zrx_stream/stream/operator/
inspect.rs

1// Copyright (c) 2025-2026 Zensical and contributors
2
3// SPDX-License-Identifier: MIT
4// All contributions are certified under the DCO
5
6// Permission is hereby granted, free of charge, to any person obtaining a copy
7// of this software and associated documentation files (the "Software"), to
8// deal in the Software without restriction, including without limitation the
9// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
10// sell copies of the Software, and to permit persons to whom the Software is
11// furnished to do so, subject to the following conditions:
12
13// The above copyright notice and this permission notice shall be included in
14// all copies or substantial portions of the Software.
15
16// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18// FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
19// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
22// IN THE SOFTWARE.
23
24// ----------------------------------------------------------------------------
25
26//! Inspect operator.
27
28use std::marker::PhantomData;
29
30use zrx_scheduler::action::context::Binding;
31use zrx_scheduler::action::{Action, Context};
32use zrx_scheduler::step::IntoSteps;
33use zrx_scheduler::{Id, Value};
34
35use crate::stream::function::{Arguments, InspectFn};
36use crate::stream::Stream;
37
38use super::Operator;
39
40// ----------------------------------------------------------------------------
41// Structs
42// ----------------------------------------------------------------------------
43
44/// Inspect operator.
45pub struct Inspect<T, F, A> {
46    /// Operator function.
47    function: F,
48    /// Capture types.
49    marker: PhantomData<(T, A)>,
50}
51
52// ----------------------------------------------------------------------------
53// Implementations
54// ----------------------------------------------------------------------------
55
56impl<I, T> Stream<I, T>
57where
58    I: Id,
59    T: Value,
60{
61    /// Inspects the stream using the provided function.
62    #[inline]
63    pub fn inspect<F, A>(&self, f: F) -> Stream<I, T>
64    where
65        F: InspectFn<A, I, T>,
66        A: Arguments,
67    {
68        self.subscribe(Inspect {
69            function: f,
70            marker: PhantomData,
71        })
72    }
73}
74
75// ----------------------------------------------------------------------------
76// Trait implementations
77// ----------------------------------------------------------------------------
78
79impl<I, T, F, A> Action<I> for Inspect<T, F, A>
80where
81    I: Id,
82    T: Value,
83    F: InspectFn<A, I, T>,
84    A: Arguments,
85{
86    type Inputs = (T,);
87    type Output<'a> = T;
88
89    /// Executes the operator.
90    fn execute(&mut self, ctx: Context<I, Self>) -> impl IntoSteps<I, Self> {
91        let Binding { scopes, inputs, mut output, .. } = ctx.bind();
92        scopes.into_iter().map(move |mut scope| {
93            let Some(value) = inputs.get(scope.key()).cloned() else {
94                output.remove(scope.key());
95                return scope.done();
96            };
97            self.function.execute(&mut scope, &value)?;
98            output.insert(scope.key().clone(), value.clone());
99            scope.done()
100        })
101    }
102}
zrx_stream/stream/operator/inspect.rs

zrx_stream/stream/operator/
inspect.rs
