Mercurial > hg
view mercurial/dagutil.py @ 31626:0febf8e4e2ce
repair: use context manager for lock management
If repo.lock() raised inside of the try block, 'tr' would have been None in the
finally block where it tries to release(). Modernize the syntax instead of just
winching the lock out of the try block.
I found several other instances of acquiring the lock inside of the 'try', but
those finally blocks handle None references. I also started switching some
trivial try/finally blocks to context managers, but didn't get them all because
indenting over 3x for lock, wlock and transaction would have spilled over 80
characters. That got me wondering if there should be a repo.rwlock(), to handle
locking and unlocking in the proper order.
It also looks like py27 supports supports multiple context managers for a single
'with' statement. Should I hold off on the rest until py26 is dropped?
author | Matt Harbison <matt_harbison@yahoo.com> |
---|---|
date | Thu, 23 Mar 2017 23:47:23 -0400 |
parents | 015ded095933 |
children | 09397d0dd3b7 |
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# dagutil.py - dag utilities for mercurial # # Copyright 2010 Benoit Boissinot <bboissin@gmail.com> # and Peter Arrenbrecht <peter@arrenbrecht.ch> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. from __future__ import absolute_import from .i18n import _ from .node import nullrev class basedag(object): '''generic interface for DAGs terms: "ix" (short for index) identifies a nodes internally, "id" identifies one externally. All params are ixs unless explicitly suffixed otherwise. Pluralized params are lists or sets. ''' def __init__(self): self._inverse = None def nodeset(self): '''set of all node ixs''' raise NotImplementedError def heads(self): '''list of head ixs''' raise NotImplementedError def parents(self, ix): '''list of parents ixs of ix''' raise NotImplementedError def inverse(self): '''inverse DAG, where parents becomes children, etc.''' raise NotImplementedError def ancestorset(self, starts, stops=None): ''' set of all ancestors of starts (incl), but stop walk at stops (excl) ''' raise NotImplementedError def descendantset(self, starts, stops=None): ''' set of all descendants of starts (incl), but stop walk at stops (excl) ''' return self.inverse().ancestorset(starts, stops) def headsetofconnecteds(self, ixs): ''' subset of connected list of ixs so that no node has a descendant in it By "connected list" we mean that if an ancestor and a descendant are in the list, then so is at least one path connecting them. ''' raise NotImplementedError def externalize(self, ix): '''return a node id''' return self._externalize(ix) def externalizeall(self, ixs): '''return a list of (or set if given a set) of node ids''' ids = self._externalizeall(ixs) if isinstance(ixs, set): return set(ids) return list(ids) def internalize(self, id): '''return a node ix''' return self._internalize(id) def internalizeall(self, ids, filterunknown=False): '''return a list of (or set if given a set) of node ixs''' ixs = self._internalizeall(ids, filterunknown) if isinstance(ids, set): return set(ixs) return list(ixs) class genericdag(basedag): '''generic implementations for DAGs''' def ancestorset(self, starts, stops=None): if stops: stops = set(stops) else: stops = set() seen = set() pending = list(starts) while pending: n = pending.pop() if n not in seen and n not in stops: seen.add(n) pending.extend(self.parents(n)) return seen def headsetofconnecteds(self, ixs): hds = set(ixs) if not hds: return hds for n in ixs: for p in self.parents(n): hds.discard(p) assert hds return hds class revlogbaseddag(basedag): '''generic dag interface to a revlog''' def __init__(self, revlog, nodeset): basedag.__init__(self) self._revlog = revlog self._heads = None self._nodeset = nodeset def nodeset(self): return self._nodeset def heads(self): if self._heads is None: self._heads = self._getheads() return self._heads def _externalize(self, ix): return self._revlog.index[ix][7] def _externalizeall(self, ixs): idx = self._revlog.index return [idx[i][7] for i in ixs] def _internalize(self, id): ix = self._revlog.rev(id) if ix == nullrev: raise LookupError(id, self._revlog.indexfile, _('nullid')) return ix def _internalizeall(self, ids, filterunknown): rl = self._revlog if filterunknown: return [r for r in map(rl.nodemap.get, ids) if (r is not None and r != nullrev and r not in rl.filteredrevs)] return map(self._internalize, ids) class revlogdag(revlogbaseddag): '''dag interface to a revlog''' def __init__(self, revlog): revlogbaseddag.__init__(self, revlog, set(revlog)) def _getheads(self): return [r for r in self._revlog.headrevs() if r != nullrev] def parents(self, ix): rlog = self._revlog idx = rlog.index revdata = idx[ix] prev = revdata[5] if prev != nullrev: prev2 = revdata[6] if prev2 == nullrev: return [prev] return [prev, prev2] prev2 = revdata[6] if prev2 != nullrev: return [prev2] return [] def inverse(self): if self._inverse is None: self._inverse = inverserevlogdag(self) return self._inverse def ancestorset(self, starts, stops=None): rlog = self._revlog idx = rlog.index if stops: stops = set(stops) else: stops = set() seen = set() pending = list(starts) while pending: rev = pending.pop() if rev not in seen and rev not in stops: seen.add(rev) revdata = idx[rev] for i in [5, 6]: prev = revdata[i] if prev != nullrev: pending.append(prev) return seen def headsetofconnecteds(self, ixs): if not ixs: return set() rlog = self._revlog idx = rlog.index headrevs = set(ixs) for rev in ixs: revdata = idx[rev] for i in [5, 6]: prev = revdata[i] if prev != nullrev: headrevs.discard(prev) assert headrevs return headrevs def linearize(self, ixs): '''linearize and topologically sort a list of revisions The linearization process tries to create long runs of revs where a child rev comes immediately after its first parent. This is done by visiting the heads of the given revs in inverse topological order, and for each visited rev, visiting its second parent, then its first parent, then adding the rev itself to the output list. ''' sorted = [] visit = list(self.headsetofconnecteds(ixs)) visit.sort(reverse=True) finished = set() while visit: cur = visit.pop() if cur < 0: cur = -cur - 1 if cur not in finished: sorted.append(cur) finished.add(cur) else: visit.append(-cur - 1) visit += [p for p in self.parents(cur) if p in ixs and p not in finished] assert len(sorted) == len(ixs) return sorted class inverserevlogdag(revlogbaseddag, genericdag): '''inverse of an existing revlog dag; see revlogdag.inverse()''' def __init__(self, orig): revlogbaseddag.__init__(self, orig._revlog, orig._nodeset) self._orig = orig self._children = {} self._roots = [] self._walkfrom = len(self._revlog) - 1 def _walkto(self, walkto): rev = self._walkfrom cs = self._children roots = self._roots idx = self._revlog.index while rev >= walkto: data = idx[rev] isroot = True for prev in [data[5], data[6]]: # parent revs if prev != nullrev: cs.setdefault(prev, []).append(rev) isroot = False if isroot: roots.append(rev) rev -= 1 self._walkfrom = rev def _getheads(self): self._walkto(nullrev) return self._roots def parents(self, ix): if ix is None: return [] if ix <= self._walkfrom: self._walkto(ix) return self._children.get(ix, []) def inverse(self): return self._orig