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, integer=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     if integer:
  96         return attempts//time
  97     return attempts/time
  98
  99 def get_average_stale_prop(tracker, share_hash, lookbehind):
 100     stales = sum(1 for share in tracker.get_chain(share_hash, lookbehind) if share.share_data['stale_info'] in [253, 254])
 101     return stales/(lookbehind + stales)
 102
 103 DONATION_SCRIPT = '4104ffd03de44a6e11b9917f3a29f9443283d9871c9d743ef30d5eddcd37094b64d1b3d8090496b53256786bf5c82932ec23c3b74d9f05a6f95a8b5529352656664bac'.decode('hex')
 104
 105 ref_type = pack.ComposedType([
 106     ('identifier', pack.FixedStrType(64//8)),
 107     ('share_info', share_info_type),
 108 ])
 109
 110 gentx_before_refhash = pack.VarStrType().pack(DONATION_SCRIPT) + pack.IntType(64).pack(0) + pack.VarStrType().pack('\x20' + pack.IntType(256).pack(0))[:2]
 111
 112 def generate_transaction(tracker, share_data, block_target, desired_timestamp, desired_target, net):
 113     previous_share = tracker.shares[share_data['previous_share_hash']] if share_data['previous_share_hash'] is not None else None
 114
 115     height, last = tracker.get_height_and_last(share_data['previous_share_hash'])
 116     assert height >= net.REAL_CHAIN_LENGTH or last is None
 117     if height < net.TARGET_LOOKBEHIND:
 118         pre_target3 = net.MAX_TARGET
 119     else:
 120         attempts_per_second = get_pool_attempts_per_second(tracker, share_data['previous_share_hash'], net.TARGET_LOOKBEHIND, min_work=True, integer=True)
 121         pre_target = 2**256//(net.SHARE_PERIOD*attempts_per_second) - 1 if attempts_per_second else 2**256-1
 122         pre_target2 = math.clip(pre_target, (previous_share.max_target*9//10, previous_share.max_target*11//10))
 123         pre_target3 = math.clip(pre_target2, (0, net.MAX_TARGET))
 124     max_bits = bitcoin_data.FloatingInteger.from_target_upper_bound(pre_target3)
 125     bits = bitcoin_data.FloatingInteger.from_target_upper_bound(math.clip(desired_target, (pre_target3//10, pre_target3)))
 126
 127     weights, total_weight, donation_weight = tracker.get_cumulative_weights(share_data['previous_share_hash'],
 128         min(height, net.REAL_CHAIN_LENGTH),
 129         65535*net.SPREAD*bitcoin_data.target_to_average_attempts(block_target),
 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))
 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'] == 2:
 182             return cls(net, peer, other_txs=None, **share1a_type.unpack(share['contents']))
 183         elif share['type'] == 3:
 184             share1b = share1b_type.unpack(share['contents'])
 185             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)
 186         else:
 187             raise ValueError('unknown share type: %r' % (share['type'],))
 188
 189     def __init__(self, net, peer, min_header, share_info, hash_link, merkle_branch, other_txs):
 190         if len(share_info['share_data']['coinbase']) > 100:
 191             raise ValueError('''coinbase too large! %i bytes''' % (len(self.share_data['coinbase']),))
 192
 193         if len(merkle_branch) > 16:
 194             raise ValueError('merkle_branch too long!')
 195
 196         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:
 197             raise ValueError('merkle_branch and other_txs do not match')
 198
 199         assert not hash_link['extra_data'], repr(hash_link['extra_data'])
 200
 201         self.net = net
 202         self.peer = peer
 203         self.min_header = min_header
 204         self.share_info = share_info
 205         self.hash_link = hash_link
 206         self.merkle_branch = merkle_branch
 207         self.other_txs = other_txs
 208
 209         self.share_data = self.share_info['share_data']
 210         self.max_target = self.share_info['max_bits'].target
 211         self.target = self.share_info['bits'].target
 212         self.timestamp = self.share_info['timestamp']
 213         self.previous_hash = self.share_data['previous_share_hash']
 214         self.new_script = bitcoin_data.pubkey_hash_to_script2(self.share_data['pubkey_hash'])
 215
 216         self.gentx_hash = check_hash_link(
 217             hash_link,
 218             pack.IntType(256).pack(bitcoin_data.hash256(ref_type.pack(dict(
 219                 identifier=net.IDENTIFIER,
 220                 share_info=share_info,
 221             )))) + pack.IntType(32).pack(0),
 222             gentx_before_refhash,
 223         )
 224         merkle_root = bitcoin_data.check_merkle_branch(self.gentx_hash, 0, merkle_branch)
 225         self.header = dict(min_header, merkle_root=merkle_root)
 226         self.pow_hash = net.PARENT.POW_FUNC(bitcoin_data.block_header_type.pack(self.header))
 227         self.header_hash = bitcoin_data.hash256(bitcoin_data.block_header_type.pack(self.header))
 228
 229         if self.pow_hash > self.target:
 230             print 'hash %x' % self.pow_hash
 231             print 'targ %x' % self.target
 232             raise ValueError('not enough work!')
 233
 234         if other_txs is not None and not self.pow_hash <= self.header['bits'].target:
 235             raise ValueError('other_txs provided when not a block solution')
 236         if other_txs is None and self.pow_hash <= self.header['bits'].target:
 237             raise ValueError('other_txs not provided when a block solution')
 238
 239         self.hash = bitcoin_data.hash256(share_type.pack(self.as_share()))
 240
 241         # XXX eww
 242         self.time_seen = time.time()
 243
 244     def __repr__(self):
 245         return '<Share %s>' % (' '.join('%s=%r' % (k, getattr(self, k)) for k in self.__slots__),)
 246
 247     def check(self, tracker):
 248         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)
 249         if share_info != self.share_info:
 250             raise ValueError('share difficulty invalid')
 251         if bitcoin_data.hash256(bitcoin_data.tx_type.pack(gentx)) != self.gentx_hash:
 252             raise ValueError('''gentx doesn't match hash_link''')
 253
 254     def as_share(self):
 255         if not self.pow_hash <= self.header['bits'].target: # share1a
 256             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)))
 257         else: # share1b
 258             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)))
 259
 260     def as_block(self, tracker):
 261         if self.other_txs is None:
 262             raise ValueError('share does not contain all txs')
 263
 264         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)
 265         assert share_info == self.share_info
 266
 267         return dict(header=self.header, txs=[gentx] + self.other_txs)
 268
 269 class OkayTracker(forest.Tracker):
 270     def __init__(self, net, my_share_hashes, my_doa_share_hashes):
 271         forest.Tracker.__init__(self, delta_type=forest.get_attributedelta_type(dict(forest.AttributeDelta.attrs,
 272             work=lambda share: bitcoin_data.target_to_average_attempts(share.target),
 273             min_work=lambda share: bitcoin_data.target_to_average_attempts(share.max_target),
 274         )))
 275         self.net = net
 276         self.verified = forest.Tracker(delta_type=forest.get_attributedelta_type(dict(forest.AttributeDelta.attrs,
 277             work=lambda share: bitcoin_data.target_to_average_attempts(share.target),
 278             my_count=lambda share: 1 if share.hash in my_share_hashes else 0,
 279             my_doa_count=lambda share: 1 if share.hash in my_doa_share_hashes else 0,
 280             my_orphan_announce_count=lambda share: 1 if share.hash in my_share_hashes and share.share_data['stale_info'] == 253 else 0,
 281             my_dead_announce_count=lambda share: 1 if share.hash in my_share_hashes and share.share_data['stale_info'] == 254 else 0,
 282         )))
 283         self.verified.get_nth_parent_hash = self.get_nth_parent_hash # self is a superset of self.verified
 284
 285         self.get_cumulative_weights = skiplists.WeightsSkipList(self)
 286
 287     def attempt_verify(self, share):
 288         if share.hash in self.verified.shares:
 289             return True
 290         height, last = self.get_height_and_last(share.hash)
 291         if height < self.net.CHAIN_LENGTH + 1 and last is not None:
 292             raise AssertionError()
 293         try:
 294             share.check(self)
 295         except:
 296             log.err(None, 'Share check failed:')
 297             return False
 298         else:
 299             self.verified.add(share)
 300             return True
 301
 302     def think(self, block_rel_height_func, previous_block, bits):
 303         desired = set()
 304
 305         # O(len(self.heads))
 306         #   make 'unverified heads' set?
 307         # for each overall head, attempt verification
 308         # if it fails, attempt on parent, and repeat
 309         # if no successful verification because of lack of parents, request parent
 310         bads = set()
 311         for head in set(self.heads) - set(self.verified.heads):
 312             head_height, last = self.get_height_and_last(head)
 313
 314             for share in self.get_chain(head, head_height if last is None else min(5, max(0, head_height - self.net.CHAIN_LENGTH))):
 315                 if self.attempt_verify(share):
 316                     break
 317                 if share.hash in self.heads:
 318                     bads.add(share.hash)
 319             else:
 320                 if last is not None:
 321                     desired.add((
 322                         self.shares[random.choice(list(self.reverse_shares[last]))].peer,
 323                         last,
 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         for bad in bads:
 328             assert bad not in self.verified.shares
 329             assert bad in self.heads
 330             if p2pool.DEBUG:
 331                 print "BAD", bad
 332             self.remove(bad)
 333
 334         # try to get at least CHAIN_LENGTH height for each verified head, requesting parents if needed
 335         for head in list(self.verified.heads):
 336             head_height, last_hash = self.verified.get_height_and_last(head)
 337             last_height, last_last_hash = self.get_height_and_last(last_hash)
 338             # XXX review boundary conditions
 339             want = max(self.net.CHAIN_LENGTH - head_height, 0)
 340             can = max(last_height - 1 - self.net.CHAIN_LENGTH, 0) if last_last_hash is not None else last_height
 341             get = min(want, can)
 342             #print 'Z', head_height, last_hash is None, last_height, last_last_hash is None, want, can, get
 343             for share in self.get_chain(last_hash, get):
 344                 if not self.attempt_verify(share):
 345                     break
 346             if head_height < self.net.CHAIN_LENGTH and last_last_hash is not None:
 347                 desired.add((
 348                     self.shares[random.choice(list(self.verified.reverse_shares[last_hash]))].peer,
 349                     last_last_hash,
 350                     max(x.timestamp for x in self.get_chain(head, min(head_height, 5))),
 351                     min(x.target for x in self.get_chain(head, min(head_height, 5))),
 352                 ))
 353
 354         # decide best tree
 355         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
 356         if p2pool.DEBUG:
 357             print len(decorated_tails), 'tails:'
 358             for score, tail_hash in decorated_tails:
 359                 print format_hash(tail_hash), score
 360         best_tail_score, best_tail = decorated_tails[-1] if decorated_tails else (None, None)
 361
 362         # decide best verified head
 363         decorated_heads = sorted(((
 364             self.verified.get_work(self.verified.get_nth_parent_hash(h, min(5, self.verified.get_height(h)))),
 365             #self.shares[h].peer is None,
 366             self.shares[h].pow_hash <= self.shares[h].header['bits'].target, # is block solution
 367             (self.shares[h].header['previous_block'], self.shares[h].header['bits']) == (previous_block, bits) or self.shares[h].peer is None,
 368             -self.shares[h].time_seen,
 369         ), h) for h in self.verified.tails.get(best_tail, []))
 370         if p2pool.DEBUG:
 371             print len(decorated_heads), 'heads. Top 10:'
 372             for score, head_hash in decorated_heads[-10:]:
 373                 print '   ', format_hash(head_hash), format_hash(self.shares[head_hash].previous_hash), score
 374         best_head_score, best = decorated_heads[-1] if decorated_heads else (None, None)
 375
 376         # eat away at heads
 377         if decorated_heads:
 378             for i in xrange(1000):
 379                 to_remove = set()
 380                 for share_hash, tail in self.heads.iteritems():
 381                     if share_hash in [head_hash for score, head_hash in decorated_heads[-5:]]:
 382                         #print 1
 383                         continue
 384                     if self.shares[share_hash].time_seen > time.time() - 300:
 385                         #print 2
 386                         continue
 387                     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
 388                         #print 3
 389                         continue
 390                     to_remove.add(share_hash)
 391                 if not to_remove:
 392                     break
 393                 for share_hash in to_remove:
 394                     self.remove(share_hash)
 395                     if share_hash in self.verified.shares:
 396                         self.verified.remove(share_hash)
 397                 #print "_________", to_remove
 398
 399         # drop tails
 400         for i in xrange(1000):
 401             to_remove = set()
 402             for tail, heads in self.tails.iteritems():
 403                 if min(self.get_height(head) for head in heads) < 2*self.net.CHAIN_LENGTH + 10:
 404                     continue
 405                 for aftertail in self.reverse_shares.get(tail, set()):
 406                     if len(self.reverse_shares[self.shares[aftertail].previous_hash]) > 1: # XXX
 407                         print "raw"
 408                         continue
 409                     to_remove.add(aftertail)
 410             if not to_remove:
 411                 break
 412             # if removed from this, it must be removed from verified
 413             #start = time.time()
 414             for aftertail in to_remove:
 415                 if self.shares[aftertail].previous_hash not in self.tails:
 416                     print "erk", aftertail, self.shares[aftertail].previous_hash
 417                     continue
 418                 self.remove(aftertail)
 419                 if aftertail in self.verified.shares:
 420                     self.verified.remove(aftertail)
 421             #end = time.time()
 422             #print "removed! %i %f" % (len(to_remove), (end - start)/len(to_remove))
 423
 424         if best is not None:
 425             best_share = self.shares[best]
 426             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:
 427                 if p2pool.DEBUG:
 428                     print 'Stale detected! %x < %x' % (best_share.header['previous_block'], previous_block)
 429                 best = best_share.previous_hash
 430
 431             timestamp_cutoff = min(int(time.time()), best_share.timestamp) - 3600
 432             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
 433         else:
 434             timestamp_cutoff = int(time.time()) - 24*60*60
 435             target_cutoff = 2**256-1
 436
 437         if p2pool.DEBUG:
 438             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))
 439             for peer, hash, ts, targ in desired:
 440                 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
 441
 442         return best, [(peer, hash) for peer, hash, ts, targ in desired if ts >= timestamp_cutoff and targ <= target_cutoff]
 443
 444     def score(self, share_hash, block_rel_height_func):
 445         # returns approximate lower bound on chain's hashrate in the last self.net.CHAIN_LENGTH*15//16*self.net.SHARE_PERIOD time
 446
 447         head_height = self.verified.get_height(share_hash)
 448         if head_height < self.net.CHAIN_LENGTH:
 449             return head_height, None
 450
 451         end_point = self.verified.get_nth_parent_hash(share_hash, self.net.CHAIN_LENGTH*15//16)
 452
 453         block_height = max(block_rel_height_func(share.header['previous_block']) for share in
 454             self.verified.get_chain(end_point, self.net.CHAIN_LENGTH//16))
 455
 456         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)
 457
 458 def format_hash(x):
 459     if x is None:
 460         return 'xxxxxxxx'
 461     return '%08x' % (x % 2**32)
 462
 463 class ShareStore(object):
 464     def __init__(self, prefix, net):
 465         self.filename = prefix
 466         self.dirname = os.path.dirname(os.path.abspath(prefix))
 467         self.filename = os.path.basename(os.path.abspath(prefix))
 468         self.net = net
 469         self.known = None # will be filename -> set of share hashes, set of verified hashes
 470         self.known_desired = None
 471
 472     def get_shares(self):
 473         if self.known is not None:
 474             raise AssertionError()
 475         known = {}
 476         filenames, next = self.get_filenames_and_next()
 477         for filename in filenames:
 478             share_hashes, verified_hashes = known.setdefault(filename, (set(), set()))
 479             with open(filename, 'rb') as f:
 480                 for line in f:
 481                     try:
 482                         type_id_str, data_hex = line.strip().split(' ')
 483                         type_id = int(type_id_str)
 484                         if type_id == 0:
 485                             pass
 486                         elif type_id == 1:
 487                             pass
 488                         elif type_id == 2:
 489                             verified_hash = int(data_hex, 16)
 490                             yield 'verified_hash', verified_hash
 491                             verified_hashes.add(verified_hash)
 492                         elif type_id == 5:
 493                             raw_share = share_type.unpack(data_hex.decode('hex'))
 494                             if raw_share['type'] in [0, 1]:
 495                                 continue
 496                             share = Share.from_share(raw_share, self.net, None)
 497                             yield 'share', share
 498                             share_hashes.add(share.hash)
 499                         else:
 500                             raise NotImplementedError("share type %i" % (type_id,))
 501                     except Exception:
 502                         log.err(None, "Error while reading saved shares, continuing where left off:")
 503         self.known = known
 504         self.known_desired = dict((k, (set(a), set(b))) for k, (a, b) in known.iteritems())
 505
 506     def _add_line(self, line):
 507         filenames, next = self.get_filenames_and_next()
 508         if filenames and os.path.getsize(filenames[-1]) < 10e6:
 509             filename = filenames[-1]
 510         else:
 511             filename = next
 512
 513         with open(filename, 'ab') as f:
 514             f.write(line + '\n')
 515
 516         return filename
 517
 518     def add_share(self, share):
 519         for filename, (share_hashes, verified_hashes) in self.known.iteritems():
 520             if share.hash in share_hashes:
 521                 break
 522         else:
 523             filename = self._add_line("%i %s" % (5, share_type.pack(share.as_share()).encode('hex')))
 524             share_hashes, verified_hashes = self.known.setdefault(filename, (set(), set()))
 525             share_hashes.add(share.hash)
 526         share_hashes, verified_hashes = self.known_desired.setdefault(filename, (set(), set()))
 527         share_hashes.add(share.hash)
 528
 529     def add_verified_hash(self, share_hash):
 530         for filename, (share_hashes, verified_hashes) in self.known.iteritems():
 531             if share_hash in verified_hashes:
 532                 break
 533         else:
 534             filename = self._add_line("%i %x" % (2, share_hash))
 535             share_hashes, verified_hashes = self.known.setdefault(filename, (set(), set()))
 536             verified_hashes.add(share_hash)
 537         share_hashes, verified_hashes = self.known_desired.setdefault(filename, (set(), set()))
 538         verified_hashes.add(share_hash)
 539
 540     def get_filenames_and_next(self):
 541         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())
 542         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)))
 543
 544     def forget_share(self, share_hash):
 545         for filename, (share_hashes, verified_hashes) in self.known_desired.iteritems():
 546             if share_hash in share_hashes:
 547                 share_hashes.remove(share_hash)
 548         self.check_remove()
 549
 550     def forget_verified_share(self, share_hash):
 551         for filename, (share_hashes, verified_hashes) in self.known_desired.iteritems():
 552             if share_hash in verified_hashes:
 553                 verified_hashes.remove(share_hash)
 554         self.check_remove()
 555
 556     def check_remove(self):
 557         to_remove = set()
 558         for filename, (share_hashes, verified_hashes) in self.known_desired.iteritems():
 559             #print filename, len(share_hashes) + len(verified_hashes)
 560             if not share_hashes and not verified_hashes:
 561                 to_remove.add(filename)
 562         for filename in to_remove:
 563             self.known.pop(filename)
 564             self.known_desired.pop(filename)
 565             os.remove(filename)
 566             print "REMOVED", filename