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feat: add ledger sync protocol
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Signed-off-by: Brandon H. Gomes <[email protected]>
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@bhgomes
bhgomes committed May 3, 2022
1 parent aa0b10d commit 36504f4
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Showing 2 changed files with 142 additions and 63 deletions.
192 changes: 135 additions & 57 deletions pallets/manta-pay/src/lib.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -71,7 +71,7 @@ use manta_crypto::{
constraint::ProofSystem,
merkle_tree::{self, forest::Configuration as _},
};
use manta_pay::config;
use manta_pay::{config, signer::Checkpoint};
use manta_primitives::{
assets::{AssetConfig, FungibleLedger as _, FungibleLedgerError},
types::{AssetId, Balance},
Expand Down Expand Up @@ -132,40 +132,29 @@ pub mod pallet {
#[pallet::hooks]
impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {}

/// Shards of the merkle tree of UTXOs
/// UTXOs and Encrypted Notes Grouped by Shard
#[pallet::storage]
pub(super) type Shards<T: Config> =
StorageDoubleMap<_, Identity, u8, Identity, u64, ([u8; 32], EncryptedNote), ValueQuery>;

/// Shard merkle trees
/// Shard Merkle Tree Paths
#[pallet::storage]
pub(super) type ShardTrees<T: Config> =
StorageMap<_, Identity, u8, UtxoMerkleTreePath, ValueQuery>;

/// Outputs of Utxo accumulator
/// Outputs of Utxo Accumulator
#[pallet::storage]
pub(super) type UtxoAccumulatorOutputs<T: Config> =
StorageMap<_, Identity, [u8; 32], (), ValueQuery>;

/// Utxo set of MantaPay protocol
/// UTXO Set
#[pallet::storage]
pub(super) type UtxoSet<T: Config> = StorageMap<_, Identity, [u8; 32], (), ValueQuery>;

/// Void number set
/// Void Number Set
#[pallet::storage]
pub(super) type VoidNumberSet<T: Config> = StorageMap<_, Identity, [u8; 32], (), ValueQuery>;

/// Void number set insertion order
/// Each element of the key is an `u64` insertion order number of void number.
#[pallet::storage]
pub(super) type VoidNumberSetInsertionOrder<T: Config> =
StorageMap<_, Identity, u64, [u8; 32], ValueQuery>;

/// The size of Void Number Set
/// FIXME: this should be removed.
#[pallet::storage]
pub(super) type VoidNumberSetSize<T: Config> = StorageValue<_, u64, ValueQuery>;

#[pallet::call]
impl<T: Config> Pallet<T> {
/// Transforms some public assets into private ones using `post`, withdrawing the public
Expand All @@ -174,15 +163,7 @@ pub mod pallet {
#[transactional]
pub fn to_private(origin: OriginFor<T>, post: TransferPost) -> DispatchResultWithPostInfo {
let origin = ensure_signed(origin)?;
let mut ledger = Self::ledger();
Self::deposit_event(
config::TransferPost::try_from(post)
.map_err(|_| Error::<T>::InvalidSerializedForm)?
.post(vec![origin], vec![], &(), &mut ledger)
.map_err(Error::<T>::from)?
.convert(None),
);
Ok(().into())
Self::post_transaction(None, vec![origin], vec![], post)
}

/// Transforms some private assets into public ones using `post`, depositing the public
Expand All @@ -191,15 +172,7 @@ pub mod pallet {
#[transactional]
pub fn to_public(origin: OriginFor<T>, post: TransferPost) -> DispatchResultWithPostInfo {
let origin = ensure_signed(origin)?;
let mut ledger = Self::ledger();
Self::deposit_event(
config::TransferPost::try_from(post)
.map_err(|_| Error::<T>::InvalidSerializedForm)?
.post(vec![], vec![origin], &(), &mut ledger)
.map_err(Error::<T>::from)?
.convert(None),
);
Ok(().into())
Self::post_transaction(None, vec![], vec![origin], post)
}

/// Transfers private assets encoded in `post`.
Expand All @@ -215,15 +188,7 @@ pub mod pallet {
post: TransferPost,
) -> DispatchResultWithPostInfo {
let origin = ensure_signed(origin)?;
let mut ledger = Self::ledger();
Self::deposit_event(
config::TransferPost::try_from(post)
.map_err(|_| Error::<T>::InvalidSerializedForm)?
.post(vec![], vec![], &(), &mut ledger)
.map_err(Error::<T>::from)?
.convert(Some(origin)),
);
Ok(().into())
Self::post_transaction(Some(origin), vec![], vec![], post)
}

/// Transfers public `asset` from `origin` to the `sink` account.
Expand Down Expand Up @@ -480,19 +445,140 @@ pub mod pallet {
where
T: Config,
{
/// Returns the ledger implementation for this pallet.
/// Maximum Number of Updates per Shard
const PULL_MAX_PER_SHARD_UPDATE_SIZE: usize = 128;

/// Maximum Size of Sender Data Update
const PULL_MAX_SENDER_UPDATE_SIZE: usize = 1024;

/// Pulls receiver data from the ledger starting at the `receiver_index`.
#[inline]
fn pull_receivers(
receiver_index: &mut [usize; 256],
) -> Result<(bool, ReceiverChunk), scale_codec::Error> {
let mut more_receivers = false;
let mut receivers = Vec::new();
for (i, index) in receiver_index.iter_mut().enumerate() {
more_receivers |= Self::pull_receivers_for_shard(i as u8, index, &mut receivers)?;
}
Ok((more_receivers, receivers))
}

/// Pulls receiver data from the shard at `shard_index` starting at the `receiver_index`,
/// pushing the results back to `receivers`.
#[inline]
fn ledger() -> Ledger<T> {
Ledger(PhantomData)
fn pull_receivers_for_shard(
shard_index: u8,
receiver_index: &mut usize,
receivers: &mut ReceiverChunk,
) -> Result<bool, scale_codec::Error> {
let mut iter = if *receiver_index == 0 {
Shards::<T>::iter_prefix(shard_index)
} else {
let raw_key = Shards::<T>::hashed_key_for(shard_index, *receiver_index as u64 - 1);
Shards::<T>::iter_prefix_from(shard_index, raw_key)
};
for _ in 0..Self::PULL_MAX_PER_SHARD_UPDATE_SIZE {
match iter.next() {
Some((_, (utxo, encrypted_note))) => {
*receiver_index += 1;
receivers.push((decode(utxo)?, encrypted_note.try_into()?));
}
_ => return Ok(false),
}
}
Ok(iter.next().is_some())
}

/// Pulls sender data from the ledger starting at the `sender_index`.
#[inline]
fn pull_senders(
sender_index: &mut usize,
) -> Result<(bool, SenderChunk), scale_codec::Error> {
let mut senders = Vec::new();
let mut iter = VoidNumberSet::<T>::iter().skip(*sender_index);
for _ in 0..Self::PULL_MAX_SENDER_UPDATE_SIZE {
match iter.next() {
Some((sender, _)) => {
*sender_index += 1;
senders.push(decode(sender)?);
}
_ => return Ok((false, senders)),
}
}
Ok((iter.next().is_some(), senders))
}

/// The account ID of AssetManager
/// Returns the update required to be synchronized with the ledger starting from
/// `checkpoint`.
#[inline]
pub fn pull(mut checkpoint: Checkpoint) -> Result<PullResponse, scale_codec::Error> {
let (more_receivers, receivers) = Self::pull_receivers(&mut checkpoint.receiver_index)?;
let (more_senders, senders) = Self::pull_senders(&mut checkpoint.sender_index)?;
Ok(PullResponse {
should_continue: more_receivers || more_senders,
checkpoint,
receivers,
senders,
})
}

/// Returns the account ID of this pallet.
#[inline]
pub fn account_id() -> T::AccountId {
T::PalletId::get().into_account()
}

/// Posts the transaction encoded in `post` to the ledger, using `sources` and `sinks` as
/// the public deposit and public withdraw accounts respectively.
#[inline]
fn post_transaction(
origin: Option<T::AccountId>,
sources: Vec<T::AccountId>,
sinks: Vec<T::AccountId>,
post: TransferPost,
) -> DispatchResultWithPostInfo {
Self::deposit_event(
config::TransferPost::try_from(post)
.map_err(|_| Error::<T>::InvalidSerializedForm)?
.post(sources, sinks, &(), &mut Ledger(PhantomData))
.map_err(Error::<T>::from)?
.convert(origin),
);
Ok(().into())
}
}
}

/// Receiver Chunk Data
pub type ReceiverChunk = Vec<(config::Utxo, config::EncryptedNote)>;

/// Sender Chunk Data
pub type SenderChunk = Vec<config::VoidNumber>;

/// Pull Response
#[derive(Clone, Debug, Default, Eq, Hash, PartialEq)]
pub struct PullResponse {
/// Pull Continuation Flag
///
/// The `should_continue` flag is set to `true` if the client should request more data from the
/// ledger to finish the pull.
pub should_continue: bool,

/// Ledger Checkpoint
///
/// If the `should_continue` flag is set to `true` then `checkpoint` is the next
/// [`Checkpoint`](Connection::Checkpoint) to request data from the ledger. Otherwise, it
/// represents the current ledger state.
pub checkpoint: Checkpoint,

/// Ledger Receiver Chunk
pub receivers: ReceiverChunk,

/// Ledger Sender Chunk
pub senders: SenderChunk,
}

/// Preprocessed Event
enum PreprocessedEvent<T>
where
Expand Down Expand Up @@ -600,16 +686,8 @@ where
I: IntoIterator<Item = (Self::ValidUtxoAccumulatorOutput, Self::ValidVoidNumber)>,
{
let _ = super_key;
let index = VoidNumberSetSize::<T>::get();
let mut i = 0;
for (_, void_number) in iter {
let void_number = encode(&void_number.0);
VoidNumberSet::<T>::insert(void_number, ());
VoidNumberSetInsertionOrder::<T>::insert(index + i, void_number);
i += 1;
}
if i != 0 {
VoidNumberSetSize::<T>::set(index + i);
VoidNumberSet::<T>::insert(encode(&void_number.0), ());
}
}
}
Expand Down
13 changes: 7 additions & 6 deletions pallets/manta-pay/src/types.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,7 @@
use super::*;
use manta_util::into_array_unchecked;
use scale_codec::Error;

/// Encodes the SCALE encodable `value` into a byte array with the given length `N`.
#[inline]
Expand All @@ -31,11 +32,11 @@ where
/// Decodes the `bytes` array of the given length `N` into the SCALE decodable type `T` returning a
/// blanket error if decoding fails.
#[inline]
pub(crate) fn decode<T, const N: usize>(bytes: [u8; N]) -> Result<T, ()>
pub(crate) fn decode<T, const N: usize>(bytes: [u8; N]) -> Result<T, Error>
where
T: Decode,
{
T::decode(&mut bytes.as_slice()).map_err(|_| ())
T::decode(&mut bytes.as_slice())
}

/// Asset
Expand Down Expand Up @@ -101,7 +102,7 @@ impl From<config::EncryptedNote> for EncryptedNote {
}

impl TryFrom<EncryptedNote> for config::EncryptedNote {
type Error = ();
type Error = Error;

#[inline]
fn try_from(encrypted_note: EncryptedNote) -> Result<Self, Self::Error> {
Expand Down Expand Up @@ -133,7 +134,7 @@ impl From<config::SenderPost> for SenderPost {
}

impl TryFrom<SenderPost> for config::SenderPost {
type Error = ();
type Error = Error;

#[inline]
fn try_from(post: SenderPost) -> Result<Self, Self::Error> {
Expand Down Expand Up @@ -165,7 +166,7 @@ impl From<config::ReceiverPost> for ReceiverPost {
}

impl TryFrom<ReceiverPost> for config::ReceiverPost {
type Error = ();
type Error = Error;

#[inline]
fn try_from(post: ReceiverPost) -> Result<Self, Self::Error> {
Expand Down Expand Up @@ -213,7 +214,7 @@ impl From<config::TransferPost> for TransferPost {
}

impl TryFrom<TransferPost> for config::TransferPost {
type Error = ();
type Error = Error;

#[inline]
fn try_from(post: TransferPost) -> Result<Self, Self::Error> {
Expand Down

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