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use json_decode::{BoxDecoder, DecodeError, Decoder}; use std::marker::PhantomData; use crate::SerializeError; pub trait Scalar: Sized { fn decode(value: &serde_json::Value) -> Result<Self, DecodeError>; fn encode(&self) -> Result<serde_json::Value, SerializeError>; } pub fn decoder<'a, S>() -> BoxDecoder<'a, S> where S: Scalar + 'a + Send + Sync, { Box::new(ScalarDecoder { phantom: PhantomData, }) } impl Scalar for i32 { fn decode(value: &serde_json::Value) -> Result<Self, DecodeError> { json_decode::integer().decode(value) } fn encode(&self) -> Result<serde_json::Value, SerializeError> { Ok((*self).into()) } } impl Scalar for f64 { fn decode(value: &serde_json::Value) -> Result<Self, DecodeError> { json_decode::float().decode(value) } fn encode(&self) -> Result<serde_json::Value, SerializeError> { Ok((*self).into()) } } impl Scalar for bool { fn decode(value: &serde_json::Value) -> Result<Self, DecodeError> { json_decode::boolean().decode(value) } fn encode(&self) -> Result<serde_json::Value, SerializeError> { Ok((*self).into()) } } impl Scalar for String { fn decode(value: &serde_json::Value) -> Result<Self, DecodeError> { json_decode::string().decode(value) } fn encode(&self) -> Result<serde_json::Value, SerializeError> { Ok(self.clone().into()) } } impl Scalar for serde_json::Value { fn decode(value: &serde_json::Value) -> Result<Self, DecodeError> { json_decode::json().decode(value) } fn encode(&self) -> Result<serde_json::Value, SerializeError> { Ok(self.clone()) } } struct ScalarDecoder<S: Scalar> { phantom: PhantomData<S>, } impl<'a, S> Decoder<'a, S> for ScalarDecoder<S> where S: Scalar + Sized, { fn decode(&self, value: &serde_json::Value) -> Result<S, DecodeError> { S::decode(value) } } #[cfg(feature = "chrono")] impl Scalar for chrono::DateTime<chrono::FixedOffset> { fn decode(value: &serde_json::Value) -> Result<Self, DecodeError> { use chrono::DateTime; match value { serde_json::Value::String(s) => { Ok(DateTime::parse_from_rfc3339(s).map_err(chrono_decode_error)?) } _ => Err(DecodeError::IncorrectType( "String".to_string(), value.to_string(), )), } } fn encode(&self) -> Result<serde_json::Value, SerializeError> { Ok(serde_json::Value::String(self.to_rfc3339())) } } #[cfg(feature = "chrono")] impl Scalar for chrono::DateTime<chrono::Utc> { fn decode(value: &serde_json::Value) -> Result<Self, DecodeError> { use chrono::{DateTime, Utc}; match value { serde_json::Value::String(s) => Ok(DateTime::parse_from_rfc3339(s) .map_err(chrono_decode_error)? .with_timezone(&Utc)), _ => Err(DecodeError::IncorrectType( "String".to_string(), value.to_string(), )), } } fn encode(&self) -> Result<serde_json::Value, SerializeError> { Ok(serde_json::Value::String(self.to_rfc3339())) } } #[cfg(feature = "chrono")] fn chrono_decode_error(err: chrono::ParseError) -> DecodeError { DecodeError::Other(err.to_string()) } #[cfg(test)] mod tests { #[cfg(feature = "chrono")] #[test] fn test_utc_datetime_scalar() { use super::*; use chrono::{DateTime, Utc}; let datetime: DateTime<Utc> = Utc::now(); assert_eq!(DateTime::decode(&datetime.encode().unwrap()), Ok(datetime)); } #[cfg(feature = "chrono")] #[test] fn test_fixed_offset_datetime_scalar() { use super::*; use chrono::{DateTime, FixedOffset, TimeZone}; let datetime: DateTime<FixedOffset> = FixedOffset::east(3600 * 5) .ymd(2016, 11, 08) .and_hms(10, 15, 20); assert_eq!(DateTime::decode(&datetime.encode().unwrap()), Ok(datetime)); } }