7 from p2pool.util import skiplist, variable
10 class TrackerSkipList(skiplist.SkipList):
11 def __init__(self, tracker):
12 skiplist.SkipList.__init__(self)
13 self.tracker = tracker
15 self.tracker.removed.watch_weakref(self, lambda self, item: self.forget_item(item.hash))
17 def previous(self, element):
18 return self.tracker._delta_type.from_element(self.tracker.items[element]).tail
21 class DistanceSkipList(TrackerSkipList):
22 def get_delta(self, element):
23 return element, 1, self.previous(element)
25 def combine_deltas(self, (from_hash1, dist1, to_hash1), (from_hash2, dist2, to_hash2)):
26 if to_hash1 != from_hash2:
27 raise AssertionError()
28 return from_hash1, dist1 + dist2, to_hash2
30 def initial_solution(self, start, (n,)):
33 def apply_delta(self, (dist1, to_hash1), (from_hash2, dist2, to_hash2), (n,)):
34 if to_hash1 != from_hash2:
35 raise AssertionError()
36 return dist1 + dist2, to_hash2
38 def judge(self, (dist, hash), (n,)):
46 def finalize(self, (dist, hash), (n,)):
50 def get_attributedelta_type(attrs): # attrs: {name: func}
51 class ProtoAttributeDelta(object):
52 __slots__ = ['head', 'tail'] + attrs.keys()
55 def get_none(cls, element_id):
56 return cls(element_id, element_id, **dict((k, 0) for k in attrs))
59 def from_element(cls, item):
60 return cls(item.hash, item.previous_hash, **dict((k, v(item)) for k, v in attrs.iteritems()))
68 return item.previous_hash
70 def __init__(self, head, tail, **kwargs):
71 self.head, self.tail = head, tail
72 for k, v in kwargs.iteritems():
75 def __add__(self, other):
76 assert self.tail == other.head
77 return self.__class__(self.head, other.tail, **dict((k, getattr(self, k) + getattr(other, k)) for k in attrs))
79 def __sub__(self, other):
80 if self.head == other.head:
81 return self.__class__(other.tail, self.tail, **dict((k, getattr(self, k) - getattr(other, k)) for k in attrs))
82 elif self.tail == other.tail:
83 return self.__class__(self.head, other.head, **dict((k, getattr(self, k) - getattr(other, k)) for k in attrs))
85 raise AssertionError()
88 return '%s(%r, %r%s)' % (self.__class__, self.head, self.tail, ''.join(', %s=%r' % (k, getattr(self, k)) for k in attrs))
89 ProtoAttributeDelta.attrs = attrs
90 return ProtoAttributeDelta
92 AttributeDelta = get_attributedelta_type(dict(
93 height=lambda item: 1,
96 class TrackerView(object):
97 def __init__(self, tracker, delta_type):
98 self._tracker = tracker
99 self._delta_type = delta_type
101 self._deltas = {} # item_hash -> delta, ref
102 self._reverse_deltas = {} # ref -> set of item_hashes
104 self._ref_generator = itertools.count()
105 self._delta_refs = {} # ref -> delta
106 self._reverse_delta_refs = {} # delta.tail -> ref
108 self._tracker.remove_special.watch_weakref(self, lambda self, item: self._handle_remove_special(item))
109 self._tracker.remove_special2.watch_weakref(self, lambda self, item: self._handle_remove_special2(item))
110 self._tracker.removed.watch_weakref(self, lambda self, item: self._handle_removed(item))
112 def _handle_remove_special(self, item):
113 delta = self._delta_type.from_element(item)
115 if delta.tail not in self._reverse_delta_refs:
118 # move delta refs referencing children down to this, so they can be moved up in one step
119 for x in list(self._reverse_deltas.get(self._reverse_delta_refs.get(delta.head, object()), set())):
122 assert delta.head not in self._reverse_delta_refs, list(self._reverse_deltas.get(self._reverse_delta_refs.get(delta.head, object()), set()))
124 if delta.tail not in self._reverse_delta_refs:
127 # move ref pointing to this up
129 ref = self._reverse_delta_refs[delta.tail]
130 cur_delta = self._delta_refs[ref]
131 assert cur_delta.tail == delta.tail
132 self._delta_refs[ref] = cur_delta - delta
133 assert self._delta_refs[ref].tail == delta.head
134 del self._reverse_delta_refs[delta.tail]
135 self._reverse_delta_refs[delta.head] = ref
137 def _handle_remove_special2(self, item):
138 delta = self._delta_type.from_element(item)
140 if delta.tail not in self._reverse_delta_refs:
143 ref = self._reverse_delta_refs.pop(delta.tail)
144 del self._delta_refs[ref]
146 for x in self._reverse_deltas.pop(ref):
149 def _handle_removed(self, item):
150 delta = self._delta_type.from_element(item)
152 # delete delta entry and ref if it is empty
153 if delta.head in self._deltas:
154 delta1, ref = self._deltas.pop(delta.head)
155 self._reverse_deltas[ref].remove(delta.head)
156 if not self._reverse_deltas[ref]:
157 del self._reverse_deltas[ref]
158 delta2 = self._delta_refs.pop(ref)
159 del self._reverse_delta_refs[delta2.tail]
162 def get_height(self, item_hash):
163 return self.get_delta_to_last(item_hash).height
165 def get_work(self, item_hash):
166 return self.get_delta_to_last(item_hash).work
168 def get_last(self, item_hash):
169 return self.get_delta_to_last(item_hash).tail
171 def get_height_and_last(self, item_hash):
172 delta = self.get_delta_to_last(item_hash)
173 return delta.height, delta.tail
175 def _get_delta(self, item_hash):
176 if item_hash in self._deltas:
177 delta1, ref = self._deltas[item_hash]
178 delta2 = self._delta_refs[ref]
179 res = delta1 + delta2
181 res = self._delta_type.from_element(self._tracker.items[item_hash])
182 assert res.head == item_hash
185 def _set_delta(self, item_hash, delta):
186 other_item_hash = delta.tail
187 if other_item_hash not in self._reverse_delta_refs:
188 ref = self._ref_generator.next()
189 assert ref not in self._delta_refs
190 self._delta_refs[ref] = self._delta_type.get_none(other_item_hash)
191 self._reverse_delta_refs[other_item_hash] = ref
194 ref = self._reverse_delta_refs[other_item_hash]
195 ref_delta = self._delta_refs[ref]
196 assert ref_delta.tail == other_item_hash
198 if item_hash in self._deltas:
199 prev_ref = self._deltas[item_hash][1]
200 self._reverse_deltas[prev_ref].remove(item_hash)
201 if not self._reverse_deltas[prev_ref] and prev_ref != ref:
202 self._reverse_deltas.pop(prev_ref)
203 x = self._delta_refs.pop(prev_ref)
204 self._reverse_delta_refs.pop(x.tail)
205 self._deltas[item_hash] = delta - ref_delta, ref
206 self._reverse_deltas.setdefault(ref, set()).add(item_hash)
208 def get_delta_to_last(self, item_hash):
209 assert isinstance(item_hash, (int, long, type(None)))
210 delta = self._delta_type.get_none(item_hash)
212 while delta.tail in self._tracker.items:
213 updates.append((delta.tail, delta))
214 this_delta = self._get_delta(delta.tail)
216 for update_hash, delta_then in updates:
217 self._set_delta(update_hash, delta - delta_then)
220 def get_delta(self, item, ancestor):
221 assert self._tracker.is_child_of(ancestor, item)
222 return self.get_delta_to_last(item) - self.get_delta_to_last(ancestor)
224 class Tracker(object):
225 def __init__(self, items=[], delta_type=AttributeDelta):
226 self.items = {} # hash -> item
227 self.reverse = {} # delta.tail -> set of item_hashes
229 self.heads = {} # head hash -> tail_hash
230 self.tails = {} # tail hash -> set of head hashes
232 self.added = variable.Event()
233 self.remove_special = variable.Event()
234 self.remove_special2 = variable.Event()
235 self.removed = variable.Event()
237 self.get_nth_parent_hash = DistanceSkipList(self)
239 self._delta_type = delta_type
240 self._default_view = TrackerView(self, delta_type)
245 def __getattr__(self, name):
246 attr = getattr(self._default_view, name)
247 setattr(self, name, attr)
251 assert not isinstance(item, (int, long, type(None)))
252 delta = self._delta_type.from_element(item)
254 if delta.head in self.items:
255 raise ValueError('item already present')
257 if delta.head in self.tails:
258 heads = self.tails.pop(delta.head)
260 heads = set([delta.head])
262 if delta.tail in self.heads:
263 tail = self.heads.pop(delta.tail)
265 tail = self.get_last(delta.tail)
267 self.items[delta.head] = item
268 self.reverse.setdefault(delta.tail, set()).add(delta.head)
270 self.tails.setdefault(tail, set()).update(heads)
271 if delta.tail in self.tails[tail]:
272 self.tails[tail].remove(delta.tail)
275 self.heads[head] = tail
277 self.added.happened(item)
279 def remove(self, item_hash):
280 assert isinstance(item_hash, (int, long, type(None)))
281 if item_hash not in self.items:
284 item = self.items[item_hash]
287 delta = self._delta_type.from_element(item)
289 children = self.reverse.get(delta.head, set())
291 if delta.head in self.heads and delta.tail in self.tails:
292 tail = self.heads.pop(delta.head)
293 self.tails[tail].remove(delta.head)
294 if not self.tails[delta.tail]:
295 self.tails.pop(delta.tail)
296 elif delta.head in self.heads:
297 tail = self.heads.pop(delta.head)
298 self.tails[tail].remove(delta.head)
299 if self.reverse[delta.tail] != set([delta.head]):
302 self.tails[tail].add(delta.tail)
303 self.heads[delta.tail] = tail
304 elif delta.tail in self.tails and len(self.reverse[delta.tail]) <= 1:
305 heads = self.tails.pop(delta.tail)
307 self.heads[head] = delta.head
308 self.tails[delta.head] = set(heads)
310 self.remove_special.happened(item)
311 elif delta.tail in self.tails and len(self.reverse[delta.tail]) > 1:
312 heads = [x for x in self.tails[delta.tail] if self.is_child_of(delta.head, x)]
313 self.tails[delta.tail] -= set(heads)
314 if not self.tails[delta.tail]:
315 self.tails.pop(delta.tail)
317 self.heads[head] = delta.head
318 assert delta.head not in self.tails
319 self.tails[delta.head] = set(heads)
321 self.remove_special2.happened(item)
323 raise NotImplementedError()
325 self.items.pop(delta.head)
326 self.reverse[delta.tail].remove(delta.head)
327 if not self.reverse[delta.tail]:
328 self.reverse.pop(delta.tail)
330 self.removed.happened(item)
332 def get_chain(self, start_hash, length):
333 assert length <= self.get_height(start_hash)
334 for i in xrange(length):
335 item = self.items[start_hash]
337 start_hash = self._delta_type.get_tail(item)
339 def is_child_of(self, item_hash, possible_child_hash):
340 height, last = self.get_height_and_last(item_hash)
341 child_height, child_last = self.get_height_and_last(possible_child_hash)
342 if child_last != last:
343 return None # not connected, so can't be determined
344 height_up = child_height - height
345 return height_up >= 0 and self.get_nth_parent_hash(possible_child_hash, height_up) == item_hash
347 class SubsetTracker(Tracker):
348 def __init__(self, subset_of, **kwargs):
349 Tracker.__init__(self, **kwargs)
350 self.get_nth_parent_hash = subset_of.get_nth_parent_hash # overwrites Tracker.__init__'s
351 self._subset_of = subset_of
354 if self._subset_of is not None:
355 assert self._delta_type.get_head(item) in self._subset_of.items
356 Tracker.add(self, item)
358 def remove(self, item_hash):
359 if self._subset_of is not None:
360 assert item_hash in self._subset_of.items
361 Tracker.remove(self, item_hash)