1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141

//! Extra support for parameter (de)serialization
use std::fmt;
mod ser;

use crate::{map, RequestParameters};
use serde::{
    de::value::{MapDeserializer, SeqDeserializer},
    Deserializer,
};

#[doc(inline)]
pub use ser::{Error, Serializer};

impl<'de, T, E: serde::de::Error> serde::de::IntoDeserializer<'de, E> for RequestParameters<T>
where
    T: serde::de::IntoDeserializer<'de, E>,
{
    type Deserializer = IntoDeserializer<'de, T, E>;

    fn into_deserializer(self) -> Self::Deserializer {
        IntoDeserializer {
            inner: match self {
                RequestParameters::ByPosition(it) => {
                    _IntoDeserializer::Seq(SeqDeserializer::new(it.into_iter()))
                }
                RequestParameters::ByName(it) => {
                    _IntoDeserializer::Map(MapDeserializer::new(it.into_iter()))
                }
            },
        }
    }
}

/// [`IntoDeserializer`](serde::de::IntoDeserializer) implementation for [`RequestParameters`].
pub struct IntoDeserializer<'de, T, E> {
    inner: _IntoDeserializer<'de, T, E>,
}

impl<'de, T, E> IntoDeserializer<'de, T, E> {
    /// Check for remaining elements.
    pub fn end(self) -> Result<(), E>
    where
        E: serde::de::Error,
    {
        let Self { inner } = self;
        match inner {
            _IntoDeserializer::Seq(it) => it.end(),
            _IntoDeserializer::Map(it) => it.end(),
        }
    }
}

impl<'de, T, E> fmt::Debug for IntoDeserializer<'de, T, E> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_struct("RequestParametersIntoDeserializer")
            .finish_non_exhaustive()
    }
}

enum _IntoDeserializer<'de, T, E> {
    Seq(SeqDeserializer<std::vec::IntoIter<T>, E>),
    Map(MapDeserializer<'de, map::IntoIter<T>, E>),
}

impl<'de, T, E> Deserializer<'de> for IntoDeserializer<'de, T, E>
where
    E: serde::de::Error,
    T: serde::de::IntoDeserializer<'de, E>,
{
    type Error = E;

    fn deserialize_any<V>(self, visitor: V) -> Result<V::Value, Self::Error>
    where
        V: serde::de::Visitor<'de>,
    {
        let Self { inner } = self;
        match inner {
            _IntoDeserializer::Seq(it) => it.deserialize_any(visitor),
            _IntoDeserializer::Map(it) => it.deserialize_any(visitor),
        }
    }

    serde::forward_to_deserialize_any! {
        i8 i16 i32 i64 i128 u8 u16 u32 u64 u128 f32 f64 char str string
        bytes byte_buf option unit unit_struct newtype_struct seq tuple
        tuple_struct map struct enum identifier ignored_any bool
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    use fmt::Debug;
    use serde::{
        de::{DeserializeOwned, IntoDeserializer as _},
        Deserialize, Serialize,
    };
    use serde_json::json;

    #[derive(Deserialize, Serialize, PartialEq, Debug)]
    struct Foo {
        name: String,
        count: u32,
    }

    #[track_caller]
    fn do_test<T: DeserializeOwned + Serialize + PartialEq + Debug>(
        item: T,
        expected: RequestParameters,
    ) {
        assert_eq!(
            &T::deserialize(expected.clone().into_deserializer()).expect("couldn't deserialize"),
            &item,
            "deserialized mismatch"
        );
        assert_eq!(
            item.serialize(Serializer).expect("couldn't serialize"),
            expected,
            "serialized mismatch"
        )
    }

    #[test]
    fn test() {
        do_test(
            (String::from("hello"), 1),
            RequestParameters::ByPosition(vec![json!("hello"), json!(1)]),
        );
        do_test(
            Foo {
                name: "string".into(),
                count: 1,
            },
            RequestParameters::ByName(crate::Map::from_iter([
                (String::from("name"), json!("string")),
                (String::from("count"), json!(1)),
            ])),
        );
    }
}