Mercurial > hg
view hgext/fetch.py @ 30561:7c0c722d568d
bdiff: early pruning of common prefix before doing expensive computations
It seems quite common that files don't change completely. New lines are often
pretty much appended, and modifications will often only change a small section
of the file which on average will be in the middle.
There can thus be a big win by pruning a common prefix before starting the more
expensive search for longest common substrings.
Worst case, it will scan through a long sequence of similar bytes without
encountering a newline. Splitlines will then have to do the same again ...
twice for each side. If similar lines are found, splitlines will save the
double iteration and hashing of the lines ... plus there will be less lines to
find common substrings in.
This change might in some cases make the algorith pick shorter or less optimal
common substrings. We can't have the cake and eat it.
This make hg --time bundle --base null -r 4.0 go from 14.5 to 15 s - a 3%
increase.
On mozilla-unified:
perfbdiff -m 3041e4d59df2
! wall 0.053088 comb 0.060000 user 0.060000 sys 0.000000 (best of 100) to
! wall 0.024618 comb 0.020000 user 0.020000 sys 0.000000 (best of 116)
perfbdiff 0e9928989e9c --alldata --count 10
! wall 0.702075 comb 0.700000 user 0.700000 sys 0.000000 (best of 15) to
! wall 0.579235 comb 0.580000 user 0.580000 sys 0.000000 (best of 18)
author | Mads Kiilerich <madski@unity3d.com> |
---|---|
date | Wed, 16 Nov 2016 19:45:35 +0100 |
parents | d5883fd055c6 |
children | 46ba2cdda476 |
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# fetch.py - pull and merge remote changes # # Copyright 2006 Vadim Gelfer <vadim.gelfer@gmail.com> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. '''pull, update and merge in one command (DEPRECATED)''' from __future__ import absolute_import from mercurial.i18n import _ from mercurial.node import ( short, ) from mercurial import ( cmdutil, commands, error, exchange, hg, lock, util, ) release = lock.release cmdtable = {} command = cmdutil.command(cmdtable) # Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for # extensions which SHIP WITH MERCURIAL. Non-mainline extensions should # be specifying the version(s) of Mercurial they are tested with, or # leave the attribute unspecified. testedwith = 'ships-with-hg-core' @command('fetch', [('r', 'rev', [], _('a specific revision you would like to pull'), _('REV')), ('e', 'edit', None, _('invoke editor on commit messages')), ('', 'force-editor', None, _('edit commit message (DEPRECATED)')), ('', 'switch-parent', None, _('switch parents when merging')), ] + commands.commitopts + commands.commitopts2 + commands.remoteopts, _('hg fetch [SOURCE]')) def fetch(ui, repo, source='default', **opts): '''pull changes from a remote repository, merge new changes if needed. This finds all changes from the repository at the specified path or URL and adds them to the local repository. If the pulled changes add a new branch head, the head is automatically merged, and the result of the merge is committed. Otherwise, the working directory is updated to include the new changes. When a merge is needed, the working directory is first updated to the newly pulled changes. Local changes are then merged into the pulled changes. To switch the merge order, use --switch-parent. See :hg:`help dates` for a list of formats valid for -d/--date. Returns 0 on success. ''' date = opts.get('date') if date: opts['date'] = util.parsedate(date) parent, _p2 = repo.dirstate.parents() branch = repo.dirstate.branch() try: branchnode = repo.branchtip(branch) except error.RepoLookupError: branchnode = None if parent != branchnode: raise error.Abort(_('working directory not at branch tip'), hint=_("use 'hg update' to check out branch tip")) wlock = lock = None try: wlock = repo.wlock() lock = repo.lock() cmdutil.bailifchanged(repo) bheads = repo.branchheads(branch) bheads = [head for head in bheads if len(repo[head].children()) == 0] if len(bheads) > 1: raise error.Abort(_('multiple heads in this branch ' '(use "hg heads ." and "hg merge" to merge)')) other = hg.peer(repo, opts, ui.expandpath(source)) ui.status(_('pulling from %s\n') % util.hidepassword(ui.expandpath(source))) revs = None if opts['rev']: try: revs = [other.lookup(rev) for rev in opts['rev']] except error.CapabilityError: err = _("other repository doesn't support revision lookup, " "so a rev cannot be specified.") raise error.Abort(err) # Are there any changes at all? modheads = exchange.pull(repo, other, heads=revs).cgresult if modheads == 0: return 0 # Is this a simple fast-forward along the current branch? newheads = repo.branchheads(branch) newchildren = repo.changelog.nodesbetween([parent], newheads)[2] if len(newheads) == 1 and len(newchildren): if newchildren[0] != parent: return hg.update(repo, newchildren[0]) else: return 0 # Are there more than one additional branch heads? newchildren = [n for n in newchildren if n != parent] newparent = parent if newchildren: newparent = newchildren[0] hg.clean(repo, newparent) newheads = [n for n in newheads if n != newparent] if len(newheads) > 1: ui.status(_('not merging with %d other new branch heads ' '(use "hg heads ." and "hg merge" to merge them)\n') % (len(newheads) - 1)) return 1 if not newheads: return 0 # Otherwise, let's merge. err = False if newheads: # By default, we consider the repository we're pulling # *from* as authoritative, so we merge our changes into # theirs. if opts['switch_parent']: firstparent, secondparent = newparent, newheads[0] else: firstparent, secondparent = newheads[0], newparent ui.status(_('updating to %d:%s\n') % (repo.changelog.rev(firstparent), short(firstparent))) hg.clean(repo, firstparent) ui.status(_('merging with %d:%s\n') % (repo.changelog.rev(secondparent), short(secondparent))) err = hg.merge(repo, secondparent, remind=False) if not err: # we don't translate commit messages message = (cmdutil.logmessage(ui, opts) or ('Automated merge with %s' % util.removeauth(other.url()))) editopt = opts.get('edit') or opts.get('force_editor') editor = cmdutil.getcommiteditor(edit=editopt, editform='fetch') n = repo.commit(message, opts['user'], opts['date'], editor=editor) ui.status(_('new changeset %d:%s merges remote changes ' 'with local\n') % (repo.changelog.rev(n), short(n))) return err finally: release(lock, wlock)