use super::StringCow;
impl serde::Serialize for StringCow<'_> {
fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
where
S: serde::Serializer,
{
serializer.serialize_str(self.as_str())
}
}
impl<'de> serde::Deserialize<'de> for StringCow<'de> {
fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
where
D: serde::Deserializer<'de>,
{
struct StringCowVisitor;
impl<'de> serde::de::Visitor<'de> for StringCowVisitor {
type Value = StringCow<'de>;
fn expecting(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
formatter.write_str("a string")
}
fn visit_borrowed_str<E>(self, v: &'de str) -> Result<Self::Value, E>
where
E: serde::de::Error,
{
Ok(StringCow::from_ref(v))
}
fn visit_string<E>(self, v: String) -> Result<Self::Value, E>
where
E: serde::de::Error,
{
Ok(StringCow::from_string(v))
}
fn visit_str<E>(self, v: &str) -> Result<Self::Value, E>
where
E: serde::de::Error,
{
Ok(StringCow::from_string(v.to_string()))
}
}
deserializer.deserialize_any(StringCowVisitor)
}
}
impl<'de, E> serde::de::IntoDeserializer<'de, E> for StringCow<'de>
where
E: serde::de::Error,
{
type Deserializer = StringCowDeserializer<'de, E>;
fn into_deserializer(self) -> Self::Deserializer {
StringCowDeserializer::<E>::new(self)
}
}
pub struct StringCowDeserializer<'a, E> {
cow: StringCow<'a>,
_marker: std::marker::PhantomData<E>,
}
impl<'a, E> StringCowDeserializer<'a, E> {
pub fn new(cow: StringCow<'a>) -> Self {
StringCowDeserializer {
cow,
_marker: std::marker::PhantomData,
}
}
}
impl<'de, E> serde::de::Deserializer<'de> for StringCowDeserializer<'de, E>
where
E: serde::de::Error,
{
type Error = E;
serde::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
}
fn deserialize_any<V>(self, visitor: V) -> Result<V::Value, Self::Error>
where
V: serde::de::Visitor<'de>,
{
match self.cow {
StringCow::Ref(slice) => visitor.visit_borrowed_str(slice),
StringCow::StaticRef(slice) => visitor.visit_borrowed_str(slice),
StringCow::String(string) => visitor.visit_string(string),
StringCow::Bytes(bytes) => visitor.visit_str(&bytes),
}
}
}
#[cfg(test)]
#[cfg_attr(all(test, coverage_nightly), coverage(off))]
mod tests {
use std::fmt::Display;
use serde::ser::Impossible;
use serde::{Deserialize, Serialize};
use crate::StringCow;
#[test]
fn serialize() {
#[derive(Debug)]
struct TestError;
impl Display for TestError {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
write!(f, "Test error")
}
}
impl std::error::Error for TestError {}
impl serde::ser::Error for TestError {
fn custom<T: std::fmt::Display>(msg: T) -> Self {
panic!("{}", msg)
}
}
struct TestSerializer;
impl serde::Serializer for TestSerializer {
type Error = TestError;
type Ok = ();
type SerializeMap = Impossible<(), Self::Error>;
type SerializeSeq = Impossible<(), Self::Error>;
type SerializeStruct = Impossible<(), Self::Error>;
type SerializeStructVariant = Impossible<(), Self::Error>;
type SerializeTuple = Impossible<(), Self::Error>;
type SerializeTupleStruct = Impossible<(), Self::Error>;
type SerializeTupleVariant = Impossible<(), Self::Error>;
fn serialize_bool(self, _v: bool) -> Result<Self::Ok, Self::Error> {
panic!("StringCow must be serialized as str")
}
fn serialize_i8(self, _v: i8) -> Result<Self::Ok, Self::Error> {
panic!("StringCow must be serialized as str")
}
fn serialize_i16(self, _v: i16) -> Result<Self::Ok, Self::Error> {
panic!("StringCow must be serialized as str")
}
fn serialize_i32(self, _v: i32) -> Result<Self::Ok, Self::Error> {
panic!("StringCow must be serialized as str")
}
fn serialize_i64(self, _v: i64) -> Result<Self::Ok, Self::Error> {
panic!("StringCow must be serialized as str")
}
fn serialize_u8(self, _v: u8) -> Result<Self::Ok, Self::Error> {
panic!("StringCow must be serialized as str")
}
fn serialize_u16(self, _v: u16) -> Result<Self::Ok, Self::Error> {
panic!("StringCow must be serialized as str")
}
fn serialize_u32(self, _v: u32) -> Result<Self::Ok, Self::Error> {
panic!("StringCow must be serialized as str")
}
fn serialize_u64(self, _v: u64) -> Result<Self::Ok, Self::Error> {
panic!("StringCow must be serialized as str")
}
fn serialize_f32(self, _v: f32) -> Result<Self::Ok, Self::Error> {
panic!("StringCow must be serialized as str")
}
fn serialize_f64(self, _v: f64) -> Result<Self::Ok, Self::Error> {
panic!("StringCow must be serialized as str")
}
fn serialize_char(self, _v: char) -> Result<Self::Ok, Self::Error> {
panic!("StringCow must be serialized as str")
}
fn serialize_str(self, v: &str) -> Result<Self::Ok, Self::Error> {
assert_eq!(v, "hello");
Ok(())
}
fn serialize_bytes(self, _v: &[u8]) -> Result<Self::Ok, Self::Error> {
panic!("StringCow must be serialized as str")
}
fn serialize_none(self) -> Result<Self::Ok, Self::Error> {
panic!("StringCow must be serialized as str")
}
fn serialize_some<T>(self, _value: &T) -> Result<Self::Ok, Self::Error>
where
T: serde::Serialize + ?Sized,
{
panic!("StringCow must be serialized as str")
}
fn serialize_unit(self) -> Result<Self::Ok, Self::Error> {
panic!("StringCow must be serialized as str")
}
fn serialize_unit_struct(self, _name: &'static str) -> Result<Self::Ok, Self::Error> {
panic!("StringCow must be serialized as str")
}
fn serialize_unit_variant(
self,
_name: &'static str,
_variant_index: u32,
_variant: &'static str,
) -> Result<Self::Ok, Self::Error> {
panic!("StringCow must be serialized as str")
}
fn serialize_newtype_variant<T>(
self,
_name: &'static str,
_variant_index: u32,
_variant: &'static str,
_value: &T,
) -> Result<Self::Ok, Self::Error>
where
T: serde::Serialize + ?Sized,
{
panic!("StringCow must be serialized as str")
}
fn serialize_seq(self, _len: Option<usize>) -> Result<Self::SerializeSeq, Self::Error> {
panic!("StringCow must be serialized as str")
}
fn serialize_tuple(self, _len: usize) -> Result<Self::SerializeTuple, Self::Error> {
panic!("StringCow must be serialized as str")
}
fn serialize_tuple_struct(
self,
_name: &'static str,
_len: usize,
) -> Result<Self::SerializeTupleStruct, Self::Error> {
panic!("StringCow must be serialized as str")
}
fn serialize_tuple_variant(
self,
_name: &'static str,
_variant_index: u32,
_variant: &'static str,
_len: usize,
) -> Result<Self::SerializeTupleVariant, Self::Error> {
panic!("StringCow must be serialized as str")
}
fn serialize_map(self, _len: Option<usize>) -> Result<Self::SerializeMap, Self::Error> {
panic!("StringCow must be serialized as str")
}
fn serialize_struct(self, _name: &'static str, _len: usize) -> Result<Self::SerializeStruct, Self::Error> {
panic!("StringCow must be serialized as str")
}
fn serialize_struct_variant(
self,
_name: &'static str,
_variant_index: u32,
_variant: &'static str,
_len: usize,
) -> Result<Self::SerializeStructVariant, Self::Error> {
panic!("StringCow must be serialized as str")
}
fn serialize_newtype_struct<T>(self, _name: &'static str, _value: &T) -> Result<Self::Ok, Self::Error>
where
T: ?Sized + serde::Serialize,
{
panic!("StringCow must be serialized as str")
}
}
let cow = StringCow::from_ref("hello");
let serializer = TestSerializer;
cow.serialize(serializer).expect("serialization failed");
}
#[test]
fn deserialize() {
#[derive(Debug)]
struct TestError;
impl Display for TestError {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
write!(f, "Test error")
}
}
impl std::error::Error for TestError {}
impl serde::de::Error for TestError {
fn custom<T: std::fmt::Display>(msg: T) -> Self {
assert_eq!(msg.to_string(), "invalid type: Option value, expected a string");
Self
}
}
enum Mode {
Str,
String,
BorrowedStr,
None,
}
struct TestDeserializer {
mode: Mode,
}
impl<'de> serde::Deserializer<'de> for TestDeserializer {
type Error = TestError;
serde::forward_to_deserialize_any! {
bool i8 i16 i32 i64 u8 u16 u32 u64 f32 f64 char str string bytes byte_buf
option unit unit_struct newtype_struct seq tuple tuple_struct
map struct enum identifier ignored_any
}
fn deserialize_any<V>(self, visitor: V) -> Result<V::Value, Self::Error>
where
V: serde::de::Visitor<'de>,
{
match self.mode {
Mode::Str => visitor.visit_str("hello"),
Mode::String => visitor.visit_string("hello".to_owned()),
Mode::BorrowedStr => visitor.visit_borrowed_str("hello"),
Mode::None => visitor.visit_none(),
}
}
}
fn test_de(de: TestDeserializer) {
let cow = StringCow::deserialize(de).expect("deserialization failed");
assert_eq!(cow.as_str(), "hello");
}
test_de(TestDeserializer { mode: Mode::Str });
test_de(TestDeserializer { mode: Mode::String });
test_de(TestDeserializer { mode: Mode::BorrowedStr });
StringCow::deserialize(TestDeserializer { mode: Mode::None }).expect_err("deserialization should fail");
}
}