risingwave_frontend/utils/
pretty_serde.rs

1// Copyright 2025 RisingWave Labs
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15//! @kwannoel:
16//! This module implements Serde for the Pretty struct. Why not implement it directly on our plan nodes?
17//! That's because Pretty already summarizes the fields that are important to us.
18//! You can see that when `explain()` is called, we directly return the `Pretty` struct.
19//! The _proper way_ to do this would be to create a new data structure that plan nodes get converted into,
20//! and then implement `Serialize` and `Deserialize` on that data structure (including to `Pretty`).
21//! But that's a lot of refactoring work.
22//! So we just wrap `Pretty` in a newtype and implement `Serialize` on that,
23//! since it's a good enough intermediate representation.
24
25use std::collections::BTreeMap;
26
27use pretty_xmlish::Pretty;
28use serde::ser::{SerializeSeq, SerializeStruct};
29use serde::{Serialize, Serializer};
30
31// Second anymous field is include_children.
32// If true the children information will be serialized.
33pub struct PrettySerde<'a>(pub Pretty<'a>, pub bool);
34
35impl Serialize for PrettySerde<'_> {
36    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
37    where
38        S: Serializer,
39    {
40        match &self.0 {
41            Pretty::Text(text) => serializer.serialize_str(text.as_ref()),
42
43            Pretty::Record(node) => {
44                let mut state = serializer.serialize_struct("XmlNode", 3)?;
45                state.serialize_field("name", node.name.as_ref())?;
46                state.serialize_field(
47                    "fields",
48                    &node
49                        .fields
50                        .iter()
51                        .map(|(k, v)| (k.as_ref(), PrettySerde(v.clone(), self.1)))
52                        .collect::<BTreeMap<_, _>>(),
53                )?;
54                if self.1 {
55                    state.serialize_field(
56                        "children",
57                        &node
58                            .children
59                            .iter()
60                            .map(|c| PrettySerde(c.clone(), self.1))
61                            .collect::<Vec<_>>(),
62                    )?;
63                }
64                state.end()
65            }
66
67            Pretty::Array(elements) => {
68                let mut seq = serializer.serialize_seq(Some(elements.len()))?;
69                for element in elements {
70                    seq.serialize_element(&PrettySerde((*element).clone(), self.1))?;
71                }
72                seq.end()
73            }
74
75            Pretty::Linearized(inner, size) => {
76                let mut state = serializer.serialize_struct("Linearized", 2)?;
77                state.serialize_field("inner", &PrettySerde((**inner).clone(), self.1))?;
78                state.serialize_field("size", size)?;
79                state.end()
80            }
81        }
82    }
83}
84
85#[cfg(test)]
86mod tests {
87    use std::fmt::Debug;
88
89    use expect_test::{Expect, expect};
90
91    use super::*;
92
93    fn check(actual: impl Debug, expect: Expect) {
94        let actual = format!("{:#?}", actual);
95        expect.assert_eq(&actual);
96    }
97
98    #[test]
99    fn test_pretty_serde() {
100        let pretty = Pretty::childless_record("root", vec![("a", Pretty::Text("1".into()))]);
101        let pretty_serde = PrettySerde(pretty, true);
102        let serialized = serde_json::to_string(&pretty_serde).unwrap();
103        check(
104            serialized,
105            expect![[r#""{\"name\":\"root\",\"fields\":{\"a\":\"1\"},\"children\":[]}""#]],
106        );
107    }
108}
risingwave_frontend/utils/pretty_serde.rs

risingwave_frontend/utils/
pretty_serde.rs
