use crate::MAX_XCM_DECODE_DEPTH;
use alloc::vec::Vec;
use codec::{Decode, DecodeLimit, Encode};
#[derive(Encode, Decode, scale_info::TypeInfo)]
#[codec(encode_bound())]
#[codec(decode_bound())]
#[scale_info(bounds(), skip_type_params(T))]
#[scale_info(replace_segment("staging_xcm", "xcm"))]
#[cfg_attr(feature = "json-schema", derive(schemars::JsonSchema))]
pub struct DoubleEncoded<T> {
encoded: Vec<u8>,
#[codec(skip)]
decoded: Option<T>,
}
impl<T> Clone for DoubleEncoded<T> {
fn clone(&self) -> Self {
Self { encoded: self.encoded.clone(), decoded: None }
}
}
impl<T> PartialEq for DoubleEncoded<T> {
fn eq(&self, other: &Self) -> bool {
self.encoded.eq(&other.encoded)
}
}
impl<T> Eq for DoubleEncoded<T> {}
impl<T> core::fmt::Debug for DoubleEncoded<T> {
fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
array_bytes::bytes2hex("0x", &self.encoded).fmt(f)
}
}
impl<T> From<Vec<u8>> for DoubleEncoded<T> {
fn from(encoded: Vec<u8>) -> Self {
Self { encoded, decoded: None }
}
}
impl<T> DoubleEncoded<T> {
pub fn into<S>(self) -> DoubleEncoded<S> {
DoubleEncoded::from(self)
}
pub fn from<S>(e: DoubleEncoded<S>) -> Self {
Self { encoded: e.encoded, decoded: None }
}
pub fn as_ref(&self) -> Option<&T> {
self.decoded.as_ref()
}
pub fn into_encoded(self) -> Vec<u8> {
self.encoded
}
}
impl<T: Decode> DoubleEncoded<T> {
pub fn ensure_decoded(&mut self) -> Result<&T, ()> {
if self.decoded.is_none() {
self.decoded =
T::decode_all_with_depth_limit(MAX_XCM_DECODE_DEPTH, &mut &self.encoded[..]).ok();
}
self.decoded.as_ref().ok_or(())
}
pub fn take_decoded(&mut self) -> Result<T, ()> {
self.decoded
.take()
.or_else(|| {
T::decode_all_with_depth_limit(MAX_XCM_DECODE_DEPTH, &mut &self.encoded[..]).ok()
})
.ok_or(())
}
pub fn try_into(mut self) -> Result<T, ()> {
self.ensure_decoded()?;
self.decoded.ok_or(())
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn ensure_decoded_works() {
let val: u64 = 42;
let mut encoded: DoubleEncoded<_> = Encode::encode(&val).into();
assert_eq!(encoded.ensure_decoded(), Ok(&val));
}
#[test]
fn take_decoded_works() {
let val: u64 = 42;
let mut encoded: DoubleEncoded<_> = Encode::encode(&val).into();
assert_eq!(encoded.take_decoded(), Ok(val));
}
#[test]
fn try_into_works() {
let val: u64 = 42;
let encoded: DoubleEncoded<_> = Encode::encode(&val).into();
assert_eq!(encoded.try_into(), Ok(val));
}
}