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()))
62 def __init__(self, head, tail, **kwargs):
63 self.head, self.tail = head, tail
64 for k, v in kwargs.iteritems():
67 def __add__(self, other):
68 assert self.tail == other.head
69 return self.__class__(self.head, other.tail, **dict((k, getattr(self, k) + getattr(other, k)) for k in attrs))
71 def __sub__(self, other):
72 if self.head == other.head:
73 return self.__class__(other.tail, self.tail, **dict((k, getattr(self, k) - getattr(other, k)) for k in attrs))
74 elif self.tail == other.tail:
75 return self.__class__(self.head, other.head, **dict((k, getattr(self, k) - getattr(other, k)) for k in attrs))
77 raise AssertionError()
80 return '%s(%r, %r%s)' % (self.__class__, self.head, self.tail, ''.join(', %s=%r' % (k, getattr(self, k)) for k in attrs))
81 ProtoAttributeDelta.attrs = attrs
82 return ProtoAttributeDelta
84 AttributeDelta = get_attributedelta_type(dict(
85 height=lambda item: 1,
88 class TrackerView(object):
89 def __init__(self, tracker, delta_type):
90 self._tracker = tracker
91 self._delta_type = delta_type
93 self._deltas = {} # item_hash -> delta, ref
94 self._reverse_deltas = {} # ref -> set of item_hashes
96 self._ref_generator = itertools.count()
97 self._delta_refs = {} # ref -> delta
98 self._reverse_delta_refs = {} # delta.tail -> ref
100 self._tracker.preremove_special.watch_weakref(self, lambda self, item: self._handle_preremove_special(item))
101 self._tracker.postremove_special.watch_weakref(self, lambda self, item: self._handle_postremove_special(item))
102 self._tracker.removed.watch_weakref(self, lambda self, item: self._handle_removed(item))
104 def _handle_preremove_special(self, item):
105 delta = self._delta_type.from_element(item)
107 # move delta refs referencing children down to this, so they can be moved up in one step
108 if delta.tail in self._reverse_delta_refs:
109 for x in list(self._reverse_deltas.get(self._reverse_delta_refs.get(delta.head, object()), set())):
111 assert delta.head not in self._reverse_delta_refs, list(self._reverse_deltas.get(self._reverse_delta_refs.get(delta.head, None), set()))
113 def _handle_postremove_special(self, item):
114 delta = self._delta_type.from_element(item)
116 # move ref pointing to this up
117 if delta.tail in self._reverse_delta_refs:
118 assert delta.head not in self._reverse_delta_refs, list(self._reverse_deltas.get(self._reverse_delta_refs.get(delta.head, object()), set()))
120 ref = self._reverse_delta_refs[delta.tail]
121 cur_delta = self._delta_refs[ref]
122 assert cur_delta.tail == delta.tail
123 self._delta_refs[ref] = cur_delta - self._delta_type.from_element(item)
124 assert self._delta_refs[ref].tail == delta.head
125 del self._reverse_delta_refs[delta.tail]
126 self._reverse_delta_refs[delta.head] = ref
128 def _handle_removed(self, item):
129 delta = self._delta_type.from_element(item)
131 # delete delta entry and ref if it is empty
132 if delta.head in self._deltas:
133 delta1, ref = self._deltas.pop(delta.head)
134 self._reverse_deltas[ref].remove(delta.head)
135 if not self._reverse_deltas[ref]:
136 del self._reverse_deltas[ref]
137 delta2 = self._delta_refs.pop(ref)
138 del self._reverse_delta_refs[delta2.tail]
141 def get_height(self, item_hash):
142 return self.get_delta_to_last(item_hash).height
144 def get_work(self, item_hash):
145 return self.get_delta_to_last(item_hash).work
147 def get_last(self, item_hash):
148 return self.get_delta_to_last(item_hash).tail
150 def get_height_and_last(self, item_hash):
151 delta = self.get_delta_to_last(item_hash)
152 return delta.height, delta.tail
154 def _get_delta(self, item_hash):
155 if item_hash in self._deltas:
156 delta1, ref = self._deltas[item_hash]
157 delta2 = self._delta_refs[ref]
158 res = delta1 + delta2
160 res = self._delta_type.from_element(self._tracker.items[item_hash])
161 assert res.head == item_hash
164 def _set_delta(self, item_hash, delta):
165 other_item_hash = delta.tail
166 if other_item_hash not in self._reverse_delta_refs:
167 ref = self._ref_generator.next()
168 assert ref not in self._delta_refs
169 self._delta_refs[ref] = self._delta_type.get_none(other_item_hash)
170 self._reverse_delta_refs[other_item_hash] = ref
173 ref = self._reverse_delta_refs[other_item_hash]
174 ref_delta = self._delta_refs[ref]
175 assert ref_delta.tail == other_item_hash
177 if item_hash in self._deltas:
178 prev_ref = self._deltas[item_hash][1]
179 self._reverse_deltas[prev_ref].remove(item_hash)
180 if not self._reverse_deltas[prev_ref] and prev_ref != ref:
181 self._reverse_deltas.pop(prev_ref)
182 x = self._delta_refs.pop(prev_ref)
183 self._reverse_delta_refs.pop(x.tail)
184 self._deltas[item_hash] = delta - ref_delta, ref
185 self._reverse_deltas.setdefault(ref, set()).add(item_hash)
187 def get_delta_to_last(self, item_hash):
188 assert isinstance(item_hash, (int, long, type(None)))
189 delta = self._delta_type.get_none(item_hash)
191 while delta.tail in self._tracker.items:
192 updates.append((delta.tail, delta))
193 this_delta = self._get_delta(delta.tail)
195 for update_hash, delta_then in updates:
196 self._set_delta(update_hash, delta - delta_then)
199 def get_delta(self, item, ancestor):
200 assert self._tracker.is_child_of(ancestor, item)
201 return self.get_delta_to_last(item) - self.get_delta_to_last(ancestor)
203 class Tracker(object):
204 def __init__(self, items=[], delta_type=AttributeDelta):
205 self.items = {} # hash -> item
206 self.reverse = {} # delta.tail -> set of item_hashes
208 self.heads = {} # head hash -> tail_hash
209 self.tails = {} # tail hash -> set of head hashes
211 self.added = variable.Event()
212 self.preremove_special = variable.Event()
213 self.postremove_special = variable.Event()
214 self.removed = variable.Event()
216 self.get_nth_parent_hash = DistanceSkipList(self)
218 self._delta_type = delta_type
219 self._default_view = TrackerView(self, delta_type)
224 def __getattr__(self, name):
225 attr = getattr(self._default_view, name)
226 setattr(self, name, attr)
230 assert not isinstance(item, (int, long, type(None)))
231 delta = self._delta_type.from_element(item)
233 if delta.head in self.items:
234 raise ValueError('item already present')
236 if delta.head in self.tails:
237 heads = self.tails.pop(delta.head)
239 heads = set([delta.head])
241 if delta.tail in self.heads:
242 tail = self.heads.pop(delta.tail)
244 tail = self.get_last(delta.tail)
246 self.items[delta.head] = item
247 self.reverse.setdefault(delta.tail, set()).add(delta.head)
249 self.tails.setdefault(tail, set()).update(heads)
250 if delta.tail in self.tails[tail]:
251 self.tails[tail].remove(delta.tail)
254 self.heads[head] = tail
256 self.added.happened(item)
258 def remove(self, item_hash):
259 assert isinstance(item_hash, (int, long, type(None)))
260 if item_hash not in self.items:
263 item = self.items[item_hash]
266 delta = self._delta_type.from_element(item)
268 children = self.reverse.get(delta.head, set())
270 if delta.head in self.heads and delta.tail in self.tails:
271 tail = self.heads.pop(delta.head)
272 self.tails[tail].remove(delta.head)
273 if not self.tails[delta.tail]:
274 self.tails.pop(delta.tail)
275 elif delta.head in self.heads:
276 tail = self.heads.pop(delta.head)
277 self.tails[tail].remove(delta.head)
278 if self.reverse[delta.tail] != set([delta.head]):
281 self.tails[tail].add(delta.tail)
282 self.heads[delta.tail] = tail
283 elif delta.tail in self.tails and len(self.reverse[delta.tail]) <= 1:
284 self.preremove_special.happened(item)
286 heads = self.tails.pop(delta.tail)
288 self.heads[head] = delta.head
289 self.tails[delta.head] = set(heads)
291 self.postremove_special.happened(item)
293 raise NotImplementedError()
295 self.items.pop(delta.head)
296 self.reverse[delta.tail].remove(delta.head)
297 if not self.reverse[delta.tail]:
298 self.reverse.pop(delta.tail)
300 self.removed.happened(item)
302 def get_chain(self, start_hash, length):
303 assert length <= self.get_height(start_hash)
304 for i in xrange(length):
305 yield self.items[start_hash]
306 start_hash = self._delta_type.from_element(self.items[start_hash]).tail
308 def is_child_of(self, item_hash, possible_child_hash):
309 height, last = self.get_height_and_last(item_hash)
310 child_height, child_last = self.get_height_and_last(possible_child_hash)
311 if child_last != last:
312 return None # not connected, so can't be determined
313 height_up = child_height - height
314 return height_up >= 0 and self.get_nth_parent_hash(possible_child_hash, height_up) == item_hash
316 class SubsetTracker(Tracker):
317 def __init__(self, subset_of, **kwargs):
318 Tracker.__init__(self, **kwargs)
319 self.get_nth_parent_hash = subset_of.get_nth_parent_hash # overwrites Tracker.__init__'s
320 self._subset_of = subset_of
323 delta = self._delta_type.from_element(item)
324 if self._subset_of is not None:
325 assert delta.head in self._subset_of.items
326 Tracker.add(self, item)
328 def remove(self, item_hash):
329 if self._subset_of is not None:
330 assert item_hash in self._subset_of.items
331 Tracker.remove(self, item_hash)