Module background 

Background work and timers, provided by the host.

tilo_host::background and ui::background re-export this module.

Toolkit services that must not block a frame (image decoding, file-history transport calls, periodic refreshes) hand their work to a Background rather than spawning threads or sleeping themselves. The host decides how that work runs:

• ThreadPool — the default when no executor is entered: a bounded pool of named threads plus one timer thread, so native behaviour needs no setup;
• Pumped — a queue and a virtual clock that run only when their owner pumps them, for deterministic headless tests and for hosts that drive work from their own loop;
• PageExecutor — the default in a browser page, which has one thread: jobs run from the page’s microtask queue and timers are setTimeouts;
• any other Executor a host installs with Background::enter.

Like crate::wake::WakeScope, the executor is captured when a service is constructed: enter it around construction, and the service keeps using it from any thread afterwards.

An executor may refuse work with Unsupported — a host with no threads of its own, for example. Callers must degrade (report the feature as unavailable, settle a request as failed) instead of retrying forever.

Structs

Background

A cheap-to-clone handle to the executor a service was constructed under.

BackgroundGuard

Restores the previously entered executor on drop. Thread-affine.

NoBackground

An executor that refuses all background work, for hosts that have none. Timers still fire, on park, so deadline-driven callers in a synchronous driver make progress.

Pumped

An executor that runs nothing until its owner pumps it.

ThreadPool

A bounded pool of named worker threads, grown on demand, plus a single timer thread for Executor::wake_at.

Unsupported

The host refused to run background work.

Traits

Executor

How a host runs background work and timers.

Type Aliases

Job

One unit of background work.