forked from zack-bitcoin/augur-core
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blockchain.py
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blockchain.py
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""" This file explains explains the rules for adding and removing blocks from the local chain.
"""
import time
import copy
import custom
import networking
import transactions
import tools
import target
def add_tx(tx, DB={}):
# Attempt to add a new transaction into the pool.
#print('top of add_tx')
out=['']
if type(tx) != type({'a':1}):
return False
address = tools.make_address(tx['pubkeys'], len(tx['signatures']))
def verify_count(tx, txs):
return tx['count'] != tools.count(address, DB)
def type_check(tx, txs):
if not tools.E_check(tx, 'type', [str, unicode]):
out[0]+='blockchain type'
return False
if tx['type'] == 'mint':
return False
if tx['type'] not in transactions.tx_check:
out[0]+='bad type'
return False
return True
def too_big_block(tx, txs):
return len(tools.package(txs+[tx])) > networking.MAX_MESSAGE_SIZE - 5000
def verify_tx(tx, txs, out):
if not type_check(tx, txs):
out[0]+='type error'
return False
if tx in txs:
out[0]+='no duplicates'
return False
if verify_count(tx, txs):
out[0]+='count error'
return False
if too_big_block(tx, txs):
out[0]+='too many txs'
return False
if not transactions.tx_check[tx['type']](tx, txs, out, DB):
out[0]+= 'tx: ' + str(tx)
return False
return True
#tools.log('attempt to add tx: ' +str(tx))
T=tools.db_get('txs')
if verify_tx(tx, T, out):
T.append(tx)
tools.db_put('txs', T)
return('added tx: ' +str(tx))
else:
return('failed to add tx because: '+out[0])
def recent_blockthings(key, size, length=0):
storage = tools.db_get(key)
def get_val(length):
leng = str(length)
if not leng in storage:
block=tools.db_get(leng)
if block==tools.default_entry:
if leng==tools.db_get('length'):
tools.db_put('length', int(leng)-1)
block=tools.db_get(leng)
else:
error()
#try:
storage[leng] = tools.db_get(leng)[key[:-1]]
tools.db_put(key, storage)
return storage[leng]
def clean_up(storage, end):
if end<0: return
if not str(end) in storage: return
else:
storage.pop(str(end))
return clean_up(storage, end-1)
if length == 0:
length = tools.db_get('length')
start = max((length-size), 0)
clean_up(storage, length-max(custom.mmm, custom.history_length)-100)
return map(get_val, range(start, length))
def hexSum(a, b):
# Sum of numbers expressed as hexidecimal strings
return tools.buffer_(str(hex(int(a, 16)+int(b, 16)))[2: -1], 64)
def hexInvert(n):
# Use double-size for division, to reduce information leakage.
return tools.buffer_(str(hex(int('f' * 128, 16) / int(n, 16)))[2: -1], 64)
def add_block(block_pair, DB={}):
"""Attempts adding a new block to the blockchain.
Median is good for weeding out liars, so long as the liars don't have 51%
hashpower. """
def median(mylist):
if len(mylist) < 1:
return 0
return sorted(mylist)[len(mylist) / 2]
def block_check(block, DB):
def log_(txt): pass #return tools.log(txt)
def tx_check(txs):
start = copy.deepcopy(txs)
out = []
start_copy = []
error_msg=['']
while True:
if start == []: return False # Block passes this test
if transactions.tx_check[start[-1]['type']](start[-1], out, error_msg, DB):
out.append(start.pop())
else:
log_('bad block: ' +str(txs))
log_('error message: ' +str(error_msg))
return True # Block is invalid
if not isinstance(block, dict): return False
if 'error' in block: return False
if not tools.E_check(block, 'length', [int]):
log_('no length')
return False
length =tools.db_get('length')
if type(block['length'])!=type(1):
log_('wrong length type')
return False
if int(block['length']) != int(length) + 1:
log_('wrong longth')
return False
if block['diffLength'] != hexSum(tools.db_get('diffLength'),
hexInvert(block['target'])):
log_('diflength error')
return False
if length >= 0:
if tools.det_hash(tools.db_get(length, DB)) != block['prevHash']:
log_('det hash error')
return False
if u'target' not in block.keys():
log_('target error')
return False
half_way=tools.make_half_way(block)
if tools.det_hash(half_way) > block['target']:
log_('det hash error 2')
return False
if block['target'] != target.target(block['length']):
log_('block: ' +str(block))
log_('target: ' +str(target.target(block['length'])))
log_('wrong target')
return False
earliest = median(recent_blockthings('times', custom.mmm))
if 'time' not in block:
log_('no time')
return False
if block['time'] > time.time()+60*6:
log_('too late')
return False
if block['time'] < earliest:
log_('too early')
return False
if tx_check(block['txs']):
log_('tx check')
return False
return True
if type(block_pair)==type([1,2,3]):
block=block_pair[0]
peer=block_pair[1]
else:
block=block_pair
peer=False
#tools.log('attempt to add block: ' +str(block))
if block_check(block, DB):
#tools.log('add_block: ' + str(block))
tools.db_put(block['length'], block, DB)
tools.db_put('length', block['length'])
tools.db_put('diffLength', block['diffLength'])
orphans = tools.db_get('txs')
tools.db_put('txs', [])
for tx in block['txs']:
transactions.update[tx['type']](tx, DB, True)
for tx in orphans:
add_tx(tx, DB)
#while tools.db_get('length')!=block['length']:
# time.sleep(0.0001)
def delete_block(DB):
""" Removes the most recent block from the blockchain. """
length=tools.db_get('length')
if length < 0:
return
try:
ts=tools.db_get('targets')
ts.pop(str(length))
tools.db_put('targets', ts)
except:
pass
try:
ts=tools.db_get('times')
ts.pop(str(length))
tools.db_put('times', ts)
except:
pass
block = tools.db_get(length, DB)
orphans = tools.db_get('txs')
tools.db_put('txs', [])
for tx in block['txs']:
orphans.append(tx)
tools.db_put('add_block', False)
transactions.update[tx['type']](tx, DB, False)
tools.db_delete(length, DB)
length-=1
tools.db_put('length', length)
if length == -1:
tools.db_put('diffLength', '0')
else:
block = tools.db_get(length, DB)
tools.db_put('diffLength', block['diffLength'])
for orphan in sorted(orphans, key=lambda x: x['count']):
add_tx(orphan, DB)
#while tools.db_get('length')!=length:
# time.sleep(0.0001)
def f(blocks_queue, txs_queue):
def bb(): return blocks_queue.empty()
def tb(): return txs_queue.empty()
def ff(queue, g, b, s):
while not b():
time.sleep(0.0001)
try:
g(queue.get(False))
except Exception as exc:
tools.log('suggestions ' + s)
tools.log(exc)
while True:
time.sleep(0.1)
if tools.db_get('stop'):
tools.dump_out(blocks_queue)
tools.dump_out(txs_queue)
return
while not bb() or not tb():
ff(blocks_queue, add_block, bb, 'block')
ff(txs_queue, add_tx, tb, 'tx')
import cProfile
def main(DB): return f(DB["suggested_blocks"], DB["suggested_txs"])
def profile(DB):
import pprint
p=cProfile.Profile()
p.run('blockchain.main(custom.DB)')
g=p.getstats()
#g=g.sorted(lambda x: x.inlinetime)
g=sorted(g, key=lambda x: x.totaltime)
g.reverse()
pprint.pprint(g)
#return f(DB['suggested_blocks'], DB['suggested_txs'])