Add multi block scanning
This commit is contained in:
Aditya Kulkarni
530
rust-lightclient/src/lightclient.rs
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530
rust-lightclient/src/lightclient.rs
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@@ -0,0 +1,530 @@
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use std::time::SystemTime;
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use pairing::bls12_381::Bls12;
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use sapling_crypto::primitives::{Diversifier, Note, PaymentAddress};
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use std::cmp;
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use std::collections::HashMap;
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use std::sync::{Arc, RwLock};
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use protobuf::*;
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use zcash_client_backend::{
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constants::testnet::HRP_SAPLING_PAYMENT_ADDRESS, encoding::encode_payment_address,
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proto::compact_formats::CompactBlock, welding_rig::scan_block,
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};
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use zcash_primitives::{
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block::BlockHash,
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merkle_tree::{CommitmentTree, IncrementalWitness},
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sapling::Node,
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transaction::{
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builder::{Builder, DEFAULT_FEE},
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components::Amount,
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TxId,
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},
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zip32::{ExtendedFullViewingKey, ExtendedSpendingKey},
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JUBJUB,
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};
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use crate::address;
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use crate::prover;
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// When the `wee_alloc` feature is enabled, use `wee_alloc` as the global
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// allocator.
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#[cfg(feature = "wee_alloc")]
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#[global_allocator]
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static ALLOC: wee_alloc::WeeAlloc = wee_alloc::WeeAlloc::INIT;
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const ANCHOR_OFFSET: u32 = 10;
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const SAPLING_ACTIVATION_HEIGHT: i32 = 280_000;
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fn now() -> f64 {
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// web_sys::window()
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// .expect("should have a Window")
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// .performance()
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// .expect("should have a Performance")
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// .now()
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SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs() as f64
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}
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struct BlockData {
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height: i32,
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hash: BlockHash,
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tree: CommitmentTree<Node>,
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}
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struct SaplingNoteData {
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account: usize,
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diversifier: Diversifier,
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note: Note<Bls12>,
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witnesses: Vec<IncrementalWitness<Node>>,
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nullifier: [u8; 32],
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spent: Option<TxId>,
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}
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impl SaplingNoteData {
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fn new(
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extfvk: &ExtendedFullViewingKey,
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output: zcash_client_backend::wallet::WalletShieldedOutput,
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witness: IncrementalWitness<Node>,
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) -> Self {
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let nf = {
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let mut nf = [0; 32];
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nf.copy_from_slice(
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&output
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.note
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.nf(&extfvk.fvk.vk, witness.position() as u64, &JUBJUB),
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);
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nf
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};
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SaplingNoteData {
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account: output.account,
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diversifier: output.to.diversifier,
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note: output.note,
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witnesses: vec![witness],
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nullifier: nf,
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spent: None,
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}
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}
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}
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struct WalletTx {
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block: i32,
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notes: Vec<SaplingNoteData>,
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}
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struct SpendableNote {
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txid: TxId,
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nullifier: [u8; 32],
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diversifier: Diversifier,
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note: Note<Bls12>,
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witness: IncrementalWitness<Node>,
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}
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impl SpendableNote {
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fn from(txid: TxId, nd: &SaplingNoteData, anchor_offset: usize) -> Option<Self> {
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if nd.spent.is_none() {
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let witness = nd.witnesses.get(nd.witnesses.len() - anchor_offset - 1);
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witness.map(|w| SpendableNote {
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txid,
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nullifier: nd.nullifier,
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diversifier: nd.diversifier,
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note: nd.note.clone(),
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witness: w.clone(),
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})
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} else {
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None
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}
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}
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}
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pub struct Client {
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extsks: [ExtendedSpendingKey; 1],
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extfvks: [ExtendedFullViewingKey; 1],
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address: PaymentAddress<Bls12>,
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blocks: Arc<RwLock<Vec<BlockData>>>,
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txs: Arc<RwLock<HashMap<TxId, WalletTx>>>,
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}
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/// Public methods, exported to JavaScript.
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impl Client {
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pub fn new() -> Self {
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let extsk = ExtendedSpendingKey::master(&[0; 32]);
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let extfvk = ExtendedFullViewingKey::from(&extsk);
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let address = extfvk.default_address().unwrap().1;
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Client {
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extsks: [extsk],
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extfvks: [extfvk],
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address,
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blocks: Arc::new(RwLock::new(vec![])),
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txs: Arc::new(RwLock::new(HashMap::new())),
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}
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}
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pub fn set_initial_block(&self, height: i32, hash: &str, sapling_tree: &str) -> bool {
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let mut blocks = self.blocks.write().unwrap();
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if !blocks.is_empty() {
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return false;
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}
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let hash = match hex::decode(hash) {
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Ok(hash) => BlockHash::from_slice(&hash),
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Err(e) => {
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eprintln!("{}", e);
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return false;
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}
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};
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let sapling_tree = match hex::decode(sapling_tree) {
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Ok(tree) => tree,
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Err(e) => {
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eprintln!("{}", e);
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return false;
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}
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};
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if let Ok(tree) = CommitmentTree::read(&sapling_tree[..]) {
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blocks.push(BlockData { height, hash, tree });
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true
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} else {
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false
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}
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}
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pub fn last_scanned_height(&self) -> i32 {
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self.blocks
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.read()
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.unwrap()
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.last()
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.map(|block| block.height)
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.unwrap_or(SAPLING_ACTIVATION_HEIGHT - 1)
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}
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/// Determines the target height for a transaction, and the offset from which to
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/// select anchors, based on the current synchronised block chain.
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fn get_target_height_and_anchor_offset(&self) -> Option<(u32, usize)> {
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match {
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let blocks = self.blocks.read().unwrap();
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(
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blocks.first().map(|block| block.height as u32),
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blocks.last().map(|block| block.height as u32),
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)
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} {
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(Some(min_height), Some(max_height)) => {
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let target_height = max_height + 1;
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// Select an anchor ANCHOR_OFFSET back from the target block,
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// unless that would be before the earliest block we have.
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let anchor_height =
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cmp::max(target_height.saturating_sub(ANCHOR_OFFSET), min_height);
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Some((target_height, (target_height - anchor_height) as usize))
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}
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_ => None,
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}
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}
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pub fn address(&self) -> String {
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encode_payment_address(HRP_SAPLING_PAYMENT_ADDRESS, &self.address)
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}
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// TODO: This will be inaccurate if the balance exceeds a u32, but u64 -> JavaScript
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// requires BigUint64Array which has limited support across browsers, and is not
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// implemented in the LTS version of Node.js. For now, let's assume that no one is
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// going to use a web wallet with more than ~21 TAZ.
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pub fn balance(&self) -> u32 {
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self.txs
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.read()
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.unwrap()
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.values()
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.map(|tx| {
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tx.notes
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.iter()
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.map(|nd| if nd.spent.is_none() { nd.note.value } else { 0 })
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.sum::<u64>()
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})
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.sum::<u64>() as u32
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}
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// TODO: This will be inaccurate if the balance exceeds a u32, but u64 -> JavaScript
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// requires BigUint64Array which has limited support across browsers, and is not
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// implemented in the LTS version of Node.js. For now, let's assume that no one is
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// going to use a web wallet with more than ~21 TAZ.
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pub fn verified_balance(&self) -> u32 {
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let anchor_height = match self.get_target_height_and_anchor_offset() {
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Some((height, anchor_offset)) => height - anchor_offset as u32,
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None => return 0,
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};
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self.txs
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.read()
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.unwrap()
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.values()
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.map(|tx| {
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if tx.block as u32 <= anchor_height {
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tx.notes
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.iter()
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.map(|nd| if nd.spent.is_none() { nd.note.value } else { 0 })
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.sum::<u64>()
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} else {
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0
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}
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})
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.sum::<u64>() as u32
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}
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pub fn scan_block(&self, block: &[u8]) -> bool {
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let block: CompactBlock = match parse_from_bytes(block) {
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Ok(block) => block,
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Err(e) => {
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eprintln!("Could not parse CompactBlock from bytes: {}", e);
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return false;
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}
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};
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// Scanned blocks MUST be height-sequential.
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let height = block.get_height() as i32;
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if height == self.last_scanned_height() {
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// If the last scanned block is rescanned, check it still matches.
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if let Some(hash) = self.blocks.read().unwrap().last().map(|block| block.hash) {
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if block.hash() != hash {
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eprintln!("Block hash does not match");
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return false;
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}
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}
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return true;
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} else if height != (self.last_scanned_height() + 1) {
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eprintln!(
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"Block is not height-sequential (expected {}, found {})",
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self.last_scanned_height() + 1,
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height
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);
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return false;
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}
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// Get the most recent scanned data.
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let mut block_data = BlockData {
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height,
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hash: block.hash(),
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tree: self
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.blocks
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.read()
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.unwrap()
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.last()
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.map(|block| block.tree.clone())
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.unwrap_or(CommitmentTree::new()),
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};
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let mut txs = self.txs.write().unwrap();
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// Create a Vec containing all unspent nullifiers.
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let nfs: Vec<_> = txs
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.iter()
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.map(|(txid, tx)| {
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let txid = *txid;
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tx.notes.iter().filter_map(move |nd| {
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if nd.spent.is_none() {
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Some((nd.nullifier, nd.account, txid))
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} else {
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None
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}
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})
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})
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.flatten()
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.collect();
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// Prepare the note witnesses for updating
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for tx in txs.values_mut() {
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for nd in tx.notes.iter_mut() {
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// Duplicate the most recent witness
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if let Some(witness) = nd.witnesses.last() {
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nd.witnesses.push(witness.clone());
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}
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// Trim the oldest witnesses
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nd.witnesses = nd
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.witnesses
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.split_off(nd.witnesses.len().saturating_sub(100));
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}
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}
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let new_txs = {
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let nf_refs: Vec<_> = nfs.iter().map(|(nf, acc, _)| (&nf[..], *acc)).collect();
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// Create a single mutable slice of all the newly-added witnesses.
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let mut witness_refs: Vec<_> = txs
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.values_mut()
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.map(|tx| tx.notes.iter_mut().filter_map(|nd| nd.witnesses.last_mut()))
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.flatten()
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.collect();
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scan_block(
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block,
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&self.extfvks,
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&nf_refs[..],
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&mut block_data.tree,
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&mut witness_refs[..],
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)
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};
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for (tx, new_witnesses) in new_txs {
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// Mark notes as spent.
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for spend in &tx.shielded_spends {
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let txid = nfs
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.iter()
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.find(|(nf, _, _)| &nf[..] == &spend.nf[..])
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.unwrap()
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.2;
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let mut spent_note = txs
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.get_mut(&txid)
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.unwrap()
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.notes
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.iter_mut()
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.find(|nd| &nd.nullifier[..] == &spend.nf[..])
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.unwrap();
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spent_note.spent = Some(tx.txid);
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}
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// Find the existing transaction entry, or create a new one.
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if !txs.contains_key(&tx.txid) {
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let tx_entry = WalletTx {
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block: block_data.height,
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notes: vec![],
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};
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txs.insert(tx.txid, tx_entry);
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}
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let tx_entry = txs.get_mut(&tx.txid).unwrap();
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// Save notes.
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for (output, witness) in tx
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.shielded_outputs
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.into_iter()
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.zip(new_witnesses.into_iter())
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{
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tx_entry.notes.push(SaplingNoteData::new(
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&self.extfvks[output.account],
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output,
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witness,
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));
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}
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}
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// Store scanned data for this block.
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self.blocks.write().unwrap().push(block_data);
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true
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}
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pub fn send_to_address(
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&self,
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consensus_branch_id: u32,
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spend_params: &[u8],
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output_params: &[u8],
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to: &str,
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value: u32,
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) -> Option<Box<[u8]>> {
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let start_time = now();
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println!(
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"0: Creating transaction sending {} tazoshis to {}",
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value,
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to
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);
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let extsk = &self.extsks[0];
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let extfvk = &self.extfvks[0];
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let ovk = extfvk.fvk.ovk;
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let to = match address::RecipientAddress::from_str(to) {
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Some(to) => to,
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None => {
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eprintln!("Invalid recipient address");
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return None;
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}
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};
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let value = Amount(value as i64);
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// Target the next block, assuming we are up-to-date.
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let (height, anchor_offset) = match self.get_target_height_and_anchor_offset() {
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Some(res) => res,
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None => {
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eprintln!("Cannot send funds before scanning any blocks");
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return None;
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}
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};
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// Select notes to cover the target value
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println!("{}: Selecting notes", now() - start_time);
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let target_value = value.0 + DEFAULT_FEE.0;
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let notes: Vec<_> = self
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.txs
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.read()
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.unwrap()
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.iter()
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.map(|(txid, tx)| tx.notes.iter().map(move |note| (*txid, note)))
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.flatten()
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.filter_map(|(txid, note)| SpendableNote::from(txid, note, anchor_offset))
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.scan(0, |running_total, spendable| {
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let value = spendable.note.value;
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let ret = if *running_total < target_value as u64 {
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Some(spendable)
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} else {
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None
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};
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*running_total = *running_total + value;
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ret
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})
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.collect();
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// Confirm we were able to select sufficient value
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let selected_value = notes
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.iter()
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.map(|selected| selected.note.value)
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.sum::<u64>();
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if selected_value < target_value as u64 {
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eprintln!(
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"Insufficient funds (have {}, need {})",
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selected_value, target_value
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);
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return None;
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}
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// Create the transaction
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println!("{}: Adding {} inputs", now() - start_time, notes.len());
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let mut builder = Builder::new(height);
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for selected in notes.iter() {
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if let Err(e) = builder.add_sapling_spend(
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extsk.clone(),
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selected.diversifier,
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selected.note.clone(),
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selected.witness.clone(),
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) {
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eprintln!("Error adding note: {:?}", e);
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return None;
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}
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}
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println!("{}: Adding output", now() - start_time);
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if let Err(e) = match to {
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address::RecipientAddress::Shielded(to) => {
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builder.add_sapling_output(ovk, to.clone(), value, None)
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}
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address::RecipientAddress::Transparent(to) => {
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builder.add_transparent_output(&to, value)
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}
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} {
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eprintln!("Error adding output: {:?}", e);
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return None;
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}
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println!("{}: Building transaction", now() - start_time);
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let (tx, _) = match builder.build(
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consensus_branch_id,
|
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prover::InMemTxProver::new(spend_params, output_params),
|
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) {
|
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Ok(res) => res,
|
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Err(e) => {
|
||||
eprintln!("Error creating transaction: {:?}", e);
|
||||
return None;
|
||||
}
|
||||
};
|
||||
println!("{}: Transaction created", now() - start_time);
|
||||
println!("Transaction ID: {}", tx.txid());
|
||||
|
||||
// Mark notes as spent.
|
||||
let mut txs = self.txs.write().unwrap();
|
||||
for selected in notes {
|
||||
let mut spent_note = txs
|
||||
.get_mut(&selected.txid)
|
||||
.unwrap()
|
||||
.notes
|
||||
.iter_mut()
|
||||
.find(|nd| &nd.nullifier[..] == &selected.nullifier[..])
|
||||
.unwrap();
|
||||
spent_note.spent = Some(tx.txid());
|
||||
}
|
||||
|
||||
// Return the encoded transaction, so the caller can send it.
|
||||
let mut raw_tx = vec![];
|
||||
tx.write(&mut raw_tx).unwrap();
|
||||
Some(raw_tx.into_boxed_slice())
|
||||
}
|
||||
}
|
||||
Reference in New Issue
Block a user