 'static so the executor can stash it across thread boundaries.

Provided Methods

fn create_periodic( _period_us: u32, _callback: extern "C" fn(*mut c_void), _user_data: *mut c_void, ) -> Result<Self::TimerHandle, TimerError>

Register a periodic timer that fires callback(user_data) every period_us microseconds. Returns the platform-native handle for later destruction.

Safety

user_data must outlive the returned handle. The callback is invoked from a platform-defined timer context (direct ISR on Zephyr / bare-metal, deferred via xTimerPendFunctionCall on FreeRTOS, signal handler on POSIX) — bodies should be short and use atomic ops only.

fn destroy(_handle: Self::TimerHandle)

Cancel + free the timer. Idempotent on already-destroyed handles. Must drain in-flight callback invocations before returning so the user_data pointer is no longer accessed.

fn create_oneshot( _timeout_us: u32, _callback: extern "C" fn(*mut c_void), _user_data: *mut c_void, ) -> Result<Self::TimerHandle, TimerError>

Phase 110.E.b follow-up — register a one-shot timer that fires callback(user_data) exactly once after timeout_us microseconds. Used by per-callback runtime measurement: arm just before dispatch with timeout_us = budget_us; on callback completion call cancel. If the timer fires first the callback overran its budget.

Default returns Unsupported so platforms without a oneshot surface inherit safe behavior.

fn cancel(_handle: &mut Self::TimerHandle) -> bool

Phase 110.E.b follow-up — cancel a previously-armed oneshot timer. Returns true when the cancellation prevented the callback from firing, false when the callback already fired (or the timer was already cancelled). Default is a no-op returning false.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors