64 lines
2.1 KiB
Rust
64 lines
2.1 KiB
Rust
//! Listen to external events in your application.
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use crate::event::{self, Event};
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use crate::Hasher;
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use iced_futures::futures::stream::BoxStream;
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/// A request to listen to external events.
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///
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/// Besides performing async actions on demand with [`Command`], most
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/// applications also need to listen to external events passively.
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///
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/// A [`Subscription`] is normally provided to some runtime, like a [`Command`],
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/// and it will generate events as long as the user keeps requesting it.
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///
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/// For instance, you can use a [`Subscription`] to listen to a WebSocket
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/// connection, keyboard presses, mouse events, time ticks, etc.
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///
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/// [`Command`]: crate::Command
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pub type Subscription<T> =
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iced_futures::Subscription<Hasher, (Event, event::Status), T>;
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/// A stream of runtime events.
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///
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/// It is the input of a [`Subscription`] in the native runtime.
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pub type EventStream = BoxStream<'static, (Event, event::Status)>;
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/// A native [`Subscription`] tracker.
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pub type Tracker =
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iced_futures::subscription::Tracker<Hasher, (Event, event::Status)>;
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pub use iced_futures::subscription::Recipe;
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mod events;
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use events::Events;
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/// Returns a [`Subscription`] to all the 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 events() -> Subscription<Event> {
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Subscription::from_recipe(Events {
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f: |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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}
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/// Returns a [`Subscription`] that filters all the runtime events with the
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/// 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 events_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 + Send,
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{
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Subscription::from_recipe(Events { f })
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}
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