json_syntax/serde/de/

number.rs

use crate::{JsonNumber, JsonNumberBuf, serde::NUMBER_TOKEN};
use de::{Deserialize, Deserializer};
use serde::{
	de::{self, value::StrDeserializer},
	forward_to_deserialize_any,
};
use std::fmt;

impl<'de> Deserialize<'de> for JsonNumberBuf {
	fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
	where
		D: Deserializer<'de>,
	{
		deserializer.deserialize_any(JsonNumberVisitor)
	}
}

/// Number visitor.
pub struct JsonNumberVisitor;

impl<'de> de::Visitor<'de> for JsonNumberVisitor {
	type Value = JsonNumberBuf;

	fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
		formatter.write_str("JSON number")
	}

	#[inline]
	fn visit_u64<E: de::Error>(self, value: u64) -> Result<JsonNumberBuf, E> {
		Ok(value.into())
	}

	#[inline]
	fn visit_i64<E: de::Error>(self, value: i64) -> Result<JsonNumberBuf, E> {
		Ok(value.into())
	}

	#[inline]
	fn visit_f64<E: de::Error>(self, value: f64) -> Result<JsonNumberBuf, E> {
		JsonNumberBuf::try_from(value)
			.map_err(|_| E::invalid_value(de::Unexpected::Float(value), &self))
	}

	fn visit_map<A>(self, mut map: A) -> Result<Self::Value, A::Error>
	where
		A: de::MapAccess<'de>,
	{
		struct Key;

		impl<'de> Deserialize<'de> for Key {
			fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
			where
				D: Deserializer<'de>,
			{
				struct KeyVisitor;

				impl<'de> de::Visitor<'de> for KeyVisitor {
					type Value = Key;

					fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
						formatter.write_str("a valid number field")
					}

					fn visit_str<E>(self, v: &str) -> Result<Self::Value, E>
					where
						E: de::Error,
					{
						if v == NUMBER_TOKEN {
							Ok(Key)
						} else {
							Err(serde::de::Error::custom("expected field with custom name"))
						}
					}
				}

				deserializer.deserialize_identifier(KeyVisitor)
			}
		}

		struct Value(JsonNumberBuf);

		impl<'de> Deserialize<'de> for Value {
			fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
			where
				D: Deserializer<'de>,
			{
				struct ValueVisitor;

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

					fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
						formatter.write_str("string containing a JSON number")
					}

					fn visit_str<E>(self, v: &str) -> Result<Self::Value, E>
					where
						E: de::Error,
					{
						self.visit_string(v.to_owned())
					}

					fn visit_string<E>(self, v: String) -> Result<Self::Value, E>
					where
						E: de::Error,
					{
						match JsonNumberBuf::new(v) {
							Ok(v) => Ok(Value(v)),
							Err(e) => Err(de::Error::custom(e)),
						}
					}
				}

				deserializer.deserialize_identifier(ValueVisitor)
			}
		}

		match map.next_key()? {
			Some(Key) => {
				let value: Value = map.next_value()?;
				Ok(value.0)
			}
			None => Err(de::Error::invalid_type(de::Unexpected::Map, &self)),
		}
	}
}

/// Unexpected value that is not a number.
#[derive(Debug)]
pub struct Unexpected(String);

impl fmt::Display for Unexpected {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		self.0.fmt(f)
	}
}

impl std::error::Error for Unexpected {}

impl de::Error for Unexpected {
	fn custom<T>(msg: T) -> Self
	where
		T: fmt::Display,
	{
		Self(msg.to_string())
	}

	fn invalid_type(unexp: de::Unexpected, exp: &dyn de::Expected) -> Self {
		if let de::Unexpected::Unit = unexp {
			Self::custom(format_args!("invalid type: null, expected {}", exp))
		} else {
			Self::custom(format_args!("invalid type: {}, expected {}", unexp, exp))
		}
	}
}

impl<'de> Deserializer<'de> for JsonNumberBuf {
	type Error = Unexpected;

	#[inline(always)]
	fn deserialize_any<V>(self, visitor: V) -> Result<V::Value, Self::Error>
	where
		V: serde::de::Visitor<'de>,
	{
		self.as_number().deserialize_any(visitor)
	}

	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 seq tuple
		tuple_struct map struct newtype_struct enum identifier ignored_any
	}
}

impl<'de> Deserializer<'de> for &JsonNumberBuf {
	type Error = Unexpected;

	#[inline(always)]
	fn deserialize_any<V>(self, visitor: V) -> Result<V::Value, Self::Error>
	where
		V: serde::de::Visitor<'de>,
	{
		self.as_number().deserialize_any(visitor)
	}

	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 seq tuple
		tuple_struct map struct newtype_struct enum identifier ignored_any
	}
}

impl<'de> Deserializer<'de> for &JsonNumber {
	type Error = Unexpected;

	#[inline(always)]
	fn deserialize_any<V>(self, visitor: V) -> Result<V::Value, Self::Error>
	where
		V: serde::de::Visitor<'de>,
	{
		//    use serde::ser::SerializeStruct;
		// let mut s = serializer.serialize_struct(TOKEN, 1)?;
		// s.serialize_field(TOKEN, self.as_str())?;
		// s.end()

		struct MapAccess<'n> {
			data: Option<&'n JsonNumber>,
		}

		impl<'de, 'n> serde::de::MapAccess<'de> for MapAccess<'n> {
			type Error = Unexpected;

			fn next_key_seed<K>(&mut self, seed: K) -> Result<Option<K::Value>, Self::Error>
			where
				K: de::DeserializeSeed<'de>,
			{
				if self.data.is_some() {
					seed.deserialize(StrDeserializer::new(NUMBER_TOKEN))
						.map(Some)
				} else {
					Ok(None)
				}
			}

			fn next_value_seed<V>(&mut self, seed: V) -> Result<V::Value, Self::Error>
			where
				V: de::DeserializeSeed<'de>,
			{
				match self.data.take() {
					Some(data) => seed.deserialize(StrDeserializer::new(data.as_str())),
					None => Err(Unexpected("value".to_owned())),
				}
			}
		}

		if let Some(u) = self.as_u64() {
			visitor.visit_u64(u)
		} else if let Some(i) = self.as_i64() {
			visitor.visit_i64(i)
		} else {
			visitor.visit_map(MapAccess { data: Some(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 seq tuple
		tuple_struct map struct newtype_struct enum identifier ignored_any
	}
}