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

use crate::Context;

use super::{Encode, Encoder};

/// Trait governing how to encode a variant.
#[must_use = "Must call end_variant to finish encoding"]
pub trait VariantEncoder {
    /// Context associated with the encoder.
    type Cx: ?Sized + Context;
    /// Result type of the encoder.
    type Ok;
    /// The encoder returned when advancing the map encoder to encode the key.
    type EncodeTag<'this>: Encoder<
        Cx = Self::Cx,
        Ok = Self::Ok,
        Error = <Self::Cx as Context>::Error,
        Mode = <Self::Cx as Context>::Mode,
    >
    where
        Self: 'this;
    /// The encoder returned when advancing the map encoder to encode the value.
    type EncodeValue<'this>: Encoder<
        Cx = Self::Cx,
        Ok = Self::Ok,
        Error = <Self::Cx as Context>::Error,
        Mode = <Self::Cx as Context>::Mode,
    >
    where
        Self: 'this;

    /// Return the encoder for the first element in the variant.
    #[must_use = "Encoders must be consumed"]
    fn encode_tag(&mut self) -> Result<Self::EncodeTag<'_>, <Self::Cx as Context>::Error>;

    /// Return encoder for the second element in the variant.
    #[must_use = "Encoders must be consumed"]
    fn encode_value(&mut self) -> Result<Self::EncodeValue<'_>, <Self::Cx as Context>::Error>;

    /// End the variant encoder.
    fn end_variant(self) -> Result<Self::Ok, <Self::Cx as Context>::Error>;

    /// Insert the variant immediately.
    #[inline]
    fn insert_variant<T, V>(
        mut self,
        tag: T,
        value: V,
    ) -> Result<Self::Ok, <Self::Cx as Context>::Error>
    where
        Self: Sized,
        T: Encode<<Self::Cx as Context>::Mode>,
        V: Encode<<Self::Cx as Context>::Mode>,
    {
        self.encode_tag()?.encode(tag)?;
        self.encode_value()?.encode(value)?;
        self.end_variant()
    }
}