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use quote::quote_spanned;
use super::{
FloType, OperatorCategory, OperatorConstraints, OperatorWriteOutput, WriteContextArgs, RANGE_0,
RANGE_1,
};
/// > 0 input streams, 1 output stream
///
/// > Arguments: The receive end of a tokio channel
///
/// Given a [`Stream`](https://docs.rs/futures/latest/futures/stream/trait.Stream.html)
/// created in Rust code, `source_stream`
/// is passed the receive endpoint of the channel and emits each of the
/// elements it receives downstream.
///
/// ```rustbook
/// let (input_send, input_recv) = dfir_rs::util::unbounded_channel::<&str>();
/// let mut flow = dfir_rs::dfir_syntax! {
/// source_stream(input_recv) -> map(|x| x.to_uppercase())
/// -> for_each(|x| println!("{}", x));
/// };
/// input_send.send("Hello").unwrap();
/// input_send.send("World").unwrap();
/// flow.run_available();
/// ```
pub const SOURCE_STREAM: OperatorConstraints = OperatorConstraints {
name: "source_stream",
categories: &[OperatorCategory::Source],
hard_range_inn: RANGE_0,
soft_range_inn: RANGE_0,
hard_range_out: RANGE_1,
soft_range_out: RANGE_1,
num_args: 1,
persistence_args: RANGE_0,
type_args: RANGE_0,
is_external_input: true,
has_singleton_output: false,
flo_type: Some(FloType::Source),
ports_inn: None,
ports_out: None,
input_delaytype_fn: |_| None,
write_fn: |wc @ &WriteContextArgs {
root,
context,
op_span,
ident,
arguments,
..
},
_| {
let receiver = &arguments[0];
let stream_ident = wc.make_ident("stream");
let write_prologue = quote_spanned! {op_span=>
let mut #stream_ident = {
#[inline(always)]
fn check_stream<Stream: #root::futures::stream::Stream<Item = Item> + ::std::marker::Unpin, Item>(stream: Stream)
-> impl #root::futures::stream::Stream<Item = Item> + ::std::marker::Unpin
{
stream
}
check_stream(#receiver)
};
};
let write_iterator = quote_spanned! {op_span=>
let #ident = #root::dfir_pipes::pull::stream_ready(
&mut #stream_ident,
#context.waker(),
);
};
Ok(OperatorWriteOutput {
write_prologue,
write_iterator,
..Default::default()
})
},
};