90 lines
3.3 KiB
Rust
90 lines
3.3 KiB
Rust
use futures::future::Either;
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use crate::{
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primitives::redjubjub::{Binding, Signature},
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sapling::{Output, Spend},
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serialization::serde_helpers,
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};
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/// A bundle of [`Spend`] and [`Output`] descriptions and signature data.
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///
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/// Spend and Output descriptions are optional, but Zcash transactions must
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/// include a binding signature if and only if there is at least one Spend *or*
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/// Output description. This wrapper type bundles at least one Spend or Output
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/// description with the required signature data, so that an
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/// `Option<ShieldedData>` correctly models the presence or absence of any
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/// shielded data.
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#[derive(Clone, Debug, Serialize, Deserialize)]
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pub struct ShieldedData {
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/// Either a spend or output description.
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///
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/// Storing this separately ensures that it is impossible to construct
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/// an invalid `ShieldedData` with no spends or outputs.
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///
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/// However, it's not necessary to access or process `first` and `rest`
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/// separately, as the [`ShieldedData::spends`] and [`ShieldedData::outputs`]
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/// methods provide iterators over all of the [`Spend`]s and
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/// [`Output`]s.
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#[serde(with = "serde_helpers::Either")]
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pub first: Either<Spend, Output>,
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/// The rest of the [`Spend`]s for this transaction.
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///
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/// Note that the [`ShieldedData::spends`] method provides an iterator
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/// over all spend descriptions.
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pub rest_spends: Vec<Spend>,
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/// The rest of the [`Output`]s for this transaction.
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///
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/// Note that the [`ShieldedData::outputs`] method provides an iterator
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/// over all output descriptions.
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pub rest_outputs: Vec<Output>,
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/// A signature on the transaction hash.
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pub binding_sig: Signature<Binding>,
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}
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impl ShieldedData {
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/// Iterate over the [`Spend`]s for this transaction.
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pub fn spends(&self) -> impl Iterator<Item = &Spend> {
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match self.first {
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Either::Left(ref spend) => Some(spend),
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Either::Right(_) => None,
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}
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.into_iter()
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.chain(self.rest_spends.iter())
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}
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/// Iterate over the [`Output`]s for this transaction.
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pub fn outputs(&self) -> impl Iterator<Item = &Output> {
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match self.first {
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Either::Left(_) => None,
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Either::Right(ref output) => Some(output),
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}
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.into_iter()
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.chain(self.rest_outputs.iter())
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}
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}
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// Technically, it's possible to construct two equivalent representations
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// of a ShieldedData with at least one spend and at least one output, depending
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// on which goes in the `first` slot. This is annoying but a smallish price to
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// pay for structural validity.
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impl std::cmp::PartialEq for ShieldedData {
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fn eq(&self, other: &Self) -> bool {
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// First check that the lengths match, so we know it is safe to use zip,
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// which truncates to the shorter of the two iterators.
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if self.spends().count() != other.spends().count() {
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return false;
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}
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if self.outputs().count() != other.outputs().count() {
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return false;
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}
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// Now check that the binding_sig, spends, outputs match.
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self.binding_sig == other.binding_sig
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&& self.spends().zip(other.spends()).all(|(a, b)| a == b)
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&& self.outputs().zip(other.outputs()).all(|(a, b)| a == b)
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}
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}
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impl std::cmp::Eq for ShieldedData {}
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