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use std::collections::HashMap;
use crate::communication::message::RefOrMut;
use crate::Data;
use crate::dataflow::channels::pact::Pipeline;
use crate::dataflow::{Stream, Scope};
use crate::dataflow::operators::generic::operator::Operator;
pub trait Accumulate<G: Scope, D: Data> {
fn accumulate<A: Data>(&self, default: A, logic: impl Fn(&mut A, RefOrMut<Vec<D>>)+'static) -> Stream<G, A>;
fn count(&self) -> Stream<G, usize> {
self.accumulate(0, |sum, data| *sum += data.len())
}
}
impl<G: Scope, D: Data> Accumulate<G, D> for Stream<G, D> {
fn accumulate<A: Data>(&self, default: A, logic: impl Fn(&mut A, RefOrMut<Vec<D>>)+'static) -> Stream<G, A> {
let mut accums = HashMap::new();
self.unary_notify(Pipeline, "Accumulate", vec![], move |input, output, notificator| {
input.for_each(|time, data| {
logic(&mut accums.entry(time.time().clone()).or_insert_with(|| default.clone()), data);
notificator.notify_at(time.retain());
});
notificator.for_each(|time,_,_| {
if let Some(accum) = accums.remove(&time) {
output.session(&time).give(accum);
}
});
})
}
}