105 lines
2.7 KiB
Rust
105 lines
2.7 KiB
Rust
use serde::de::value::{Error, MapDeserializer, SeqDeserializer};
|
|
use serde::de::{
|
|
DeserializeSeed, EnumAccess, IgnoredAny, IntoDeserializer, VariantAccess, Visitor,
|
|
};
|
|
use serde::{forward_to_deserialize_any, Deserialize, Deserializer};
|
|
|
|
#[derive(PartialEq, Debug, Deserialize)]
|
|
enum Target {
|
|
Unit,
|
|
Newtype(i32),
|
|
Tuple(i32, i32),
|
|
Struct { a: i32 },
|
|
}
|
|
|
|
struct Enum(&'static str);
|
|
|
|
impl<'de> Deserializer<'de> for Enum {
|
|
type Error = Error;
|
|
|
|
fn deserialize_any<V>(self, visitor: V) -> Result<V::Value, Self::Error>
|
|
where
|
|
V: Visitor<'de>,
|
|
{
|
|
visitor.visit_enum(self)
|
|
}
|
|
|
|
forward_to_deserialize_any! {
|
|
bool 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
|
|
}
|
|
}
|
|
|
|
impl<'de> EnumAccess<'de> for Enum {
|
|
type Error = Error;
|
|
type Variant = Self;
|
|
|
|
fn variant_seed<V>(self, seed: V) -> Result<(V::Value, Self::Variant), Self::Error>
|
|
where
|
|
V: DeserializeSeed<'de>,
|
|
{
|
|
let v = seed.deserialize(self.0.into_deserializer())?;
|
|
Ok((v, self))
|
|
}
|
|
}
|
|
|
|
impl<'de> VariantAccess<'de> for Enum {
|
|
type Error = Error;
|
|
|
|
fn unit_variant(self) -> Result<(), Self::Error> {
|
|
Ok(())
|
|
}
|
|
|
|
fn newtype_variant_seed<T>(self, seed: T) -> Result<T::Value, Self::Error>
|
|
where
|
|
T: DeserializeSeed<'de>,
|
|
{
|
|
seed.deserialize(10i32.into_deserializer())
|
|
}
|
|
|
|
fn tuple_variant<V>(self, _len: usize, visitor: V) -> Result<V::Value, Self::Error>
|
|
where
|
|
V: Visitor<'de>,
|
|
{
|
|
let seq = SeqDeserializer::new(vec![1i32, 2].into_iter());
|
|
visitor.visit_seq(seq)
|
|
}
|
|
|
|
fn struct_variant<V>(
|
|
self,
|
|
_fields: &'static [&'static str],
|
|
visitor: V,
|
|
) -> Result<V::Value, Self::Error>
|
|
where
|
|
V: Visitor<'de>,
|
|
{
|
|
let map = MapDeserializer::new(vec![("a", 10i32)].into_iter());
|
|
visitor.visit_map(map)
|
|
}
|
|
}
|
|
|
|
#[test]
|
|
fn test_deserialize_enum() {
|
|
// First just make sure the Deserializer impl works
|
|
assert_eq!(Target::Unit, Target::deserialize(Enum("Unit")).unwrap());
|
|
assert_eq!(
|
|
Target::Newtype(10),
|
|
Target::deserialize(Enum("Newtype")).unwrap()
|
|
);
|
|
assert_eq!(
|
|
Target::Tuple(1, 2),
|
|
Target::deserialize(Enum("Tuple")).unwrap()
|
|
);
|
|
assert_eq!(
|
|
Target::Struct { a: 10 },
|
|
Target::deserialize(Enum("Struct")).unwrap()
|
|
);
|
|
|
|
// Now try IgnoredAny
|
|
IgnoredAny::deserialize(Enum("Unit")).unwrap();
|
|
IgnoredAny::deserialize(Enum("Newtype")).unwrap();
|
|
IgnoredAny::deserialize(Enum("Tuple")).unwrap();
|
|
IgnoredAny::deserialize(Enum("Struct")).unwrap();
|
|
}
|