128 lines
3.8 KiB
Rust
128 lines
3.8 KiB
Rust
#![allow(missing_docs)]
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use dioxus_core::{
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prelude::{spawn, use_hook},
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ScopeState, Task,
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};
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use dioxus_signals::*;
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use futures_util::{future, pin_mut, FutureExt};
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use std::{any::Any, cell::Cell, future::Future, pin::Pin, rc::Rc, sync::Arc, task::Poll};
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/// A future that resolves to a value.
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///
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/// This runs the future only once - though the future may be regenerated
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/// through the [`UseFuture::restart`] method.
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///
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/// This is commonly used for components that cannot be rendered until some
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/// asynchronous operation has completed.
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///
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/// Whenever the hooks dependencies change, the future will be re-evaluated.
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/// If a future is pending when the dependencies change, the previous future
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/// will be canceled before the new one is started.
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///
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/// - dependencies: a tuple of references to values that are PartialEq + Clone
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pub fn use_resource<T, F>(future: impl Fn() -> F) -> UseResource<T>
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where
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T: 'static,
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F: Future<Output = T> + 'static,
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{
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let mut value = use_signal(|| None);
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let mut state = use_signal(|| UseResourceState::Pending);
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let task = use_signal(|| {
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// Create the user's task
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let fut = future();
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// Spawn a wrapper task that polls the innner future and watch its dependencies
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let task = spawn(async move {
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// move the future here and pin it so we can poll it
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let fut = fut;
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pin_mut!(fut);
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let res = future::poll_fn(|cx| {
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// Set the effect stack properly
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// Poll the inner future
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let ready = fut.poll_unpin(cx);
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// add any dependencies to the effect stack that we need to watch when restarting the future
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ready
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})
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.await;
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// Set the value
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value.set(Some(res));
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});
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Some(task)
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});
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UseResource { task, value, state }
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}
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pub struct UseResource<T: 'static> {
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value: Signal<Option<T>>,
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task: Signal<Option<Task>>,
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state: Signal<UseResourceState<T>>,
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}
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impl<T> UseResource<T> {
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/// Restart the future with new dependencies.
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///
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/// Will not cancel the previous future, but will ignore any values that it
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/// generates.
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pub fn restart(&self) {
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// self.needs_regen.set(true);
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// (self.update)();
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}
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/// Forcefully cancel a future
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pub fn cancel(&self) {
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// if let Some(task) = self.task.take() {
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// cx.remove_future(task);
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// }
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}
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// Manually set the value in the future slot without starting the future over
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pub fn set(&mut self, new_value: T) {
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self.value.set(Some(new_value));
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}
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/// Return any value, even old values if the future has not yet resolved.
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///
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/// If the future has never completed, the returned value will be `None`.
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pub fn value(&self) -> Signal<Option<T>> {
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self.value
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}
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/// Get the ID of the future in Dioxus' internal scheduler
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pub fn task(&self) -> Option<Task> {
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todo!()
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// self.task.get()
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}
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/// Get the current state of the future.
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pub fn state(&self) -> UseResourceState<T> {
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todo!()
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// match (&self.task.get(), &self.value()) {
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// // If we have a task and an existing value, we're reloading
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// (Some(_), Some(val)) => UseResourceState::Reloading(val),
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// // no task, but value - we're done
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// (None, Some(val)) => UseResourceState::Complete(val),
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// // no task, no value - something's wrong? return pending
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// (None, None) => UseResourceState::Pending,
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// // Task, no value - we're still pending
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// (Some(_), None) => UseResourceState::Pending,
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// }
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}
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}
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pub enum UseResourceState<T: 'static> {
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Pending,
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Complete(Signal<T>),
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Regenerating(Signal<T>), // the old value
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}
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