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Implement SSZ union type (#2579)

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## Issue Addressed

NA

## Proposed Changes

Implements the "union" type from the SSZ spec for `ssz`, `ssz_derive`, `tree_hash` and `tree_hash_derive` so it may be derived for `enums`:

https://github.com/ethereum/consensus-specs/blob/v1.1.0-beta.3/ssz/simple-serialize.md#union

The union type is required for the merge, since the `Transaction` type is defined as a single-variant union `Union[OpaqueTransaction]`.

### Crate Updates

This PR will (hopefully) cause CI to publish new versions for the following crates:

- `eth2_ssz_derive`: `0.2.1` -> `0.3.0`
- `eth2_ssz`: `0.3.0` -> `0.4.0`
- `eth2_ssz_types`: `0.2.0` -> `0.2.1`
- `tree_hash`: `0.3.0` -> `0.4.0`
- `tree_hash_derive`: `0.3.0` -> `0.4.0`

These these crates depend on each other, I've had to add a workspace-level `[patch]` for these crates. A follow-up PR will need to remove this patch, ones the new versions are published.

### Union Behaviors

We already had SSZ `Encode` and `TreeHash` derive for enums, however it just did a "transparent" pass-through of the inner value. Since the "union" decoding from the spec is in conflict with the transparent method, I've required that all `enum` have exactly one of the following enum-level attributes:

#### SSZ

-  `#[ssz(enum_behaviour = "union")]`
    - matches the spec used for the merge
-  `#[ssz(enum_behaviour = "transparent")]`
    - maintains existing functionality
    - not supported for `Decode` (never was)
    
#### TreeHash

-  `#[tree_hash(enum_behaviour = "union")]`
    - matches the spec used for the merge
-  `#[tree_hash(enum_behaviour = "transparent")]`
    - maintains existing functionality

This means that we can maintain the existing transparent behaviour, but all existing users will get a compile-time error until they explicitly opt-in to being transparent.

### Legacy Option Encoding

Before this PR, we already had a union-esque encoding for `Option<T>`. However, this was with the *old* SSZ spec where the union selector was 4 bytes. During merge specification, the spec was changed to use 1 byte for the selector.

Whilst the 4-byte `Option` encoding was never used in the spec, we used it in our database. Writing a migrate script for all occurrences of `Option` in the database would be painful, especially since it's used in the `CommitteeCache`. To avoid the migrate script, I added a serde-esque `#[ssz(with = "module")]` field-level attribute to `ssz_derive` so that we can opt into the 4-byte encoding on a field-by-field basis.

The `ssz::legacy::four_byte_impl!` macro allows a one-liner to define the module required for the `#[ssz(with = "module")]` for some `Option<T> where T: Encode + Decode`.

Notably, **I have removed `Encode` and `Decode` impls for `Option`**. I've done this to force a break on downstream users. Like I mentioned, `Option` isn't used in the spec so I don't think it'll be *that* annoying. I think it's nicer than quietly having two different union implementations or quietly breaking the existing `Option` impl.

### Crate Publish Ordering

I've modified the order in which CI publishes crates to ensure that we don't publish a crate without ensuring we already published a crate that it depends upon.

## TODO

- [ ] Queue a follow-up `[patch]`-removing PR.
This commit is contained in:
Paul Hauner
2021-09-25 05:58:36 +00:00
parent a844ce5ba9
commit fe52322088
63 changed files with 1515 additions and 571 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
consensus/ssz/Cargo.toml
View File

@@ -1,6 +1,6 @@
[package]
name = "eth2_ssz"
version = "0.3.0"
version = "0.4.0"
authors = ["Paul Hauner <paul@sigmaprime.io>"]
edition = "2018"
description = "SimpleSerialize (SSZ) as used in Ethereum 2.0"
@@ -10,7 +10,7 @@ license = "Apache-2.0"
name = "ssz"
[dev-dependencies]
eth2_ssz_derive = "0.2.1"
eth2_ssz_derive = "0.3.0"
[dependencies]
ethereum-types = "0.11.0"

42
consensus/ssz/src/decode.rs
View File

@@ -48,6 +48,8 @@ pub enum DecodeError {
ZeroLengthItem,
/// The given bytes were invalid for some application-level reason.
BytesInvalid(String),
/// The given union selector is out of bounds.
UnionSelectorInvalid(u8),
}
/// Performs checks on the `offset` based upon the other parameters provided.
@@ -172,9 +174,18 @@ impl<'a> SszDecoderBuilder<'a> {
/// Declares that some type `T` is the next item in `bytes`.
pub fn register_type<T: Decode>(&mut self) -> Result<(), DecodeError> {
if T::is_ssz_fixed_len() {
self.register_type_parameterized(T::is_ssz_fixed_len(), T::ssz_fixed_len())
}
/// Declares that a type with the given parameters is the next item in `bytes`.
pub fn register_type_parameterized(
&mut self,
is_ssz_fixed_len: bool,
ssz_fixed_len: usize,
) -> Result<(), DecodeError> {
if is_ssz_fixed_len {
let start = self.items_index;
self.items_index += T::ssz_fixed_len();
self.items_index += ssz_fixed_len;
let slice = self.bytes.get(start..self.items_index).ok_or_else(|| {
DecodeError::InvalidByteLength {
@@ -300,7 +311,7 @@ impl<'a> SszDecoder<'a> {
///
/// Panics when attempting to decode more items than actually exist.
pub fn decode_next<T: Decode>(&mut self) -> Result<T, DecodeError> {
T::from_ssz_bytes(self.items.remove(0))
self.decode_next_with(|slice| T::from_ssz_bytes(slice))
}
/// Decodes the next item using the provided function.
@@ -312,15 +323,30 @@ impl<'a> SszDecoder<'a> {
}
}
/// Reads a `BYTES_PER_LENGTH_OFFSET`-byte union index from `bytes`, where `bytes.len() >=
/// BYTES_PER_LENGTH_OFFSET`.
pub fn read_union_index(bytes: &[u8]) -> Result<usize, DecodeError> {
read_offset(bytes)
/// Takes `bytes`, assuming it is the encoding for a SSZ union, and returns the union-selector and
/// the body (trailing bytes).
///
/// ## Errors
///
/// Returns an error if:
///
/// - `bytes` is empty.
/// - the union selector is not a valid value (i.e., larger than the maximum number of variants.
pub fn split_union_bytes(bytes: &[u8]) -> Result<(UnionSelector, &[u8]), DecodeError> {
let selector = bytes
.first()
.copied()
.ok_or(DecodeError::OutOfBoundsByte { i: 0 })
.and_then(UnionSelector::new)?;
let body = bytes
.get(1..)
.ok_or(DecodeError::OutOfBoundsByte { i: 1 })?;
Ok((selector, body))
}
/// Reads a `BYTES_PER_LENGTH_OFFSET`-byte length from `bytes`, where `bytes.len() >=
/// BYTES_PER_LENGTH_OFFSET`.
fn read_offset(bytes: &[u8]) -> Result<usize, DecodeError> {
pub fn read_offset(bytes: &[u8]) -> Result<usize, DecodeError> {
decode_offset(bytes.get(0..BYTES_PER_LENGTH_OFFSET).ok_or_else(|| {
DecodeError::InvalidLengthPrefix {
len: bytes.len(),

30
consensus/ssz/src/decode/impls.rs
View File

@@ -242,36 +242,6 @@ impl Decode for NonZeroUsize {
}
}
/// The SSZ union type.
impl<T: Decode> Decode for Option<T> {
fn is_ssz_fixed_len() -> bool {
false
}
fn from_ssz_bytes(bytes: &[u8]) -> Result<Self, DecodeError> {
if bytes.len() < BYTES_PER_LENGTH_OFFSET {
return Err(DecodeError::InvalidByteLength {
len: bytes.len(),
expected: BYTES_PER_LENGTH_OFFSET,
});
}
let (index_bytes, value_bytes) = bytes.split_at(BYTES_PER_LENGTH_OFFSET);
let index = read_union_index(index_bytes)?;
if index == 0 {
Ok(None)
} else if index == 1 {
Ok(Some(T::from_ssz_bytes(value_bytes)?))
} else {
Err(DecodeError::BytesInvalid(format!(
"{} is not a valid union index for Option<T>",
index
)))
}
}
}
impl<T: Decode> Decode for Arc<T> {
fn is_ssz_fixed_len() -> bool {
T::is_ssz_fixed_len()

21
consensus/ssz/src/encode.rs
View File

@@ -104,13 +104,21 @@ impl<'a> SszEncoder<'a> {
/// Append some `item` to the SSZ bytes.
pub fn append<T: Encode>(&mut self, item: &T) {
if T::is_ssz_fixed_len() {
item.ssz_append(&mut self.buf);
self.append_parameterized(T::is_ssz_fixed_len(), |buf| item.ssz_append(buf))
}
/// Uses `ssz_append` to append the encoding of some item to the SSZ bytes.
pub fn append_parameterized<F>(&mut self, is_ssz_fixed_len: bool, ssz_append: F)
where
F: Fn(&mut Vec<u8>),
{
if is_ssz_fixed_len {
ssz_append(&mut self.buf);
} else {
self.buf
.extend_from_slice(&encode_length(self.offset + self.variable_bytes.len()));
item.ssz_append(&mut self.variable_bytes);
ssz_append(&mut self.variable_bytes);
}
}
@@ -125,13 +133,6 @@ impl<'a> SszEncoder<'a> {
}
}
/// Encode `index` as a little-endian byte array of `BYTES_PER_LENGTH_OFFSET` length.
///
/// If `len` is larger than `2 ^ BYTES_PER_LENGTH_OFFSET`, a `debug_assert` is raised.
pub fn encode_union_index(index: usize) -> [u8; BYTES_PER_LENGTH_OFFSET] {
encode_length(index)
}
/// Encode `len` as a little-endian byte array of `BYTES_PER_LENGTH_OFFSET` length.
///
/// If `len` is larger than `2 ^ BYTES_PER_LENGTH_OFFSET`, a `debug_assert` is raised.

49
consensus/ssz/src/encode/impls.rs
View File

@@ -202,36 +202,6 @@ impl_encode_for_tuples! {
}
}
/// The SSZ "union" type.
impl<T: Encode> Encode for Option<T> {
fn is_ssz_fixed_len() -> bool {
false
}
fn ssz_bytes_len(&self) -> usize {
if let Some(some) = self {
let len = if <T as Encode>::is_ssz_fixed_len() {
<T as Encode>::ssz_fixed_len()
} else {
some.ssz_bytes_len()
};
len + BYTES_PER_LENGTH_OFFSET
} else {
BYTES_PER_LENGTH_OFFSET
}
}
fn ssz_append(&self, buf: &mut Vec<u8>) {
match self {
None => buf.extend_from_slice(&encode_union_index(0)),
Some(t) => {
buf.extend_from_slice(&encode_union_index(1));
t.ssz_append(buf);
}
}
}
}
impl<T: Encode> Encode for Arc<T> {
fn is_ssz_fixed_len() -> bool {
T::is_ssz_fixed_len()
@@ -456,25 +426,6 @@ mod tests {
);
}
#[test]
fn ssz_encode_option_u16() {
assert_eq!(Some(65535_u16).as_ssz_bytes(), vec![1, 0, 0, 0, 255, 255]);
let none: Option<u16> = None;
assert_eq!(none.as_ssz_bytes(), vec![0, 0, 0, 0]);
}
#[test]
fn ssz_encode_option_vec_u16() {
assert_eq!(
Some(vec![0_u16, 1]).as_ssz_bytes(),
vec![1, 0, 0, 0, 0, 0, 1, 0]
);
let none: Option<Vec<u16>> = None;
assert_eq!(none.as_ssz_bytes(), vec![0, 0, 0, 0]);
}
#[test]
fn ssz_encode_u8() {
assert_eq!(0_u8.as_ssz_bytes(), vec![0]);

265
consensus/ssz/src/legacy.rs Normal file
View File

@@ -0,0 +1,265 @@
//! Provides a "legacy" version of SSZ encoding for `Option<T> where T: Encode + Decode`.
//!
//! The SSZ specification changed in 2021 to use a 1-byte union selector, instead of a 4-byte one
//! which was used in the Lighthouse database.
//!
//! Users can use the `four_byte_option_impl` macro to define a module that can be used with the
//! `#[ssz(with = "module")]`.
//!
//! ## Example
//!
//! ```rust
//! use ssz_derive::{Encode, Decode};
//! use ssz::four_byte_option_impl;
//!
//! four_byte_option_impl!(impl_for_u64, u64);
//!
//! #[derive(Encode, Decode)]
//! struct Foo {
//! #[ssz(with = "impl_for_u64")]
//! a: Option<u64>,
//! }
//! ```
use crate::*;
#[macro_export]
macro_rules! four_byte_option_impl {
($mod_name: ident, $type: ty) => {
#[allow(dead_code)]
mod $mod_name {
use super::*;
pub mod encode {
use super::*;
#[allow(unused_imports)]
use ssz::*;
pub fn is_ssz_fixed_len() -> bool {
false
}
pub fn ssz_fixed_len() -> usize {
BYTES_PER_LENGTH_OFFSET
}
pub fn ssz_bytes_len(opt: &Option<$type>) -> usize {
if let Some(some) = opt {
let len = if <$type as Encode>::is_ssz_fixed_len() {
<$type as Encode>::ssz_fixed_len()
} else {
<$type as Encode>::ssz_bytes_len(some)
};
len + BYTES_PER_LENGTH_OFFSET
} else {
BYTES_PER_LENGTH_OFFSET
}
}
pub fn ssz_append(opt: &Option<$type>, buf: &mut Vec<u8>) {
match opt {
None => buf.extend_from_slice(&legacy::encode_four_byte_union_selector(0)),
Some(t) => {
buf.extend_from_slice(&legacy::encode_four_byte_union_selector(1));
t.ssz_append(buf);
}
}
}
pub fn as_ssz_bytes(opt: &Option<$type>) -> Vec<u8> {
let mut buf = vec![];
ssz_append(opt, &mut buf);
buf
}
}
pub mod decode {
use super::*;
#[allow(unused_imports)]
use ssz::*;
pub fn is_ssz_fixed_len() -> bool {
false
}
pub fn ssz_fixed_len() -> usize {
BYTES_PER_LENGTH_OFFSET
}
pub fn from_ssz_bytes(bytes: &[u8]) -> Result<Option<$type>, DecodeError> {
if bytes.len() < BYTES_PER_LENGTH_OFFSET {
return Err(DecodeError::InvalidByteLength {
len: bytes.len(),
expected: BYTES_PER_LENGTH_OFFSET,
});
}
let (index_bytes, value_bytes) = bytes.split_at(BYTES_PER_LENGTH_OFFSET);
let index = legacy::read_four_byte_union_selector(index_bytes)?;
if index == 0 {
Ok(None)
} else if index == 1 {
Ok(Some(<$type as ssz::Decode>::from_ssz_bytes(value_bytes)?))
} else {
Err(DecodeError::BytesInvalid(format!(
"{} is not a valid union index for Option<T>",
index
)))
}
}
}
}
};
}
pub fn encode_four_byte_union_selector(selector: usize) -> [u8; BYTES_PER_LENGTH_OFFSET] {
encode_length(selector)
}
pub fn read_four_byte_union_selector(bytes: &[u8]) -> Result<usize, DecodeError> {
read_offset(bytes)
}
#[cfg(test)]
mod test {
use super::*;
use crate as ssz;
use ssz_derive::{Decode, Encode};
type VecU16 = Vec<u16>;
four_byte_option_impl!(impl_u16, u16);
four_byte_option_impl!(impl_vec_u16, VecU16);
#[test]
fn ssz_encode_option_u16() {
let item = Some(65535_u16);
let bytes = vec![1, 0, 0, 0, 255, 255];
assert_eq!(impl_u16::encode::as_ssz_bytes(&item), bytes);
assert_eq!(impl_u16::decode::from_ssz_bytes(&bytes).unwrap(), item);
let item = None;
let bytes = vec![0, 0, 0, 0];
assert_eq!(impl_u16::encode::as_ssz_bytes(&item), bytes);
assert_eq!(impl_u16::decode::from_ssz_bytes(&bytes).unwrap(), None);
}
#[test]
fn ssz_encode_option_vec_u16() {
let item = Some(vec![0_u16, 1]);
let bytes = vec![1, 0, 0, 0, 0, 0, 1, 0];
assert_eq!(impl_vec_u16::encode::as_ssz_bytes(&item), bytes);
assert_eq!(impl_vec_u16::decode::from_ssz_bytes(&bytes).unwrap(), item);
let item = None;
let bytes = vec![0, 0, 0, 0];
assert_eq!(impl_vec_u16::encode::as_ssz_bytes(&item), bytes);
assert_eq!(impl_vec_u16::decode::from_ssz_bytes(&bytes).unwrap(), item);
}
fn round_trip<T: Encode + Decode + std::fmt::Debug + PartialEq>(items: Vec<T>) {
for item in items {
let encoded = &item.as_ssz_bytes();
assert_eq!(item.ssz_bytes_len(), encoded.len());
assert_eq!(T::from_ssz_bytes(encoded), Ok(item));
}
}
#[derive(Debug, PartialEq, Encode, Decode)]
struct TwoVariableLenOptions {
a: u16,
#[ssz(with = "impl_u16")]
b: Option<u16>,
#[ssz(with = "impl_vec_u16")]
c: Option<Vec<u16>>,
#[ssz(with = "impl_vec_u16")]
d: Option<Vec<u16>>,
}
#[test]
#[allow(clippy::zero_prefixed_literal)]
fn two_variable_len_options_encoding() {
let s = TwoVariableLenOptions {
a: 42,
b: None,
c: Some(vec![0]),
d: None,
};
let bytes = vec![
// 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
// | option<u16> | offset | offset | option<u16 | 1st list
42, 00, 14, 00, 00, 00, 18, 00, 00, 00, 24, 00, 00, 00, 00, 00, 00, 00, 01, 00, 00, 00,
// 23 24 25 26 27
// | 2nd list
00, 00, 00, 00, 00, 00,
];
assert_eq!(s.as_ssz_bytes(), bytes);
}
#[test]
fn two_variable_len_options_round_trip() {
let vec: Vec<TwoVariableLenOptions> = vec![
TwoVariableLenOptions {
a: 42,
b: Some(12),
c: Some(vec![0]),
d: Some(vec![1]),
},
TwoVariableLenOptions {
a: 42,
b: Some(12),
c: Some(vec![0]),
d: None,
},
TwoVariableLenOptions {
a: 42,
b: None,
c: Some(vec![0]),
d: None,
},
TwoVariableLenOptions {
a: 42,
b: None,
c: None,
d: None,
},
];
round_trip(vec);
}
#[test]
fn tuple_u8_u16() {
let vec: Vec<(u8, u16)> = vec![
(0, 0),
(0, 1),
(1, 0),
(u8::max_value(), u16::max_value()),
(0, u16::max_value()),
(u8::max_value(), 0),
(42, 12301),
];
round_trip(vec);
}
#[test]
fn tuple_vec_vec() {
let vec: Vec<(u64, Vec<u8>, Vec<Vec<u16>>)> = vec![
(0, vec![], vec![vec![]]),
(99, vec![101], vec![vec![], vec![]]),
(
42,
vec![12, 13, 14],
vec![vec![99, 98, 97, 96], vec![42, 44, 46, 48, 50]],
),
];
round_trip(vec);
}
}

14
consensus/ssz/src/lib.rs
View File

@@ -36,11 +36,15 @@
mod decode;
mod encode;
pub mod legacy;
mod union_selector;
pub use decode::{
impls::decode_list_of_variable_length_items, Decode, DecodeError, SszDecoder, SszDecoderBuilder,
impls::decode_list_of_variable_length_items, read_offset, split_union_bytes, Decode,
DecodeError, SszDecoder, SszDecoderBuilder,
};
pub use encode::{Encode, SszEncoder};
pub use encode::{encode_length, Encode, SszEncoder};
pub use union_selector::UnionSelector;
/// The number of bytes used to represent an offset.
pub const BYTES_PER_LENGTH_OFFSET: usize = 4;
@@ -50,6 +54,12 @@ pub const MAX_LENGTH_VALUE: usize = (std::u32::MAX >> (8 * (4 - BYTES_PER_LENGTH
#[cfg(target_pointer_width = "64")]
pub const MAX_LENGTH_VALUE: usize = (std::u64::MAX >> (8 * (8 - BYTES_PER_LENGTH_OFFSET))) as usize;
/// The number of bytes used to indicate the variant of a union.
pub const BYTES_PER_UNION_SELECTOR: usize = 1;
/// The highest possible union selector value (higher values are reserved for backwards compatible
/// extensions).
pub const MAX_UNION_SELECTOR: u8 = 127;
/// Convenience function to SSZ encode an object supporting ssz::Encode.
///
/// Equivalent to `val.as_ssz_bytes()`.

29
consensus/ssz/src/union_selector.rs Normal file
View File

@@ -0,0 +1,29 @@
use crate::*;
/// Provides the one-byte "selector" from the SSZ union specification:
///
/// https://github.com/ethereum/consensus-specs/blob/v1.1.0-beta.3/ssz/simple-serialize.md#union
#[derive(Copy, Clone)]
pub struct UnionSelector(u8);
impl From<UnionSelector> for u8 {
fn from(union_selector: UnionSelector) -> u8 {
union_selector.0
}
}
impl PartialEq<u8> for UnionSelector {
fn eq(&self, other: &u8) -> bool {
self.0 == *other
}
}
impl UnionSelector {
/// Instantiate `self`, returning an error if `selector > MAX_UNION_SELECTOR`.
pub fn new(selector: u8) -> Result<Self, DecodeError> {
Some(selector)
.filter(|_| selector <= MAX_UNION_SELECTOR)
.map(Self)
.ok_or(DecodeError::UnionSelectorInvalid(selector))
}
}

204
consensus/ssz/tests/tests.rs
View File

@@ -292,68 +292,6 @@ mod round_trip {
);
}
#[derive(Debug, PartialEq, Encode, Decode)]
struct TwoVariableLenOptions {
a: u16,
b: Option<u16>,
c: Option<Vec<u16>>,
d: Option<Vec<u16>>,
}
#[test]
#[allow(clippy::zero_prefixed_literal)]
fn two_variable_len_options_encoding() {
let s = TwoVariableLenOptions {
a: 42,
b: None,
c: Some(vec![0]),
d: None,
};
let bytes = vec![
// 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
// | option<u16> | offset | offset | option<u16 | 1st list
42, 00, 14, 00, 00, 00, 18, 00, 00, 00, 24, 00, 00, 00, 00, 00, 00, 00, 01, 00, 00, 00,
// 23 24 25 26 27
// | 2nd list
00, 00, 00, 00, 00, 00,
];
assert_eq!(s.as_ssz_bytes(), bytes);
}
#[test]
fn two_variable_len_options_round_trip() {
let vec: Vec<TwoVariableLenOptions> = vec![
TwoVariableLenOptions {
a: 42,
b: Some(12),
c: Some(vec![0]),
d: Some(vec![1]),
},
TwoVariableLenOptions {
a: 42,
b: Some(12),
c: Some(vec![0]),
d: None,
},
TwoVariableLenOptions {
a: 42,
b: None,
c: Some(vec![0]),
d: None,
},
TwoVariableLenOptions {
a: 42,
b: None,
c: None,
d: None,
},
];
round_trip(vec);
}
#[test]
fn tuple_u8_u16() {
let vec: Vec<(u8, u16)> = vec![
@@ -384,3 +322,145 @@ mod round_trip {
round_trip(vec);
}
}
mod derive_macro {
use ssz::{Decode, Encode};
use ssz_derive::{Decode, Encode};
use std::fmt::Debug;
fn assert_encode<T: Encode>(item: &T, bytes: &[u8]) {
assert_eq!(item.as_ssz_bytes(), bytes);
}
fn assert_encode_decode<T: Encode + Decode + PartialEq + Debug>(item: &T, bytes: &[u8]) {
assert_encode(item, bytes);
assert_eq!(T::from_ssz_bytes(bytes).unwrap(), *item);
}
#[derive(PartialEq, Debug, Encode, Decode)]
#[ssz(enum_behaviour = "union")]
enum TwoFixedUnion {
U8(u8),
U16(u16),
}
#[derive(PartialEq, Debug, Encode, Decode)]
struct TwoFixedUnionStruct {
a: TwoFixedUnion,
}
#[test]
fn two_fixed_union() {
let eight = TwoFixedUnion::U8(1);
let sixteen = TwoFixedUnion::U16(1);
assert_encode_decode(&eight, &[0, 1]);
assert_encode_decode(&sixteen, &[1, 1, 0]);
assert_encode_decode(&TwoFixedUnionStruct { a: eight }, &[4, 0, 0, 0, 0, 1]);
assert_encode_decode(&TwoFixedUnionStruct { a: sixteen }, &[4, 0, 0, 0, 1, 1, 0]);
}
#[derive(PartialEq, Debug, Encode, Decode)]
struct VariableA {
a: u8,
b: Vec<u8>,
}
#[derive(PartialEq, Debug, Encode, Decode)]
struct VariableB {
a: Vec<u8>,
b: u8,
}
#[derive(PartialEq, Debug, Encode)]
#[ssz(enum_behaviour = "transparent")]
enum TwoVariableTrans {
A(VariableA),
B(VariableB),
}
#[derive(PartialEq, Debug, Encode)]
struct TwoVariableTransStruct {
a: TwoVariableTrans,
}
#[derive(PartialEq, Debug, Encode, Decode)]
#[ssz(enum_behaviour = "union")]
enum TwoVariableUnion {
A(VariableA),
B(VariableB),
}
#[derive(PartialEq, Debug, Encode, Decode)]
struct TwoVariableUnionStruct {
a: TwoVariableUnion,
}
#[test]
fn two_variable_trans() {
let trans_a = TwoVariableTrans::A(VariableA {
a: 1,
b: vec![2, 3],
});
let trans_b = TwoVariableTrans::B(VariableB {
a: vec![1, 2],
b: 3,
});
assert_encode(&trans_a, &[1, 5, 0, 0, 0, 2, 3]);
assert_encode(&trans_b, &[5, 0, 0, 0, 3, 1, 2]);
assert_encode(
&TwoVariableTransStruct { a: trans_a },
&[4, 0, 0, 0, 1, 5, 0, 0, 0, 2, 3],
);
assert_encode(
&TwoVariableTransStruct { a: trans_b },
&[4, 0, 0, 0, 5, 0, 0, 0, 3, 1, 2],
);
}
#[test]
fn two_variable_union() {
let union_a = TwoVariableUnion::A(VariableA {
a: 1,
b: vec![2, 3],
});
let union_b = TwoVariableUnion::B(VariableB {
a: vec![1, 2],
b: 3,
});
assert_encode_decode(&union_a, &[0, 1, 5, 0, 0, 0, 2, 3]);
assert_encode_decode(&union_b, &[1, 5, 0, 0, 0, 3, 1, 2]);
assert_encode_decode(
&TwoVariableUnionStruct { a: union_a },
&[4, 0, 0, 0, 0, 1, 5, 0, 0, 0, 2, 3],
);
assert_encode_decode(
&TwoVariableUnionStruct { a: union_b },
&[4, 0, 0, 0, 1, 5, 0, 0, 0, 3, 1, 2],
);
}
#[derive(PartialEq, Debug, Encode, Decode)]
#[ssz(enum_behaviour = "union")]
enum TwoVecUnion {
A(Vec<u8>),
B(Vec<u8>),
}
#[test]
fn two_vec_union() {
assert_encode_decode(&TwoVecUnion::A(vec![]), &[0]);
assert_encode_decode(&TwoVecUnion::B(vec![]), &[1]);
assert_encode_decode(&TwoVecUnion::A(vec![0]), &[0, 0]);
assert_encode_decode(&TwoVecUnion::B(vec![0]), &[1, 0]);
assert_encode_decode(&TwoVecUnion::A(vec![0, 1]), &[0, 0, 1]);
assert_encode_decode(&TwoVecUnion::B(vec![0, 1]), &[1, 0, 1]);
}
}