1 from __future__ import division
8 from twisted.python import log
11 from p2pool import skiplists
12 from p2pool.bitcoin import data as bitcoin_data, script, sha256
13 from p2pool.util import math, forest, pack
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()),
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)
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())
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)),
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
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)),
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),
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)),
81 share_type = pack.ComposedType([
82 ('type', pack.VarIntType()),
83 ('contents', pack.VarStrType()),
87 def get_pool_attempts_per_second(tracker, previous_share_hash, dist, min_work=False):
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
97 def get_average_stale_prop(tracker, share_hash, lookbehind):
98 stales = sum(1 for share in tracker.get_chain(share_hash, lookbehind) if share.share_data['stale_info'] in [253, 254])
99 return stales/(lookbehind + stales)
101 DONATION_SCRIPT = '4104ffd03de44a6e11b9917f3a29f9443283d9871c9d743ef30d5eddcd37094b64d1b3d8090496b53256786bf5c82932ec23c3b74d9f05a6f95a8b5529352656664bac'.decode('hex')
103 ref_type = pack.ComposedType([
104 ('identifier', pack.FixedStrType(64//8)),
105 ('share_info', share_info_type),
108 gentx_before_refhash = pack.VarStrType().pack(DONATION_SCRIPT) + pack.IntType(64).pack(0) + pack.VarStrType().pack('\x20' + pack.IntType(256).pack(0))[:2]
110 def generate_transaction(tracker, share_data, block_target, desired_timestamp, desired_target, net):
111 previous_share = tracker.shares[share_data['previous_share_hash']] if share_data['previous_share_hash'] is not None else None
113 height, last = tracker.get_height_and_last(share_data['previous_share_hash'])
114 assert height >= net.REAL_CHAIN_LENGTH or last is None
115 if height < net.TARGET_LOOKBEHIND:
116 pre_target3 = net.MAX_TARGET
118 attempts_per_second = get_pool_attempts_per_second(tracker, share_data['previous_share_hash'], net.TARGET_LOOKBEHIND, min_work=True)
119 pre_target = 2**256//(net.SHARE_PERIOD*attempts_per_second) - 1
120 pre_target2 = math.clip(pre_target, (previous_share.max_target*9//10, previous_share.max_target*11//10))
121 pre_target3 = math.clip(pre_target2, (0, net.MAX_TARGET))
122 max_bits = bitcoin_data.FloatingInteger.from_target_upper_bound(pre_target3)
123 bits = bitcoin_data.FloatingInteger.from_target_upper_bound(math.clip(desired_target, (pre_target3//10, pre_target3)))
125 weights, total_weight, donation_weight = tracker.get_cumulative_weights(share_data['previous_share_hash'],
126 min(height, net.REAL_CHAIN_LENGTH),
127 65535*net.SPREAD*bitcoin_data.target_to_average_attempts(block_target),
129 assert total_weight == sum(weights.itervalues()) + donation_weight, (total_weight, sum(weights.itervalues()) + donation_weight)
131 amounts = dict((script, share_data['subsidy']*(199*weight)//(200*total_weight)) for script, weight in weights.iteritems()) # 99.5% goes according to weights prior to this share
132 this_script = bitcoin_data.pubkey_hash_to_script2(share_data['pubkey_hash'])
133 amounts[this_script] = amounts.get(this_script, 0) + share_data['subsidy']//200 # 0.5% goes to block finder
134 amounts[DONATION_SCRIPT] = amounts.get(DONATION_SCRIPT, 0) + share_data['subsidy'] - sum(amounts.itervalues()) # all that's left over is the donation weight and some extra satoshis due to rounding
136 if sum(amounts.itervalues()) != share_data['subsidy'] or any(x < 0 for x in amounts.itervalues()):
139 dests = sorted(amounts.iterkeys(), key=lambda script: (script == DONATION_SCRIPT, amounts[script], script))[-4000:] # block length limit, unlikely to ever be hit
142 share_data=share_data,
145 timestamp=math.clip(desired_timestamp, (
146 (previous_share.timestamp + net.SHARE_PERIOD) - (net.SHARE_PERIOD - 1), # = previous_share.timestamp + 1
147 (previous_share.timestamp + net.SHARE_PERIOD) + (net.SHARE_PERIOD - 1),
148 )) if previous_share is not None else desired_timestamp,
151 return share_info, dict(
154 previous_output=None,
156 script=share_data['coinbase'].ljust(2, '\x00'),
158 tx_outs=[dict(value=amounts[script], script=script) for script in dests if amounts[script]] + [dict(
160 script='\x20' + pack.IntType(256).pack(bitcoin_data.hash256(ref_type.pack(dict(
161 identifier=net.IDENTIFIER,
162 share_info=share_info,
168 def get_expected_payouts(tracker, best_share_hash, block_target, subsidy, net):
169 weights, total_weight, donation_weight = tracker.get_cumulative_weights(best_share_hash, min(tracker.get_height(best_share_hash), net.REAL_CHAIN_LENGTH), 65535*net.SPREAD*bitcoin_data.target_to_average_attempts(block_target))
170 res = dict((script, subsidy*weight//total_weight) for script, weight in weights.iteritems())
171 res[DONATION_SCRIPT] = res.get(DONATION_SCRIPT, 0) + subsidy - sum(res.itervalues())
175 __slots__ = 'net min_header share_info hash_link merkle_branch other_txs hash share_data max_target target timestamp previous_hash new_script gentx_hash header pow_hash header_hash time_seen peer'.split(' ')
178 def from_share(cls, share, net, peer):
179 if share['type'] == 2:
180 res = cls(net, peer, **share1a_type.unpack(share['contents']))
181 if not (res.pow_hash > res.header['bits'].target):
182 raise ValueError('invalid share type')
184 elif share['type'] == 3:
185 share1b = share1b_type.unpack(share['contents'])
186 res = 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)
187 if not (res.pow_hash <= res.header['bits'].target):
188 raise ValueError('invalid share type')
191 raise ValueError('unknown share type: %r' % (share['type'],))
193 def __init__(self, net, peer, min_header, share_info, hash_link, merkle_branch, other_txs=None):
194 if len(share_info['share_data']['coinbase']) > 100:
195 raise ValueError('''coinbase too large! %i bytes''' % (len(self.share_data['coinbase']),))
197 if len(merkle_branch) > 16:
198 raise ValueError('merkle_branch too long!')
200 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:
201 raise ValueError('merkle_branch and other_txs do not match')
203 assert not hash_link['extra_data'], repr(hash_link['extra_data'])
207 self.min_header = min_header
208 self.share_info = share_info
209 self.hash_link = hash_link
210 self.merkle_branch = merkle_branch
211 self.other_txs = other_txs
213 self.hash = bitcoin_data.hash256(share_type.pack(self.as_share(block_hint=other_txs is not None)))
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'])
221 self.gentx_hash = check_hash_link(
223 pack.IntType(256).pack(bitcoin_data.hash256(ref_type.pack(dict(
224 identifier=net.IDENTIFIER,
225 share_info=share_info,
226 )))) + pack.IntType(32).pack(0),
227 gentx_before_refhash,
229 merkle_root = bitcoin_data.check_merkle_branch(self.gentx_hash, 0, merkle_branch)
230 self.header = dict(min_header, merkle_root=merkle_root)
231 self.pow_hash = net.PARENT.POW_FUNC(bitcoin_data.block_header_type.pack(self.header))
232 self.header_hash = bitcoin_data.hash256(bitcoin_data.block_header_type.pack(self.header))
234 if self.pow_hash > self.target:
235 print 'hash %x' % self.pow_hash
236 print 'targ %x' % self.target
237 raise ValueError('not enough work!')
239 if other_txs is not None and not self.pow_hash <= self.header['bits'].target:
240 raise ValueError('other_txs provided when not a block solution')
241 if other_txs is None and self.pow_hash <= self.header['bits'].target:
242 raise ValueError('other_txs not provided when a block solution')
245 self.time_seen = time.time()
248 return '<Share %s>' % (' '.join('%s=%r' % (k, getattr(self, k)) for k in self.__slots__),)
250 def check(self, tracker):
251 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)
252 if share_info != self.share_info:
253 raise ValueError('share difficulty invalid')
254 if bitcoin_data.hash256(bitcoin_data.tx_type.pack(gentx)) != self.gentx_hash:
255 raise ValueError('''gentx doesn't match hash_link''')
257 def as_share(self, block_hint=None):
258 if block_hint is None:
259 block_hint = self.pow_hash <= self.header['bits'].target
260 if not block_hint: # share1a
261 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)))
263 if self.other_txs is None:
264 raise ValueError('share does not contain all txs')
265 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)))
267 def as_block(self, tracker):
268 if self.other_txs is None:
269 raise ValueError('share does not contain all txs')
271 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)
272 assert share_info == self.share_info
274 return dict(header=self.header, txs=[gentx] + self.other_txs)
276 class OkayTracker(forest.Tracker):
277 def __init__(self, net, my_share_hashes, my_doa_share_hashes):
278 forest.Tracker.__init__(self, delta_type=forest.get_attributedelta_type(dict(forest.AttributeDelta.attrs,
279 work=lambda share: bitcoin_data.target_to_average_attempts(share.target),
280 min_work=lambda share: bitcoin_data.target_to_average_attempts(share.max_target),
283 self.verified = forest.Tracker(delta_type=forest.get_attributedelta_type(dict(forest.AttributeDelta.attrs,
284 work=lambda share: bitcoin_data.target_to_average_attempts(share.target),
285 my_count=lambda share: 1 if share.hash in my_share_hashes else 0,
286 my_doa_count=lambda share: 1 if share.hash in my_doa_share_hashes else 0,
287 my_orphan_announce_count=lambda share: 1 if share.hash in my_share_hashes and share.share_data['stale_info'] == 253 else 0,
288 my_dead_announce_count=lambda share: 1 if share.hash in my_share_hashes and share.share_data['stale_info'] == 254 else 0,
290 self.verified.get_nth_parent_hash = self.get_nth_parent_hash # self is a superset of self.verified
292 self.get_cumulative_weights = skiplists.WeightsSkipList(self)
294 def attempt_verify(self, share):
295 if share.hash in self.verified.shares:
297 height, last = self.get_height_and_last(share.hash)
298 if height < self.net.CHAIN_LENGTH + 1 and last is not None:
299 raise AssertionError()
303 log.err(None, 'Share check failed:')
306 self.verified.add(share)
309 def think(self, block_rel_height_func, previous_block, bits):
313 # make 'unverified heads' set?
314 # for each overall head, attempt verification
315 # if it fails, attempt on parent, and repeat
316 # if no successful verification because of lack of parents, request parent
318 for head in set(self.heads) - set(self.verified.heads):
319 head_height, last = self.get_height_and_last(head)
321 for share in self.get_chain(head, head_height if last is None else min(5, max(0, head_height - self.net.CHAIN_LENGTH))):
322 if self.attempt_verify(share):
324 if share.hash in self.heads:
329 self.shares[random.choice(list(self.reverse_shares[last]))].peer,
331 max(x.timestamp for x in self.get_chain(head, min(head_height, 5))),
332 min(x.target for x in self.get_chain(head, min(head_height, 5))),
335 assert bad not in self.verified.shares
336 assert bad in self.heads
341 # try to get at least CHAIN_LENGTH height for each verified head, requesting parents if needed
342 for head in list(self.verified.heads):
343 head_height, last_hash = self.verified.get_height_and_last(head)
344 last_height, last_last_hash = self.get_height_and_last(last_hash)
345 # XXX review boundary conditions
346 want = max(self.net.CHAIN_LENGTH - head_height, 0)
347 can = max(last_height - 1 - self.net.CHAIN_LENGTH, 0) if last_last_hash is not None else last_height
349 #print 'Z', head_height, last_hash is None, last_height, last_last_hash is None, want, can, get
350 for share in self.get_chain(last_hash, get):
351 if not self.attempt_verify(share):
353 if head_height < self.net.CHAIN_LENGTH and last_last_hash is not None:
355 self.shares[random.choice(list(self.verified.reverse_shares[last_hash]))].peer,
357 max(x.timestamp for x in self.get_chain(head, min(head_height, 5))),
358 min(x.target for x in self.get_chain(head, min(head_height, 5))),
362 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
364 print len(decorated_tails), 'tails:'
365 for score, tail_hash in decorated_tails:
366 print format_hash(tail_hash), score
367 best_tail_score, best_tail = decorated_tails[-1] if decorated_tails else (None, None)
369 # decide best verified head
370 decorated_heads = sorted(((
371 self.verified.get_work(self.verified.get_nth_parent_hash(h, min(5, self.verified.get_height(h)))),
372 #self.shares[h].peer is None,
373 self.shares[h].pow_hash < self.shares[h].header['bits'].target, # is block solution
374 (self.shares[h].header['previous_block'], self.shares[h].header['bits']) == (previous_block, bits) or self.shares[h].peer is None,
375 -self.shares[h].time_seen,
376 ), h) for h in self.verified.tails.get(best_tail, []))
378 print len(decorated_heads), 'heads. Top 10:'
379 for score, head_hash in decorated_heads[-10:]:
380 print ' ', format_hash(head_hash), format_hash(self.shares[head_hash].previous_hash), score
381 best_head_score, best = decorated_heads[-1] if decorated_heads else (None, None)
385 for i in xrange(1000):
387 for share_hash, tail in self.heads.iteritems():
388 if share_hash in [head_hash for score, head_hash in decorated_heads[-5:]]:
391 if self.shares[share_hash].time_seen > time.time() - 300:
394 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
397 to_remove.add(share_hash)
400 for share_hash in to_remove:
401 self.remove(share_hash)
402 if share_hash in self.verified.shares:
403 self.verified.remove(share_hash)
404 #print "_________", to_remove
407 for i in xrange(1000):
409 for tail, heads in self.tails.iteritems():
410 if min(self.get_height(head) for head in heads) < 2*self.net.CHAIN_LENGTH + 10:
412 for aftertail in self.reverse_shares.get(tail, set()):
413 if len(self.reverse_shares[self.shares[aftertail].previous_hash]) > 1: # XXX
416 to_remove.add(aftertail)
419 # if removed from this, it must be removed from verified
421 for aftertail in to_remove:
422 if self.shares[aftertail].previous_hash not in self.tails:
423 print "erk", aftertail, self.shares[aftertail].previous_hash
425 self.remove(aftertail)
426 if aftertail in self.verified.shares:
427 self.verified.remove(aftertail)
429 #print "removed! %i %f" % (len(to_remove), (end - start)/len(to_remove))
432 best_share = self.shares[best]
433 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:
435 print 'Stale detected! %x < %x' % (best_share.header['previous_block'], previous_block)
436 best = best_share.previous_hash
438 timestamp_cutoff = min(int(time.time()), best_share.timestamp) - 3600
439 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
441 timestamp_cutoff = int(time.time()) - 24*60*60
442 target_cutoff = 2**256-1
445 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))
446 for peer, hash, ts, targ in desired:
447 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
449 return best, [(peer, hash) for peer, hash, ts, targ in desired if ts >= timestamp_cutoff and targ <= target_cutoff]
451 def score(self, share_hash, block_rel_height_func):
452 # returns approximate lower bound on chain's hashrate in the last self.net.CHAIN_LENGTH*15//16*self.net.SHARE_PERIOD time
454 head_height = self.verified.get_height(share_hash)
455 if head_height < self.net.CHAIN_LENGTH:
456 return head_height, None
458 end_point = self.verified.get_nth_parent_hash(share_hash, self.net.CHAIN_LENGTH*15//16)
460 block_height = max(block_rel_height_func(share.header['previous_block']) for share in
461 self.verified.get_chain(end_point, self.net.CHAIN_LENGTH//16))
463 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)
468 return '%08x' % (x % 2**32)
470 class ShareStore(object):
471 def __init__(self, prefix, net):
472 self.filename = prefix
473 self.dirname = os.path.dirname(os.path.abspath(prefix))
474 self.filename = os.path.basename(os.path.abspath(prefix))
476 self.known = None # will be filename -> set of share hashes, set of verified hashes
477 self.known_desired = None
479 def get_shares(self):
480 if self.known is not None:
481 raise AssertionError()
483 filenames, next = self.get_filenames_and_next()
484 for filename in filenames:
485 share_hashes, verified_hashes = known.setdefault(filename, (set(), set()))
486 with open(filename, 'rb') as f:
489 type_id_str, data_hex = line.strip().split(' ')
490 type_id = int(type_id_str)
496 verified_hash = int(data_hex, 16)
497 yield 'verified_hash', verified_hash
498 verified_hashes.add(verified_hash)
500 share = Share.from_share(share_type.unpack(data_hex.decode('hex')), self.net, None)
502 share_hashes.add(share.hash)
504 raise NotImplementedError("share type %i" % (type_id,))
506 log.err(None, "Error while reading saved shares, continuing where left off:")
508 self.known_desired = dict((k, (set(a), set(b))) for k, (a, b) in known.iteritems())
510 def _add_line(self, line):
511 filenames, next = self.get_filenames_and_next()
512 if filenames and os.path.getsize(filenames[-1]) < 10e6:
513 filename = filenames[-1]
517 with open(filename, 'ab') as f:
522 def add_share(self, share):
523 for filename, (share_hashes, verified_hashes) in self.known.iteritems():
524 if share.hash in share_hashes:
527 filename = self._add_line("%i %s" % (5, share_type.pack(share.as_share()).encode('hex')))
528 share_hashes, verified_hashes = self.known.setdefault(filename, (set(), set()))
529 share_hashes.add(share.hash)
530 share_hashes, verified_hashes = self.known_desired.setdefault(filename, (set(), set()))
531 share_hashes.add(share.hash)
533 def add_verified_hash(self, share_hash):
534 for filename, (share_hashes, verified_hashes) in self.known.iteritems():
535 if share_hash in verified_hashes:
538 filename = self._add_line("%i %x" % (2, share_hash))
539 share_hashes, verified_hashes = self.known.setdefault(filename, (set(), set()))
540 verified_hashes.add(share_hash)
541 share_hashes, verified_hashes = self.known_desired.setdefault(filename, (set(), set()))
542 verified_hashes.add(share_hash)
544 def get_filenames_and_next(self):
545 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())
546 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)))
548 def forget_share(self, share_hash):
549 for filename, (share_hashes, verified_hashes) in self.known_desired.iteritems():
550 if share_hash in share_hashes:
551 share_hashes.remove(share_hash)
554 def forget_verified_share(self, share_hash):
555 for filename, (share_hashes, verified_hashes) in self.known_desired.iteritems():
556 if share_hash in verified_hashes:
557 verified_hashes.remove(share_hash)
560 def check_remove(self):
562 for filename, (share_hashes, verified_hashes) in self.known_desired.iteritems():
563 #print filename, len(share_hashes) + len(verified_hashes)
564 if not share_hashes and not verified_hashes:
565 to_remove.add(filename)
566 for filename in to_remove:
567 self.known.pop(filename)
568 self.known_desired.pop(filename)
570 print "REMOVED", filename