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use crate::{
num_conv::top_encode_number_to_output, EncodeError, NestedEncodeOutput, TryStaticCast,
};
use alloc::{boxed::Box, vec::Vec};
/// Specifies objects that can receive the result of a TopEncode computation.
/// in principle from NestedEncode performed on nested items.
///
/// All methods consume the object, so they can only be called once.
///
/// The trait is used in 3 scenarios:
/// - SC results
/// - `#[storage_set(...)]`
/// - Serialize async call.
pub trait TopEncodeOutput: Sized {
/// Type of `NestedEncodeOutput` that can be spawned to gather serializations of children.
type NestedBuffer: NestedEncodeOutput;
fn set_slice_u8(self, bytes: &[u8]);
#[inline]
#[allow(clippy::boxed_local)]
fn set_boxed_bytes(self, bytes: Box<[u8]>) {
self.set_slice_u8(&*bytes);
}
fn set_u64(self, value: u64) {
let mut buffer = Vec::<u8>::with_capacity(8);
top_encode_number_to_output(&mut buffer, value, false);
self.set_slice_u8(&buffer[..]);
}
fn set_i64(self, value: i64) {
let mut buffer = Vec::<u8>::with_capacity(8);
top_encode_number_to_output(&mut buffer, value as u64, true);
self.set_slice_u8(&buffer[..]);
}
/// The unit type `()` is serializable, but some TopEncodeOutput implementations might want to treat it differently.
/// For instance, SC function result units do not cause `finish` to be called, no empty result produced.
#[doc(hidden)]
#[inline]
fn set_unit(self) {
self.set_slice_u8(&[]);
}
/// Allows special handling of special types.
/// Also requires an alternative serialization, in case the special handling is not covered.
/// The alternative serialization, `else_serialization` is only called when necessary and
/// is normally compiled out via monomorphization.
#[inline]
fn set_specialized<T, F>(self, _value: &T, else_serialization: F) -> Result<(), EncodeError>
where
T: TryStaticCast,
F: FnOnce(Self) -> Result<(), EncodeError>,
{
else_serialization(self)
}
fn start_nested_encode(&self) -> Self::NestedBuffer;
fn finalize_nested_encode(self, nb: Self::NestedBuffer);
}
impl TopEncodeOutput for &mut Vec<u8> {
type NestedBuffer = Vec<u8>;
fn set_slice_u8(self, bytes: &[u8]) {
self.extend_from_slice(bytes);
}
fn start_nested_encode(&self) -> Self::NestedBuffer {
Vec::<u8>::new()
}
fn finalize_nested_encode(self, nb: Self::NestedBuffer) {
*self = nb;
}
}