p2pool/data.py

   1 from __future__ import division
   2
   3 import hashlib
   4 import os
   5 import random
   6 import sys
   7 import time
   8
   9 from twisted.python import log
  10
  11 import p2pool
  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 share_type = pack.ComposedType([
  38     ('type', pack.VarIntType()),
  39     ('contents', pack.VarStrType()),
  40 ])
  41
  42 def load_share(share, net, peer):
  43     if share['type'] in [0, 1, 2, 3]:
  44         from p2pool import p2p
  45         raise p2p.PeerMisbehavingError('sent an obsolete share')
  46     elif share['type'] == 4:
  47         return Share(net, peer, other_txs=None, **Share.share1a_type.unpack(share['contents']))
  48     elif share['type'] == 5:
  49         share1b = Share.share1b_type.unpack(share['contents'])
  50         return Share(net, peer, merkle_link=bitcoin_data.calculate_merkle_link([0] + [bitcoin_data.hash256(bitcoin_data.tx_type.pack(x)) for x in share1b['other_txs']], 0), **share1b)
  51     elif share['type'] == NewShare.VERSION:
  52         return NewShare(net, peer, NewShare.share_type.unpack(share['contents']))
  53     else:
  54         raise ValueError('unknown share type: %r' % (share['type'],))
  55
  56 DONATION_SCRIPT = '4104ffd03de44a6e11b9917f3a29f9443283d9871c9d743ef30d5eddcd37094b64d1b3d8090496b53256786bf5c82932ec23c3b74d9f05a6f95a8b5529352656664bac'.decode('hex')
  57
  58 class Share(object):
  59     small_block_header_type = pack.ComposedType([
  60         ('version', pack.VarIntType()), # XXX must be constrained to 32 bits
  61         ('previous_block', pack.PossiblyNoneType(0, pack.IntType(256))),
  62         ('timestamp', pack.IntType(32)),
  63         ('bits', bitcoin_data.FloatingIntegerType()),
  64         ('nonce', pack.IntType(32)),
  65     ])
  66
  67     share_data_type = pack.ComposedType([
  68         ('previous_share_hash', pack.PossiblyNoneType(0, pack.IntType(256))),
  69         ('coinbase', pack.VarStrType()),
  70         ('nonce', pack.IntType(32)),
  71         ('pubkey_hash', pack.IntType(160)),
  72         ('subsidy', pack.IntType(64)),
  73         ('donation', pack.IntType(16)),
  74         ('stale_info', pack.EnumType(pack.IntType(8), dict((k, {0: None, 253: 'orphan', 254: 'doa'}.get(k, 'unk%i' % (k,))) for k in xrange(256)))),
  75         ('desired_version', pack.VarIntType()),
  76     ])
  77
  78     share_info_type = pack.ComposedType([
  79         ('share_data', share_data_type),
  80         ('far_share_hash', pack.PossiblyNoneType(0, pack.IntType(256))),
  81         ('max_bits', bitcoin_data.FloatingIntegerType()),
  82         ('bits', bitcoin_data.FloatingIntegerType()),
  83         ('timestamp', pack.IntType(32)),
  84     ])
  85
  86     share_common_type = pack.ComposedType([
  87         ('min_header', small_block_header_type),
  88         ('share_info', share_info_type),
  89         ('ref_merkle_link', pack.ComposedType([
  90             ('branch', pack.ListType(pack.IntType(256))),
  91             ('index', pack.VarIntType()),
  92         ])),
  93         ('hash_link', hash_link_type),
  94     ])
  95     share1a_type = pack.ComposedType([
  96         ('common', share_common_type),
  97         ('merkle_link', pack.ComposedType([
  98             ('branch', pack.ListType(pack.IntType(256))),
  99             ('index', pack.IntType(0)), # it will always be 0
 100         ])),
 101     ])
 102     share1b_type = pack.ComposedType([
 103         ('common', share_common_type),
 104         ('other_txs', pack.ListType(bitcoin_data.tx_type)),
 105     ])
 106
 107     ref_type = pack.ComposedType([
 108         ('identifier', pack.FixedStrType(64//8)),
 109         ('share_info', share_info_type),
 110     ])
 111
 112     gentx_before_refhash = pack.VarStrType().pack(DONATION_SCRIPT) + pack.IntType(64).pack(0) + pack.VarStrType().pack('\x20' + pack.IntType(256).pack(0))[:2]
 113
 114     @classmethod
 115     def generate_transaction(cls, tracker, share_data, block_target, desired_timestamp, desired_target, ref_merkle_link, desired_other_transaction_hashes, net, known_txs=None):
 116         previous_share = tracker.items[share_data['previous_share_hash']] if share_data['previous_share_hash'] is not None else None
 117
 118         height, last = tracker.get_height_and_last(share_data['previous_share_hash'])
 119         assert height >= net.REAL_CHAIN_LENGTH or last is None
 120         if height < net.TARGET_LOOKBEHIND:
 121             pre_target3 = net.MAX_TARGET
 122         else:
 123             attempts_per_second = get_pool_attempts_per_second(tracker, share_data['previous_share_hash'], net.TARGET_LOOKBEHIND, min_work=True, integer=True)
 124             pre_target = 2**256//(net.SHARE_PERIOD*attempts_per_second) - 1 if attempts_per_second else 2**256-1
 125             pre_target2 = math.clip(pre_target, (previous_share.max_target*9//10, previous_share.max_target*11//10))
 126             pre_target3 = math.clip(pre_target2, (0, net.MAX_TARGET))
 127         max_bits = bitcoin_data.FloatingInteger.from_target_upper_bound(pre_target3)
 128         bits = bitcoin_data.FloatingInteger.from_target_upper_bound(math.clip(desired_target, (pre_target3//10, pre_target3)))
 129
 130         weights, total_weight, donation_weight = tracker.get_cumulative_weights(share_data['previous_share_hash'],
 131             min(height, net.REAL_CHAIN_LENGTH),
 132             65535*net.SPREAD*bitcoin_data.target_to_average_attempts(block_target),
 133         )
 134         assert total_weight == sum(weights.itervalues()) + donation_weight, (total_weight, sum(weights.itervalues()) + donation_weight)
 135
 136         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
 137         this_script = bitcoin_data.pubkey_hash_to_script2(share_data['pubkey_hash'])
 138         amounts[this_script] = amounts.get(this_script, 0) + share_data['subsidy']//200 # 0.5% goes to block finder
 139         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
 140
 141         if sum(amounts.itervalues()) != share_data['subsidy'] or any(x < 0 for x in amounts.itervalues()):
 142             raise ValueError()
 143
 144         dests = sorted(amounts.iterkeys(), key=lambda script: (script == DONATION_SCRIPT, amounts[script], script))[-4000:] # block length limit, unlikely to ever be hit
 145
 146         share_info = dict(
 147             share_data=share_data,
 148             far_share_hash=None if last is None and height < 99 else tracker.get_nth_parent_hash(share_data['previous_share_hash'], 99),
 149             max_bits=max_bits,
 150             bits=bits,
 151             timestamp=math.clip(desired_timestamp, (
 152                 (previous_share.timestamp + net.SHARE_PERIOD) - (net.SHARE_PERIOD - 1), # = previous_share.timestamp + 1
 153                 (previous_share.timestamp + net.SHARE_PERIOD) + (net.SHARE_PERIOD - 1),
 154             )) if previous_share is not None else desired_timestamp,
 155         )
 156
 157         gentx = dict(
 158             version=1,
 159             tx_ins=[dict(
 160                 previous_output=None,
 161                 sequence=None,
 162                 script=share_data['coinbase'].ljust(2, '\x00'),
 163             )],
 164             tx_outs=[dict(value=amounts[script], script=script) for script in dests if amounts[script] or script == DONATION_SCRIPT] + [dict(
 165                 value=0,
 166                 script='\x20' + cls.get_ref_hash(net, share_info, ref_merkle_link),
 167             )],
 168             lock_time=0,
 169         )
 170
 171         def get_share(header, transactions):
 172             assert transactions[0] == gentx and [bitcoin_data.hash256(bitcoin_data.tx_type.pack(tx)) for tx in transactions[1:]] == desired_other_transaction_hashes
 173             min_header = dict(header);del min_header['merkle_root']
 174             hash_link = prefix_to_hash_link(bitcoin_data.tx_type.pack(gentx)[:-32-4], cls.gentx_before_refhash)
 175             merkle_link = bitcoin_data.calculate_merkle_link([None] + desired_other_transaction_hashes, 0)
 176             pow_hash = net.PARENT.POW_FUNC(bitcoin_data.block_header_type.pack(header))
 177             return cls(net, None, dict(
 178                 min_header=min_header, share_info=share_info, hash_link=hash_link,
 179                 ref_merkle_link=dict(branch=[], index=0),
 180             ), merkle_link=merkle_link, other_txs=transactions[1:] if pow_hash <= header['bits'].target else None)
 181
 182         return share_info, gentx, desired_other_transaction_hashes, get_share
 183
 184     @classmethod
 185     def get_ref_hash(cls, net, share_info, ref_merkle_link):
 186         return pack.IntType(256).pack(bitcoin_data.check_merkle_link(bitcoin_data.hash256(cls.ref_type.pack(dict(
 187             identifier=net.IDENTIFIER,
 188             share_info=share_info,
 189         ))), ref_merkle_link))
 190
 191     __slots__ = 'net peer common min_header share_info hash_link merkle_link other_txs hash share_data max_target target timestamp previous_hash new_script desired_version gentx_hash header pow_hash header_hash new_transaction_hashes time_seen'.split(' ')
 192
 193     def __init__(self, net, peer, common, merkle_link, other_txs):
 194         self.net = net
 195         self.peer = peer
 196         self.common = common
 197         self.min_header = common['min_header']
 198         self.share_info = common['share_info']
 199         self.hash_link = common['hash_link']
 200         self.merkle_link = merkle_link
 201         self.other_txs = other_txs
 202
 203         if len(self.share_info['share_data']['coinbase']) > 100:
 204             raise ValueError('''coinbase too large! %i bytes''' % (len(self.share_info['share_data']['coinbase']),))
 205
 206         if len(merkle_link['branch']) > 16:
 207             raise ValueError('merkle branch too long!')
 208
 209         if p2pool.DEBUG and other_txs is not None and bitcoin_data.calculate_merkle_link([0] + [bitcoin_data.hash256(bitcoin_data.tx_type.pack(x)) for x in other_txs], 0) != merkle_link:
 210             raise ValueError('merkle_link and other_txs do not match')
 211
 212         assert not self.hash_link['extra_data'], repr(self.hash_link['extra_data'])
 213
 214         self.share_data = self.share_info['share_data']
 215         self.max_target = self.share_info['max_bits'].target
 216         self.target = self.share_info['bits'].target
 217         self.timestamp = self.share_info['timestamp']
 218         self.previous_hash = self.share_data['previous_share_hash']
 219         self.new_script = bitcoin_data.pubkey_hash_to_script2(self.share_data['pubkey_hash'])
 220         self.desired_version = self.share_data['desired_version']
 221
 222         self.gentx_hash = check_hash_link(
 223             self.hash_link,
 224             self.get_ref_hash(net, self.share_info, common['ref_merkle_link']) + pack.IntType(32).pack(0),
 225             self.gentx_before_refhash,
 226         )
 227         merkle_root = bitcoin_data.check_merkle_link(self.gentx_hash, merkle_link)
 228         self.header = dict(self.min_header, merkle_root=merkle_root)
 229         self.pow_hash = net.PARENT.POW_FUNC(bitcoin_data.block_header_type.pack(self.header))
 230         self.hash = self.header_hash = bitcoin_data.hash256(bitcoin_data.block_header_type.pack(self.header))
 231
 232         if self.pow_hash > self.target:
 233             from p2pool import p2p
 234             raise p2p.PeerMisbehavingError('share PoW invalid')
 235
 236         if other_txs is not None and not self.pow_hash <= self.header['bits'].target:
 237             raise ValueError('other_txs provided when not a block solution')
 238         if other_txs is None and self.pow_hash <= self.header['bits'].target:
 239             raise ValueError('other_txs not provided when a block solution')
 240
 241         self.new_transaction_hashes = []
 242
 243         # XXX eww
 244         self.time_seen = time.time()
 245
 246     def __repr__(self):
 247         return '<Share %s>' % (' '.join('%s=%r' % (k, getattr(self, k)) for k in self.__slots__),)
 248
 249     def as_share1a(self):
 250         return dict(type=4, contents=self.share1a_type.pack(dict(common=self.common, merkle_link=self.merkle_link)))
 251
 252     def as_share1b(self):
 253         return dict(type=5, contents=self.share1b_type.pack(dict(common=self.common, other_txs=self.other_txs)))
 254
 255     def as_share(self):
 256         if not self.pow_hash <= self.header['bits'].target: # share1a
 257             return self.as_share1a()
 258         else:
 259             return self.as_share1b()
 260
 261     def check(self, tracker):
 262         if self.share_data['previous_share_hash'] is not None:
 263             previous_share = tracker.items[self.share_data['previous_share_hash']]
 264             if isinstance(previous_share, NewShare):
 265                 from p2pool import p2p
 266                 raise p2p.PeerMisbehavingError('''Share can't follow NewShare''')
 267         share_info, gentx, other_transaction_hashes, get_share = self.generate_transaction(tracker, self.share_info['share_data'], self.header['bits'].target, self.share_info['timestamp'], self.share_info['bits'].target, self.common['ref_merkle_link'], [], self.net) # ok because desired_other_transaction_hashes is only used in get_share
 268         if share_info != self.share_info:
 269             raise ValueError('share_info invalid')
 270         if bitcoin_data.hash256(bitcoin_data.tx_type.pack(gentx)) != self.gentx_hash:
 271             raise ValueError('''gentx doesn't match hash_link''')
 272         return gentx # only used by as_block
 273
 274     def get_other_tx_hashes(self, tracker):
 275         return []
 276
 277     def should_punish_reason(self, previous_block, bits, tracker, known_txs):
 278         if (self.header['previous_block'], self.header['bits']) != (previous_block, bits) and self.header_hash != previous_block and self.peer is not None:
 279             return True, 'Block-stale detected! %x < %x' % (self.header['previous_block'], previous_block)
 280
 281         if self.pow_hash <= self.header['bits'].target:
 282             return -1, 'block solution'
 283
 284         return False, None
 285
 286     def as_block(self, tracker, known_txs):
 287         if self.other_txs is None:
 288             raise ValueError('share does not contain all txs')
 289         return dict(header=self.header, txs=[self.check(tracker)] + self.other_txs)
 290
 291 class NewShare(object):
 292     VERSION = 8
 293
 294     other_txs = None
 295
 296     small_block_header_type = pack.ComposedType([
 297         ('version', pack.VarIntType()),
 298         ('previous_block', pack.PossiblyNoneType(0, pack.IntType(256))),
 299         ('timestamp', pack.IntType(32)),
 300         ('bits', bitcoin_data.FloatingIntegerType()),
 301         ('nonce', pack.IntType(32)),
 302     ])
 303
 304     share_info_type = pack.ComposedType([
 305         ('share_data', pack.ComposedType([
 306             ('previous_share_hash', pack.PossiblyNoneType(0, pack.IntType(256))),
 307             ('coinbase', pack.VarStrType()),
 308             ('nonce', pack.IntType(32)),
 309             ('pubkey_hash', pack.IntType(160)),
 310             ('subsidy', pack.IntType(64)),
 311             ('donation', pack.IntType(16)),
 312             ('stale_info', pack.EnumType(pack.IntType(8), dict((k, {0: None, 253: 'orphan', 254: 'doa'}.get(k, 'unk%i' % (k,))) for k in xrange(256)))),
 313             ('desired_version', pack.VarIntType()),
 314         ])),
 315         ('new_transaction_hashes', pack.ListType(pack.IntType(256))),
 316         ('transaction_hash_refs', pack.ListType(pack.ComposedType([ # compressed by referencing previous shares' hashes
 317             ('share_count', pack.VarIntType()),
 318             ('tx_count', pack.VarIntType()),
 319         ]))),
 320         ('far_share_hash', pack.PossiblyNoneType(0, pack.IntType(256))),
 321         ('max_bits', bitcoin_data.FloatingIntegerType()),
 322         ('bits', bitcoin_data.FloatingIntegerType()),
 323         ('timestamp', pack.IntType(32)),
 324     ])
 325
 326     share_type = pack.ComposedType([
 327         ('min_header', small_block_header_type),
 328         ('share_info', share_info_type),
 329         ('ref_merkle_link', pack.ComposedType([
 330             ('branch', pack.ListType(pack.IntType(256))),
 331             ('index', pack.IntType(0)),
 332         ])),
 333         ('hash_link', hash_link_type),
 334         ('merkle_link', pack.ComposedType([
 335             ('branch', pack.ListType(pack.IntType(256))),
 336             ('index', pack.IntType(0)), # it will always be 0
 337         ])),
 338     ])
 339
 340     ref_type = pack.ComposedType([
 341         ('identifier', pack.FixedStrType(64//8)),
 342         ('share_info', share_info_type),
 343     ])
 344
 345     gentx_before_refhash = pack.VarStrType().pack(DONATION_SCRIPT) + pack.IntType(64).pack(0) + pack.VarStrType().pack('\x20' + pack.IntType(256).pack(0))[:2]
 346
 347     @classmethod
 348     def generate_transaction(cls, tracker, share_data, block_target, desired_timestamp, desired_target, ref_merkle_link, desired_other_transaction_hashes, net, known_txs=None):
 349         previous_share = tracker.items[share_data['previous_share_hash']] if share_data['previous_share_hash'] is not None else None
 350
 351         height, last = tracker.get_height_and_last(share_data['previous_share_hash'])
 352         assert height >= net.REAL_CHAIN_LENGTH or last is None
 353         if height < net.TARGET_LOOKBEHIND:
 354             pre_target3 = net.MAX_TARGET
 355         else:
 356             attempts_per_second = get_pool_attempts_per_second(tracker, share_data['previous_share_hash'], net.TARGET_LOOKBEHIND, min_work=True, integer=True)
 357             pre_target = 2**256//(net.SHARE_PERIOD*attempts_per_second) - 1 if attempts_per_second else 2**256-1
 358             pre_target2 = math.clip(pre_target, (previous_share.max_target*9//10, previous_share.max_target*11//10))
 359             pre_target3 = math.clip(pre_target2, (0, net.MAX_TARGET))
 360         max_bits = bitcoin_data.FloatingInteger.from_target_upper_bound(pre_target3)
 361         bits = bitcoin_data.FloatingInteger.from_target_upper_bound(math.clip(desired_target, (pre_target3//10, pre_target3)))
 362
 363         weights, total_weight, donation_weight = tracker.get_cumulative_weights(share_data['previous_share_hash'],
 364             min(height, net.REAL_CHAIN_LENGTH),
 365             65535*net.SPREAD*bitcoin_data.target_to_average_attempts(block_target),
 366         )
 367         assert total_weight == sum(weights.itervalues()) + donation_weight, (total_weight, sum(weights.itervalues()) + donation_weight)
 368
 369         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
 370         this_script = bitcoin_data.pubkey_hash_to_script2(share_data['pubkey_hash'])
 371         amounts[this_script] = amounts.get(this_script, 0) + share_data['subsidy']//200 # 0.5% goes to block finder
 372         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
 373
 374         if sum(amounts.itervalues()) != share_data['subsidy'] or any(x < 0 for x in amounts.itervalues()):
 375             raise ValueError()
 376
 377         dests = sorted(amounts.iterkeys(), key=lambda script: (script == DONATION_SCRIPT, amounts[script], script))[-4000:] # block length limit, unlikely to ever be hit
 378
 379         new_transaction_hashes = []
 380         new_transaction_size = 0
 381         transaction_hash_refs = []
 382         other_transaction_hashes = []
 383
 384         for tx_hash in desired_other_transaction_hashes:
 385             for i, share in enumerate(tracker.get_chain(share_data['previous_share_hash'], min(height, 100))):
 386                 if tx_hash in share.new_transaction_hashes:
 387                     this = dict(share_count=i+1, tx_count=share.new_transaction_hashes.index(tx_hash))
 388                     break
 389             else:
 390                 if known_txs is not None:
 391                     this_size = len(bitcoin_data.tx_type.pack(known_txs[tx_hash]))
 392                     if new_transaction_size + this_size > 50000: # only allow 50 kB of new txns/share
 393                         break
 394                     new_transaction_size += this_size
 395                 new_transaction_hashes.append(tx_hash)
 396                 this = dict(share_count=0, tx_count=len(new_transaction_hashes)-1)
 397             transaction_hash_refs.append(this)
 398             other_transaction_hashes.append(tx_hash)
 399
 400         share_info = dict(
 401             share_data=share_data,
 402             far_share_hash=None if last is None and height < 99 else tracker.get_nth_parent_hash(share_data['previous_share_hash'], 99),
 403             max_bits=max_bits,
 404             bits=bits,
 405             timestamp=math.clip(desired_timestamp, (
 406                 (previous_share.timestamp + net.SHARE_PERIOD) - (net.SHARE_PERIOD - 1), # = previous_share.timestamp + 1
 407                 (previous_share.timestamp + net.SHARE_PERIOD) + (net.SHARE_PERIOD - 1),
 408             )) if previous_share is not None else desired_timestamp,
 409             new_transaction_hashes=new_transaction_hashes,
 410             transaction_hash_refs=transaction_hash_refs,
 411         )
 412
 413         gentx = dict(
 414             version=1,
 415             tx_ins=[dict(
 416                 previous_output=None,
 417                 sequence=None,
 418                 script=share_data['coinbase'],
 419             )],
 420             tx_outs=[dict(value=amounts[script], script=script) for script in dests if amounts[script] or script == DONATION_SCRIPT] + [dict(
 421                 value=0,
 422                 script='\x20' + cls.get_ref_hash(net, share_info, ref_merkle_link),
 423             )],
 424             lock_time=0,
 425         )
 426
 427         def get_share(header, transactions):
 428             min_header=dict(header);del min_header['merkle_root']
 429             return cls(net, None, dict(
 430                 min_header=min_header,
 431                 share_info=share_info,
 432                 ref_merkle_link=dict(branch=[], index=0),
 433                 hash_link=prefix_to_hash_link(bitcoin_data.tx_type.pack(gentx)[:-32-4], cls.gentx_before_refhash),
 434                 merkle_link=bitcoin_data.calculate_merkle_link([None] + other_transaction_hashes, 0),
 435             ))
 436
 437         return share_info, gentx, other_transaction_hashes, get_share
 438
 439     @classmethod
 440     def get_ref_hash(cls, net, share_info, ref_merkle_link):
 441         return pack.IntType(256).pack(bitcoin_data.check_merkle_link(bitcoin_data.hash256(cls.ref_type.pack(dict(
 442             identifier=net.IDENTIFIER,
 443             share_info=share_info,
 444         ))), ref_merkle_link))
 445
 446     __slots__ = 'net peer contents min_header share_info hash_link merkle_link hash share_data max_target target timestamp previous_hash new_script desired_version gentx_hash header pow_hash header_hash new_transaction_hashes time_seen'.split(' ')
 447
 448     def __init__(self, net, peer, contents):
 449         self.net = net
 450         self.peer = peer
 451         self.contents = contents
 452
 453         self.min_header = contents['min_header']
 454         self.share_info = contents['share_info']
 455         self.hash_link = contents['hash_link']
 456         self.merkle_link = contents['merkle_link']
 457
 458         if not (2 <= len(self.share_info['share_data']['coinbase']) <= 100):
 459             raise ValueError('''bad coinbase size! %i bytes''' % (len(self.share_info['share_data']['coinbase']),))
 460
 461         if len(self.merkle_link['branch']) > 16:
 462             raise ValueError('merkle branch too long!')
 463
 464         assert not self.hash_link['extra_data'], repr(self.hash_link['extra_data'])
 465
 466         self.share_data = self.share_info['share_data']
 467         self.max_target = self.share_info['max_bits'].target
 468         self.target = self.share_info['bits'].target
 469         self.timestamp = self.share_info['timestamp']
 470         self.previous_hash = self.share_data['previous_share_hash']
 471         self.new_script = bitcoin_data.pubkey_hash_to_script2(self.share_data['pubkey_hash'])
 472         self.desired_version = self.share_data['desired_version']
 473
 474         for x in self.share_info['transaction_hash_refs']:
 475             assert x['share_count'] < 110
 476         for i, x in enumerate(self.share_info['new_transaction_hashes']):
 477             assert dict(share_count=0, tx_count=i) in self.share_info['transaction_hash_refs']
 478
 479         self.gentx_hash = check_hash_link(
 480             self.hash_link,
 481             self.get_ref_hash(net, self.share_info, contents['ref_merkle_link']) + pack.IntType(32).pack(0),
 482             self.gentx_before_refhash,
 483         )
 484         merkle_root = bitcoin_data.check_merkle_link(self.gentx_hash, self.merkle_link)
 485         self.header = dict(self.min_header, merkle_root=merkle_root)
 486         self.pow_hash = net.PARENT.POW_FUNC(bitcoin_data.block_header_type.pack(self.header))
 487         self.hash = self.header_hash = bitcoin_data.hash256(bitcoin_data.block_header_type.pack(self.header))
 488
 489         if self.target > net.MAX_TARGET:
 490             from p2pool import p2p
 491             raise p2p.PeerMisbehavingError('share target invalid')
 492
 493         if self.pow_hash > self.target:
 494             from p2pool import p2p
 495             raise p2p.PeerMisbehavingError('share PoW invalid')
 496
 497         self.new_transaction_hashes = self.share_info['new_transaction_hashes']
 498
 499         # XXX eww
 500         self.time_seen = time.time()
 501
 502     def __repr__(self):
 503         return 'Share' + repr((self.net, self.peer, self.contents))
 504
 505     def as_share(self):
 506         return dict(type=self.VERSION, contents=self.share_type.pack(self.contents))
 507
 508     def check(self, tracker):
 509         if self.share_data['previous_share_hash'] is not None:
 510             previous_share = tracker.items[self.share_data['previous_share_hash']]
 511             if isinstance(previous_share, Share):
 512                 if tracker.get_height(previous_share.hash) < self.net.CHAIN_LENGTH:
 513                     from p2pool import p2p
 514                     raise p2p.PeerMisbehavingError('NewShare without enough history')
 515                 else:
 516                     # Share -> NewShare only valid if 85% of hashes in [self.net.CHAIN_LENGTH*9//10, self.net.CHAIN_LENGTH] for new version
 517                     counts = get_desired_version_counts(tracker,
 518                         tracker.get_nth_parent_hash(previous_share.hash, self.net.CHAIN_LENGTH*9//10), self.net.CHAIN_LENGTH//10)
 519                     if counts.get(self.VERSION, 0) < sum(counts.itervalues())*85//100:
 520                         from p2pool import p2p
 521                         raise p2p.PeerMisbehavingError('NewShare without enough hash power upgraded')
 522
 523         other_tx_hashes = [tracker.items[tracker.get_nth_parent_hash(self.hash, x['share_count'])].share_info['new_transaction_hashes'][x['tx_count']] for x in self.share_info['transaction_hash_refs']]
 524
 525         share_info, gentx, other_tx_hashes2, get_share = self.generate_transaction(tracker, self.share_info['share_data'], self.header['bits'].target, self.share_info['timestamp'], self.share_info['bits'].target, self.contents['ref_merkle_link'], other_tx_hashes, self.net)
 526         assert other_tx_hashes2 == other_tx_hashes
 527         if share_info != self.share_info:
 528             raise ValueError('share_info invalid')
 529         if bitcoin_data.hash256(bitcoin_data.tx_type.pack(gentx)) != self.gentx_hash:
 530             raise ValueError('''gentx doesn't match hash_link''')
 531
 532         if bitcoin_data.calculate_merkle_link([None] + other_tx_hashes, 0) != self.merkle_link:
 533             raise ValueError('merkle_link and other_tx_hashes do not match')
 534
 535         return gentx # only used by as_block
 536
 537     def get_other_tx_hashes(self, tracker):
 538         return [tracker.items[tracker.get_nth_parent_hash(self.hash, x['share_count'])].share_info['new_transaction_hashes'][x['tx_count']] for x in self.share_info['transaction_hash_refs']]
 539
 540     def _get_other_txs(self, tracker, known_txs):
 541         other_tx_hashes = self.get_other_tx_hashes(tracker)
 542
 543         if not all(tx_hash in known_txs for tx_hash in other_tx_hashes):
 544             return None # not all txs present
 545
 546         return [known_txs[tx_hash] for tx_hash in other_tx_hashes]
 547
 548     def should_punish_reason(self, previous_block, bits, tracker, known_txs):
 549         if (self.header['previous_block'], self.header['bits']) != (previous_block, bits) and self.header_hash != previous_block and self.peer is not None:
 550             return True, 'Block-stale detected! %x < %x' % (self.header['previous_block'], previous_block)
 551
 552         if self.pow_hash <= self.header['bits'].target:
 553             return -1, 'block solution'
 554
 555         other_txs = self._get_other_txs(tracker, known_txs)
 556         if other_txs is None:
 557             return True, 'not all txs present'
 558
 559         all_txs_size = sum(len(bitcoin_data.tx_type.pack(tx)) for tx in other_txs)
 560         if all_txs_size > 1000000:
 561             return True, 'txs over block size limit'
 562
 563         new_txs_size = sum(len(bitcoin_data.tx_type.pack(known_txs[tx_hash])) for tx_hash in self.share_info['new_transaction_hashes'])
 564         if new_txs_size > 50000:
 565             return True, 'new txs over limit'
 566
 567         return False, None
 568
 569     def as_block(self, tracker, known_txs):
 570         other_txs = self._get_other_txs(tracker, known_txs)
 571         if other_txs is None:
 572             return None # not all txs present
 573         return dict(header=self.header, txs=[self.check(tracker)] + other_txs)
 574
 575
 576 class WeightsSkipList(forest.TrackerSkipList):
 577     # share_count, weights, total_weight
 578
 579     def get_delta(self, element):
 580         from p2pool.bitcoin import data as bitcoin_data
 581         share = self.tracker.items[element]
 582         att = bitcoin_data.target_to_average_attempts(share.target)
 583         return 1, {share.new_script: att*(65535-share.share_data['donation'])}, att*65535, att*share.share_data['donation']
 584
 585     def combine_deltas(self, (share_count1, weights1, total_weight1, total_donation_weight1), (share_count2, weights2, total_weight2, total_donation_weight2)):
 586         return share_count1 + share_count2, math.add_dicts(weights1, weights2), total_weight1 + total_weight2, total_donation_weight1 + total_donation_weight2
 587
 588     def initial_solution(self, start, (max_shares, desired_weight)):
 589         assert desired_weight % 65535 == 0, divmod(desired_weight, 65535)
 590         return 0, None, 0, 0
 591
 592     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)):
 593         if total_weight1 + total_weight2 > desired_weight and share_count2 == 1:
 594             assert (desired_weight - total_weight1) % 65535 == 0
 595             script, = weights2.iterkeys()
 596             new_weights = {script: (desired_weight - total_weight1)//65535*weights2[script]//(total_weight2//65535)}
 597             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)
 598         return share_count1 + share_count2, (weights_list, weights2), total_weight1 + total_weight2, total_donation_weight1 + total_donation_weight2
 599
 600     def judge(self, (share_count, weights_list, total_weight, total_donation_weight), (max_shares, desired_weight)):
 601         if share_count > max_shares or total_weight > desired_weight:
 602             return 1
 603         elif share_count == max_shares or total_weight == desired_weight:
 604             return 0
 605         else:
 606             return -1
 607
 608     def finalize(self, (share_count, weights_list, total_weight, total_donation_weight), (max_shares, desired_weight)):
 609         assert share_count <= max_shares and total_weight <= desired_weight
 610         assert share_count == max_shares or total_weight == desired_weight
 611         return math.add_dicts(*math.flatten_linked_list(weights_list)), total_weight, total_donation_weight
 612
 613 class OkayTracker(forest.Tracker):
 614     def __init__(self, net):
 615         forest.Tracker.__init__(self, delta_type=forest.get_attributedelta_type(dict(forest.AttributeDelta.attrs,
 616             work=lambda share: bitcoin_data.target_to_average_attempts(share.target),
 617             min_work=lambda share: bitcoin_data.target_to_average_attempts(share.max_target),
 618         )))
 619         self.net = net
 620         self.verified = forest.SubsetTracker(delta_type=forest.get_attributedelta_type(dict(forest.AttributeDelta.attrs,
 621             work=lambda share: bitcoin_data.target_to_average_attempts(share.target),
 622         )), subset_of=self)
 623         self.get_cumulative_weights = WeightsSkipList(self)
 624
 625     def attempt_verify(self, share):
 626         if share.hash in self.verified.items:
 627             return True
 628         height, last = self.get_height_and_last(share.hash)
 629         if height < self.net.CHAIN_LENGTH + 1 and last is not None:
 630             raise AssertionError()
 631         try:
 632             share.check(self)
 633         except:
 634             log.err(None, 'Share check failed:')
 635             return False
 636         else:
 637             self.verified.add(share)
 638             return True
 639
 640     def think(self, block_rel_height_func, previous_block, bits, known_txs):
 641         desired = set()
 642
 643         # O(len(self.heads))
 644         #   make 'unverified heads' set?
 645         # for each overall head, attempt verification
 646         # if it fails, attempt on parent, and repeat
 647         # if no successful verification because of lack of parents, request parent
 648         bads = set()
 649         for head in set(self.heads) - set(self.verified.heads):
 650             head_height, last = self.get_height_and_last(head)
 651
 652             for share in self.get_chain(head, head_height if last is None else min(5, max(0, head_height - self.net.CHAIN_LENGTH))):
 653                 if self.attempt_verify(share):
 654                     break
 655                 if share.hash in self.heads:
 656                     bads.add(share.hash)
 657             else:
 658                 if last is not None:
 659                     desired.add((
 660                         self.items[random.choice(list(self.reverse[last]))].peer,
 661                         last,
 662                         max(x.timestamp for x in self.get_chain(head, min(head_height, 5))),
 663                         min(x.target for x in self.get_chain(head, min(head_height, 5))),
 664                     ))
 665         for bad in bads:
 666             assert bad not in self.verified.items
 667             assert bad in self.heads
 668             if p2pool.DEBUG:
 669                 print "BAD", bad
 670             self.remove(bad)
 671
 672         # try to get at least CHAIN_LENGTH height for each verified head, requesting parents if needed
 673         for head in list(self.verified.heads):
 674             head_height, last_hash = self.verified.get_height_and_last(head)
 675             last_height, last_last_hash = self.get_height_and_last(last_hash)
 676             # XXX review boundary conditions
 677             want = max(self.net.CHAIN_LENGTH - head_height, 0)
 678             can = max(last_height - 1 - self.net.CHAIN_LENGTH, 0) if last_last_hash is not None else last_height
 679             get = min(want, can)
 680             #print 'Z', head_height, last_hash is None, last_height, last_last_hash is None, want, can, get
 681             for share in self.get_chain(last_hash, get):
 682                 if not self.attempt_verify(share):
 683                     break
 684             if head_height < self.net.CHAIN_LENGTH and last_last_hash is not None:
 685                 desired.add((
 686                     self.items[random.choice(list(self.verified.reverse[last_hash]))].peer,
 687                     last_last_hash,
 688                     max(x.timestamp for x in self.get_chain(head, min(head_height, 5))),
 689                     min(x.target for x in self.get_chain(head, min(head_height, 5))),
 690                 ))
 691
 692         # decide best tree
 693         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)
 694         if p2pool.DEBUG:
 695             print len(decorated_tails), 'tails:'
 696             for score, tail_hash in decorated_tails:
 697                 print format_hash(tail_hash), score
 698         best_tail_score, best_tail = decorated_tails[-1] if decorated_tails else (None, None)
 699
 700         # decide best verified head
 701         decorated_heads = sorted(((
 702             self.verified.get_work(self.verified.get_nth_parent_hash(h, min(5, self.verified.get_height(h)))),
 703             #self.items[h].peer is None,
 704             -self.items[h].should_punish_reason(previous_block, bits, self, known_txs)[0],
 705             -self.items[h].time_seen,
 706         ), h) for h in self.verified.tails.get(best_tail, []))
 707         if p2pool.DEBUG:
 708             print len(decorated_heads), 'heads. Top 10:'
 709             for score, head_hash in decorated_heads[-10:]:
 710                 print '   ', format_hash(head_hash), format_hash(self.items[head_hash].previous_hash), score
 711         best_head_score, best = decorated_heads[-1] if decorated_heads else (None, None)
 712
 713         if best is not None:
 714             best_share = self.items[best]
 715             punish, punish_reason = best_share.should_punish_reason(previous_block, bits, self, known_txs)
 716             if punish > 0:
 717                 if p2pool.DEBUG:
 718                     print >>sys.stderr, 'Punishing share for %r! Jumping from %s to %s!' % (punish_reason, format_hash(best), format_hash(best_share.previous_hash))
 719                 best = best_share.previous_hash
 720
 721             timestamp_cutoff = min(int(time.time()), best_share.timestamp) - 3600
 722             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
 723         else:
 724             timestamp_cutoff = int(time.time()) - 24*60*60
 725             target_cutoff = 2**256-1
 726
 727         if p2pool.DEBUG:
 728             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))
 729             for peer, hash, ts, targ in desired:
 730                 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
 731
 732         return best, [(peer, hash) for peer, hash, ts, targ in desired if ts >= timestamp_cutoff], decorated_heads
 733
 734     def score(self, share_hash, block_rel_height_func):
 735         # returns approximate lower bound on chain's hashrate in the last self.net.CHAIN_LENGTH*15//16*self.net.SHARE_PERIOD time
 736
 737         head_height = self.verified.get_height(share_hash)
 738         if head_height < self.net.CHAIN_LENGTH:
 739             return head_height, None
 740
 741         end_point = self.verified.get_nth_parent_hash(share_hash, self.net.CHAIN_LENGTH*15//16)
 742
 743         block_height = max(block_rel_height_func(share.header['previous_block']) for share in
 744             self.verified.get_chain(end_point, self.net.CHAIN_LENGTH//16))
 745
 746         return self.net.CHAIN_LENGTH, self.verified.get_delta(share_hash, end_point).work//((0 - block_height + 1)*self.net.PARENT.BLOCK_PERIOD)
 747
 748 def get_pool_attempts_per_second(tracker, previous_share_hash, dist, min_work=False, integer=False):
 749     assert dist >= 2
 750     near = tracker.items[previous_share_hash]
 751     far = tracker.items[tracker.get_nth_parent_hash(previous_share_hash, dist - 1)]
 752     attempts = tracker.get_delta(near.hash, far.hash).work if not min_work else tracker.get_delta(near.hash, far.hash).min_work
 753     time = near.timestamp - far.timestamp
 754     if time <= 0:
 755         time = 1
 756     if integer:
 757         return attempts//time
 758     return attempts/time
 759
 760 def get_average_stale_prop(tracker, share_hash, lookbehind):
 761     stales = sum(1 for share in tracker.get_chain(share_hash, lookbehind) if share.share_data['stale_info'] is not None)
 762     return stales/(lookbehind + stales)
 763
 764 def get_stale_counts(tracker, share_hash, lookbehind, rates=False):
 765     res = {}
 766     for share in tracker.get_chain(share_hash, lookbehind - 1):
 767         res['good'] = res.get('good', 0) + bitcoin_data.target_to_average_attempts(share.target)
 768         s = share.share_data['stale_info']
 769         if s is not None:
 770             res[s] = res.get(s, 0) + bitcoin_data.target_to_average_attempts(share.target)
 771     if rates:
 772         dt = tracker.items[share_hash].timestamp - tracker.items[tracker.get_nth_parent_hash(share_hash, lookbehind - 1)].timestamp
 773         res = dict((k, v/dt) for k, v in res.iteritems())
 774     return res
 775
 776 def get_user_stale_props(tracker, share_hash, lookbehind):
 777     res = {}
 778     for share in tracker.get_chain(share_hash, lookbehind - 1):
 779         stale, total = res.get(share.share_data['pubkey_hash'], (0, 0))
 780         total += 1
 781         if share.share_data['stale_info'] is not None:
 782             stale += 1
 783             total += 1
 784         res[share.share_data['pubkey_hash']] = stale, total
 785     return dict((pubkey_hash, stale/total) for pubkey_hash, (stale, total) in res.iteritems())
 786
 787 def get_expected_payouts(tracker, best_share_hash, block_target, subsidy, net):
 788     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))
 789     res = dict((script, subsidy*weight//total_weight) for script, weight in weights.iteritems())
 790     res[DONATION_SCRIPT] = res.get(DONATION_SCRIPT, 0) + subsidy - sum(res.itervalues())
 791     return res
 792
 793 def get_desired_version_counts(tracker, best_share_hash, dist):
 794     res = {}
 795     for share in tracker.get_chain(best_share_hash, dist):
 796         res[share.desired_version] = res.get(share.desired_version, 0) + bitcoin_data.target_to_average_attempts(share.target)
 797     return res
 798
 799 def get_warnings(tracker, best_share, net, bitcoind_warning, bitcoind_work_value):
 800     res = []
 801
 802     desired_version_counts = get_desired_version_counts(tracker, best_share,
 803         min(net.CHAIN_LENGTH, 60*60//net.SHARE_PERIOD, tracker.get_height(best_share)))
 804     majority_desired_version = max(desired_version_counts, key=lambda k: desired_version_counts[k])
 805     if majority_desired_version > NewShare.VERSION and desired_version_counts[majority_desired_version] > sum(desired_version_counts.itervalues())/2:
 806         res.append('A MAJORITY OF SHARES CONTAIN A VOTE FOR AN UNSUPPORTED SHARE IMPLEMENTATION! (v%i with %i%% support)\n'
 807             'An upgrade is likely necessary. Check http://p2pool.forre.st/ for more information.' % (
 808                 majority_desired_version, 100*desired_version_counts[majority_desired_version]/sum(desired_version_counts.itervalues())))
 809
 810     if bitcoind_warning is not None:
 811         res.append('(from bitcoind) %s' % (bitcoind_warning,))
 812
 813     if time.time() > bitcoind_work_value['last_update'] + 60:
 814         res.append('''LOST CONTACT WITH BITCOIND for %s! Check that it isn't frozen or dead!''' % (math.format_dt(time.time() - bitcoind_work_value['last_update']),))
 815
 816     return res
 817
 818 def format_hash(x):
 819     if x is None:
 820         return 'xxxxxxxx'
 821     return '%08x' % (x % 2**32)
 822
 823 class ShareStore(object):
 824     def __init__(self, prefix, net):
 825         self.filename = prefix
 826         self.dirname = os.path.dirname(os.path.abspath(prefix))
 827         self.filename = os.path.basename(os.path.abspath(prefix))
 828         self.net = net
 829         self.known = None # will be filename -> set of share hashes, set of verified hashes
 830         self.known_desired = None
 831
 832     def get_shares(self):
 833         if self.known is not None:
 834             raise AssertionError()
 835         known = {}
 836         filenames, next = self.get_filenames_and_next()
 837         for filename in filenames:
 838             share_hashes, verified_hashes = known.setdefault(filename, (set(), set()))
 839             with open(filename, 'rb') as f:
 840                 for line in f:
 841                     try:
 842                         type_id_str, data_hex = line.strip().split(' ')
 843                         type_id = int(type_id_str)
 844                         if type_id == 0:
 845                             pass
 846                         elif type_id == 1:
 847                             pass
 848                         elif type_id == 2:
 849                             verified_hash = int(data_hex, 16)
 850                             yield 'verified_hash', verified_hash
 851                             verified_hashes.add(verified_hash)
 852                         elif type_id == 5:
 853                             raw_share = share_type.unpack(data_hex.decode('hex'))
 854                             if raw_share['type'] in [0, 1, 2, 3, 6, 7]:
 855                                 continue
 856                             share = load_share(raw_share, self.net, None)
 857                             yield 'share', share
 858                             share_hashes.add(share.hash)
 859                         else:
 860                             raise NotImplementedError("share type %i" % (type_id,))
 861                     except Exception:
 862                         log.err(None, "HARMLESS error while reading saved shares, continuing where left off:")
 863         self.known = known
 864         self.known_desired = dict((k, (set(a), set(b))) for k, (a, b) in known.iteritems())
 865
 866     def _add_line(self, line):
 867         filenames, next = self.get_filenames_and_next()
 868         if filenames and os.path.getsize(filenames[-1]) < 10e6:
 869             filename = filenames[-1]
 870         else:
 871             filename = next
 872
 873         with open(filename, 'ab') as f:
 874             f.write(line + '\n')
 875
 876         return filename
 877
 878     def add_share(self, share):
 879         for filename, (share_hashes, verified_hashes) in self.known.iteritems():
 880             if share.hash in share_hashes:
 881                 break
 882         else:
 883             filename = self._add_line("%i %s" % (5, share_type.pack(share.as_share()).encode('hex')))
 884             share_hashes, verified_hashes = self.known.setdefault(filename, (set(), set()))
 885             share_hashes.add(share.hash)
 886         share_hashes, verified_hashes = self.known_desired.setdefault(filename, (set(), set()))
 887         share_hashes.add(share.hash)
 888
 889     def add_verified_hash(self, share_hash):
 890         for filename, (share_hashes, verified_hashes) in self.known.iteritems():
 891             if share_hash in verified_hashes:
 892                 break
 893         else:
 894             filename = self._add_line("%i %x" % (2, share_hash))
 895             share_hashes, verified_hashes = self.known.setdefault(filename, (set(), set()))
 896             verified_hashes.add(share_hash)
 897         share_hashes, verified_hashes = self.known_desired.setdefault(filename, (set(), set()))
 898         verified_hashes.add(share_hash)
 899
 900     def get_filenames_and_next(self):
 901         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())
 902         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)))
 903
 904     def forget_share(self, share_hash):
 905         for filename, (share_hashes, verified_hashes) in self.known_desired.iteritems():
 906             if share_hash in share_hashes:
 907                 share_hashes.remove(share_hash)
 908         self.check_remove()
 909
 910     def forget_verified_share(self, share_hash):
 911         for filename, (share_hashes, verified_hashes) in self.known_desired.iteritems():
 912             if share_hash in verified_hashes:
 913                 verified_hashes.remove(share_hash)
 914         self.check_remove()
 915
 916     def check_remove(self):
 917         to_remove = set()
 918         for filename, (share_hashes, verified_hashes) in self.known_desired.iteritems():
 919             #print filename, len(share_hashes) + len(verified_hashes)
 920             if not share_hashes and not verified_hashes:
 921                 to_remove.add(filename)
 922         for filename in to_remove:
 923             self.known.pop(filename)
 924             self.known_desired.pop(filename)
 925             os.remove(filename)
 926             print "REMOVED", filename