Mercurial > hg
view mercurial/unionrepo.py @ 32151:4d504e541d3d
rebase: use matcher to optimize manifestmerge
The old merge code would call manifestmerge and calculate the complete diff
between the source to the destination. In many cases, like rebase, the vast
majority of differences between the source and destination are irrelevant
because they are differences between the destination and the common ancestor
only, and therefore don't affect the merge. Since most actions are 'keep', all
the effort to compute them is wasted.
Instead, let's compute the difference between the source and the common ancestor
and only perform the diff of those files against the merge destination. When
using treemanifest, this lets us avoid loading almost the entire tree when
rebasing from a very old ancestor. This speeds up rebase of an old stack of 27
commits by 20x.
In mozilla-central, without treemanifest, when rebasing a commit from
default~100000 to default, this speeds up the manifestmerge step from 2.6s to
1.2s. However, the additional diff adds an overhead to all manifestmerge calls,
especially for flat manifests. When rebasing a commit from default~1 to default
it appears to add 100ms in mozilla-central. While we could put this optimization
behind a flag, I think the fact that it makes merge O(number of changes being
applied) instead of O(number of changes between X and Y) justifies it.
author | Durham Goode <durham@fb.com> |
---|---|
date | Wed, 03 May 2017 10:43:59 -0700 |
parents | f1e0446e804c |
children | 634997248c97 |
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# unionrepo.py - repository class for viewing union of repository changesets # # Derived from bundlerepo.py # Copyright 2006, 2007 Benoit Boissinot <bboissin@gmail.com> # Copyright 2013 Unity Technologies, Mads Kiilerich <madski@unity3d.com> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. """Repository class for "in-memory pull" of one local repository to another, allowing operations like diff and log with revsets. """ from __future__ import absolute_import from .i18n import _ from .node import nullid from . import ( changelog, cmdutil, error, filelog, localrepo, manifest, mdiff, pathutil, pycompat, revlog, util, vfs as vfsmod, ) class unionrevlog(revlog.revlog): def __init__(self, opener, indexfile, revlog2, linkmapper): # How it works: # To retrieve a revision, we just need to know the node id so we can # look it up in revlog2. # # To differentiate a rev in the second revlog from a rev in the revlog, # we check revision against repotiprev. opener = vfsmod.readonlyvfs(opener) revlog.revlog.__init__(self, opener, indexfile) self.revlog2 = revlog2 n = len(self) self.repotiprev = n - 1 self.bundlerevs = set() # used by 'bundle()' revset expression for rev2 in self.revlog2: rev = self.revlog2.index[rev2] # rev numbers - in revlog2, very different from self.rev _start, _csize, _rsize, base, linkrev, p1rev, p2rev, node = rev flags = _start & 0xFFFF if linkmapper is None: # link is to same revlog assert linkrev == rev2 # we never link back link = n else: # rev must be mapped from repo2 cl to unified cl by linkmapper link = linkmapper(linkrev) if linkmapper is not None: # link is to same revlog base = linkmapper(base) if node in self.nodemap: # this happens for the common revlog revisions self.bundlerevs.add(self.nodemap[node]) continue p1node = self.revlog2.node(p1rev) p2node = self.revlog2.node(p2rev) e = (flags, None, None, base, link, self.rev(p1node), self.rev(p2node), node) self.index.insert(-1, e) self.nodemap[node] = n self.bundlerevs.add(n) n += 1 def _chunk(self, rev): if rev <= self.repotiprev: return revlog.revlog._chunk(self, rev) return self.revlog2._chunk(self.node(rev)) def revdiff(self, rev1, rev2): """return or calculate a delta between two revisions""" if rev1 > self.repotiprev and rev2 > self.repotiprev: return self.revlog2.revdiff( self.revlog2.rev(self.node(rev1)), self.revlog2.rev(self.node(rev2))) elif rev1 <= self.repotiprev and rev2 <= self.repotiprev: return self.baserevdiff(rev1, rev2) return mdiff.textdiff(self.revision(rev1), self.revision(rev2)) def revision(self, nodeorrev, raw=False): """return an uncompressed revision of a given node or revision number. """ if isinstance(nodeorrev, int): rev = nodeorrev node = self.node(rev) else: node = nodeorrev rev = self.rev(node) if node == nullid: return "" if rev > self.repotiprev: text = self.revlog2.revision(node) self._cache = (node, rev, text) else: text = self.baserevision(rev) # already cached return text def baserevision(self, nodeorrev): # Revlog subclasses may override 'revision' method to modify format of # content retrieved from revlog. To use unionrevlog with such class one # needs to override 'baserevision' and make more specific call here. return revlog.revlog.revision(self, nodeorrev) def baserevdiff(self, rev1, rev2): # Exists for the same purpose as baserevision. return revlog.revlog.revdiff(self, rev1, rev2) def addrevision(self, text, transaction, link, p1=None, p2=None, d=None): raise NotImplementedError def addgroup(self, revs, linkmapper, transaction): raise NotImplementedError def strip(self, rev, minlink): raise NotImplementedError def checksize(self): raise NotImplementedError class unionchangelog(unionrevlog, changelog.changelog): def __init__(self, opener, opener2): changelog.changelog.__init__(self, opener) linkmapper = None changelog2 = changelog.changelog(opener2) unionrevlog.__init__(self, opener, self.indexfile, changelog2, linkmapper) def baserevision(self, nodeorrev): # Although changelog doesn't override 'revision' method, some extensions # may replace this class with another that does. Same story with # manifest and filelog classes. return changelog.changelog.revision(self, nodeorrev) def baserevdiff(self, rev1, rev2): return changelog.changelog.revdiff(self, rev1, rev2) class unionmanifest(unionrevlog, manifest.manifestrevlog): def __init__(self, opener, opener2, linkmapper): manifest.manifestrevlog.__init__(self, opener) manifest2 = manifest.manifestrevlog(opener2) unionrevlog.__init__(self, opener, self.indexfile, manifest2, linkmapper) def baserevision(self, nodeorrev): return manifest.manifestrevlog.revision(self, nodeorrev) def baserevdiff(self, rev1, rev2): return manifest.manifestrevlog.revdiff(self, rev1, rev2) class unionfilelog(unionrevlog, filelog.filelog): def __init__(self, opener, path, opener2, linkmapper, repo): filelog.filelog.__init__(self, opener, path) filelog2 = filelog.filelog(opener2, path) unionrevlog.__init__(self, opener, self.indexfile, filelog2, linkmapper) self._repo = repo def baserevision(self, nodeorrev): return filelog.filelog.revision(self, nodeorrev) def baserevdiff(self, rev1, rev2): return filelog.filelog.revdiff(self, rev1, rev2) def iscensored(self, rev): """Check if a revision is censored.""" if rev <= self.repotiprev: return filelog.filelog.iscensored(self, rev) node = self.node(rev) return self.revlog2.iscensored(self.revlog2.rev(node)) class unionpeer(localrepo.localpeer): def canpush(self): return False class unionrepository(localrepo.localrepository): def __init__(self, ui, path, path2): localrepo.localrepository.__init__(self, ui, path) self.ui.setconfig('phases', 'publish', False, 'unionrepo') self._url = 'union:%s+%s' % (util.expandpath(path), util.expandpath(path2)) self.repo2 = localrepo.localrepository(ui, path2) @localrepo.unfilteredpropertycache def changelog(self): return unionchangelog(self.svfs, self.repo2.svfs) def _clrev(self, rev2): """map from repo2 changelog rev to temporary rev in self.changelog""" node = self.repo2.changelog.node(rev2) return self.changelog.rev(node) def _constructmanifest(self): return unionmanifest(self.svfs, self.repo2.svfs, self.unfiltered()._clrev) def url(self): return self._url def file(self, f): return unionfilelog(self.svfs, f, self.repo2.svfs, self.unfiltered()._clrev, self) def close(self): self.repo2.close() def cancopy(self): return False def peer(self): return unionpeer(self) def getcwd(self): return pycompat.getcwd() # always outside the repo def instance(ui, path, create): if create: raise error.Abort(_('cannot create new union repository')) parentpath = ui.config("bundle", "mainreporoot", "") if not parentpath: # try to find the correct path to the working directory repo parentpath = cmdutil.findrepo(pycompat.getcwd()) if parentpath is None: parentpath = '' if parentpath: # Try to make the full path relative so we get a nice, short URL. # In particular, we don't want temp dir names in test outputs. cwd = pycompat.getcwd() if parentpath == cwd: parentpath = '' else: cwd = pathutil.normasprefix(cwd) if parentpath.startswith(cwd): parentpath = parentpath[len(cwd):] if path.startswith('union:'): s = path.split(":", 1)[1].split("+", 1) if len(s) == 1: repopath, repopath2 = parentpath, s[0] else: repopath, repopath2 = s else: repopath, repopath2 = parentpath, path return unionrepository(ui, repopath, repopath2)