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use std::collections::BTreeMap;
use serde::de::Visitor;
use serde::forward_to_deserialize_any;
use crate::{Error, Result, Value};
pub struct Deserializer {
val: Value,
}
impl Deserializer {
pub fn from_value(input: Value) -> Self {
Deserializer { val: input }
}
}
impl<'de> serde::Deserializer<'de> for Deserializer {
type Error = Error;
fn deserialize_any<V>(self, visitor: V) -> Result<V::Value>
where
V: Visitor<'de>,
{
match self.val {
Value::Int(v) => visitor.visit_i32(v),
Value::Int64(v) => visitor.visit_i64(v),
Value::Bool(v) => visitor.visit_bool(v),
Value::String(v) => visitor.visit_string(v),
Value::Double(v) => visitor.visit_f64(v),
Value::DateTime(v) => visitor.visit_string(v.to_string()),
Value::Base64(v) => visitor.visit_bytes(v.as_slice()),
Value::Struct(v) => {
let map_deserializer = MapDeserializer::new(v);
visitor.visit_map(map_deserializer)
}
Value::Array(v) => {
let seq_deserializer = SeqDeserializer::new(v);
visitor.visit_seq(seq_deserializer)
}
Value::Nil => visitor.visit_none(),
}
}
fn deserialize_option<V>(self, visitor: V) -> Result<V::Value>
where
V: Visitor<'de>,
{
if let Value::Nil = self.val {
visitor.visit_none()
} else {
visitor.visit_some(self)
}
}
forward_to_deserialize_any!(
bool i8 i16 i32 i64 u8 u16 u32 u64 f32 f64 char str string bytes
byte_buf unit unit_struct newtype_struct seq tuple
tuple_struct map struct enum identifier ignored_any
);
}
struct SeqDeserializer {
iter: std::vec::IntoIter<Value>,
}
impl SeqDeserializer {
fn new(vec: Vec<Value>) -> Self {
SeqDeserializer {
iter: vec.into_iter(),
}
}
}
impl<'de> serde::de::SeqAccess<'de> for SeqDeserializer {
type Error = Error;
fn next_element_seed<T>(&mut self, seed: T) -> Result<Option<T::Value>>
where
T: serde::de::DeserializeSeed<'de>,
{
match self.iter.next() {
Some(value) => seed.deserialize(Deserializer::from_value(value)).map(Some),
None => Ok(None),
}
}
}
struct MapDeserializer {
iter: <BTreeMap<String, Value> as IntoIterator>::IntoIter,
value: Option<Value>,
}
impl MapDeserializer {
fn new(map: BTreeMap<String, Value>) -> Self {
MapDeserializer {
iter: map.into_iter(),
value: None,
}
}
}
impl<'de> serde::de::MapAccess<'de> for MapDeserializer {
type Error = Error;
fn next_key_seed<T>(&mut self, seed: T) -> Result<Option<T::Value>>
where
T: serde::de::DeserializeSeed<'de>,
{
match self.iter.next() {
Some((key, value)) => {
self.value = Some(value);
seed.deserialize(Deserializer::from_value(Value::String(key)))
.map(Some)
}
None => Ok(None),
}
}
fn next_value_seed<T>(&mut self, seed: T) -> Result<T::Value>
where
T: serde::de::DeserializeSeed<'de>,
{
match self.value.take() {
Some(value) => seed.deserialize(Deserializer::from_value(value)),
None => Err(serde::de::Error::custom("value is missing")),
}
}
fn size_hint(&self) -> Option<usize> {
match self.iter.size_hint() {
(lower, Some(upper)) if lower == upper => Some(upper),
_ => None,
}
}
}
#[cfg(test)]
mod test {
use serde::Deserialize;
#[derive(Deserialize, Debug, PartialEq)]
struct Test {
hello: String,
}
#[derive(Deserialize, Debug, PartialEq)]
struct Test2 {
val: Option<String>,
}
#[test]
fn test_serde() {
use std::collections::BTreeMap;
use std::iter::FromIterator;
use super::Deserializer;
use crate::Value;
let x = Value::Int(42);
let y = i32::deserialize(Deserializer::from_value(x)).unwrap();
assert_eq!(y, 42);
let x = Value::Array(vec![Value::String("hello world".to_string())]);
let y: Vec<String> = Vec::deserialize(Deserializer::from_value(x)).unwrap();
assert_eq!(y, vec!["hello world".to_string()]);
let x = Value::Struct(BTreeMap::from_iter(
vec![("hello".to_string(), Value::String("world".to_string()))].into_iter(),
));
let y = Test::deserialize(Deserializer::from_value(x)).unwrap();
assert_eq!(
y,
Test {
hello: "world".to_string(),
},
);
let x = Value::Struct(BTreeMap::new());
let y = Test2::deserialize(Deserializer::from_value(x)).unwrap();
assert_eq!(y, Test2 { val: None },);
let x = Value::Struct(BTreeMap::from_iter(
vec![("val".to_string(), Value::Nil)].into_iter(),
));
let y = Test2::deserialize(Deserializer::from_value(x)).unwrap();
assert_eq!(y, Test2 { val: None },);
let x = Value::Struct(BTreeMap::from_iter(
vec![("val".to_string(), Value::String("hello".to_string()))].into_iter(),
));
let y = Test2::deserialize(Deserializer::from_value(x)).unwrap();
assert_eq!(
y,
Test2 {
val: Some("hello".to_string())
},
);
}
}
|
