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

use crate::value::Value;
use serde::de::{MapAccess, SeqAccess, Visitor};
use serde::{de, Deserialize, Deserializer};
use std::collections::HashMap;
use std::fmt;

impl<'de> Deserialize<'de> for Value {
    fn deserialize<D: Deserializer<'de>>(de: D) -> Result<Value, D::Error> {
        de.deserialize_any(ValueVisitor)
    }
}

pub struct ValueVisitor;

macro_rules! visit_fn {
    ($name:ident: $T:ty => $V:path) => {
        #[inline]
        fn $name<E: serde::de::Error>(self, v: $T) -> Result<Self::Value, E> {
            Ok(v.into())
        }
    };
}

impl<'de> Visitor<'de> for ValueVisitor {
    type Value = Value;

    fn expecting(&self, f: &mut fmt::Formatter) -> fmt::Result {
        f.write_str("a config value")
    }

    visit_fn!(visit_bool: bool => Value::Bool);
    visit_fn!(visit_char: char => Value::String);
    visit_fn!(visit_str: &str => Value::String);
    visit_fn!(visit_string: String => Value::String);

    visit_fn!(visit_u8: u8 => Value::Number);
    visit_fn!(visit_u16: u16 => Value::Number);
    visit_fn!(visit_u32: u32 => Value::Number);
    visit_fn!(visit_u64: u64 => Value::Number);

    visit_fn!(visit_i8: i8 => Value::Number);
    visit_fn!(visit_i16: i16 => Value::Number);
    visit_fn!(visit_i32: i32 => Value::Number);
    visit_fn!(visit_i64: i64 => Value::Number);

    visit_fn!(visit_f32: f32 => Value::Number);
    visit_fn!(visit_f64: f64 => Value::Number);

    fn visit_none<E: de::Error>(self) -> Result<Self::Value, E> {
        Ok(Value::None)
    }

    fn visit_some<D>(self, deserializer: D) -> Result<Self::Value, D::Error>
        where
            D: Deserializer<'de>,
    {
        deserializer.deserialize_any(self)
    }

    fn visit_unit<E: de::Error>(self) -> Result<Self::Value, E> {
        Ok(Value::None)
    }

    fn visit_seq<A>(self, mut seq: A) -> Result<Self::Value, A::Error>
        where
            A: SeqAccess<'de>,
    {
        let mut array: Vec<Value> = Vec::with_capacity(seq.size_hint().unwrap_or(0));
        while let Some(elem) = seq.next_element()? {
            array.push(elem);
        }

        Ok(array.into())
    }

    fn visit_map<A>(self, mut map: A) -> Result<Self::Value, A::Error>
        where
            A: MapAccess<'de>,
    {
        let mut dict: HashMap<String, Value> = HashMap::new();

        while let Some((key, value)) = map.next_entry()? {
            dict.insert(key, value);
        }

        Ok(dict.into())
    }
}