p2pool/data.py

   1 from __future__ import division
   2
   3 import random
   4 import time
   5 import os
   6
   7 from twisted.python import log
   8
   9 import p2pool
  10 from p2pool import skiplists
  11 from p2pool.bitcoin import data as bitcoin_data, script
  12 from p2pool.util import math, forest, pack
  13
  14
  15 share_data_type = pack.ComposedType([
  16     ('previous_share_hash', pack.PossiblyNoneType(0, pack.IntType(256))),
  17     ('coinbase', pack.VarStrType()),
  18     ('nonce', pack.VarStrType()),
  19     ('new_script', pack.VarStrType()),
  20     ('subsidy', pack.IntType(64)),
  21     ('donation', pack.IntType(16)),
  22     ('stale_info', pack.IntType(8)), # 0 nothing, 253 orphan, 254 doa
  23 ])
  24
  25 share_info_type = pack.ComposedType([
  26     ('share_data', share_data_type),
  27     ('bits', bitcoin_data.FloatingIntegerType()),
  28     ('timestamp', pack.IntType(32)),
  29 ])
  30
  31 share1a_type = pack.ComposedType([
  32     ('header', bitcoin_data.block_header_type),
  33     ('share_info', share_info_type),
  34     ('merkle_branch', bitcoin_data.merkle_branch_type),
  35 ])
  36
  37 share1b_type = pack.ComposedType([
  38     ('header', bitcoin_data.block_header_type),
  39     ('share_info', share_info_type),
  40     ('other_txs', pack.ListType(bitcoin_data.tx_type)),
  41 ])
  42
  43 # type:
  44 # 0: share1a
  45 # 1: share1b
  46
  47 share_type = pack.ComposedType([
  48     ('type', pack.VarIntType()),
  49     ('contents', pack.VarStrType()),
  50 ])
  51
  52 class Share(object):
  53     __slots__ = 'header share_info merkle_branch other_txs timestamp share_data previous_hash target pow_hash header_hash hash time_seen peer net'.split(' ')
  54
  55     @classmethod
  56     def from_share(cls, share, net):
  57         if share['type'] == 0:
  58             res = cls.from_share1a(share1a_type.unpack(share['contents']), net)
  59             if not (res.pow_hash > res.header['bits'].target):
  60                 raise ValueError('invalid share type')
  61             return res
  62         elif share['type'] == 1:
  63             res = cls.from_share1b(share1b_type.unpack(share['contents']), net)
  64             if not (res.pow_hash <= res.header['bits'].target):
  65                 raise ValueError('invalid share type')
  66             return res
  67         else:
  68             raise ValueError('unknown share type: %r' % (share['type'],))
  69
  70     @classmethod
  71     def from_share1a(cls, share1a, net):
  72         return cls(net, **share1a)
  73
  74     @classmethod
  75     def from_share1b(cls, share1b, net):
  76         return cls(net, 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)
  77
  78     def __init__(self, net, header, share_info, merkle_branch, other_txs=None):
  79         self.net = net
  80
  81         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:
  82             raise ValueError('merkle_branch and other_txs do not match')
  83
  84         if len(merkle_branch) > 16:
  85             raise ValueError('merkle_branch too long!')
  86
  87         self.header = header
  88         self.share_info = share_info
  89         self.merkle_branch = merkle_branch
  90
  91         self.share_data = self.share_info['share_data']
  92         self.target = self.share_info['bits'].target
  93         self.timestamp = self.share_info['timestamp']
  94
  95         if len(self.share_data['new_script']) > 100:
  96             raise ValueError('new_script too long!')
  97         if script.get_sigop_count(self.share_data['new_script']) > 1:
  98             raise ValueError('too many sigops!')
  99
 100         self.previous_hash = self.share_data['previous_share_hash']
 101
 102         if len(self.share_data['nonce']) > 100:
 103             raise ValueError('nonce too long!')
 104
 105         if len(self.share_data['coinbase']) > 100:
 106             raise ValueError('''coinbase too large! %i bytes''' % (len(self.share_data['coinbase']),))
 107
 108         self.pow_hash = net.PARENT.POW_FUNC(bitcoin_data.block_header_type.pack(header))
 109         self.header_hash = bitcoin_data.hash256(bitcoin_data.block_header_type.pack(header))
 110
 111         self.hash = bitcoin_data.hash256(share1a_type.pack(self.as_share1a()))
 112
 113         if self.pow_hash > self.target:
 114             print 'hash %x' % self.pow_hash
 115             print 'targ %x' % self.target
 116             raise ValueError('not enough work!')
 117
 118         if other_txs is not None and not self.pow_hash <= self.header['bits'].target:
 119             raise ValueError('other_txs provided when not a block solution')
 120         if other_txs is None and self.pow_hash <= self.header['bits'].target:
 121             raise ValueError('other_txs not provided when a block solution')
 122
 123         self.other_txs = other_txs
 124
 125         # XXX eww
 126         self.time_seen = time.time()
 127         self.peer = None
 128
 129     def __repr__(self):
 130         return '<Share %s>' % (' '.join('%s=%r' % (k, getattr(self, k)) for k in self.__slots__),)
 131
 132     def check(self, tracker):
 133         share_info, gentx = generate_transaction(tracker, self.share_info['share_data'], self.header['bits'].target, self.share_info['timestamp'], self.net)
 134         if share_info != self.share_info:
 135             raise ValueError('share difficulty invalid')
 136
 137         if bitcoin_data.check_merkle_branch(bitcoin_data.hash256(bitcoin_data.tx_type.pack(gentx)), 0, self.merkle_branch) != self.header['merkle_root']:
 138             raise ValueError('''gentx doesn't match header via merkle_branch''')
 139
 140     def as_share(self):
 141         if self.pow_hash > self.header['bits'].target: # share1a
 142             return dict(type=0, contents=share1a_type.pack(self.as_share1a()))
 143         elif self.pow_hash <= self.header['bits'].target: # share1b
 144             return dict(type=1, contents=share1b_type.pack(self.as_share1b()))
 145         else:
 146             raise AssertionError()
 147
 148     def as_share1a(self):
 149         return dict(header=self.header, share_info=self.share_info, merkle_branch=self.merkle_branch)
 150
 151     def as_share1b(self):
 152         if self.other_txs is None:
 153             raise ValueError('share does not contain all txs')
 154
 155         return dict(header=self.header, share_info=self.share_info, other_txs=self.other_txs)
 156
 157     def as_block(self, tracker):
 158         if self.other_txs is None:
 159             raise ValueError('share does not contain all txs')
 160
 161         share_info, gentx = generate_transaction(tracker, self.share_info['share_data'], self.header['bits'].target, self.share_info['timestamp'], self.net)
 162         assert share_info == self.share_info
 163
 164         return dict(header=self.header, txs=[gentx] + self.other_txs)
 165
 166 def get_pool_attempts_per_second(tracker, previous_share_hash, dist):
 167     assert dist >= 2
 168     near = tracker.shares[previous_share_hash]
 169     far = tracker.shares[tracker.get_nth_parent_hash(previous_share_hash, dist - 1)]
 170     attempts = tracker.get_work(near.hash) - tracker.get_work(far.hash)
 171     time = near.timestamp - far.timestamp
 172     if time <= 0:
 173         time = 1
 174     return attempts//time
 175
 176 def get_average_stale_prop(tracker, share_hash, lookbehind):
 177     stales = sum(1 for share in tracker.get_chain(share_hash, lookbehind) if share.share_data['stale_info'] in [253, 254])
 178     return stales/(lookbehind + stales)
 179
 180 def generate_transaction(tracker, share_data, block_target, desired_timestamp, net):
 181     previous_share_hash = share_data['previous_share_hash']
 182     new_script = share_data['new_script']
 183     subsidy = share_data['subsidy']
 184     donation = share_data['donation']
 185     assert 0 <= donation <= 65535
 186
 187     if len(share_data['coinbase']) > 100:
 188         raise ValueError('coinbase too long!')
 189
 190     previous_share = tracker.shares[previous_share_hash] if previous_share_hash is not None else None
 191
 192     chain_length = getattr(net, 'REAL_CHAIN_LENGTH_FUNC', lambda _: net.REAL_CHAIN_LENGTH)(previous_share.timestamp if previous_share is not None else None)
 193
 194     height, last = tracker.get_height_and_last(previous_share_hash)
 195     assert height >= chain_length or last is None
 196     if height < net.TARGET_LOOKBEHIND:
 197         bits = bitcoin_data.FloatingInteger.from_target_upper_bound(net.MAX_TARGET)
 198     else:
 199         attempts_per_second = get_pool_attempts_per_second(tracker, previous_share_hash, net.TARGET_LOOKBEHIND)
 200         pre_target = 2**256//(net.SHARE_PERIOD*attempts_per_second) - 1
 201         pre_target2 = math.clip(pre_target, (previous_share.target*9//10, previous_share.target*11//10))
 202         pre_target3 = math.clip(pre_target2, (0, net.MAX_TARGET))
 203         bits = bitcoin_data.FloatingInteger.from_target_upper_bound(pre_target3)
 204
 205     attempts_to_block = bitcoin_data.target_to_average_attempts(block_target)
 206     max_att = net.SPREAD * attempts_to_block
 207
 208     this_att = min(bitcoin_data.target_to_average_attempts(bits.target), max_att)
 209     other_weights, other_total_weight, other_donation_weight = tracker.get_cumulative_weights(previous_share_hash, min(height, chain_length), 65535*max(0, max_att - this_att))
 210     assert other_total_weight == sum(other_weights.itervalues()) + other_donation_weight, (other_total_weight, sum(other_weights.itervalues()) + other_donation_weight)
 211     weights, total_weight, donation_weight = math.add_dicts({new_script: this_att*(65535-donation)}, other_weights), this_att*65535 + other_total_weight, this_att*donation + other_donation_weight
 212     assert total_weight == sum(weights.itervalues()) + donation_weight, (total_weight, sum(weights.itervalues()) + donation_weight)
 213
 214     SCRIPT = '4104ffd03de44a6e11b9917f3a29f9443283d9871c9d743ef30d5eddcd37094b64d1b3d8090496b53256786bf5c82932ec23c3b74d9f05a6f95a8b5529352656664bac'.decode('hex')
 215
 216     # 1 satoshi is always donated so that a list of p2pool generated blocks can be easily found by looking at the donation address
 217     amounts = dict((script, (subsidy-1)*(199*weight)//(200*total_weight)) for (script, weight) in weights.iteritems())
 218     amounts[new_script] = amounts.get(new_script, 0) + (subsidy-1)//200
 219     amounts[SCRIPT] = amounts.get(SCRIPT, 0) + (subsidy-1)*(199*donation_weight)//(200*total_weight)
 220     amounts[SCRIPT] = amounts.get(SCRIPT, 0) + subsidy - sum(amounts.itervalues()) # collect any extra satoshis :P
 221
 222     if sum(amounts.itervalues()) != subsidy:
 223         raise ValueError()
 224     if any(x < 0 for x in amounts.itervalues()):
 225         raise ValueError()
 226
 227     dests = sorted(amounts.iterkeys(), key=lambda script: (amounts[script], script))
 228     dests = dests[-4000:] # block length limit, unlikely to ever be hit
 229
 230     share_info = dict(
 231         share_data=share_data,
 232         bits=bits,
 233         timestamp=math.clip(desired_timestamp, (previous_share.timestamp - 60, previous_share.timestamp + 60)) if previous_share is not None else desired_timestamp,
 234     )
 235
 236     return share_info, dict(
 237         version=1,
 238         tx_ins=[dict(
 239             previous_output=None,
 240             sequence=None,
 241             script=share_data['coinbase'].ljust(2, '\x00'),
 242         )],
 243         tx_outs=[dict(value=0, script='\x20' + pack.IntType(256).pack(bitcoin_data.hash256(share_info_type.pack(share_info))))] + [dict(value=amounts[script], script=script) for script in dests if amounts[script]],
 244         lock_time=0,
 245     )
 246
 247 class OkayTracker(forest.Tracker):
 248     def __init__(self, net, my_share_hashes, my_doa_share_hashes):
 249         forest.Tracker.__init__(self)
 250         self.net = net
 251         self.verified = forest.Tracker(delta_type=forest.get_attributedelta_type(dict(forest.AttributeDelta.attrs,
 252             my_count=lambda share: 1 if share.hash in my_share_hashes else 0,
 253             my_doa_count=lambda share: 1 if share.hash in my_doa_share_hashes else 0,
 254             my_orphan_announce_count=lambda share: 1 if share.hash in my_share_hashes and share.share_data['stale_info'] == 253 else 0,
 255             my_dead_announce_count=lambda share: 1 if share.hash in my_share_hashes and share.share_data['stale_info'] == 254 else 0,
 256         )))
 257         self.verified.get_nth_parent_hash = self.get_nth_parent_hash # self is a superset of self.verified
 258
 259         self.get_cumulative_weights = skiplists.WeightsSkipList(self)
 260
 261     def attempt_verify(self, share):
 262         if share.hash in self.verified.shares:
 263             return True
 264         height, last = self.get_height_and_last(share.hash)
 265         if height < self.net.CHAIN_LENGTH + 1 and last is not None:
 266             raise AssertionError()
 267         try:
 268             share.check(self)
 269         except:
 270             log.err(None, 'Share check failed:')
 271             return False
 272         else:
 273             self.verified.add(share)
 274             return True
 275
 276     def think(self, block_rel_height_func, previous_block, bits):
 277         desired = set()
 278
 279         # O(len(self.heads))
 280         #   make 'unverified heads' set?
 281         # for each overall head, attempt verification
 282         # if it fails, attempt on parent, and repeat
 283         # if no successful verification because of lack of parents, request parent
 284         bads = set()
 285         for head in set(self.heads) - set(self.verified.heads):
 286             head_height, last = self.get_height_and_last(head)
 287
 288             for share in self.get_chain(head, head_height if last is None else min(5, max(0, head_height - self.net.CHAIN_LENGTH))):
 289                 if self.attempt_verify(share):
 290                     break
 291                 if share.hash in self.heads:
 292                     bads.add(share.hash)
 293             else:
 294                 if last is not None:
 295                     desired.add((
 296                         self.shares[random.choice(list(self.reverse_shares[last]))].peer,
 297                         last,
 298                         max(x.timestamp for x in self.get_chain(head, min(head_height, 5))),
 299                         min(x.target for x in self.get_chain(head, min(head_height, 5))),
 300                     ))
 301         for bad in bads:
 302             assert bad not in self.verified.shares
 303             assert bad in self.heads
 304             if p2pool.DEBUG:
 305                 print "BAD", bad
 306             self.remove(bad)
 307
 308         # try to get at least CHAIN_LENGTH height for each verified head, requesting parents if needed
 309         for head in list(self.verified.heads):
 310             head_height, last_hash = self.verified.get_height_and_last(head)
 311             last_height, last_last_hash = self.get_height_and_last(last_hash)
 312             # XXX review boundary conditions
 313             want = max(self.net.CHAIN_LENGTH - head_height, 0)
 314             can = max(last_height - 1 - self.net.CHAIN_LENGTH, 0) if last_last_hash is not None else last_height
 315             get = min(want, can)
 316             #print 'Z', head_height, last_hash is None, last_height, last_last_hash is None, want, can, get
 317             for share in self.get_chain(last_hash, get):
 318                 if not self.attempt_verify(share):
 319                     break
 320             if head_height < self.net.CHAIN_LENGTH and last_last_hash is not None:
 321                 desired.add((
 322                     self.verified.shares[random.choice(list(self.verified.reverse_shares[last_hash]))].peer,
 323                     last_last_hash,
 324                     max(x.timestamp for x in self.get_chain(head, min(head_height, 5))),
 325                     min(x.target for x in self.get_chain(head, min(head_height, 5))),
 326                 ))
 327
 328         # decide best tree
 329         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
 330         if p2pool.DEBUG:
 331             print len(decorated_tails), 'tails:'
 332             for score, tail_hash in decorated_tails:
 333                 print format_hash(tail_hash), score
 334         best_tail_score, best_tail = decorated_tails[-1] if decorated_tails else (None, None)
 335
 336         # decide best verified head
 337         decorated_heads = sorted(((
 338             self.verified.get_work(self.verified.get_nth_parent_hash(h, min(5, self.verified.get_height(h)))),
 339             #self.verified.shares[h].peer is None,
 340             (self.verified.shares[h].header['previous_block'], self.verified.shares[h].header['bits']) == (previous_block, bits) or self.verified.shares[h].peer is None,
 341             -self.verified.shares[h].time_seen,
 342         ), h) for h in self.verified.tails.get(best_tail, []))
 343         if p2pool.DEBUG:
 344             print len(decorated_heads), 'heads. Top 10:'
 345             for score, head_hash in decorated_heads[-10:]:
 346                 print '   ', format_hash(head_hash), format_hash(self.verified.shares[head_hash].previous_hash), score
 347         best_head_score, best = decorated_heads[-1] if decorated_heads else (None, None)
 348
 349         # eat away at heads
 350         if decorated_heads:
 351             for i in xrange(1000):
 352                 to_remove = set()
 353                 for share_hash, tail in self.heads.iteritems():
 354                     if share_hash in [head_hash for score, head_hash in decorated_heads[-5:]]:
 355                         #print 1
 356                         continue
 357                     if self.shares[share_hash].time_seen > time.time() - 300:
 358                         #print 2
 359                         continue
 360                     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
 361                         #print 3
 362                         continue
 363                     to_remove.add(share_hash)
 364                 if not to_remove:
 365                     break
 366                 for share_hash in to_remove:
 367                     self.remove(share_hash)
 368                     if share_hash in self.verified.shares:
 369                         self.verified.remove(share_hash)
 370                 #print "_________", to_remove
 371
 372         # drop tails
 373         for i in xrange(1000):
 374             to_remove = set()
 375             for tail, heads in self.tails.iteritems():
 376                 if min(self.get_height(head) for head in heads) < 2*self.net.CHAIN_LENGTH + 10:
 377                     continue
 378                 for aftertail in self.reverse_shares.get(tail, set()):
 379                     if len(self.reverse_shares[self.shares[aftertail].previous_hash]) > 1: # XXX
 380                         print "raw"
 381                         continue
 382                     to_remove.add(aftertail)
 383             if not to_remove:
 384                 break
 385             # if removed from this, it must be removed from verified
 386             #start = time.time()
 387             for aftertail in to_remove:
 388                 if self.shares[aftertail].previous_hash not in self.tails:
 389                     print "erk", aftertail, self.shares[aftertail].previous_hash
 390                     continue
 391                 self.remove(aftertail)
 392                 if aftertail in self.verified.shares:
 393                     self.verified.remove(aftertail)
 394             #end = time.time()
 395             #print "removed! %i %f" % (len(to_remove), (end - start)/len(to_remove))
 396
 397         if best is not None:
 398             best_share = self.verified.shares[best]
 399             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:
 400                 if p2pool.DEBUG:
 401                     print 'Stale detected! %x < %x' % (best_share.header['previous_block'], previous_block)
 402                 best = best_share.previous_hash
 403
 404             timestamp_cutoff = min(int(time.time()), best_share.timestamp) - 3600
 405             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
 406         else:
 407             timestamp_cutoff = int(time.time()) - 24*60*60
 408             target_cutoff = 2**256-1
 409
 410         if p2pool.DEBUG:
 411             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))
 412             for peer, hash, ts, targ in desired:
 413                 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
 414
 415         return best, [(peer, hash) for peer, hash, ts, targ in desired if ts >= timestamp_cutoff and targ <= target_cutoff]
 416
 417     def score(self, share_hash, block_rel_height_func):
 418         # returns approximate lower bound on chain's hashrate in the last self.net.CHAIN_LENGTH*15//16*self.net.SHARE_PERIOD time
 419
 420         head_height = self.verified.get_height(share_hash)
 421         if head_height < self.net.CHAIN_LENGTH:
 422             return head_height, None
 423
 424         end_point = self.verified.get_nth_parent_hash(share_hash, self.net.CHAIN_LENGTH*15//16)
 425
 426         block_height = max(block_rel_height_func(share.header['previous_block']) for share in
 427             self.verified.get_chain(end_point, self.net.CHAIN_LENGTH//16))
 428
 429         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)
 430
 431 def format_hash(x):
 432     if x is None:
 433         return 'xxxxxxxx'
 434     return '%08x' % (x % 2**32)
 435
 436 class ShareStore(object):
 437     def __init__(self, prefix, net):
 438         self.filename = prefix
 439         self.dirname = os.path.dirname(os.path.abspath(prefix))
 440         self.filename = os.path.basename(os.path.abspath(prefix))
 441         self.net = net
 442         self.known = None # will be filename -> set of share hashes, set of verified hashes
 443         self.known_desired = None
 444
 445     def get_shares(self):
 446         if self.known is not None:
 447             raise AssertionError()
 448         known = {}
 449         filenames, next = self.get_filenames_and_next()
 450         for filename in filenames:
 451             share_hashes, verified_hashes = known.setdefault(filename, (set(), set()))
 452             with open(filename, 'rb') as f:
 453                 for line in f:
 454                     try:
 455                         type_id_str, data_hex = line.strip().split(' ')
 456                         type_id = int(type_id_str)
 457                         if type_id == 0:
 458                             pass
 459                         elif type_id == 1:
 460                             pass
 461                         elif type_id == 2:
 462                             verified_hash = int(data_hex, 16)
 463                             yield 'verified_hash', verified_hash
 464                             verified_hashes.add(verified_hash)
 465                         elif type_id == 5:
 466                             share = Share.from_share(share_type.unpack(data_hex.decode('hex')), self.net)
 467                             yield 'share', share
 468                             share_hashes.add(share.hash)
 469                         else:
 470                             raise NotImplementedError("share type %i" % (type_id,))
 471                     except Exception:
 472                         log.err(None, "Error while reading saved shares, continuing where left off:")
 473         self.known = known
 474         self.known_desired = dict((k, (set(a), set(b))) for k, (a, b) in known.iteritems())
 475
 476     def _add_line(self, line):
 477         filenames, next = self.get_filenames_and_next()
 478         if filenames and os.path.getsize(filenames[-1]) < 10e6:
 479             filename = filenames[-1]
 480         else:
 481             filename = next
 482
 483         with open(filename, 'ab') as f:
 484             f.write(line + '\n')
 485
 486         return filename
 487
 488     def add_share(self, share):
 489         for filename, (share_hashes, verified_hashes) in self.known.iteritems():
 490             if share.hash in share_hashes:
 491                 break
 492         else:
 493             filename = self._add_line("%i %s" % (5, share_type.pack(share.as_share()).encode('hex')))
 494             share_hashes, verified_hashes = self.known.setdefault(filename, (set(), set()))
 495             share_hashes.add(share.hash)
 496         share_hashes, verified_hashes = self.known_desired.setdefault(filename, (set(), set()))
 497         share_hashes.add(share.hash)
 498
 499     def add_verified_hash(self, share_hash):
 500         for filename, (share_hashes, verified_hashes) in self.known.iteritems():
 501             if share_hash in verified_hashes:
 502                 break
 503         else:
 504             filename = self._add_line("%i %x" % (2, share_hash))
 505             share_hashes, verified_hashes = self.known.setdefault(filename, (set(), set()))
 506             verified_hashes.add(share_hash)
 507         share_hashes, verified_hashes = self.known_desired.setdefault(filename, (set(), set()))
 508         verified_hashes.add(share_hash)
 509
 510     def get_filenames_and_next(self):
 511         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())
 512         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)))
 513
 514     def forget_share(self, share_hash):
 515         for filename, (share_hashes, verified_hashes) in self.known_desired.iteritems():
 516             if share_hash in share_hashes:
 517                 share_hashes.remove(share_hash)
 518         self.check_remove()
 519
 520     def forget_verified_share(self, share_hash):
 521         for filename, (share_hashes, verified_hashes) in self.known_desired.iteritems():
 522             if share_hash in verified_hashes:
 523                 verified_hashes.remove(share_hash)
 524         self.check_remove()
 525
 526     def check_remove(self):
 527         to_remove = set()
 528         for filename, (share_hashes, verified_hashes) in self.known_desired.iteritems():
 529             #print filename, len(share_hashes) + len(verified_hashes)
 530             if not share_hashes and not verified_hashes:
 531                 to_remove.add(filename)
 532         for filename in to_remove:
 533             self.known.pop(filename)
 534             self.known_desired.pop(filename)
 535             os.remove(filename)
 536             print "REMOVED", filename