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// Inspired by David Tolnay's serde-rs
// https://github.com/serde-rs/json/blob/master/src/raw.rs
// Licensed under either of Apache License, Version 2.0 or MIT license at your option.
use alloc::{borrow::ToOwned, boxed::Box, format, string::String};
use core::{fmt, ops::Range};
use serde::{de, ser, Deserialize, Serialize};
use crate::{
error::{Error, SpannedResult},
options::Options,
};
// NOTE: Keep synchronised with fuzz/arbitrary::typed_data::RAW_VALUE_TOKEN
pub(crate) const RAW_VALUE_TOKEN: &str = "$ron::private::RawValue";
#[allow(clippy::module_name_repetitions)]
#[derive(PartialEq, Eq, PartialOrd, Ord, Hash)]
#[repr(transparent)]
pub struct RawValue {
ron: str,
}
#[allow(unsafe_code)]
impl RawValue {
fn from_borrowed_str(ron: &str) -> &Self {
// Safety: RawValue is a transparent newtype around str
unsafe { &*(ron as *const str as *const RawValue) }
fn from_boxed_str(ron: Box<str>) -> Box<Self> {
unsafe { core::mem::transmute::<Box<str>, Box<RawValue>>(ron) }
fn into_boxed_str(raw_value: Box<Self>) -> Box<str> {
unsafe { core::mem::transmute::<Box<RawValue>, Box<str>>(raw_value) }
#[allow(clippy::expect_used)]
fn trim_range(ron: &str) -> Range<usize> {
fn trim_range_inner(ron: &str) -> Result<Range<usize>, Error> {
let mut deserializer = crate::Deserializer::from_str(ron).map_err(Error::from)?;
deserializer.parser.skip_ws()?;
let start_offset = ron.len() - deserializer.parser.src().len();
let _ = serde::de::IgnoredAny::deserialize(&mut deserializer)?;
let end_offset = deserializer.parser.pre_ws_src().len();
Ok(start_offset..(ron.len() - end_offset))
trim_range_inner(ron).expect("RawValue must contain valid ron")
impl Clone for Box<RawValue> {
fn clone(&self) -> Self {
(**self).to_owned()
impl ToOwned for RawValue {
type Owned = Box<RawValue>;
fn to_owned(&self) -> Self::Owned {
RawValue::from_boxed_str(self.ron.to_owned().into_boxed_str())
impl fmt::Debug for RawValue {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
f.debug_tuple("RawValue")
.field(&format_args!("{}", &self.ron))
.finish()
impl fmt::Display for RawValue {
f.write_str(&self.ron)
/// Get the inner raw RON string, which is guaranteed to contain valid RON.
#[must_use]
pub fn get_ron(&self) -> &str {
&self.ron
/// Helper function to validate a RON string and turn it into a
/// [`RawValue`].
pub fn from_ron(ron: &str) -> SpannedResult<&Self> {
let mut deserializer = crate::Deserializer::from_str(ron)?;
// raw values can be used everywhere but extensions cannot
if !deserializer.extensions().is_empty() {
return Err(deserializer.span_error(Error::Message(String::from(
"ron::value::RawValue cannot enable extensions",
))));
// neither can global attributes like `#![type = ".."]`
if deserializer.parser.global_attributes {
"ron::value::RawValue cannot contain attributes",
let _ = de::Deserializer::deserialize_newtype_struct(
&mut deserializer,
RAW_VALUE_TOKEN,
de::IgnoredAny,
)
.map_err(|e| deserializer.span_error(e))?;
deserializer.end().map_err(|e| deserializer.span_error(e))?;
Ok(Self::from_borrowed_str(ron))
pub fn from_boxed_ron(ron: Box<str>) -> SpannedResult<Box<Self>> {
match Self::from_ron(&ron) {
Ok(_) => Ok(Self::from_boxed_str(ron)),
Err(err) => Err(err),
/// Helper function to deserialize the inner RON string into `T`.
pub fn into_rust<'de, T: Deserialize<'de>>(&'de self) -> SpannedResult<T> {
Options::default().from_str(&self.ron)
/// Helper function to serialize `value` into a RON string.
pub fn from_rust<T: Serialize>(value: &T) -> Result<Box<Self>, Error> {
let ron = Options::default().to_string(value)?;
Ok(RawValue::from_boxed_str(ron.into_boxed_str()))
/// Trims any leadning and trailing whitespace off the raw RON string,
/// including whitespace characters and comments.
pub fn trim(&self) -> &Self {
Self::from_borrowed_str(&self.ron[RawValue::trim_range(&self.ron)])
/// Trims any leadning and trailing whitespace off the boxed raw RON string,
pub fn trim_boxed(self: Box<Self>) -> Box<Self> {
let trim_range = RawValue::trim_range(&self.ron);
let mut boxed_ron = RawValue::into_boxed_str(self).into_string();
boxed_ron.truncate(trim_range.end);
boxed_ron.drain(..trim_range.start);
RawValue::from_boxed_str(boxed_ron.into_boxed_str())
impl From<Box<RawValue>> for Box<str> {
fn from(raw_value: Box<RawValue>) -> Self {
RawValue::into_boxed_str(raw_value)
impl Serialize for RawValue {
fn serialize<S: ser::Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
serializer.serialize_newtype_struct(RAW_VALUE_TOKEN, &self.ron)
impl<'de: 'a, 'a> Deserialize<'de> for &'a RawValue {
fn deserialize<D: de::Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
struct ReferenceVisitor;
impl<'de> de::Visitor<'de> for ReferenceVisitor {
type Value = &'de RawValue;
fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
// This error message only shows up with foreign Deserializers
write!(formatter, "any valid borrowed RON-value-string")
fn visit_borrowed_str<E: de::Error>(self, ron: &'de str) -> Result<Self::Value, E> {
match RawValue::from_ron(ron) {
Ok(raw_value) => Ok(raw_value),
Err(err) => Err(de::Error::custom(format!("invalid RON value at {}", err))),
fn visit_newtype_struct<D: de::Deserializer<'de>>(
self,
deserializer: D,
) -> Result<Self::Value, D::Error> {
deserializer.deserialize_str(self)
deserializer.deserialize_newtype_struct(RAW_VALUE_TOKEN, ReferenceVisitor)
impl<'de> Deserialize<'de> for Box<RawValue> {
struct BoxedVisitor;
impl<'de> de::Visitor<'de> for BoxedVisitor {
type Value = Box<RawValue>;
write!(formatter, "any valid RON-value-string")
fn visit_str<E: de::Error>(self, ron: &str) -> Result<Self::Value, E> {
Ok(raw_value) => Ok(raw_value.to_owned()),
fn visit_string<E: de::Error>(self, ron: String) -> Result<Self::Value, E> {
match RawValue::from_boxed_ron(ron.into_boxed_str()) {
deserializer.deserialize_string(self)
deserializer.deserialize_newtype_struct(RAW_VALUE_TOKEN, BoxedVisitor)