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