1use serde::de::value::BorrowedStrDeserializer;
2use serde::de::IntoDeserializer as _;
3
4use super::Error;
5
6pub(crate) struct SpannedDeserializer<'de, T: serde::de::IntoDeserializer<'de, Error>> {
7 phantom_data: std::marker::PhantomData<&'de ()>,
8 start: Option<usize>,
9 end: Option<usize>,
10 value: Option<T>,
11}
12
13impl<'de, T> SpannedDeserializer<'de, T>
14where
15 T: serde::de::IntoDeserializer<'de, Error>,
16{
17 pub(crate) fn new(value: T, span: std::ops::Range<usize>) -> Self {
18 Self {
19 phantom_data: Default::default(),
20 start: Some(span.start),
21 end: Some(span.end),
22 value: Some(value),
23 }
24 }
25}
26
27impl<'de, T> serde::de::MapAccess<'de> for SpannedDeserializer<'de, T>
28where
29 T: serde::de::IntoDeserializer<'de, Error>,
30{
31 type Error = Error;
32 fn next_key_seed<K>(&mut self, seed: K) -> Result<Option<K::Value>, Error>
33 where
34 K: serde::de::DeserializeSeed<'de>,
35 {
36 if self.start.is_some() {
37 seed.deserialize(BorrowedStrDeserializer::new(
38 serde_spanned::__unstable::START_FIELD,
39 ))
40 .map(Some)
41 } else if self.end.is_some() {
42 seed.deserialize(BorrowedStrDeserializer::new(
43 serde_spanned::__unstable::END_FIELD,
44 ))
45 .map(Some)
46 } else if self.value.is_some() {
47 seed.deserialize(BorrowedStrDeserializer::new(
48 serde_spanned::__unstable::VALUE_FIELD,
49 ))
50 .map(Some)
51 } else {
52 Ok(None)
53 }
54 }
55
56 fn next_value_seed<V>(&mut self, seed: V) -> Result<V::Value, Error>
57 where
58 V: serde::de::DeserializeSeed<'de>,
59 {
60 if let Some(start) = self.start.take() {
61 seed.deserialize(start.into_deserializer())
62 } else if let Some(end) = self.end.take() {
63 seed.deserialize(end.into_deserializer())
64 } else if let Some(value) = self.value.take() {
65 seed.deserialize(value.into_deserializer())
66 } else {
67 panic!("next_value_seed called before next_key_seed")
68 }
69 }
70}
71