def backup_blocks(self, raw_blocks):
"""Backup the raw blocks and flush.
The blocks should be in order of decreasing height, starting at.
self.height. A flush is performed once the blocks are backed up.
"""
self.db.assert_flushed(self.flush_data())
assert self.height >= len(raw_blocks)
coin = self.coin
for raw_block in raw_blocks:
# Check and update self.tip
block = coin.block(raw_block, self.height)
header_hash = coin.header_hash(block.header)
if header_hash != self.tip:
raise ChainError(
'backup block {} not tip {} at height {:,d}'.format(
hash_to_hex_str(header_hash),
hash_to_hex_str(self.tip), self.height))
self.tip = coin.header_prevhash(block.header)
self.backup_txs(block.transactions)
self.height -= 1
self.db.tx_counts.pop()
self.logger.info(f'backed up to height {self.height:,d}')
def spend_utxo(self, tx_hash, tx_idx):
"""Spend a UTXO and return the 33-byte value.
If the UTXO is not in the cache it must be on disk. We store
all UTXOs so not finding one indicates a logic error or DB
corruption.
"""
# Fast track is it being in the cache
idx_packed = pack('<H', tx_idx)
cache_value = self.utxo_cache.pop(tx_hash + idx_packed, None)
if cache_value:
return cache_value
# Spend it from the DB.
# Key: b'h' + compressed_tx_hash + tx_idx + tx_num
# Value: hashX
prefix = b'h' + tx_hash[:4] + idx_packed
candidates = {
db_key: hashX
for db_key, hashX in self.db.utxo_db.iterator(prefix=prefix)
}
for hdb_key, hashX in candidates.items():
tx_num_packed = hdb_key[-4:]
if len(candidates) > 1:
tx_num, = unpack('<I', tx_num_packed)
try:
hash, height = self.db.fs_tx_hash(tx_num)
except IndexError:
self.logger.error(
"data integrity error for hashx history: %s missing tx #%s (%s:%s)",
hashX.hex(), tx_num, hash_to_hex_str(tx_hash), tx_idx)
continue
if hash != tx_hash:
assert hash is not None # Should always be found
continue
# Key: b'u' + address_hashX + tx_idx + tx_num
# Value: the UTXO value as a 64-bit unsigned integer
udb_key = b'u' + hashX + hdb_key[-6:]
utxo_value_packed = self.db.utxo_db.get(udb_key)
if utxo_value_packed is None:
self.logger.warning("%s:%s is not found in UTXO db for %s",
hash_to_hex_str(tx_hash), tx_idx,
hash_to_hex_str(hashX))
raise ChainError(
f"{hash_to_hex_str(tx_hash)}:{tx_idx} is not found in UTXO db for {hash_to_hex_str(hashX)}"
)
# Remove both entries for this UTXO
self.db_deletes.append(hdb_key)
self.db_deletes.append(udb_key)
return hashX + tx_num_packed + utxo_value_packed
self.logger.error(
'UTXO {hash_to_hex_str(tx_hash)} / {tx_idx} not found in "h" table'
)
raise ChainError('UTXO {} / {:,d} not found in "h" table'.format(
hash_to_hex_str(tx_hash), tx_idx))
def electrum_header(cls, header, height):
h = dict(zip(cls.HEADER_VALUES, cls.HEADER_UNPACK(header)))
# Add the height that is not present in the header itself
h['block_height'] = height
# Convert bytes to str
h['prev_block_hash'] = hash_to_hex_str(h['prev_block_hash'])
h['merkle_root'] = hash_to_hex_str(h['merkle_root'])
return h
def electrum_header(cls, header, height):
version, = struct.unpack('<I', header[:4])
timestamp, bits, nonce = struct.unpack('<III', header[100:112])
return {
'version': version,
'prev_block_hash': hash_to_hex_str(header[4:36]),
'merkle_root': hash_to_hex_str(header[36:68]),
'claim_trie_root': hash_to_hex_str(header[68:100]),
'timestamp': timestamp,
'bits': bits,
'nonce': nonce,
'block_height': height,
}
async def calc_reorg_range(self, count):
"""Calculate the reorg range"""
def diff_pos(hashes1, hashes2):
"""Returns the index of the first difference in the hash lists.
If both lists match returns their length."""
for n, (hash1, hash2) in enumerate(zip(hashes1, hashes2)):
if hash1 != hash2:
return n
return len(hashes)
if count is None:
# A real reorg
start = self.height - 1
count = 1
while start > 0:
hashes = await self.db.fs_block_hashes(start, count)
hex_hashes = [hash_to_hex_str(hash) for hash in hashes]
d_hex_hashes = await self.daemon.block_hex_hashes(start, count)
n = diff_pos(hex_hashes, d_hex_hashes)
if n > 0:
start += n
break
count = min(count * 2, start)
start -= count
count = (self.height - start) + 1
else:
start = (self.height - count) + 1
return start, count
async def reorg_chain(self, count=None):
"""Handle a chain reorganisation.
Count is the number of blocks to simulate a reorg, or None for
a real reorg."""
if count is None:
self.logger.info('chain reorg detected')
else:
self.logger.info(f'faking a reorg of {count:,d} blocks')
await self.flush(True)
async def get_raw_blocks(last_height, hex_hashes):
heights = range(last_height, last_height - len(hex_hashes), -1)
try:
blocks = [self.db.read_raw_block(height) for height in heights]
self.logger.info(f'read {len(blocks)} blocks from disk')
return blocks
except FileNotFoundError:
return await self.daemon.raw_blocks(hex_hashes)
def flush_backup():
# self.touched can include other addresses which is
# harmless, but remove None.
self.touched.discard(None)
self.db.flush_backup(self.flush_data(), self.touched)
start, last, hashes = await self.reorg_hashes(count)
# Reverse and convert to hex strings.
hashes = [hash_to_hex_str(hash) for hash in reversed(hashes)]
for hex_hashes in chunks(hashes, 50):
raw_blocks = await get_raw_blocks(last, hex_hashes)
await self.run_in_thread_with_lock(self.backup_blocks, raw_blocks)
await self.run_in_thread_with_lock(flush_backup)
last -= len(raw_blocks)
await self.prefetcher.reset_height(self.height)
def _compact_hashX(self, hashX, hist_map, hist_list, write_items,
keys_to_delete):
"""Compress history for a hashX. hist_list is an ordered list of
the histories to be compressed."""
# History entries (tx numbers) are 4 bytes each. Distribute
# over rows of up to 50KB in size. A fixed row size means
# future compactions will not need to update the first N - 1
# rows.
max_row_size = self.max_hist_row_entries * 4
full_hist = b''.join(hist_list)
nrows = (len(full_hist) + max_row_size - 1) // max_row_size
if nrows > 4:
self.logger.info('hashX {} is large: {:,d} entries across '
'{:,d} rows'.format(hash_to_hex_str(hashX),
len(full_hist) // 4, nrows))
# Find what history needs to be written, and what keys need to
# be deleted. Start by assuming all keys are to be deleted,
# and then remove those that are the same on-disk as when
# compacted.
write_size = 0
keys_to_delete.update(hist_map)
for n, chunk in enumerate(util.chunks(full_hist, max_row_size)):
key = hashX + pack_be_uint16(n)
if hist_map.get(key) == chunk:
keys_to_delete.remove(key)
else:
write_items.append((key, chunk))
write_size += len(chunk)
assert n + 1 == nrows
self.comp_flush_count = max(self.comp_flush_count, n)
return write_size
async def tx_merkle(self, tx_num, tx_height):
if tx_height == -1:
return {'block_height': -1}
tx_counts = self.tx_counts
tx_pos = tx_num - tx_counts[tx_height - 1]
def _update_block_txs_cache():
block_txs = list(
self.tx_db.iterator(
start=TX_HASH_PREFIX +
util.pack_be_uint64(tx_counts[tx_height - 1]),
stop=None if tx_height +
1 == len(tx_counts) else TX_HASH_PREFIX +
util.pack_be_uint64(tx_counts[tx_height]),
include_key=False))
if tx_height + 100 > self.db_height:
return block_txs
self._block_txs_cache[tx_height] = block_txs
uncached = None
if (tx_num, tx_height) in self._merkle_tx_cache:
return self._merkle_tx_cache[(tx_num, tx_height)]
if tx_height not in self._block_txs_cache:
uncached = await asyncio.get_event_loop().run_in_executor(
self.executor, _update_block_txs_cache)
block_txs = self._block_txs_cache.get(tx_height, uncached)
branch, root = self.merkle.branch_and_root(block_txs, tx_pos)
merkle = {
'block_height': tx_height,
'merkle': [hash_to_hex_str(hash) for hash in branch],
'pos': tx_pos
}
if tx_height + 100 < self.db_height:
self._merkle_tx_cache[(tx_num, tx_height)] = merkle
return merkle
def genesis_block(cls, block):
"""Check the Genesis block is the right one for this coin.
Return the block less its unspendable coinbase.
"""
header = cls.block_header(block, 0)
header_hex_hash = hash_to_hex_str(cls.header_hash(header))
if header_hex_hash != cls.GENESIS_HASH:
raise CoinError(
f'genesis block has hash {header_hex_hash} expected {cls.GENESIS_HASH}'
)
return header + bytes(1)
async def _fetch_and_accept(self, hashes, all_hashes, touched):
"""Fetch a list of mempool transactions."""
hex_hashes_iter = (hash_to_hex_str(hash) for hash in hashes)
raw_txs = await self.api.raw_transactions(hex_hashes_iter)
def deserialize_txs(): # This function is pure
to_hashX = self.coin.hashX_from_script
deserializer = self.coin.DESERIALIZER
txs = {}
for hash, raw_tx in zip(hashes, raw_txs):
# The daemon may have evicted the tx from its
# mempool or it may have gotten in a block
if not raw_tx:
continue
tx, tx_size = deserializer(raw_tx).read_tx_and_vsize()
# Convert the inputs and outputs into (hashX, value) pairs
# Drop generation-like inputs from MemPoolTx.prevouts
txin_pairs = tuple((txin.prev_hash, txin.prev_idx)
for txin in tx.inputs
if not txin.is_generation())
txout_pairs = tuple((to_hashX(txout.pk_script), txout.value)
for txout in tx.outputs)
txs[hash] = MemPoolTx(txin_pairs, None, txout_pairs, 0,
tx_size)
return txs
# Thread this potentially slow operation so as not to block
tx_map = await asyncio.get_event_loop().run_in_executor(
self.executor, deserialize_txs)
# Determine all prevouts not in the mempool, and fetch the
# UTXO information from the database. Failed prevout lookups
# return None - concurrent database updates happen - which is
# relied upon by _accept_transactions. Ignore prevouts that are
# generation-like.
prevouts = tuple(prevout for tx in tx_map.values()
for prevout in tx.prevouts
if prevout[0] not in all_hashes)
utxos = await self.api.lookup_utxos(prevouts)
utxo_map = {prevout: utxo for prevout, utxo in zip(prevouts, utxos)}
return self._accept_transactions(tx_map, utxo_map, touched)
def _fs_transactions(self, txids: Iterable[str]):
unpack_be_uint64 = util.unpack_be_uint64
tx_counts = self.tx_counts
tx_db_get = self.tx_db.get
tx_cache = self._tx_and_merkle_cache
tx_infos = {}
for tx_hash in txids:
cached_tx = tx_cache.get(tx_hash)
if cached_tx:
tx, merkle = cached_tx
else:
tx_hash_bytes = bytes.fromhex(tx_hash)[::-1]
tx_num = tx_db_get(TX_NUM_PREFIX + tx_hash_bytes)
tx = None
tx_height = -1
if tx_num is not None:
tx_num = unpack_be_uint64(tx_num)
tx_height = bisect_right(tx_counts, tx_num)
if tx_height < self.db_height:
tx = tx_db_get(TX_PREFIX + tx_hash_bytes)
if tx_height == -1:
merkle = {
'block_height': -1
}
else:
tx_pos = tx_num - tx_counts[tx_height - 1]
branch, root = self.merkle.branch_and_root(
self.total_transactions[tx_counts[tx_height - 1]:tx_counts[tx_height]], tx_pos
)
merkle = {
'block_height': tx_height,
'merkle': [
hash_to_hex_str(hash)
for hash in branch
],
'pos': tx_pos
}
if tx_height + 10 < self.db_height:
tx_cache[tx_hash] = tx, merkle
tx_infos[tx_hash] = (None if not tx else tx.hex(), merkle)
return tx_infos
def __str__(self):
script = self.script.hex()
prev_hash = hash_to_hex_str(self.prev_hash)
return (
f"Input({prev_hash}, {self.prev_idx:d}, script={script}, sequence={self.sequence:d})"
)
def __str__(self):
prev_hash = hash_to_hex_str(self.prev_hash)
return (
f"Input({prev_hash}, {self.prev_idx:d}, tree={self.tree}, sequence={self.sequence:d})"
)
