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Simplify run and unfold helpers to build a Subscription

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This commit is contained in:
Héctor Ramón Jiménez 2022-01-17 15:29:41 +07:00
parent 88f1168a0b
commit ddbbe7353b
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GPG key ID: 140CC052C94F138E
2 changed files with 69 additions and 96 deletions
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58
examples/download_progress/src/download.rs
View file

@ -1,22 +1,15 @@
use futures::Stream;
use iced_futures::futures;
use iced_native::subscription;
use std::hash::Hash;
// Just a little utility function
pub fn file<I: 'static + Hash + Copy + Send, T: ToString>(
pub fn file<I: 'static + Hash + Copy + Send + Sync, T: ToString>(
id: I,
url: T,
) -> iced::Subscription<(I, Progress)> {
subscription::run(
id,
Download {
id,
url: url.to_string(),
},
download,
)
subscription::unfold(id, State::Ready(url.to_string()), move |state| {
download(id, state)
})
}
#[derive(Debug, Hash, Clone)]
@ -25,14 +18,10 @@ pub struct Download<I> {
url: String,
}
fn download<I: Copy>(
download: Download<I>,
) -> impl Stream<Item = (I, Progress)> {
let id = download.id;
futures::stream::unfold(
State::Ready(download.url),
move |state| async move {
async fn download<I: Copy>(
id: I,
state: State,
) -> (Option<(I, Progress)>, State) {
match state {
State::Ready(url) => {
let response = reqwest::get(&url).await;
@ -40,21 +29,19 @@ fn download<I: Copy>(
match response {
Ok(response) => {
if let Some(total) = response.content_length() {
Some((
(id, Progress::Started),
(
Some((id, Progress::Started)),
State::Downloading {
response,
total,
downloaded: 0,
},
))
)
} else {
Some(((id, Progress::Errored), State::Finished))
(Some((id, Progress::Errored)), State::Finished)
}
}
Err(_) => {
Some(((id, Progress::Errored), State::Finished))
}
Err(_) => (Some((id, Progress::Errored)), State::Finished),
}
}
State::Downloading {
@ -65,22 +52,19 @@ fn download<I: Copy>(
Ok(Some(chunk)) => {
let downloaded = downloaded + chunk.len() as u64;
let percentage =
(downloaded as f32 / total as f32) * 100.0;
let percentage = (downloaded as f32 / total as f32) * 100.0;
Some((
(id, Progress::Advanced(percentage)),
(
Some((id, Progress::Advanced(percentage))),
State::Downloading {
response,
total,
downloaded,
},
))
)
}
Ok(None) => {
Some(((id, Progress::Finished), State::Finished))
}
Err(_) => Some(((id, Progress::Errored), State::Finished)),
Ok(None) => (Some((id, Progress::Finished)), State::Finished),
Err(_) => (Some((id, Progress::Errored)), State::Finished),
},
State::Finished => {
// We do not let the stream die, as it would start a
@ -88,11 +72,9 @@ fn download<I: Copy>(
// in case of errors.
let _: () = iced::futures::future::pending().await;
None
unreachable!()
}
}
},
)
}
#[derive(Debug, Clone)]

43
native/src/subscription.rs
View file

@ -60,8 +60,7 @@ where
{
Subscription::from_recipe(Runner {
id: f,
initial: (),
spawn: move |_, events| {
spawn: move |events| {
use futures::future;
use futures::stream::StreamExt;
@ -73,31 +72,25 @@ where
}
/// Returns a [`Subscription`] that will create and asynchronously run the
/// [`Stream`] returned by the provided closure.
/// given [`Stream`].
///
/// The `initial` state will be used to uniquely identify the [`Subscription`].
pub fn run<I, T, S, Message>(
id: I,
initial: T,
f: impl FnOnce(T) -> S + 'static,
) -> Subscription<Message>
/// The `id` will be used to uniquely identify the [`Subscription`].
pub fn run<I, S, Message>(id: I, stream: S) -> Subscription<Message>
where
I: Hash + 'static,
T: 'static,
S: Stream<Item = Message> + Send + 'static,
Message: 'static,
{
Subscription::from_recipe(Runner {
id,
initial,
spawn: move |initial, _| f(initial),
spawn: move |_| stream,
})
}
/// Returns a [`Subscription`] that will create and asynchronously run a
/// [`Stream`] that will call the provided closure to produce every `Message`.
///
/// The `initial` state will be used to uniquely identify the [`Subscription`].
/// The `id` will be used to uniquely identify the [`Subscription`].
pub fn unfold<I, T, Fut, Message>(
id: I,
initial: T,
@ -112,41 +105,39 @@ where
use futures::future::{self, FutureExt};
use futures::stream::StreamExt;
run(id, initial, move |initial| {
run(
id,
futures::stream::unfold(initial, move |state| f(state).map(Some))
.filter_map(future::ready)
})
.filter_map(future::ready),
)
}
struct Runner<I, T, F, S, Message>
struct Runner<I, F, S, Message>
where
F: FnOnce(T, EventStream) -> S,
F: FnOnce(EventStream) -> S,
S: Stream<Item = Message>,
{
id: I,
initial: T,
spawn: F,
}
impl<I, T, S, F, Message> Recipe<Hasher, (Event, event::Status)>
for Runner<I, T, F, S, Message>
impl<I, S, F, Message> Recipe<Hasher, (Event, event::Status)>
for Runner<I, F, S, Message>
where
I: Hash + 'static,
T: 'static,
F: FnOnce(T, EventStream) -> S,
F: FnOnce(EventStream) -> S,
S: Stream<Item = Message> + Send + 'static,
{
type Output = Message;
fn hash(&self, state: &mut Hasher) {
std::any::TypeId::of::<T>().hash(state);
std::any::TypeId::of::<I>().hash(state);
self.id.hash(state);
}
fn stream(self: Box<Self>, input: EventStream) -> BoxStream<Self::Output> {
use futures::stream::StreamExt;
(self.spawn)(self.initial, input).boxed()
(self.spawn)(input).boxed()
}
}