Mercurial > hg
view mercurial/ancestor.py @ 21062:e7c0a65a5c9c
bundle2: use headerless HG10UN stream in changegroup
Using `readbundle` in the part handlers creates a circular import hell. We are
now using a simple `HG10UN` stream with no header. Some parameters may
later be introduced on the part to change parameter.
Producers are updated as well.
author | Pierre-Yves David <pierre-yves.david@fb.com> |
---|---|
date | Mon, 14 Apr 2014 14:46:32 -0400 |
parents | 231ccc08670c |
children | 64911a12dc28 |
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# ancestor.py - generic DAG ancestor algorithm for mercurial # # Copyright 2006 Matt Mackall <mpm@selenic.com> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. import heapq import util from node import nullrev def ancestors(pfunc, *orignodes): """ Returns the common ancestors of a and b that are furthest from a root (as measured by longest path). pfunc must return a list of parent vertices for a given vertex. """ if not isinstance(orignodes, set): orignodes = set(orignodes) if nullrev in orignodes: return set() if len(orignodes) <= 1: return orignodes def candidates(nodes): allseen = (1 << len(nodes)) - 1 seen = [0] * (max(nodes) + 1) for i, n in enumerate(nodes): seen[n] = 1 << i poison = 1 << (i + 1) gca = set() interesting = len(nodes) nv = len(seen) - 1 while nv >= 0 and interesting: v = nv nv -= 1 if not seen[v]: continue sv = seen[v] if sv < poison: interesting -= 1 if sv == allseen: gca.add(v) sv |= poison if v in nodes: # history is linear return set([v]) if sv < poison: for p in pfunc(v): sp = seen[p] if p == nullrev: continue if sp == 0: seen[p] = sv interesting += 1 elif sp != sv: seen[p] |= sv else: for p in pfunc(v): if p == nullrev: continue sp = seen[p] if sp and sp < poison: interesting -= 1 seen[p] = sv return gca def deepest(nodes): interesting = {} count = max(nodes) + 1 depth = [0] * count seen = [0] * count mapping = [] for (i, n) in enumerate(sorted(nodes)): depth[n] = 1 b = 1 << i seen[n] = b interesting[b] = 1 mapping.append((b, n)) nv = count - 1 while nv >= 0 and len(interesting) > 1: v = nv nv -= 1 dv = depth[v] if dv == 0: continue sv = seen[v] for p in pfunc(v): if p == nullrev: continue dp = depth[p] nsp = sp = seen[p] if dp <= dv: depth[p] = dv + 1 if sp != sv: interesting[sv] += 1 nsp = seen[p] = sv if sp: interesting[sp] -= 1 if interesting[sp] == 0: del interesting[sp] elif dv == dp - 1: nsp = sp | sv if nsp == sp: continue seen[p] = nsp interesting.setdefault(nsp, 0) interesting[nsp] += 1 interesting[sp] -= 1 if interesting[sp] == 0: del interesting[sp] interesting[sv] -= 1 if interesting[sv] == 0: del interesting[sv] if len(interesting) != 1: return [] k = 0 for i in interesting: k |= i return set(n for (i, n) in mapping if k & i) gca = candidates(orignodes) if len(gca) <= 1: return gca return deepest(gca) def missingancestors(revs, bases, pfunc): """Return all the ancestors of revs that are not ancestors of bases. This may include elements from revs. Equivalent to the revset (::revs - ::bases). Revs are returned in revision number order, which is a topological order. revs and bases should both be iterables. pfunc must return a list of parent revs for a given revs. """ revsvisit = set(revs) basesvisit = set(bases) if not revsvisit: return [] if not basesvisit: basesvisit.add(nullrev) start = max(max(revsvisit), max(basesvisit)) bothvisit = revsvisit.intersection(basesvisit) revsvisit.difference_update(bothvisit) basesvisit.difference_update(bothvisit) # At this point, we hold the invariants that: # - revsvisit is the set of nodes we know are an ancestor of at least one # of the nodes in revs # - basesvisit is the same for bases # - bothvisit is the set of nodes we know are ancestors of at least one of # the nodes in revs and one of the nodes in bases # - a node may be in none or one, but not more, of revsvisit, basesvisit # and bothvisit at any given time # Now we walk down in reverse topo order, adding parents of nodes already # visited to the sets while maintaining the invariants. When a node is # found in both revsvisit and basesvisit, it is removed from them and # added to bothvisit instead. When revsvisit becomes empty, there are no # more ancestors of revs that aren't also ancestors of bases, so exit. missing = [] for curr in xrange(start, nullrev, -1): if not revsvisit: break if curr in bothvisit: bothvisit.remove(curr) # curr's parents might have made it into revsvisit or basesvisit # through another path for p in pfunc(curr): revsvisit.discard(p) basesvisit.discard(p) bothvisit.add(p) continue # curr will never be in both revsvisit and basesvisit, since if it # were it'd have been pushed to bothvisit if curr in revsvisit: missing.append(curr) thisvisit = revsvisit othervisit = basesvisit elif curr in basesvisit: thisvisit = basesvisit othervisit = revsvisit else: # not an ancestor of revs or bases: ignore continue thisvisit.remove(curr) for p in pfunc(curr): if p == nullrev: pass elif p in othervisit or p in bothvisit: # p is implicitly in thisvisit. This means p is or should be # in bothvisit revsvisit.discard(p) basesvisit.discard(p) bothvisit.add(p) else: # visit later thisvisit.add(p) missing.reverse() return missing class lazyancestors(object): def __init__(self, cl, revs, stoprev=0, inclusive=False): """Create a new object generating ancestors for the given revs. Does not generate revs lower than stoprev. This is computed lazily starting from revs. The object supports iteration and membership. cl should be a changelog and revs should be an iterable. inclusive is a boolean that indicates whether revs should be included. Revs lower than stoprev will not be generated. Result does not include the null revision.""" self._parentrevs = cl.parentrevs self._initrevs = revs self._stoprev = stoprev self._inclusive = inclusive # Initialize data structures for __contains__. # For __contains__, we use a heap rather than a deque because # (a) it minimizes the number of parentrevs calls made # (b) it makes the loop termination condition obvious # Python's heap is a min-heap. Multiply all values by -1 to convert it # into a max-heap. self._containsvisit = [-rev for rev in revs] heapq.heapify(self._containsvisit) if inclusive: self._containsseen = set(revs) else: self._containsseen = set() def __iter__(self): """Generate the ancestors of _initrevs in reverse topological order. If inclusive is False, yield a sequence of revision numbers starting with the parents of each revision in revs, i.e., each revision is *not* considered an ancestor of itself. Results are in breadth-first order: parents of each rev in revs, then parents of those, etc. If inclusive is True, yield all the revs first (ignoring stoprev), then yield all the ancestors of revs as when inclusive is False. If an element in revs is an ancestor of a different rev it is not yielded again.""" seen = set() revs = self._initrevs if self._inclusive: for rev in revs: yield rev seen.update(revs) parentrevs = self._parentrevs stoprev = self._stoprev visit = util.deque(revs) while visit: for parent in parentrevs(visit.popleft()): if parent >= stoprev and parent not in seen: visit.append(parent) seen.add(parent) yield parent def __contains__(self, target): """Test whether target is an ancestor of self._initrevs.""" # Trying to do both __iter__ and __contains__ using the same visit # heap and seen set is complex enough that it slows down both. Keep # them separate. seen = self._containsseen if target in seen: return True parentrevs = self._parentrevs visit = self._containsvisit stoprev = self._stoprev heappop = heapq.heappop heappush = heapq.heappush targetseen = False while visit and -visit[0] > target and not targetseen: for parent in parentrevs(-heappop(visit)): if parent < stoprev or parent in seen: continue # We need to make sure we push all parents into the heap so # that we leave it in a consistent state for future calls. heappush(visit, -parent) seen.add(parent) if parent == target: targetseen = True return targetseen