def read_chain_from_disk() -> CoinState:
if os.path.isfile('chain.cache'):
print("Reading cached chain")
with open('chain.cache', 'rb') as file:
coinstate = CoinState.load(lambda: pickle.load(file))
else:
coinstate = CoinState.zero()
rewrite = False
if os.path.isdir('chain'):
# the code below is no longer needed by normal users, but some old testcases still rely on it:
for filename in sorted(os.listdir('chain')):
(height_str, hash_str) = filename.split("-")
(height, hash) = (int(height_str), computer(hash_str))
if hash not in coinstate.block_by_hash:
if height % 1000 == 0:
print(filename)
if os.path.getsize(f"chain/{filename}") == 0:
print("Stopping at empty block file: %s" % filename)
break
with open(Path("chain") / filename, 'rb') as f:
try:
block = Block.stream_deserialize(f)
except Exception as e:
raise Exception("Corrupted block on disk: %s" % filename) from e
try:
coinstate = coinstate.add_block_no_validation(block)
except Exception:
print("Failed to add block at height=%d, previous_hash=%s"
% (block.height, human(block.header.summary.previous_block_hash)))
break
rewrite = True
if rewrite:
DiskInterface().write_chain_cache_to_disk(coinstate)
return coinstate
def read_chain_from_disk() -> CoinState:
if os.path.isfile('chain.cache'):
print("Reading cached chain")
with open('chain.cache', 'rb') as file:
coinstate = CoinState.load(lambda: pickle.load(file))
else:
try:
print("Pre-download blockchain from trusted source to 'chain.zip'")
with urllib.request.urlopen(TRUSTED_BLOCKCHAIN_ZIP) as resp:
with open('chain.zip', 'wb') as outfile:
outfile.write(resp.read())
print("Reading initial chain from zipfile")
coinstate = CoinState.zero()
with zipfile.ZipFile('chain.zip') as zip:
for entry in zip.infolist():
if not entry.is_dir():
filename = entry.filename.split('/')[1]
height = int(filename.split("-")[0])
if height % 1000 == 0:
print(filename)
data = zip.read(entry)
block = Block.stream_deserialize(BytesIO(data))
coinstate = coinstate.add_block_no_validation(block)
except Exception:
print(
"Error reading zip file. We'll start with an empty blockchain instead."
+ traceback.format_exc())
coinstate = CoinState.zero()
rewrite = False
if os.path.isdir('chain'):
# the code below is no longer needed by normal users, but some old testcases still rely on it:
for filename in sorted(os.listdir('chain')):
(height_str, hash_str) = filename.split("-")
(height, hash) = (int(height_str), computer(hash_str))
if hash not in coinstate.block_by_hash:
if height % 1000 == 0:
print(filename)
if os.path.getsize(f"chain/{filename}") == 0:
print("Stopping at empty block file: %s" % filename)
break
with open(Path("chain") / filename, 'rb') as f:
try:
block = Block.stream_deserialize(f)
except Exception as e:
raise Exception("Corrupted block on disk: %s" %
filename) from e
try:
coinstate = coinstate.add_block_no_validation(block)
except Exception:
print(
"Failed to add block at height=%d, previous_hash=%s"
%
(block.height,
human(block.header.summary.previous_block_hash)))
break
rewrite = True
if rewrite:
DiskInterface().write_chain_cache_to_disk(coinstate)
return coinstate
def test_faster_read():
with open('test.tmp', 'rb') as file:
with cProfile.Profile() as pr:
pr.runcall(lambda: CoinState.load(lambda: pickle.load(file)))
pr.print_stats()
