Mercurial > hg
view mercurial/dagutil.py @ 30758:76104a4899ad
commands: config option to control bundle compression level
Currently, bundle compression uses the default compression level
for the active compression engine. The default compression level
is tuned as a compromise between speed and size.
Some scenarios may call for a different compression level. For
example, with clone bundles, bundles are generated once and used
several times. Since the cost to generate is paid infrequently,
server operators may wish to trade extra CPU time for better
compression ratios.
This patch introduces an experimental and undocumented config
option to control the bundle compression level. As the inline
comment says, this approach is a bit hacky. I'd prefer for
the compression level to be encoded in the bundle spec. e.g.
"zstd-v2;complevel=15." However, given that the 4.1 freeze is
imminent, I'm not comfortable implementing this user-facing
change without much time to test and consider the implications.
So, we're going with the quick and dirty solution for now.
Having this option in the 4.1 release will enable Mozilla to
easily produce and test zlib and zstd bundles with non-default
compression levels in production. This will help drive future
development of the feature and zstd integration with Mercurial.
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Tue, 10 Jan 2017 11:20:32 -0800 |
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