Struct Profiler 

pub struct Profiler { /* private fields */ }

A bounded, cloneable span collector. It starts no threads, keeps no global state, and reads only the clock you give it.

Implementations

impl Profiler

pub fn new(clock: impl Clock + 'static, capacity: usize) -> Self

Keep up to capacity finished spans. Later spans are dropped and counted, so every export shows incomplete coverage.

pub fn set_report_timing(&self, enabled: bool)

Time reports as well as checks, in spans started from now on.

Off by default because it reads the clock at every instrumented report. With it on, each span records its longest ReportGap. DiagnosticPulse turns it on.

pub fn metadata(&self, key: impl Into<String>, value: impl Into<String>)

Record a key/value pair, such as a configuration or build identity. A repeated key replaces the earlier value.

pub fn span( &self, node: impl Into<Option<NodeId>>, task: impl Into<String>, kind: SpanKind, ) -> Span

Start a span for one task. node ties it to a progress-tree phase; pass None for work outside a tree.

use how_far_along::{Outcome, Unstoppable};
use how_far_really::profile::{Profiler, SpanKind, StdClock};

let profiler = Profiler::new(StdClock::new(), 16);
let span = profiler.span(None, "decode", SpanKind::Work);
let stop = span.instrument(Unstoppable);
// decode(&input, &stop)?;
span.finish(Outcome::Succeeded);
assert_eq!(profiler.snapshot().spans.len(), 1);

pub fn measure_callback<R>( &self, task: impl Into<String>, callback: impl FnOnce() -> R, ) -> R

Run one callback inside a Callback span. A panic records the span as abandoned and keeps unwinding.

pub fn cancellation_requested(&self)

Record when cancellation was actually requested. Call it next to the application’s cancel call, not when a callback notices.

pub fn operation_returned(&self)

Record when the operation returned, after every worker joined and cleanup finished.

pub fn snapshot(&self) -> Trace

Copy the finished spans. Active and dropped counts show what is missing.

pub fn try_snapshot(&self) -> Option<Trace>

snapshot without waiting: None if another thread holds the collector’s lock. UI threads keep their last trace and retry.

Trait Implementations

impl Clone for Profiler

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Profiler

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

Formats the value using the given formatter.