// Copyright 2017 The Grin Developers
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//! Top-level Pool type, methods, and tests
use types::{Pool, BlockChain, Orphans, Parent, PoolError, TxSource, TransactionGraphContainer};
pub use graph;
use core::core::transaction;
use core::core::block;
use core::core::hash;
use core::consensus;
use secp;
use secp::pedersen::Commitment;
use std::sync::Arc;
use std::collections::HashMap;
/// The pool itself.
/// The transactions HashMap holds ownership of all transactions in the pool,
/// keyed by their transaction hash.
pub struct TransactionPool<T> {
/// All transactions in the pool
pub transactions: HashMap<hash::Hash, Box<transaction::Transaction>>,
/// The pool itself
pub pool : Pool,
/// Orphans in the pool
pub orphans: Orphans,
// blockchain is a DummyChain, for now, which mimics what the future
// chain will offer to the pool
blockchain: Arc<T>,
}
impl<T> TransactionPool<T> where T: BlockChain {
/// Create a new transaction pool
pub fn new(chain: Arc<T>) -> TransactionPool<T> {
TransactionPool{
transactions: HashMap::new(),
pool: Pool::empty(),
orphans: Orphans::empty(),
blockchain: chain,
}
}
/// Searches for an output, designated by its commitment, from the current
/// best UTXO view, presented by taking the best blockchain UTXO set (as
/// determined by the blockchain component) and rectifying pool spent and
/// unspents.
/// Detects double spends and unknown references from the pool and
/// blockchain only; any conflicts with entries in the orphans set must
/// be accounted for separately, if relevant.
pub fn search_for_best_output(&self, output_commitment: &Commitment) -> Parent {
// The current best unspent set is:
// Pool unspent + (blockchain unspent - pool->blockchain spent)
// Pool unspents are unconditional so we check those first
self.pool.get_available_output(output_commitment).
map(|x| Parent::PoolTransaction{tx_ref: x.source_hash().unwrap()}).
or(self.search_blockchain_unspents(output_commitment)).
or(self.search_pool_spents(output_commitment)).
unwrap_or(Parent::Unknown)
}
// search_blockchain_unspents searches the current view of the blockchain
// unspent set, represented by blockchain unspents - pool spents, for an
// output designated by output_commitment.
fn search_blockchain_unspents(&self, output_commitment: &Commitment) -> Option<Parent> {
self.blockchain.get_unspent(output_commitment).
ok().
map(|output| match self.pool.get_blockchain_spent(output_commitment) {
Some(x) => Parent::AlreadySpent{other_tx: x.destination_hash().unwrap()},
None => Parent::BlockTransaction{output},
})
}
// search_pool_spents is the second half of pool input detection, after the
// available_outputs have been checked. This returns either a
// Parent::AlreadySpent or None.
fn search_pool_spents(&self, output_commitment: &Commitment) -> Option<Parent> {
self.pool.get_internal_spent(output_commitment).
map(|x| Parent::AlreadySpent{other_tx: x.destination_hash().unwrap()})
}
/// Get the number of transactions in the pool
pub fn pool_size(&self) -> usize {
self.pool.num_transactions()
}
/// Get the number of orphans in the pool
pub fn orphans_size(&self) -> usize {
self.orphans.num_transactions()
}
/// Get the total size (transactions + orphans) of the pool
pub fn total_size(&self) -> usize {
self.pool.num_transactions() + self.orphans.num_transactions()
}
/// Attempts to add a transaction to the pool.
///
/// Adds a transaction to the memory pool, deferring to the orphans pool
/// if necessary, and performing any connection-related validity checks.
/// Happens under an exclusive mutable reference gated by the write portion
/// of a RWLock.
pub fn add_to_memory_pool(&mut self, _: TxSource, tx: transaction::Transaction) -> Result<(), PoolError> {
// Making sure the transaction is valid before anything else.
let secp = secp::Secp256k1::with_caps(secp::ContextFlag::Commit);
tx.validate(&secp).map_err(|_| PoolError::Invalid)?;
// The first check involves ensuring that an identical transaction is
// not already in the pool's transaction set.
// A non-authoritative similar check should be performed under the
// pool's read lock before we get to this point, which would catch the
// majority of duplicate cases. The race condition is caught here.
// TODO: When the transaction identifier is finalized, the assumptions
// here may change depending on the exact coverage of the identifier.
// The current tx.hash() method, for example, does not cover changes
// to fees or other elements of the signature preimage.
let tx_hash = graph::transaction_identifier(&tx);
if self.transactions.contains_key(&tx_hash) {
return Err(PoolError::AlreadyInPool)
}
// The next issue is to identify all unspent outputs that
// this transaction will consume and make sure they exist in the set.
let mut pool_refs: Vec<graph::Edge> = Vec::new();
let mut orphan_refs: Vec<graph::Edge> = Vec::new();
let mut blockchain_refs: Vec<graph::Edge> = Vec::new();
for input in &tx.inputs {
let base = graph::Edge::new(None, Some(tx_hash), input.commitment());
// Note that search_for_best_output does not examine orphans, by
// design. If an incoming transaction consumes pool outputs already
// spent by the orphans set, this does not preclude its inclusion
// into the pool.
match self.search_for_best_output(&input.commitment()) {
Parent::PoolTransaction{tx_ref: x} => pool_refs.push(base.with_source(Some(x))),
Parent::BlockTransaction{output} => {
// TODO - pull this out into a separate function?
if output.features.contains(transaction::COINBASE_OUTPUT) {
if let Ok(out_header) = self.blockchain.get_block_header_by_output_commit(&output.commitment()) {
if let Ok(head_header) = self.blockchain.head_header() {
if head_header.height <= out_header.height + consensus::COINBASE_MATURITY {
return Err(PoolError::ImmatureCoinbase{
header: out_header,
output: output.commitment()
})
};
};
};
};
blockchain_refs.push(base);
},
Parent::Unknown => orphan_refs.push(base),
Parent::AlreadySpent{other_tx: x} => return Err(PoolError::DoubleSpend{other_tx: x, spent_output: input.commitment()}),
}
}
let is_orphan = orphan_refs.len() > 0;
// Next we examine the outputs this transaction creates and ensure
// that they do not already exist.
// I believe its worth preventing duplicate outputs from being
// accepted, even though it is possible for them to be mined
// with strict ordering. In the future, if desirable, this could
// be node policy config or more intelligent.
for output in &tx.outputs {
self.check_duplicate_outputs(output, is_orphan)?
}
// Assertion: we have exactly as many resolved spending references as
// inputs to the transaction.
assert_eq!(tx.inputs.len(),
blockchain_refs.len() + pool_refs.len() + orphan_refs.len());
// At this point we know if we're spending all known unspents and not
// creating any duplicate unspents.
let pool_entry = graph::PoolEntry::new(&tx);
let new_unspents = tx.outputs.iter().
map(|x| graph::Edge::new(Some(tx_hash), None, x.commitment())).
collect();
if !is_orphan {
// In the non-orphan (pool) case, we've ensured that every input
// maps one-to-one with an unspent (available) output, and each
// output is unique. No further checks are necessary.
self.pool.add_pool_transaction(pool_entry, blockchain_refs,
pool_refs, new_unspents);
self.reconcile_orphans().unwrap();
self.transactions.insert(tx_hash, Box::new(tx));
Ok(())
} else {
// At this point, we're pretty sure the transaction is an orphan,
// but we have to explicitly check for double spends against the
// orphans set; we do not check this as part of the connectivity
// checking above.
// First, any references resolved to the pool need to be compared
// against active orphan pool_connections.
// Note that pool_connections here also does double duty to
// account for blockchain connections.
for pool_ref in pool_refs.iter().chain(blockchain_refs.iter()) {
match self.orphans.get_external_spent_output(&pool_ref.output_commitment()){
// Should the below err be subtyped to orphans somehow?
Some(x) => return Err(PoolError::DoubleSpend{other_tx: x.destination_hash().unwrap(), spent_output: x.output_commitment()}),
None => {},
}
}
// Next, we have to consider the possibility of double spends
// within the orphans set.
// We also have to distinguish now between missing and internal
// references.
let missing_refs = self.resolve_orphan_refs(tx_hash, &mut orphan_refs)?;
// We have passed all failure modes.
pool_refs.append(&mut blockchain_refs);
self.orphans.add_orphan_transaction(pool_entry,
pool_refs, orphan_refs, missing_refs, new_unspents);
Err(PoolError::OrphanTransaction)
}
}
/// Check the output for a conflict with an existing output.
///
/// Checks the output (by commitment) against outputs in the blockchain
/// or in the pool. If the transaction is destined for orphans, the
/// orphans set is checked as well.
fn check_duplicate_outputs(&self, output : &transaction::Output, is_orphan: bool) -> Result<(), PoolError> {
// Checking against current blockchain unspent outputs
// We want outputs even if they're spent by pool txs, so we ignore
// consumed_blockchain_outputs
if self.blockchain.get_unspent(&output.commitment()).is_ok() {
return Err(PoolError::DuplicateOutput{
other_tx: None,
in_chain: true,
output: output.commitment()})
}
// Check for existence of this output in the pool
match self.pool.find_output(&output.commitment()) {
Some(x) => {
return Err(PoolError::DuplicateOutput{
other_tx: Some(x),
in_chain: false,
output: output.commitment()})
},
None => {},
};
// If the transaction might go into orphans, perform the same
// checks as above but against the orphan set instead.
if is_orphan {
// Checking against orphan outputs
match self.orphans.find_output(&output.commitment()){
Some(x) => {
return Err(PoolError::DuplicateOutput{
other_tx: Some(x),
in_chain: false,
output: output.commitment()})
},
None => {},
};
// No need to check pool connections since those are covered
// by pool unspents and blockchain connections.
}
Ok(())
}
/// Distinguish between missing, unspent, and spent orphan refs.
///
/// Takes the set of orphans_refs produced during transaction connectivity
/// validation, which do not point at valid unspents in the blockchain or
/// pool. These references point at either a missing (orphaned) commitment,
/// an unspent output of the orphans set, or a spent output either within
/// the orphans set or externally from orphans to the pool or blockchain.
/// The last case results in a failure condition and transaction acceptance
/// is aborted.
fn resolve_orphan_refs(&self, tx_hash: hash::Hash, orphan_refs: &mut Vec<graph::Edge>) -> Result<HashMap<usize, ()>, PoolError> {
let mut missing_refs: HashMap<usize, ()> = HashMap::new();
for (i, orphan_ref) in orphan_refs.iter_mut().enumerate() {
let orphan_commitment = &orphan_ref.output_commitment();
match self.orphans.get_available_output(&orphan_commitment) {
// If the edge is an available output of orphans,
// update the prepared edge
Some(x) => *orphan_ref = x.with_destination(Some(tx_hash)),
// If the edge is not an available output, it is either
// already consumed or it belongs in missing_refs.
None => {
match self.orphans.get_internal_spent(&orphan_commitment) {
Some(x) => return Err(PoolError::DoubleSpend{
other_tx: x.destination_hash().unwrap(),
spent_output: x.output_commitment()}),
None => {
// The reference does not resolve to anything.
// Make sure this missing_output has not already
// been claimed, then add this entry to
// missing_refs
match self.orphans.get_unknown_output(&orphan_commitment) {
Some(x) => return Err(PoolError::DoubleSpend{
other_tx: x.destination_hash().unwrap(),
spent_output: x.output_commitment()}),
None => missing_refs.insert(i, ()),
};
},
};
},
};
}
Ok(missing_refs)
}
/// The primary goal of the reconcile_orphans method is to eliminate any
/// orphans who conflict with the recently accepted pool transaction.
/// TODO: How do we handle fishing orphans out that look like they could
/// be freed? Current thought is to do so under a different lock domain
/// so that we don't have the potential for long recursion under the write
/// lock.
pub fn reconcile_orphans(&self)-> Result<(),PoolError> {
Ok(())
}
/// Updates the pool with the details of a new block.
///
/// Along with add_to_memory_pool, reconcile_block is the other major entry
/// point for the transaction pool. This method reconciles the records in
/// the transaction pool with the updated view presented by the incoming
/// block. This involves removing any transactions which appear to conflict
/// with inputs and outputs consumed in the block, and invalidating any
/// descendents or parents of the removed transaction, where relevant.
///
/// Returns a list of transactions which have been evicted from the pool
/// due to the recent block. Because transaction association information is
/// irreversibly lost in the blockchain, we must keep track of these
/// evicted transactions elsewhere so that we can make a best effort at
/// returning them to the pool in the event of a reorg that invalidates
/// this block.
pub fn reconcile_block(&mut self, block: &block::Block) -> Result<Vec<Box<transaction::Transaction>>, PoolError> {
// If this pool has been kept in sync correctly, serializing all
// updates, then the inputs must consume only members of the blockchain
// utxo set.
// If the block has been resolved properly and reduced fully to its
// canonical form, no inputs may consume outputs generated by previous
// transactions in the block; they would be cut-through. TODO: If this
// is not consensus enforced, then logic must be added here to account
// for that.
// Based on this, we operate under the following algorithm:
// For each block input, we examine the pool transaction, if any, that
// consumes the same blockchain output.
// If one exists, we mark the transaction and then examine its
// children. Recursively, we mark each child until a child is
// fully satisfied by outputs in the updated utxo view (after
// reconciliation of the block), or there are no more children.
//
// Additionally, to protect our invariant dictating no duplicate
// outputs, each output generated by the new utxo set is checked
// against outputs generated by the pool and the corresponding
// transactions are also marked.
//
// After marking concludes, sweeping begins. In order, the marked
// transactions are removed, the vertexes corresponding to the
// transactions are removed, all the marked transactions' outputs are
// removed, and all remaining non-blockchain inputs are returned to the
// unspent_outputs set.
//
// After the pool has been successfully processed, an orphans
// reconciliation job is triggered.
let mut marked_transactions: HashMap<hash::Hash, ()> = HashMap::new();
{
let mut conflicting_txs: Vec<hash::Hash> = block.inputs.iter().
filter_map(|x|
self.pool.get_external_spent_output(&x.commitment())).
map(|x| x.destination_hash().unwrap()).
collect();
let mut conflicting_outputs: Vec<hash::Hash> = block.outputs.iter().
filter_map(|x: &transaction::Output|
self.pool.get_internal_spent_output(&x.commitment()).
or(self.pool.get_available_output(&x.commitment()))).
map(|x| x.source_hash().unwrap()).
collect();
conflicting_txs.append(&mut conflicting_outputs);
for txh in conflicting_txs {
self.mark_transaction(txh, &mut marked_transactions);
}
}
let freed_txs = self.sweep_transactions(marked_transactions);
self.reconcile_orphans().unwrap();
Ok(freed_txs)
}
/// The mark portion of our mark-and-sweep pool cleanup.
///
/// The transaction designated by conflicting_tx is immediately marked.
/// Each output of this transaction is then examined; if a transaction in
/// the pool spends this output and the output is not replaced by an
/// identical output included in the updated UTXO set, the child is marked
/// as well and the process continues recursively.
///
/// Marked transactions are added to the mutable marked_txs HashMap which
/// is supplied by the calling function.
fn mark_transaction(&self, conflicting_tx: hash::Hash,
marked_txs: &mut HashMap<hash::Hash, ()>) {
marked_txs.insert(conflicting_tx, ());
let tx_ref = self.transactions.get(&conflicting_tx);
for output in &tx_ref.unwrap().outputs {
match self.pool.get_internal_spent_output(&output.commitment()) {
Some(x) => {
if self.blockchain.get_unspent(&x.output_commitment()).is_err() {
self.mark_transaction(x.destination_hash().unwrap(), marked_txs);
}
},
None => {},
};
}
}
/// The sweep portion of mark-and-sweep pool cleanup.
///
/// The transactions that exist in the hashmap are removed from the
/// heap storage as well as the vertex set. Any incoming edges are removed
/// and added to a list of freed edges. Any outbound edges are removed from
/// both the graph and the list of freed edges. It is the responsibility of
/// this method to ensure that the list of freed edges (inputs) are
/// consistent.
///
/// TODO: There's some iteration overlap between this and the mark step.
/// Additional bookkeeping in the mark step could optimize that away.
fn sweep_transactions(&mut self,
marked_transactions: HashMap<hash::Hash, ()>,)
->Vec<Box<transaction::Transaction>> {
let mut removed_txs = Vec::new();
for tx_hash in marked_transactions.keys() {
let removed_tx = self.transactions.remove(tx_hash).unwrap();
self.pool.remove_pool_transaction(&removed_tx,
&marked_transactions);
removed_txs.push(removed_tx);
}
removed_txs
}
/// Fetch mineable transactions.
///
/// Select a set of mineable transactions for block building.
pub fn prepare_mineable_transactions(&self, num_to_fetch: u32) -> Vec<Box<transaction::Transaction>>{
self.pool.get_mineable_transactions(num_to_fetch).iter().
map(|x| self.transactions.get(x).unwrap().clone()).collect()
}
}
#[cfg(test)]
mod tests {
use super::*;
use types::*;
use secp::{Secp256k1, ContextFlag, constants};
use secp::key;
use core::core::build;
use blockchain::{DummyChain, DummyChainImpl, DummyUtxoSet};
use std::sync::{Arc, RwLock};
macro_rules! expect_output_parent {
($pool:expr, $expected:pat, $( $output:expr ),+ ) => {
$(
match $pool.search_for_best_output(&test_output($output).commitment()) {
$expected => {},
x => panic!("Unexpected result from output search for {:?}, got {:?}", $output, x),
};
)*
}
}
#[test]
/// A basic test; add a pair of transactions to the pool.
fn test_basic_pool_add() {
let mut dummy_chain = DummyChainImpl::new();
let parent_transaction = test_transaction(vec![5,6,7], vec![11,4]);
// We want this transaction to be rooted in the blockchain.
let new_utxo = DummyUtxoSet::empty().
with_output(test_output(5)).
with_output(test_output(6)).
with_output(test_output(7)).
with_output(test_output(8));
// Prepare a second transaction, connected to the first.
let child_transaction = test_transaction(vec![11,4], vec![12]);
dummy_chain.update_utxo_set(new_utxo);
// To mirror how this construction is intended to be used, the pool
// is placed inside a RwLock.
let pool = RwLock::new(test_setup(&Arc::new(dummy_chain)));
// Take the write lock and add a pool entry
{
let mut write_pool = pool.write().unwrap();
assert_eq!(write_pool.total_size(), 0);
// First, add the transaction rooted in the blockchain
let result = write_pool.add_to_memory_pool(test_source(),
parent_transaction);
if result.is_err() {
panic!("got an error adding parent tx: {:?}",
result.err().unwrap());
}
// Now, add the transaction connected as a child to the first
let child_result = write_pool.add_to_memory_pool(test_source(),
child_transaction);
if child_result.is_err() {
panic!("got an error adding child tx: {:?}",
child_result.err().unwrap());
}
}
// Now take the read lock and use a few exposed methods to check
// consistency
{
let read_pool = pool.read().unwrap();
assert_eq!(read_pool.total_size(), 2);
expect_output_parent!(read_pool,
Parent::PoolTransaction{tx_ref: _}, 12);
expect_output_parent!(read_pool,
Parent::AlreadySpent{other_tx: _}, 11, 5);
expect_output_parent!(read_pool,
Parent::BlockTransaction{output: _}, 8);
expect_output_parent!(read_pool,
Parent::Unknown, 20);
}
}
#[test]
/// Testing various expected error conditions
pub fn test_pool_add_error() {
let mut dummy_chain = DummyChainImpl::new();
let new_utxo = DummyUtxoSet::empty().
with_output(test_output(5)).
with_output(test_output(6)).
with_output(test_output(7));
dummy_chain.update_utxo_set(new_utxo);
let pool = RwLock::new(test_setup(&Arc::new(dummy_chain)));
{
let mut write_pool = pool.write().unwrap();
assert_eq!(write_pool.total_size(), 0);
// First expected failure: duplicate output
let duplicate_tx = test_transaction(vec![5,6], vec![7]);
match write_pool.add_to_memory_pool(test_source(),
duplicate_tx) {
Ok(_) => panic!("Got OK from add_to_memory_pool when dup was expected"),
Err(x) =>{ match x {
PoolError::DuplicateOutput{other_tx, in_chain, output} => {
if other_tx.is_some() || !in_chain || output != test_output(7).commitment() {
panic!("Unexpected parameter in DuplicateOutput: {:?}", x);
}
},
_ => panic!("Unexpected error when adding duplicate output transaction: {:?}", x),
};},
};
// To test DoubleSpend and AlreadyInPool conditions, we need to add
// a valid transaction.
let valid_transaction = test_transaction(vec![5,6], vec![8]);
match write_pool.add_to_memory_pool(test_source(),
valid_transaction) {
Ok(_) => {},
Err(x) => panic!("Unexpected error while adding a valid transaction: {:?}", x),
};
// Now, test a DoubleSpend by consuming the same blockchain unspent
// as valid_transaction:
let double_spend_transaction = test_transaction(vec![6], vec![2]);
match write_pool.add_to_memory_pool(test_source(),
double_spend_transaction) {
Ok(_) => panic!("Expected error when adding double spend, got Ok"),
Err(x) => {
match x {
PoolError::DoubleSpend{other_tx: _, spent_output} => {
if spent_output != test_output(6).commitment() {
panic!("Unexpected parameter in DoubleSpend: {:?}", x);
}
},
_ => panic!("Unexpected error when adding double spend transaction: {:?}", x),
};
},
};
let already_in_pool = test_transaction(vec![5,6], vec![8]);
match write_pool.add_to_memory_pool(test_source(),
already_in_pool) {
Ok(_) => panic!("Expected error when adding already in pool, got Ok"),
Err(x) => {
match x {
PoolError::AlreadyInPool => {},
_ => panic!("Unexpected error when adding already in pool tx: {:?}",
x),
};
}
};
assert_eq!(write_pool.total_size(), 1);
}
}
#[test]
fn test_immature_coinbase() {
let mut dummy_chain = DummyChainImpl::new();
let coinbase_output = test_coinbase_output(15);
dummy_chain.update_utxo_set(DummyUtxoSet::empty().with_output(coinbase_output));
let chain_ref = Arc::new(dummy_chain);
let pool = RwLock::new(test_setup(&chain_ref));
{
let mut write_pool = pool.write().unwrap();
let coinbase_header = block::BlockHeader {height: 1, ..block::BlockHeader::default()};
chain_ref.store_header_by_output_commitment(coinbase_output.commitment(), &coinbase_header);
let head_header = block::BlockHeader {height: 2, ..block::BlockHeader::default()};
chain_ref.store_head_header(&head_header);
let txn = test_transaction(vec![15], vec![10, 4]);
let result = write_pool.add_to_memory_pool(test_source(), txn);
match result {
Err(PoolError::ImmatureCoinbase{header: _, output: out}) => {
assert_eq!(out, coinbase_output.commitment());
},
_ => panic!("expected ImmatureCoinbase error here"),
};
let head_header = block::BlockHeader {height: 4, ..block::BlockHeader::default()};
chain_ref.store_head_header(&head_header);
let txn = test_transaction(vec![15], vec![10, 4]);
let result = write_pool.add_to_memory_pool(test_source(), txn);
match result {
Err(PoolError::ImmatureCoinbase{header: _, output: out}) => {
assert_eq!(out, coinbase_output.commitment());
},
_ => panic!("expected ImmatureCoinbase error here"),
};
let head_header = block::BlockHeader {height: 5, ..block::BlockHeader::default()};
chain_ref.store_head_header(&head_header);
let txn = test_transaction(vec![15], vec![10, 4]);
let result = write_pool.add_to_memory_pool(test_source(), txn);
match result {
Ok(_) => {},
Err(_) => panic!("this should not return an error here"),
};
}
}
#[test]
/// Testing an expected orphan
fn test_add_orphan() {
// TODO we need a test here
}
#[test]
/// Testing block reconciliation
fn test_block_reconciliation() {
let mut dummy_chain = DummyChainImpl::new();
let new_utxo = DummyUtxoSet::empty().
with_output(test_output(10)).
with_output(test_output(20)).
with_output(test_output(30)).
with_output(test_output(40));
dummy_chain.update_utxo_set(new_utxo);
let chain_ref = Arc::new(dummy_chain);
let pool = RwLock::new(test_setup(&chain_ref));
// Preparation: We will introduce a three root pool transactions.
// 1. A transaction that should be invalidated because it is exactly
// contained in the block.
// 2. A transaction that should be invalidated because the input is
// consumed in the block, although it is not exactly consumed.
// 3. A transaction that should remain after block reconciliation.
let block_transaction = test_transaction(vec![10], vec![8]);
let conflict_transaction = test_transaction(vec![20], vec![12,7]);
let valid_transaction = test_transaction(vec![30], vec![14,15]);
// We will also introduce a few children:
// 4. A transaction that descends from transaction 1, that is in
// turn exactly contained in the block.
let block_child = test_transaction(vec![8], vec![4,3]);
// 5. A transaction that descends from transaction 4, that is not
// contained in the block at all and should be valid after
// reconciliation.
let pool_child = test_transaction(vec![4], vec![1]);
// 6. A transaction that descends from transaction 2 that does not
// conflict with anything in the block in any way, but should be
// invalidated (orphaned).
let conflict_child = test_transaction(vec![12], vec![11]);
// 7. A transaction that descends from transaction 2 that should be
// valid due to its inputs being satisfied by the block.
let conflict_valid_child = test_transaction(vec![7], vec![5]);
// 8. A transaction that descends from transaction 3 that should be
// invalidated due to an output conflict.
let valid_child_conflict = test_transaction(vec![14], vec![9]);
// 9. A transaction that descends from transaction 3 that should remain
// valid after reconciliation.
let valid_child_valid = test_transaction(vec![15], vec![13]);
// 10. A transaction that descends from both transaction 6 and
// transaction 9
let mixed_child = test_transaction(vec![11,13], vec![2]);
// Add transactions.
// Note: There are some ordering constraints that must be followed here
// until orphans is 100% implemented. Once the orphans process has
// stabilized, we can mix these up to exercise that path a bit.
let mut txs_to_add = vec![block_transaction, conflict_transaction,
valid_transaction, block_child, pool_child, conflict_child,
conflict_valid_child, valid_child_conflict, valid_child_valid,
mixed_child];
let expected_pool_size = txs_to_add.len();
// First we add the above transactions to the pool; all should be
// accepted.
{
let mut write_pool = pool.write().unwrap();
assert_eq!(write_pool.total_size(), 0);
for tx in txs_to_add.drain(..) {
assert!(write_pool.add_to_memory_pool(test_source(),
tx).is_ok());
}
assert_eq!(write_pool.total_size(), expected_pool_size);
}
// Now we prepare the block that will cause the above condition.
// First, the transactions we want in the block:
// - Copy of 1
let block_tx_1 = test_transaction(vec![10], vec![8]);
// - Conflict w/ 2, satisfies 7
let block_tx_2 = test_transaction(vec![20], vec![7]);
// - Copy of 4
let block_tx_3 = test_transaction(vec![8], vec![4,3]);
// - Output conflict w/ 8
let block_tx_4 = test_transaction(vec![40], vec![9]);
let block_transactions = vec![&block_tx_1, &block_tx_2, &block_tx_3,
&block_tx_4];
let block = block::Block::new(&block::BlockHeader::default(),
block_transactions, key::ONE_KEY).unwrap();
chain_ref.apply_block(&block);
// Block reconciliation
{
let mut write_pool = pool.write().unwrap();
let evicted_transactions = write_pool.reconcile_block(&block);
assert!(evicted_transactions.is_ok());
assert_eq!(evicted_transactions.unwrap().len(), 6);
// TODO: Txids are not yet deterministic. When they are, we should
// check the specific transactions that were evicted.
}
// Using the pool's methods to validate a few end conditions.
{
let read_pool = pool.read().unwrap();
assert_eq!(read_pool.total_size(), 4);
// We should have available blockchain outputs at 9 and 3
expect_output_parent!(read_pool, Parent::BlockTransaction{output: _}, 9, 3);
// We should have spent blockchain outputs at 4 and 7
expect_output_parent!(read_pool,
Parent::AlreadySpent{other_tx: _}, 4, 7);
// We should have spent pool references at 15
expect_output_parent!(read_pool,
Parent::AlreadySpent{other_tx: _}, 15);
// We should have unspent pool references at 1, 13, 14
expect_output_parent!(read_pool,
Parent::PoolTransaction{tx_ref: _}, 1, 13, 14);
// References internal to the block should be unknown
expect_output_parent!(read_pool, Parent::Unknown, 8);
// Evicted transactions should have unknown outputs
expect_output_parent!(read_pool, Parent::Unknown, 2, 11);
}
}
#[test]
/// Test transaction selection and block building.
fn test_block_building() {
// Add a handful of transactions
let mut dummy_chain = DummyChainImpl::new();
let new_utxo = DummyUtxoSet::empty().
with_output(test_output(10)).
with_output(test_output(20)).
with_output(test_output(30)).
with_output(test_output(40));
dummy_chain.update_utxo_set(new_utxo);
let chain_ref = Arc::new(dummy_chain);
let pool = RwLock::new(test_setup(&chain_ref));
let root_tx_1 = test_transaction(vec![10,20], vec![25]);
let root_tx_2 = test_transaction(vec![30], vec![28]);
let root_tx_3 = test_transaction(vec![40], vec![38]);
let child_tx_1 = test_transaction(vec![25],vec![23]);
let child_tx_2 = test_transaction(vec![38],vec![32]);
{
let mut write_pool = pool.write().unwrap();
assert_eq!(write_pool.total_size(), 0);
assert!(write_pool.add_to_memory_pool(test_source(),
root_tx_1).is_ok());
assert!(write_pool.add_to_memory_pool(test_source(),
root_tx_2).is_ok());
assert!(write_pool.add_to_memory_pool(test_source(),
root_tx_3).is_ok());
assert!(write_pool.add_to_memory_pool(test_source(),
child_tx_1).is_ok());
assert!(write_pool.add_to_memory_pool(test_source(),
child_tx_2).is_ok());
assert_eq!(write_pool.total_size(), 5);
}
// Request blocks
let block: block::Block;
let mut txs: Vec<Box<transaction::Transaction>>;
{
let read_pool = pool.read().unwrap();
txs = read_pool.prepare_mineable_transactions(3);
assert_eq!(txs.len(), 3);
// TODO: This is ugly, either make block::new take owned
// txs instead of mut refs, or change
// prepare_mineable_transactions to return mut refs
let block_txs: Vec<transaction::Transaction> = txs.drain(..).map(|x| *x).collect();
let tx_refs = block_txs.iter().collect();
block = block::Block::new(&block::BlockHeader::default(),
tx_refs, key::ONE_KEY).unwrap();
}
chain_ref.apply_block(&block);
// Reconcile block
{
let mut write_pool = pool.write().unwrap();
let evicted_transactions = write_pool.reconcile_block(&block);
assert!(evicted_transactions.is_ok());
assert_eq!(evicted_transactions.unwrap().len(), 3);
assert_eq!(write_pool.total_size(), 2);
}
}
fn test_setup(dummy_chain: &Arc<DummyChainImpl>) -> TransactionPool<DummyChainImpl> {
TransactionPool{
transactions: HashMap::new(),
pool: Pool::empty(),
orphans: Orphans::empty(),
blockchain: dummy_chain.clone(),
}
}
/// Cobble together a test transaction for testing the transaction pool.
///
/// Connectivity here is the most important element.
/// Every output is given a blinding key equal to its value, so that the
/// entire commitment can be derived deterministically from just the value.
///
/// Fees are the remainder between input and output values, so the numbers
/// should make sense.
fn test_transaction(input_values: Vec<u64>, output_values: Vec<u64>) -> transaction::Transaction {
let fees: i64 = input_values.iter().sum::<u64>() as i64 - output_values.iter().sum::<u64>() as i64;
assert!(fees >= 0);
let mut tx_elements = Vec::new();
for input_value in input_values {
tx_elements.push(build::input(input_value, test_key(input_value)));
}
for output_value in output_values {
tx_elements.push(build::output(output_value, test_key(output_value)));
}
tx_elements.push(build::with_fee(fees as u64));
let (tx, _) = build::transaction(tx_elements).unwrap();
tx
}
/// Deterministically generate an output defined by our test scheme
fn test_output(value: u64) -> transaction::Output {
let ec = Secp256k1::with_caps(ContextFlag::Commit);
let output_key = test_key(value);
let output_commitment = ec.commit(value, output_key).unwrap();
transaction::Output{
features: transaction::DEFAULT_OUTPUT,
commit: output_commitment,
proof: ec.range_proof(0, value, output_key, output_commitment, ec.nonce())}
}
/// Deterministically generate a coinbase output defined by our test scheme
fn test_coinbase_output(value: u64) -> transaction::Output {
let ec = Secp256k1::with_caps(ContextFlag::Commit);
let output_key = test_key(value);
let output_commitment = ec.commit(value, output_key).unwrap();
transaction::Output{
features: transaction::COINBASE_OUTPUT,
commit: output_commitment,
proof: ec.range_proof(0, value, output_key, output_commitment, ec.nonce())}
}
/// Makes a SecretKey from a single u64
fn test_key(value: u64) -> key::SecretKey {
let ec = Secp256k1::with_caps(ContextFlag::Commit);
// SecretKey takes a SECRET_KEY_SIZE slice of u8.
assert!(constants::SECRET_KEY_SIZE > 8);
// (SECRET_KEY_SIZE - 8) zeros, followed by value as a big-endian byte
// sequence
let mut key_slice = vec![0;constants::SECRET_KEY_SIZE - 8];
key_slice.push((value >> 56) as u8);
key_slice.push((value >> 48) as u8);
key_slice.push((value >> 40) as u8);
key_slice.push((value >> 32) as u8);
key_slice.push((value >> 24) as u8);
key_slice.push((value >> 16) as u8);
key_slice.push((value >> 8) as u8);
key_slice.push(value as u8);
key::SecretKey::from_slice(&ec, &key_slice).unwrap()
}
/// A generic TxSource representing a test
fn test_source() -> TxSource{
TxSource{
debug_name: "test".to_string(),
identifier: "127.0.0.1".to_string(),
}
}
}