p2pool/data.py

   1 from __future__ import division
   2
   3 import hashlib
   4 import os
   5 import random
   6 import time
   7
   8 from twisted.python import log
   9
  10 import p2pool
  11 from p2pool.bitcoin import data as bitcoin_data, script, sha256
  12 from p2pool.util import math, forest, pack
  13
  14 # hashlink
  15
  16 hash_link_type = pack.ComposedType([
  17     ('state', pack.FixedStrType(32)),
  18     ('extra_data', pack.FixedStrType(0)), # bit of a hack, but since the donation script is at the end, const_ending is long enough to always make this empty
  19     ('length', pack.VarIntType()),
  20 ])
  21
  22 def prefix_to_hash_link(prefix, const_ending=''):
  23     assert prefix.endswith(const_ending), (prefix, const_ending)
  24     x = sha256.sha256(prefix)
  25     return dict(state=x.state, extra_data=x.buf[:max(0, len(x.buf)-len(const_ending))], length=x.length//8)
  26
  27 def check_hash_link(hash_link, data, const_ending=''):
  28     extra_length = hash_link['length'] % (512//8)
  29     assert len(hash_link['extra_data']) == max(0, extra_length - len(const_ending))
  30     extra = (hash_link['extra_data'] + const_ending)[len(hash_link['extra_data']) + len(const_ending) - extra_length:]
  31     assert len(extra) == extra_length
  32     return pack.IntType(256).unpack(hashlib.sha256(sha256.sha256(data, (hash_link['state'], extra, 8*hash_link['length'])).digest()).digest())
  33
  34 # shares
  35
  36 small_block_header_type = pack.ComposedType([
  37     ('version', pack.VarIntType()), # XXX must be constrained to 32 bits
  38     ('previous_block', pack.PossiblyNoneType(0, pack.IntType(256))),
  39     ('timestamp', pack.IntType(32)),
  40     ('bits', bitcoin_data.FloatingIntegerType()),
  41     ('nonce', pack.IntType(32)),
  42 ])
  43
  44 share_data_type = pack.ComposedType([
  45     ('previous_share_hash', pack.PossiblyNoneType(0, pack.IntType(256))),
  46     ('coinbase', pack.VarStrType()),
  47     ('nonce', pack.IntType(32)),
  48     ('pubkey_hash', pack.IntType(160)),
  49     ('subsidy', pack.IntType(64)),
  50     ('donation', pack.IntType(16)),
  51     ('stale_info', pack.IntType(8)), # 0 nothing, 253 orphan, 254 doa
  52 ])
  53
  54 share_info_type = pack.ComposedType([
  55     ('share_data', share_data_type),
  56     ('max_bits', bitcoin_data.FloatingIntegerType()),
  57     ('bits', bitcoin_data.FloatingIntegerType()),
  58     ('timestamp', pack.IntType(32)),
  59 ])
  60
  61 share1a_type = pack.ComposedType([
  62     ('min_header', small_block_header_type),
  63     ('share_info', share_info_type),
  64     ('hash_link', hash_link_type),
  65     ('merkle_branch', bitcoin_data.merkle_branch_type),
  66 ])
  67
  68 share1b_type = pack.ComposedType([
  69     ('min_header', small_block_header_type),
  70     ('share_info', share_info_type),
  71     ('hash_link', hash_link_type),
  72     ('other_txs', pack.ListType(bitcoin_data.tx_type)),
  73 ])
  74
  75
  76 # type:
  77 # 2: share1a
  78 # 3: share1b
  79
  80 share_type = pack.ComposedType([
  81     ('type', pack.VarIntType()),
  82     ('contents', pack.VarStrType()),
  83 ])
  84
  85
  86 def get_pool_attempts_per_second(tracker, previous_share_hash, dist, min_work=False, integer=False):
  87     assert dist >= 2
  88     near = tracker.shares[previous_share_hash]
  89     far = tracker.shares[tracker.get_nth_parent_hash(previous_share_hash, dist - 1)]
  90     attempts = tracker.get_work(near.hash) - tracker.get_work(far.hash) if not min_work else tracker.get_delta(near.hash).min_work - tracker.get_delta(far.hash).min_work
  91     time = near.timestamp - far.timestamp
  92     if time <= 0:
  93         time = 1
  94     if integer:
  95         return attempts//time
  96     return attempts/time
  97
  98 def get_average_stale_prop(tracker, share_hash, lookbehind):
  99     stales = sum(1 for share in tracker.get_chain(share_hash, lookbehind) if share.share_data['stale_info'] in [253, 254])
 100     return stales/(lookbehind + stales)
 101
 102 DONATION_SCRIPT = '4104ffd03de44a6e11b9917f3a29f9443283d9871c9d743ef30d5eddcd37094b64d1b3d8090496b53256786bf5c82932ec23c3b74d9f05a6f95a8b5529352656664bac'.decode('hex')
 103
 104 ref_type = pack.ComposedType([
 105     ('identifier', pack.FixedStrType(64//8)),
 106     ('share_info', share_info_type),
 107 ])
 108
 109 gentx_before_refhash = pack.VarStrType().pack(DONATION_SCRIPT) + pack.IntType(64).pack(0) + pack.VarStrType().pack('\x20' + pack.IntType(256).pack(0))[:2]
 110
 111 def generate_transaction(tracker, share_data, block_target, desired_timestamp, desired_target, net):
 112     previous_share = tracker.shares[share_data['previous_share_hash']] if share_data['previous_share_hash'] is not None else None
 113
 114     height, last = tracker.get_height_and_last(share_data['previous_share_hash'])
 115     assert height >= net.REAL_CHAIN_LENGTH or last is None
 116     if height < net.TARGET_LOOKBEHIND:
 117         pre_target3 = net.MAX_TARGET
 118     else:
 119         attempts_per_second = get_pool_attempts_per_second(tracker, share_data['previous_share_hash'], net.TARGET_LOOKBEHIND, min_work=True, integer=True)
 120         pre_target = 2**256//(net.SHARE_PERIOD*attempts_per_second) - 1 if attempts_per_second else 2**256-1
 121         pre_target2 = math.clip(pre_target, (previous_share.max_target*9//10, previous_share.max_target*11//10))
 122         pre_target3 = math.clip(pre_target2, (0, net.MAX_TARGET))
 123     max_bits = bitcoin_data.FloatingInteger.from_target_upper_bound(pre_target3)
 124     bits = bitcoin_data.FloatingInteger.from_target_upper_bound(math.clip(desired_target, (pre_target3//10, pre_target3)))
 125
 126     weights, total_weight, donation_weight = tracker.get_cumulative_weights(share_data['previous_share_hash'],
 127         min(height, net.REAL_CHAIN_LENGTH),
 128         65535*net.SPREAD*bitcoin_data.target_to_average_attempts(block_target),
 129         True,
 130     )
 131     assert total_weight == sum(weights.itervalues()) + donation_weight, (total_weight, sum(weights.itervalues()) + donation_weight)
 132
 133     amounts = dict((script, share_data['subsidy']*(199*weight)//(200*total_weight)) for script, weight in weights.iteritems()) # 99.5% goes according to weights prior to this share
 134     this_script = bitcoin_data.pubkey_hash_to_script2(share_data['pubkey_hash'])
 135     amounts[this_script] = amounts.get(this_script, 0) + share_data['subsidy']//200 # 0.5% goes to block finder
 136     amounts[DONATION_SCRIPT] = amounts.get(DONATION_SCRIPT, 0) + share_data['subsidy'] - sum(amounts.itervalues()) # all that's left over is the donation weight and some extra satoshis due to rounding
 137
 138     if sum(amounts.itervalues()) != share_data['subsidy'] or any(x < 0 for x in amounts.itervalues()):
 139         raise ValueError()
 140
 141     dests = sorted(amounts.iterkeys(), key=lambda script: (script == DONATION_SCRIPT, amounts[script], script))[-4000:] # block length limit, unlikely to ever be hit
 142
 143     share_info = dict(
 144         share_data=share_data,
 145         max_bits=max_bits,
 146         bits=bits,
 147         timestamp=math.clip(desired_timestamp, (
 148             (previous_share.timestamp + net.SHARE_PERIOD) - (net.SHARE_PERIOD - 1), # = previous_share.timestamp + 1
 149             (previous_share.timestamp + net.SHARE_PERIOD) + (net.SHARE_PERIOD - 1),
 150         )) if previous_share is not None else desired_timestamp,
 151     )
 152
 153     return share_info, dict(
 154         version=1,
 155         tx_ins=[dict(
 156             previous_output=None,
 157             sequence=None,
 158             script=share_data['coinbase'].ljust(2, '\x00'),
 159         )],
 160         tx_outs=[dict(value=amounts[script], script=script) for script in dests if amounts[script]] + [dict(
 161             value=0,
 162             script='\x20' + pack.IntType(256).pack(bitcoin_data.hash256(ref_type.pack(dict(
 163                 identifier=net.IDENTIFIER,
 164                 share_info=share_info,
 165             )))),
 166         )],
 167         lock_time=0,
 168     )
 169
 170 def get_expected_payouts(tracker, best_share_hash, block_target, subsidy, net):
 171     weights, total_weight, donation_weight = tracker.get_cumulative_weights(best_share_hash, min(tracker.get_height(best_share_hash), net.REAL_CHAIN_LENGTH), 65535*net.SPREAD*bitcoin_data.target_to_average_attempts(block_target), False)
 172     res = dict((script, subsidy*weight//total_weight) for script, weight in weights.iteritems())
 173     res[DONATION_SCRIPT] = res.get(DONATION_SCRIPT, 0) + subsidy - sum(res.itervalues())
 174     return res
 175
 176 class Share(object):
 177     __slots__ = 'net min_header share_info hash_link merkle_branch other_txs hash share_data max_target target timestamp previous_hash new_script gentx_hash header pow_hash header_hash time_seen peer'.split(' ')
 178
 179     @classmethod
 180     def from_share(cls, share, net, peer):
 181         if share['type'] in [0, 1]:
 182             from p2pool import p2p
 183             raise p2p.PeerMisbehavingError('sent an obsolete share')
 184         elif share['type'] == 2:
 185             return cls(net, peer, other_txs=None, **share1a_type.unpack(share['contents']))
 186         elif share['type'] == 3:
 187             share1b = share1b_type.unpack(share['contents'])
 188             return cls(net, peer, merkle_branch=bitcoin_data.calculate_merkle_branch([0] + [bitcoin_data.hash256(bitcoin_data.tx_type.pack(x)) for x in share1b['other_txs']], 0), **share1b)
 189         else:
 190             raise ValueError('unknown share type: %r' % (share['type'],))
 191
 192     def __init__(self, net, peer, min_header, share_info, hash_link, merkle_branch, other_txs):
 193         if len(share_info['share_data']['coinbase']) > 100:
 194             raise ValueError('''coinbase too large! %i bytes''' % (len(self.share_data['coinbase']),))
 195
 196         if len(merkle_branch) > 16:
 197             raise ValueError('merkle_branch too long!')
 198
 199         if p2pool.DEBUG and other_txs is not None and bitcoin_data.calculate_merkle_branch([0] + [bitcoin_data.hash256(bitcoin_data.tx_type.pack(x)) for x in other_txs], 0) != merkle_branch:
 200             raise ValueError('merkle_branch and other_txs do not match')
 201
 202         assert not hash_link['extra_data'], repr(hash_link['extra_data'])
 203
 204         self.net = net
 205         self.peer = peer
 206         self.min_header = min_header
 207         self.share_info = share_info
 208         self.hash_link = hash_link
 209         self.merkle_branch = merkle_branch
 210         self.other_txs = other_txs
 211
 212         self.share_data = self.share_info['share_data']
 213         self.max_target = self.share_info['max_bits'].target
 214         self.target = self.share_info['bits'].target
 215         self.timestamp = self.share_info['timestamp']
 216         self.previous_hash = self.share_data['previous_share_hash']
 217         self.new_script = bitcoin_data.pubkey_hash_to_script2(self.share_data['pubkey_hash'])
 218
 219         self.gentx_hash = check_hash_link(
 220             hash_link,
 221             pack.IntType(256).pack(bitcoin_data.hash256(ref_type.pack(dict(
 222                 identifier=net.IDENTIFIER,
 223                 share_info=share_info,
 224             )))) + pack.IntType(32).pack(0),
 225             gentx_before_refhash,
 226         )
 227         merkle_root = bitcoin_data.check_merkle_branch(self.gentx_hash, 0, merkle_branch)
 228         self.header = dict(min_header, merkle_root=merkle_root)
 229         self.pow_hash = net.PARENT.POW_FUNC(bitcoin_data.block_header_type.pack(self.header))
 230         self.header_hash = bitcoin_data.hash256(bitcoin_data.block_header_type.pack(self.header))
 231
 232         if self.pow_hash > self.target:
 233             raise p2p.PeerMisbehavingError('share PoW invalid')
 234
 235         if other_txs is not None and not self.pow_hash <= self.header['bits'].target:
 236             raise ValueError('other_txs provided when not a block solution')
 237         if other_txs is None and self.pow_hash <= self.header['bits'].target:
 238             raise ValueError('other_txs not provided when a block solution')
 239
 240         self.hash = bitcoin_data.hash256(share_type.pack(self.as_share()))
 241
 242         # XXX eww
 243         self.time_seen = time.time()
 244
 245     def __repr__(self):
 246         return '<Share %s>' % (' '.join('%s=%r' % (k, getattr(self, k)) for k in self.__slots__),)
 247
 248     def check(self, tracker):
 249         share_info, gentx = generate_transaction(tracker, self.share_info['share_data'], self.header['bits'].target, self.share_info['timestamp'], self.share_info['bits'].target, self.net)
 250         if share_info != self.share_info:
 251             raise ValueError('share difficulty invalid')
 252         if bitcoin_data.hash256(bitcoin_data.tx_type.pack(gentx)) != self.gentx_hash:
 253             raise ValueError('''gentx doesn't match hash_link''')
 254
 255     def as_share(self):
 256         if not self.pow_hash <= self.header['bits'].target: # share1a
 257             return dict(type=2, contents=share1a_type.pack(dict(min_header=self.min_header, share_info=self.share_info, hash_link=self.hash_link, merkle_branch=self.merkle_branch)))
 258         else: # share1b
 259             return dict(type=3, contents=share1b_type.pack(dict(min_header=self.min_header, share_info=self.share_info, hash_link=self.hash_link, other_txs=self.other_txs)))
 260
 261     def as_block(self, tracker):
 262         if self.other_txs is None:
 263             raise ValueError('share does not contain all txs')
 264
 265         share_info, gentx = generate_transaction(tracker, self.share_info['share_data'], self.header['bits'].target, self.share_info['timestamp'], self.share_info['bits'].target, self.net)
 266         assert share_info == self.share_info
 267
 268         return dict(header=self.header, txs=[gentx] + self.other_txs)
 269
 270 class WeightsSkipList(forest.TrackerSkipList):
 271     # share_count, weights, total_weight
 272
 273     def get_delta(self, element):
 274         from p2pool.bitcoin import data as bitcoin_data
 275         share = self.tracker.shares[element]
 276         att = bitcoin_data.target_to_average_attempts(share.target)
 277         return 1, {share.new_script: att*(65535-share.share_data['donation'])}, att*65535, att*share.share_data['donation']
 278
 279     def combine_deltas(self, (share_count1, weights1, total_weight1, total_donation_weight1), (share_count2, weights2, total_weight2, total_donation_weight2)):
 280         return share_count1 + share_count2, math.add_dicts(weights1, weights2), total_weight1 + total_weight2, total_donation_weight1 + total_donation_weight2
 281
 282     def initial_solution(self, start, (max_shares, desired_weight, broken_mode)):
 283         assert desired_weight % 65535 == 0, divmod(desired_weight, 65535)
 284         return 0, None, 0, 0
 285
 286     def apply_delta(self, (share_count1, weights_list, total_weight1, total_donation_weight1), (share_count2, weights2, total_weight2, total_donation_weight2), (max_shares, desired_weight, broken_mode)):
 287         if total_weight1 + total_weight2 > desired_weight and share_count2 == 1:
 288             assert (desired_weight - total_weight1) % 65535 == 0
 289             script, = weights2.iterkeys()
 290             if broken_mode:
 291                 new_weights = dict(script=(desired_weight - total_weight1)//65535*weights2[script]//(total_weight2//65535))
 292             else:
 293                 new_weights = {script: (desired_weight - total_weight1)//65535*weights2[script]//(total_weight2//65535)}
 294             return share_count1 + share_count2, (weights_list, new_weights), desired_weight, total_donation_weight1 + (desired_weight - total_weight1)//65535*total_donation_weight2//(total_weight2//65535)
 295         return share_count1 + share_count2, (weights_list, weights2), total_weight1 + total_weight2, total_donation_weight1 + total_donation_weight2
 296
 297     def judge(self, (share_count, weights_list, total_weight, total_donation_weight), (max_shares, desired_weight, broken_mode)):
 298         if share_count > max_shares or total_weight > desired_weight:
 299             return 1
 300         elif share_count == max_shares or total_weight == desired_weight:
 301             return 0
 302         else:
 303             return -1
 304
 305     def finalize(self, (share_count, weights_list, total_weight, total_donation_weight), (max_shares, desired_weight, broken_mode)):
 306         assert share_count <= max_shares and total_weight <= desired_weight
 307         assert share_count == max_shares or total_weight == desired_weight
 308         return math.add_dicts(*math.flatten_linked_list(weights_list)), total_weight, total_donation_weight
 309
 310 class OkayTracker(forest.Tracker):
 311     def __init__(self, net, my_share_hashes, my_doa_share_hashes):
 312         forest.Tracker.__init__(self, delta_type=forest.get_attributedelta_type(dict(forest.AttributeDelta.attrs,
 313             work=lambda share: bitcoin_data.target_to_average_attempts(share.target),
 314             min_work=lambda share: bitcoin_data.target_to_average_attempts(share.max_target),
 315         )))
 316         self.net = net
 317         self.verified = forest.Tracker(delta_type=forest.get_attributedelta_type(dict(forest.AttributeDelta.attrs,
 318             work=lambda share: bitcoin_data.target_to_average_attempts(share.target),
 319             my_count=lambda share: 1 if share.hash in my_share_hashes else 0,
 320             my_doa_count=lambda share: 1 if share.hash in my_doa_share_hashes else 0,
 321             my_orphan_announce_count=lambda share: 1 if share.hash in my_share_hashes and share.share_data['stale_info'] == 253 else 0,
 322             my_dead_announce_count=lambda share: 1 if share.hash in my_share_hashes and share.share_data['stale_info'] == 254 else 0,
 323         )))
 324         self.verified.get_nth_parent_hash = self.get_nth_parent_hash # self is a superset of self.verified
 325
 326         self.get_cumulative_weights = WeightsSkipList(self)
 327
 328     def attempt_verify(self, share):
 329         if share.hash in self.verified.shares:
 330             return True
 331         height, last = self.get_height_and_last(share.hash)
 332         if height < self.net.CHAIN_LENGTH + 1 and last is not None:
 333             raise AssertionError()
 334         try:
 335             share.check(self)
 336         except:
 337             log.err(None, 'Share check failed:')
 338             return False
 339         else:
 340             self.verified.add(share)
 341             return True
 342
 343     def think(self, block_rel_height_func, previous_block, bits):
 344         desired = set()
 345
 346         # O(len(self.heads))
 347         #   make 'unverified heads' set?
 348         # for each overall head, attempt verification
 349         # if it fails, attempt on parent, and repeat
 350         # if no successful verification because of lack of parents, request parent
 351         bads = set()
 352         for head in set(self.heads) - set(self.verified.heads):
 353             head_height, last = self.get_height_and_last(head)
 354
 355             for share in self.get_chain(head, head_height if last is None else min(5, max(0, head_height - self.net.CHAIN_LENGTH))):
 356                 if self.attempt_verify(share):
 357                     break
 358                 if share.hash in self.heads:
 359                     bads.add(share.hash)
 360             else:
 361                 if last is not None:
 362                     desired.add((
 363                         self.shares[random.choice(list(self.reverse_shares[last]))].peer,
 364                         last,
 365                         max(x.timestamp for x in self.get_chain(head, min(head_height, 5))),
 366                         min(x.target for x in self.get_chain(head, min(head_height, 5))),
 367                     ))
 368         for bad in bads:
 369             assert bad not in self.verified.shares
 370             assert bad in self.heads
 371             if p2pool.DEBUG:
 372                 print "BAD", bad
 373             self.remove(bad)
 374
 375         # try to get at least CHAIN_LENGTH height for each verified head, requesting parents if needed
 376         for head in list(self.verified.heads):
 377             head_height, last_hash = self.verified.get_height_and_last(head)
 378             last_height, last_last_hash = self.get_height_and_last(last_hash)
 379             # XXX review boundary conditions
 380             want = max(self.net.CHAIN_LENGTH - head_height, 0)
 381             can = max(last_height - 1 - self.net.CHAIN_LENGTH, 0) if last_last_hash is not None else last_height
 382             get = min(want, can)
 383             #print 'Z', head_height, last_hash is None, last_height, last_last_hash is None, want, can, get
 384             for share in self.get_chain(last_hash, get):
 385                 if not self.attempt_verify(share):
 386                     break
 387             if head_height < self.net.CHAIN_LENGTH and last_last_hash is not None:
 388                 desired.add((
 389                     self.shares[random.choice(list(self.verified.reverse_shares[last_hash]))].peer,
 390                     last_last_hash,
 391                     max(x.timestamp for x in self.get_chain(head, min(head_height, 5))),
 392                     min(x.target for x in self.get_chain(head, min(head_height, 5))),
 393                 ))
 394
 395         # decide best tree
 396         decorated_tails = sorted((self.score(max(self.verified.tails[tail_hash], key=self.verified.get_work), block_rel_height_func), tail_hash) for tail_hash in self.verified.tails)
 397         if p2pool.DEBUG:
 398             print len(decorated_tails), 'tails:'
 399             for score, tail_hash in decorated_tails:
 400                 print format_hash(tail_hash), score
 401         best_tail_score, best_tail = decorated_tails[-1] if decorated_tails else (None, None)
 402
 403         # decide best verified head
 404         decorated_heads = sorted(((
 405             self.verified.get_work(self.verified.get_nth_parent_hash(h, min(5, self.verified.get_height(h)))),
 406             #self.shares[h].peer is None,
 407             self.shares[h].pow_hash <= self.shares[h].header['bits'].target, # is block solution
 408             (self.shares[h].header['previous_block'], self.shares[h].header['bits']) == (previous_block, bits) or self.shares[h].peer is None,
 409             -self.shares[h].time_seen,
 410         ), h) for h in self.verified.tails.get(best_tail, []))
 411         if p2pool.DEBUG:
 412             print len(decorated_heads), 'heads. Top 10:'
 413             for score, head_hash in decorated_heads[-10:]:
 414                 print '   ', format_hash(head_hash), format_hash(self.shares[head_hash].previous_hash), score
 415         best_head_score, best = decorated_heads[-1] if decorated_heads else (None, None)
 416
 417         # eat away at heads
 418         if decorated_heads:
 419             for i in xrange(1000):
 420                 to_remove = set()
 421                 for share_hash, tail in self.heads.iteritems():
 422                     if share_hash in [head_hash for score, head_hash in decorated_heads[-5:]]:
 423                         #print 1
 424                         continue
 425                     if self.shares[share_hash].time_seen > time.time() - 300:
 426                         #print 2
 427                         continue
 428                     if share_hash not in self.verified.shares and max(self.shares[after_tail_hash].time_seen for after_tail_hash in self.reverse_shares.get(tail)) > time.time() - 120: # XXX stupid
 429                         #print 3
 430                         continue
 431                     to_remove.add(share_hash)
 432                 if not to_remove:
 433                     break
 434                 for share_hash in to_remove:
 435                     self.remove(share_hash)
 436                     if share_hash in self.verified.shares:
 437                         self.verified.remove(share_hash)
 438                 #print "_________", to_remove
 439
 440         # drop tails
 441         for i in xrange(1000):
 442             to_remove = set()
 443             for tail, heads in self.tails.iteritems():
 444                 if min(self.get_height(head) for head in heads) < 2*self.net.CHAIN_LENGTH + 10:
 445                     continue
 446                 for aftertail in self.reverse_shares.get(tail, set()):
 447                     if len(self.reverse_shares[self.shares[aftertail].previous_hash]) > 1: # XXX
 448                         print "raw"
 449                         continue
 450                     to_remove.add(aftertail)
 451             if not to_remove:
 452                 break
 453             # if removed from this, it must be removed from verified
 454             #start = time.time()
 455             for aftertail in to_remove:
 456                 if self.shares[aftertail].previous_hash not in self.tails:
 457                     print "erk", aftertail, self.shares[aftertail].previous_hash
 458                     continue
 459                 self.remove(aftertail)
 460                 if aftertail in self.verified.shares:
 461                     self.verified.remove(aftertail)
 462             #end = time.time()
 463             #print "removed! %i %f" % (len(to_remove), (end - start)/len(to_remove))
 464
 465         if best is not None:
 466             best_share = self.shares[best]
 467             if (best_share.header['previous_block'], best_share.header['bits']) != (previous_block, bits) and best_share.header_hash != previous_block and best_share.peer is not None:
 468                 if p2pool.DEBUG:
 469                     print 'Stale detected! %x < %x' % (best_share.header['previous_block'], previous_block)
 470                 best = best_share.previous_hash
 471
 472             timestamp_cutoff = min(int(time.time()), best_share.timestamp) - 3600
 473             target_cutoff = 2**256//(self.net.SHARE_PERIOD*best_tail_score[1] + 1) * 2 if best_tail_score[1] is not None else 2**256-1
 474         else:
 475             timestamp_cutoff = int(time.time()) - 24*60*60
 476             target_cutoff = 2**256-1
 477
 478         if p2pool.DEBUG:
 479             print 'Desire %i shares. Cutoff: %s old diff>%.2f' % (len(desired), math.format_dt(time.time() - timestamp_cutoff), bitcoin_data.target_to_difficulty(target_cutoff))
 480             for peer, hash, ts, targ in desired:
 481                 print '   ', '%s:%i' % peer.addr if peer is not None else None, format_hash(hash), math.format_dt(time.time() - ts), bitcoin_data.target_to_difficulty(targ), ts >= timestamp_cutoff, targ <= target_cutoff
 482
 483         return best, [(peer, hash) for peer, hash, ts, targ in desired if ts >= timestamp_cutoff and targ <= target_cutoff]
 484
 485     def score(self, share_hash, block_rel_height_func):
 486         # returns approximate lower bound on chain's hashrate in the last self.net.CHAIN_LENGTH*15//16*self.net.SHARE_PERIOD time
 487
 488         head_height = self.verified.get_height(share_hash)
 489         if head_height < self.net.CHAIN_LENGTH:
 490             return head_height, None
 491
 492         end_point = self.verified.get_nth_parent_hash(share_hash, self.net.CHAIN_LENGTH*15//16)
 493
 494         block_height = max(block_rel_height_func(share.header['previous_block']) for share in
 495             self.verified.get_chain(end_point, self.net.CHAIN_LENGTH//16))
 496
 497         return self.net.CHAIN_LENGTH, (self.verified.get_work(share_hash) - self.verified.get_work(end_point))//((0 - block_height + 1)*self.net.PARENT.BLOCK_PERIOD)
 498
 499 def format_hash(x):
 500     if x is None:
 501         return 'xxxxxxxx'
 502     return '%08x' % (x % 2**32)
 503
 504 class ShareStore(object):
 505     def __init__(self, prefix, net):
 506         self.filename = prefix
 507         self.dirname = os.path.dirname(os.path.abspath(prefix))
 508         self.filename = os.path.basename(os.path.abspath(prefix))
 509         self.net = net
 510         self.known = None # will be filename -> set of share hashes, set of verified hashes
 511         self.known_desired = None
 512
 513     def get_shares(self):
 514         if self.known is not None:
 515             raise AssertionError()
 516         known = {}
 517         filenames, next = self.get_filenames_and_next()
 518         for filename in filenames:
 519             share_hashes, verified_hashes = known.setdefault(filename, (set(), set()))
 520             with open(filename, 'rb') as f:
 521                 for line in f:
 522                     try:
 523                         type_id_str, data_hex = line.strip().split(' ')
 524                         type_id = int(type_id_str)
 525                         if type_id == 0:
 526                             pass
 527                         elif type_id == 1:
 528                             pass
 529                         elif type_id == 2:
 530                             verified_hash = int(data_hex, 16)
 531                             yield 'verified_hash', verified_hash
 532                             verified_hashes.add(verified_hash)
 533                         elif type_id == 5:
 534                             raw_share = share_type.unpack(data_hex.decode('hex'))
 535                             if raw_share['type'] in [0, 1]:
 536                                 continue
 537                             share = Share.from_share(raw_share, self.net, None)
 538                             yield 'share', share
 539                             share_hashes.add(share.hash)
 540                         else:
 541                             raise NotImplementedError("share type %i" % (type_id,))
 542                     except Exception:
 543                         log.err(None, "Error while reading saved shares, continuing where left off:")
 544         self.known = known
 545         self.known_desired = dict((k, (set(a), set(b))) for k, (a, b) in known.iteritems())
 546
 547     def _add_line(self, line):
 548         filenames, next = self.get_filenames_and_next()
 549         if filenames and os.path.getsize(filenames[-1]) < 10e6:
 550             filename = filenames[-1]
 551         else:
 552             filename = next
 553
 554         with open(filename, 'ab') as f:
 555             f.write(line + '\n')
 556
 557         return filename
 558
 559     def add_share(self, share):
 560         for filename, (share_hashes, verified_hashes) in self.known.iteritems():
 561             if share.hash in share_hashes:
 562                 break
 563         else:
 564             filename = self._add_line("%i %s" % (5, share_type.pack(share.as_share()).encode('hex')))
 565             share_hashes, verified_hashes = self.known.setdefault(filename, (set(), set()))
 566             share_hashes.add(share.hash)
 567         share_hashes, verified_hashes = self.known_desired.setdefault(filename, (set(), set()))
 568         share_hashes.add(share.hash)
 569
 570     def add_verified_hash(self, share_hash):
 571         for filename, (share_hashes, verified_hashes) in self.known.iteritems():
 572             if share_hash in verified_hashes:
 573                 break
 574         else:
 575             filename = self._add_line("%i %x" % (2, share_hash))
 576             share_hashes, verified_hashes = self.known.setdefault(filename, (set(), set()))
 577             verified_hashes.add(share_hash)
 578         share_hashes, verified_hashes = self.known_desired.setdefault(filename, (set(), set()))
 579         verified_hashes.add(share_hash)
 580
 581     def get_filenames_and_next(self):
 582         suffixes = sorted(int(x[len(self.filename):]) for x in os.listdir(self.dirname) if x.startswith(self.filename) and x[len(self.filename):].isdigit())
 583         return [os.path.join(self.dirname, self.filename + str(suffix)) for suffix in suffixes], os.path.join(self.dirname, self.filename + (str(suffixes[-1] + 1) if suffixes else str(0)))
 584
 585     def forget_share(self, share_hash):
 586         for filename, (share_hashes, verified_hashes) in self.known_desired.iteritems():
 587             if share_hash in share_hashes:
 588                 share_hashes.remove(share_hash)
 589         self.check_remove()
 590
 591     def forget_verified_share(self, share_hash):
 592         for filename, (share_hashes, verified_hashes) in self.known_desired.iteritems():
 593             if share_hash in verified_hashes:
 594                 verified_hashes.remove(share_hash)
 595         self.check_remove()
 596
 597     def check_remove(self):
 598         to_remove = set()
 599         for filename, (share_hashes, verified_hashes) in self.known_desired.iteritems():
 600             #print filename, len(share_hashes) + len(verified_hashes)
 601             if not share_hashes and not verified_hashes:
 602                 to_remove.add(filename)
 603         for filename in to_remove:
 604             self.known.pop(filename)
 605             self.known_desired.pop(filename)
 606             os.remove(filename)
 607             print "REMOVED", filename