use paste::paste;
use serde::ser;
#[derive(Debug)]
pub struct EnsureScalar<T>(pub T);
#[derive(Debug)]
struct EnsureScalarSerializer<S>(S);
impl<T: ser::Serialize> ser::Serialize for EnsureScalar<T> {
fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
where
S: serde::Serializer,
{
self.0.serialize(EnsureScalarSerializer(serializer))
}
}
macro_rules! forward_scalar_types {
($($target:ident)*) => {paste!{$(
fn [<serialize_ $target>](self, v: $target) -> Result<Self::Ok, Self::Error> {
self.0.[<serialize_ $target>](v)
}
)*}};
}
impl<S: ser::Serializer> ser::Serializer for EnsureScalarSerializer<S> {
type Ok = S::Ok;
type Error = S::Error;
type SerializeSeq = ser::Impossible<S::Ok, S::Error>;
type SerializeTuple = ser::Impossible<S::Ok, S::Error>;
type SerializeTupleStruct = ser::Impossible<S::Ok, S::Error>;
type SerializeTupleVariant = ser::Impossible<S::Ok, S::Error>;
type SerializeMap = ser::Impossible<S::Ok, S::Error>;
type SerializeStruct = ser::Impossible<S::Ok, S::Error>;
type SerializeStructVariant = ser::Impossible<S::Ok, S::Error>;
forward_scalar_types!(bool i8 i16 i32 i64 u8 u16 u32 u64 f32 f64 char);
fn serialize_str(self, v: &str) -> Result<Self::Ok, Self::Error> {
self.0.serialize_str(v)
}
fn serialize_bytes(self, v: &[u8]) -> Result<Self::Ok, Self::Error> {
self.0.serialize_bytes(v)
}
fn serialize_none(self) -> Result<Self::Ok, Self::Error> {
self.0.serialize_none()
}
fn serialize_some<T: ?Sized>(self, value: &T) -> Result<Self::Ok, Self::Error>
where
T: serde::Serialize,
{
self.0.serialize_some(value)
}
fn serialize_unit(self) -> Result<Self::Ok, Self::Error> {
self.0.serialize_unit()
}
fn serialize_unit_struct(self, name: &'static str) -> Result<Self::Ok, Self::Error> {
self.0.serialize_unit_struct(name)
}
fn serialize_unit_variant(
self,
name: &'static str,
variant_index: u32,
variant: &'static str,
) -> Result<Self::Ok, Self::Error> {
self.0.serialize_unit_variant(name, variant_index, variant)
}
fn serialize_newtype_struct<T: ?Sized>(
self,
name: &'static str,
value: &T,
) -> Result<Self::Ok, Self::Error>
where
T: serde::Serialize,
{
self.0.serialize_newtype_struct(name, value)
}
fn serialize_newtype_variant<T: ?Sized>(
self,
_name: &'static str,
_variant_index: u32,
_variant: &'static str,
_value: &T,
) -> Result<Self::Ok, Self::Error>
where
T: serde::Serialize,
{
Err(ser::Error::custom(
"variant types with fields are not supported",
))
}
fn serialize_seq(self, _len: Option<usize>) -> Result<Self::SerializeSeq, Self::Error> {
Err(ser::Error::custom("sequence types are not supported"))
}
fn serialize_tuple(self, _len: usize) -> Result<Self::SerializeTuple, Self::Error> {
Err(ser::Error::custom("tuple types are not supported"))
}
fn serialize_tuple_struct(
self,
_name: &'static str,
_len: usize,
) -> Result<Self::SerializeTupleStruct, Self::Error> {
Err(ser::Error::custom("tuple types are not supported"))
}
fn serialize_tuple_variant(
self,
_name: &'static str,
_variant_index: u32,
_variant: &'static str,
_len: usize,
) -> Result<Self::SerializeTupleVariant, Self::Error> {
Err(ser::Error::custom("tuple types are not supported"))
}
fn serialize_map(self, _len: Option<usize>) -> Result<Self::SerializeMap, Self::Error> {
Err(ser::Error::custom("map types are not supported"))
}
fn serialize_struct(
self,
_name: &'static str,
_len: usize,
) -> Result<Self::SerializeStruct, Self::Error> {
Err(ser::Error::custom("struct types are not supported"))
}
fn serialize_struct_variant(
self,
_name: &'static str,
_variant_index: u32,
_variant: &'static str,
_len: usize,
) -> Result<Self::SerializeStructVariant, Self::Error> {
Err(ser::Error::custom("struct variant types are not supported"))
}
}