Zebra/zebra-chain/src/transaction/joinsplit.rs

96 lines
3.8 KiB
Rust

use serde::{Deserialize, Serialize};
use crate::{
amount::{self, Amount, NegativeAllowed},
primitives::{ed25519, ZkSnarkProof},
sprout::{self, JoinSplit, Nullifier},
};
/// A bundle of [`JoinSplit`] descriptions and signature data.
///
/// JoinSplit descriptions are optional, but Zcash transactions must include a
/// JoinSplit signature and verification key if and only if there is at least one
/// JoinSplit description. This wrapper type bundles at least one JoinSplit
/// description with the required signature data, so that an
/// `Option<JoinSplitData>` correctly models the presence or absence of any
/// JoinSplit data.
#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
pub struct JoinSplitData<P: ZkSnarkProof> {
/// The first JoinSplit description in the transaction,
/// using proofs of type `P`.
///
/// Storing this separately from `rest` ensures that it is impossible
/// to construct an invalid `JoinSplitData` with no `JoinSplit`s.
///`
/// However, it's not necessary to access or process `first` and `rest`
/// separately, as the [`JoinSplitData::joinsplits`] method provides an
/// iterator over all of the `JoinSplit`s.
#[serde(bound(
serialize = "JoinSplit<P>: Serialize",
deserialize = "JoinSplit<P>: Deserialize<'de>"
))]
pub first: JoinSplit<P>,
/// The rest of the JoinSplit descriptions, using proofs of type `P`,
/// in the order they appear in the transaction.
///
/// The [`JoinSplitData::joinsplits`] method provides an iterator over
/// all `JoinSplit`s.
#[serde(bound(
serialize = "JoinSplit<P>: Serialize",
deserialize = "JoinSplit<P>: Deserialize<'de>"
))]
pub rest: Vec<JoinSplit<P>>,
/// The public key for the JoinSplit signature.
pub pub_key: ed25519::VerificationKeyBytes,
/// The JoinSplit signature.
pub sig: ed25519::Signature,
}
impl<P: ZkSnarkProof> JoinSplitData<P> {
/// Iterate over the [`JoinSplit`]s in `self`, in the order they appear
/// in the transaction.
pub fn joinsplits(&self) -> impl Iterator<Item = &JoinSplit<P>> {
std::iter::once(&self.first).chain(self.rest.iter())
}
/// Modify the [`JoinSplit`]s in `self`,
/// in the order they appear in the transaction.
#[cfg(any(test, feature = "proptest-impl"))]
pub fn joinsplits_mut(&mut self) -> impl Iterator<Item = &mut JoinSplit<P>> {
std::iter::once(&mut self.first).chain(self.rest.iter_mut())
}
/// Iterate over the [`Nullifier`]s in `self`.
pub fn nullifiers(&self) -> impl Iterator<Item = &Nullifier> {
self.joinsplits()
.flat_map(|joinsplit| joinsplit.nullifiers.iter())
}
/// Return the sprout value balance,
/// the change in the transaction value pool due to sprout [`JoinSplit`]s.
///
/// https://zebra.zfnd.org/dev/rfcs/0012-value-pools.html#definitions
///
/// See [`Transaction::sprout_value_balance`] for details.
pub fn value_balance(&self) -> Result<Amount<NegativeAllowed>, amount::Error> {
self.joinsplit_value_balances().sum()
}
/// Return a list of sprout value balances,
/// the changes in the transaction value pool due to each sprout [`JoinSplit`].
///
/// See [`Transaction::sprout_value_balance`] for details.
pub fn joinsplit_value_balances(
&self,
) -> Box<dyn Iterator<Item = Amount<NegativeAllowed>> + '_> {
Box::new(self.joinsplits().map(JoinSplit::value_balance))
}
/// Collect the Sprout note commitments for this transaction, if it contains [`Output`]s,
/// in the order they appear in the transaction.
pub fn note_commitments(&self) -> impl Iterator<Item = &sprout::commitment::NoteCommitment> {
self.joinsplits()
.flat_map(|joinsplit| &joinsplit.commitments)
}
}