Struct TrackingSystemTimeNow

pub struct TrackingSystemTimeNow {
    now: SystemTime,
    earliest: Cell<Option<SystemTime>>,
}

Utility to track timeouts based on SystemTime (wall clock time)

Represents the current SystemTime (from when it was created). See the module-level documentation for the general overview.

To operate a timeout, you should calculate the SystemTime at which you should time out, and compare that future planned wakeup time with this TrackingSystemTimeNow (via .cmp() or inequality operators and PartialOrd).

Fields

now: SystemTime

Current time

earliest: Cell<Option<SystemTime>>

Earliest time at which we should wake up

Implementations

impl TrackingSystemTimeNow

pub fn new(now: SystemTime) -> Self

Creates a new timeout tracker, given a value for the current time

pub fn now(r: &impl SleepProvider) -> Self

Creates a new timeout tracker from the current time as seen by a runtime

pub fn get_now_untracked(&self) -> SystemTime

Return the “current time” value in use

If you do comparisons with this, they won’t be tracked, obviously.

fn update_unconditional( earliest: &Cell<Option<SystemTime>>, maybe_earlier: SystemTime, )

Core of a tracked update: updates earliest with maybe_earlier

fn update_conditional( o: Ordering, earliest: &Cell<Option<SystemTime>>, maybe_earlier: SystemTime, )

Core of a tracked update: updates earliest with maybe_earlier, if necessary

o is what we are about to return: Less if the current time hasn’t reached maybe_earlier yet.

impl TrackingSystemTimeNow

pub async fn wait_for_earliest(self, runtime: &impl SleepProvider)

Wait for the earliest timeout implied by any of the comparisons

Waits until the earliest future time at which any of the comparisons performed might change their answer.

If there were no comparisons there are no timeouts, so we wait forever.

impl TrackingSystemTimeNow

pub fn earliest(self) -> Option<SystemTime>

Return the earliest future SystemTime with which this has been compared

pub fn shortest(self) -> Option<Duration>

Return the shortest Duration until any future SystemTime with which this has been compared

impl TrackingSystemTimeNow

fn cmp(&self, t: SystemTime) -> Ordering

Check if time t has been reached yet (and remember that we want to wake up then)

Also available via PartialOrd

Trait Implementations

impl Clone for TrackingSystemTimeNow

fn clone(&self) -> TrackingSystemTimeNow

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for TrackingSystemTimeNow

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

Formats the value using the given formatter.

impl PartialEq<SystemTime> for TrackingSystemTimeNow

Check if time t has been reached yet (and if not, remember that we want to wake up then)

Always returns Some.

fn eq(&self, t: &SystemTime) -> 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 PartialEq<TrackingSystemTimeNow> for SystemTime

Check if we have reached time t yet (and if not, remember that we want to wake up then)

Always returns Some.

fn eq(&self, t: &TrackingSystemTimeNow) -> 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 PartialOrd<SystemTime> for TrackingSystemTimeNow

Check if time t has been reached yet (and if not, remember that we want to wake up then)

Always returns Some.

fn partial_cmp(&self, t: &SystemTime) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl PartialOrd<TrackingSystemTimeNow> for SystemTime

Check if we have reached time t yet (and if not, remember that we want to wake up then)

Always returns Some.

fn partial_cmp(&self, t: &TrackingSystemTimeNow) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Update<SystemTime> for TrackingSystemTimeNow

fn update(&self, t: SystemTime)

Update the “earliest timeout” notion, to ensure it’s at least as early as t

impl Sealed for TrackingSystemTimeNow