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use quote::quote_spanned;
use super::{
OpInstGenerics, OperatorCategory, OperatorConstraints, OperatorInstance,
OperatorWriteOutput, Persistence, WriteContextArgs, RANGE_0, RANGE_1,
};
use crate::diagnostic::{Diagnostic, Level};
/// Takes one stream as input and filters out any duplicate occurrences. The output
/// contains all unique values from the input.
///
/// ```hydroflow
/// source_iter(vec![1, 1, 2, 3, 2, 1, 3])
/// -> unique()
/// -> assert_eq([1, 2, 3]);
/// ```
///
/// `unique` can also be provided with one generic lifetime persistence argument, either
/// `'tick` or `'static`, to specify how data persists. The default is `'tick`.
/// With `'tick`, uniqueness is only considered within the current tick, so across multiple ticks
/// duplicate values may be emitted.
/// With `'static`, values will be remembered across ticks and no duplicates will ever be emitted.
///
/// ```rustbook
/// let (input_send, input_recv) = hydroflow::util::unbounded_channel::<usize>();
/// let mut flow = hydroflow::hydroflow_syntax! {
/// source_stream(input_recv)
/// -> unique::<'tick>()
/// -> for_each(|n| println!("{}", n));
/// };
///
/// input_send.send(3).unwrap();
/// input_send.send(3).unwrap();
/// input_send.send(4).unwrap();
/// input_send.send(3).unwrap();
/// flow.run_available();
/// // 3, 4
///
/// input_send.send(3).unwrap();
/// input_send.send(5).unwrap();
/// flow.run_available();
/// // 3, 5
/// // Note: 3 is emitted again.
/// ```
pub const UNIQUE: OperatorConstraints = OperatorConstraints {
name: "unique",
categories: &[OperatorCategory::Persistence],
hard_range_inn: RANGE_1,
soft_range_inn: RANGE_1,
hard_range_out: RANGE_1,
soft_range_out: RANGE_1,
num_args: 0,
persistence_args: &(0..=1),
type_args: RANGE_0,
is_external_input: false,
has_singleton_output: false,
ports_inn: None,
ports_out: None,
input_delaytype_fn: |_| None,
write_fn: |wc @ &WriteContextArgs {
root,
op_span,
context,
hydroflow,
ident,
inputs,
outputs,
is_pull,
op_inst:
OperatorInstance {
generics:
OpInstGenerics {
persistence_args, ..
},
..
},
..
},
diagnostics| {
let persistence = match persistence_args[..] {
[] => Persistence::Tick,
[a] => a,
_ => unreachable!(),
};
let input = &inputs[0];
let output = &outputs[0];
let uniquedata_ident = wc.make_ident("uniquedata");
let (write_prologue, get_set) = match persistence {
Persistence::Tick => {
let write_prologue = quote_spanned! {op_span=>
let #uniquedata_ident = #hydroflow.add_state(::std::cell::RefCell::new(
#root::util::monotonic_map::MonotonicMap::<_, #root::rustc_hash::FxHashSet<_>>::default(),
));
};
let get_set = quote_spanned! {op_span=>
let mut borrow = #context.state_ref(#uniquedata_ident).borrow_mut();
let set = borrow.get_mut_clear((#context.current_tick(), #context.current_stratum()));
};
(write_prologue, get_set)
}
Persistence::Static => {
let write_prologue = quote_spanned! {op_span=>
let #uniquedata_ident = #hydroflow.add_state(::std::cell::RefCell::new(#root::rustc_hash::FxHashSet::default()));
};
let get_set = quote_spanned! {op_span=>
let mut set = #context.state_ref(#uniquedata_ident).borrow_mut();
};
(write_prologue, get_set)
}
Persistence::Mutable => {
diagnostics.push(Diagnostic::spanned(
op_span,
Level::Error,
"An implementation of 'mutable does not exist",
));
return Err(());
}
};
let filter_fn = quote_spanned! {op_span=>
|item| {
#get_set
if !set.contains(item) {
set.insert(::std::clone::Clone::clone(item));
true
} else {
false
}
}
};
let write_iterator = if is_pull {
quote_spanned! {op_span=>
let #ident = #input.filter(#filter_fn);
}
} else {
quote_spanned! {op_span=>
let #ident = #root::pusherator::filter::Filter::new(#filter_fn, #output);
}
};
Ok(OperatorWriteOutput {
write_prologue,
write_iterator,
..Default::default()
})
},
};