zec
/
librustzcash
mirror of https://github.com/zcash/librustzcash.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

Do not require wallet database for chain scan.

This commit is contained in:
Kris Nuttycombe 2020-10-19 15:16:06 -06:00
parent e6de7c07f0
commit b2cc240454
3 changed files with 43 additions and 35 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
zcash_client_backend/src/data_api.rs
View File

@ -53,6 +53,16 @@ pub trait DBOps {
fn get_block_hash(&self, block_height: BlockHeight) -> Result<Option<BlockHash>, Self::Error>;
fn get_max_height_hash(&self) -> Result<Option<(BlockHeight, BlockHash)>, Self::Error> {
self.block_height_extrema().and_then(|extrema_opt| {
extrema_opt.map(|(_, max_height)| {
self.get_block_hash(max_height).map(|hash_opt|
hash_opt.map(move |hash| (max_height, hash))
)
}).transpose()
}).map(|oo| oo.flatten())
}
fn get_tx_height(&self, txid: TxId) -> Result<Option<BlockHeight>, Self::Error>;
fn get_address<P: consensus::Parameters>(

46
zcash_client_backend/src/data_api/chain.rs
View File

@ -24,6 +24,12 @@ use crate::{
/// This follows from the design (and trust) assumption that the `lightwalletd` server
/// provides accurate block information as of the time it was requested.
///
/// Arguments:
/// - `parameters` Network parameters
/// - `cache` Source of compact blocks
/// - `from_tip` Height & hash of last validated block; if no validation has previously
/// been performed, this will begin scanning from `sapling_activation_height - 1`
///
/// Returns:
/// - `Ok(())` if the combined chain is valid.
/// - `Err(ErrorKind::InvalidChain(upper_bound, cause))` if the combined chain is invalid.
@ -32,30 +38,26 @@ use crate::{
/// - `Err(e)` if there was an error during validation unrelated to chain validity.
///
/// This function does not mutate either of the databases.
pub fn validate_combined_chain<'db, E0, N, E, P, C, D>(
pub fn validate_combined_chain<'db, E0, N, E, P, C>(
parameters: &P,
cache: &C,
data: &'db D,
validate_from: Option<(BlockHeight, BlockHash)>
) -> Result<(), E>
where
E: From<Error<E0, N>>,
P: consensus::Parameters,
C: CacheOps<Error = E>,
&'db D: DBOps<Error = E>,
{
let sapling_activation_height = parameters
.activation_height(NetworkUpgrade::Sapling)
.ok_or(Error::SaplingNotActive)?;
// Recall where we synced up to previously.
// If we have never synced, use Sapling activation height to select all cached CompactBlocks.
let data_max_height = data.block_height_extrema()?.map(|(_, max)| max);
// The cache will contain blocks above the maximum height of data in the database;
// validate from that maximum height up to the chain tip, returning the
// hash of the block at data_max_height
let from_height = data_max_height.unwrap_or(sapling_activation_height - 1);
let cached_hash_opt = cache.validate_chain(from_height, |top_block, next_block| {
// The cache will contain blocks above the `validate_from` height. Validate from that maximum
// height up to the chain tip, returning the hash of the block found in the cache at the
// `validate_from` height, which can then be used to verify chain integrity by comparing
// against the `validate_from` hash.
let from_height = validate_from.map(|(height, _)| height).unwrap_or(sapling_activation_height - 1);
let scan_start_hash = cache.validate_chain(from_height, |top_block, next_block| {
if next_block.height() != top_block.height() - 1 {
Err(
ChainInvalid::block_height_mismatch(top_block.height() - 1, next_block.height())
@ -68,20 +70,14 @@ where
}
})?;
match (cached_hash_opt, data_max_height) {
(Some(cached_hash), Some(h)) => match data.get_block_hash(h)? {
Some(data_scan_max_hash) => {
if cached_hash == data_scan_max_hash {
Ok(())
} else {
Err(ChainInvalid::prev_hash_mismatch(h).into())
}
match (scan_start_hash, validate_from) {
(Some(scan_start_hash), Some((validate_from_height, validate_from_hash))) => {
if scan_start_hash == validate_from_hash {
Ok(())
} else {
Err(ChainInvalid::prev_hash_mismatch(validate_from_height).into())
}
None => Err(Error::CorruptedData(
"No block hash available for block at maximum chain height.",
)
.into()),
},
}
_ => {
// No cached blocks are present, or the max data height is absent, this is fine.
Ok(())

22
zcash_client_sqlite/src/chain.rs
View File

@ -10,6 +10,7 @@
//!
//! use zcash_client_backend::{
//! data_api::{
//! DBOps,
//! chain::{
//! validate_combined_chain,
//! scan_cached_blocks,
@ -36,7 +37,7 @@
//! //
//! // Given that we assume the server always gives us correct-at-the-time blocks, any
//! // errors are in the blocks we have previously cached or scanned.
//! if let Err(e) = validate_combined_chain(&network, &db_cache, &db_data) {
//! if let Err(e) = validate_combined_chain(&network, &db_cache, (&db_data).get_max_height_hash().unwrap()) {
//! match e.0 {
//! Error::InvalidChain(upper_bound, _) => {
//! // a) Pick a height to rewind to.
@ -192,6 +193,7 @@ mod tests {
zip32::{ExtendedFullViewingKey, ExtendedSpendingKey},
};
use zcash_client_backend::data_api::DBOps;
use zcash_client_backend::data_api::{
chain::{scan_cached_blocks, validate_combined_chain},
error::{ChainInvalid, Error},
@ -227,7 +229,7 @@ mod tests {
init_accounts_table(&db_data, &tests::network(), &[extfvk.clone()]).unwrap();
// Empty chain should be valid
validate_combined_chain(&tests::network(), &db_cache, &db_data).unwrap();
validate_combined_chain(&tests::network(), &db_cache, (&db_data).get_max_height_hash().unwrap()).unwrap();
// Create a fake CompactBlock sending value to the address
let (cb, _) = fake_compact_block(
@ -239,13 +241,13 @@ mod tests {
insert_into_cache(&db_cache, &cb);
// Cache-only chain should be valid
validate_combined_chain(&tests::network(), &db_cache, &db_data).unwrap();
validate_combined_chain(&tests::network(), &db_cache, (&db_data).get_max_height_hash().unwrap()).unwrap();
// Scan the cache
scan_cached_blocks(&tests::network(), &db_cache, &db_data, None).unwrap();
// Data-only chain should be valid
validate_combined_chain(&tests::network(), &db_cache, &db_data).unwrap();
validate_combined_chain(&tests::network(), &db_cache, (&db_data).get_max_height_hash().unwrap()).unwrap();
// Create a second fake CompactBlock sending more value to the address
let (cb2, _) = fake_compact_block(
@ -257,13 +259,13 @@ mod tests {
insert_into_cache(&db_cache, &cb2);
// Data+cache chain should be valid
validate_combined_chain(&tests::network(), &db_cache, &db_data).unwrap();
validate_combined_chain(&tests::network(), &db_cache, (&db_data).get_max_height_hash().unwrap()).unwrap();
// Scan the cache again
scan_cached_blocks(&tests::network(), &db_cache, &db_data, None).unwrap();
// Data-only chain should be valid
validate_combined_chain(&tests::network(), &db_cache, &db_data).unwrap();
validate_combined_chain(&tests::network(), &db_cache, (&db_data).get_max_height_hash().unwrap()).unwrap();
}
#[test]
@ -301,7 +303,7 @@ mod tests {
scan_cached_blocks(&tests::network(), &db_cache, &db_data, None).unwrap();
// Data-only chain should be valid
validate_combined_chain(&tests::network(), &db_cache, &db_data).unwrap();
validate_combined_chain(&tests::network(), &db_cache, (&db_data).get_max_height_hash().unwrap()).unwrap();
// Create more fake CompactBlocks that don't connect to the scanned ones
let (cb3, _) = fake_compact_block(
@ -320,7 +322,7 @@ mod tests {
insert_into_cache(&db_cache, &cb4);
// Data+cache chain should be invalid at the data/cache boundary
match validate_combined_chain(&tests::network(), &db_cache, &db_data).map_err(|e| e.0) {
match validate_combined_chain(&tests::network(), &db_cache, (&db_data).get_max_height_hash().unwrap()).map_err(|e| e.0) {
Err(Error::InvalidChain(upper_bound, _)) => {
assert_eq!(upper_bound, sapling_activation_height() + 1)
}
@ -363,7 +365,7 @@ mod tests {
scan_cached_blocks(&tests::network(), &db_cache, &db_data, None).unwrap();
// Data-only chain should be valid
validate_combined_chain(&tests::network(), &db_cache, &db_data).unwrap();
validate_combined_chain(&tests::network(), &db_cache, (&db_data).get_max_height_hash().unwrap()).unwrap();
// Create more fake CompactBlocks that contain a reorg
let (cb3, _) = fake_compact_block(
@ -382,7 +384,7 @@ mod tests {
insert_into_cache(&db_cache, &cb4);
// Data+cache chain should be invalid inside the cache
match validate_combined_chain(&tests::network(), &db_cache, &db_data).map_err(|e| e.0) {
match validate_combined_chain(&tests::network(), &db_cache, (&db_data).get_max_height_hash().unwrap()).map_err(|e| e.0) {
Err(Error::InvalidChain(upper_bound, _)) => {
assert_eq!(upper_bound, sapling_activation_height() + 2)
}