59 lines
1.8 KiB
Rust
59 lines
1.8 KiB
Rust
//! Listen to runtime events.
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use crate::core::event::{self, Event};
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use crate::core::window;
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use crate::subscription::{self, Subscription};
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use crate::MaybeSend;
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/// Returns a [`Subscription`] to all the ignored runtime events.
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///
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/// This subscription will notify your application of any [`Event`] that was
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/// not captured by any widget.
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pub fn listen() -> Subscription<Event> {
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listen_with(|event, status| match status {
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event::Status::Ignored => Some(event),
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event::Status::Captured => None,
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})
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}
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/// Creates a [`Subscription`] that listens and filters all the runtime events
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/// with the provided function, producing messages accordingly.
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///
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/// This subscription will call the provided function for every [`Event`]
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/// handled by the runtime. If the function:
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///
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/// - Returns `None`, the [`Event`] will be discarded.
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/// - Returns `Some` message, the `Message` will be produced.
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pub fn listen_with<Message>(
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f: fn(Event, event::Status) -> Option<Message>,
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) -> Subscription<Message>
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where
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Message: 'static + MaybeSend,
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{
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#[derive(Hash)]
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struct EventsWith;
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subscription::filter_map(
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(EventsWith, f),
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move |event, status| match event {
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Event::Window(_, window::Event::RedrawRequested(_)) => None,
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_ => f(event, status),
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},
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)
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}
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/// Creates a [`Subscription`] that produces a message for every runtime event,
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/// including the redraw request events.
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///
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/// **Warning:** This [`Subscription`], if unfiltered, may produce messages in
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/// an infinite loop.
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pub fn listen_raw<Message>(
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f: fn(Event, event::Status) -> Option<Message>,
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) -> Subscription<Message>
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where
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Message: 'static + MaybeSend,
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{
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#[derive(Hash)]
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struct RawEvents;
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subscription::filter_map((RawEvents, f), f)
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}
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