view mercurial/logcmdutil.py @ 42044:bb271ec2fbfb

compression: introduce a `storage.revlog.zstd.level` configuration This option control the zstd compression level used when compressing revlog chunk. The usage of zstd for revlog compression has not graduated from experimental yet, but we intend to fix that soon. The option name for the compression level is more straight forward to pick, so this changesets comes first. Having a dedicated option for each compression engine is useful because they don't support the same range of values. I ran the same measurement as for the zlib compression level (in the parent changesets). The variation in repository size is stay mostly in the same (small) range. The "read/write" performance see smallish variation, but are overall much better than zlib. Write performance show the same tend of having better write performance for when reaching high-end compression. Again, we don't intend to change the default zstd compression level (currently: 3) in this series. However this is worth investigating in the future. The Performance comparison of zlib vs zstd is quite impressive. The repository size stay in the same range, but the performance are much better in all situations. Comparison summary ================== We are looking at: - performance range for zlib - performance range for zstd - comparison of default zstd (level-3) to default zlib (level 6) - comparison of the slowest zstd time to the fastest zlib time Read performance: ----------------- | zlib | zstd | cmp | f2s mercurial | 0.170159 - 0.189219 | 0.144127 - 0.149624 | 80% | 88% pypy | 2.679217 - 2.768691 | 1.532317 - 1.705044 | 60% | 63% netbeans | 122.477027 - 141.620281 | 72.996346 - 89.731560 | 58% | 73% mozilla | 147.867662 - 170.572118 | 91.700995 - 105.853099 | 56% | 71% Write performance: ------------------ | zlib | zstd | cmp | f2s mercurial | 53.250304 - 56.2936129 | 40.877025 - 45.677286 | 75% | 86% pypy | 460.721984 - 476.589918 | 270.545409 - 301.002219 | 63% | 65% netbeans | 520.560316 - 715.930400 | 370.356311 - 428.329652 | 55% | 82% mozilla | 739.803002 - 987.056093 | 505.152906 - 591.930683 | 57% | 80% Raw data -------- repo alg lvl .hg/store size 00manifest.d read write mercurial zlib 1 49,402,813 5,963,475 0.170159 53.250304 mercurial zlib 6 47,197,397 5,875,730 0.182820 56.264320 mercurial zlib 9 47,121,596 5,849,781 0.189219 56.293612 mercurial zstd 1 49,737,084 5,966,355 0.144127 40.877025 mercurial zstd 3 48,961,867 5,895,208 0.146376 42.268142 mercurial zstd 5 48,200,592 5,938,676 0.149624 43.162875 mercurial zstd 10 47,833,520 5,913,353 0.145185 44.012489 mercurial zstd 15 47,314,604 5,728,679 0.147686 45.677286 mercurial zstd 20 47,330,502 5,830,539 0.145789 45.025407 mercurial zstd 22 47,330,076 5,830,539 0.143996 44.690460 pypy zlib 1 370,830,572 28,462,425 2.679217 460.721984 pypy zlib 6 340,112,317 27,648,747 2.768691 467.537158 pypy zlib 9 338,360,736 27,639,003 2.763495 476.589918 pypy zstd 1 362,377,479 27,916,214 1.532317 270.545409 pypy zstd 3 354,137,693 27,905,988 1.686718 294.951509 pypy zstd 5 342,640,043 27,655,774 1.705044 301.002219 pypy zstd 10 334,224,327 27,164,493 1.567287 285.186239 pypy zstd 15 329,000,363 26,645,965 1.637729 299.561332 pypy zstd 20 324,534,039 26,199,547 1.526813 302.149827 pypy zstd 22 324,530,595 26,198,932 1.525718 307.821218 netbeans zlib 1 1,281,847,810 165,495,457 122.477027 520.560316 netbeans zlib 6 1,205,284,353 159,161,207 139.876147 715.930400 netbeans zlib 9 1,197,135,671 155,034,586 141.620281 678.297064 netbeans zstd 1 1,259,581,737 160,840,613 72.996346 370.356311 netbeans zstd 3 1,232,978,122 157,691,551 81.622317 396.733087 netbeans zstd 5 1,208,034,075 160,246,880 83.080549 364.342626 netbeans zstd 10 1,188,624,176 156,083,417 79.323935 403.594602 netbeans zstd 15 1,176,973,589 153,859,477 89.731560 428.329652 netbeans zstd 20 1,162,958,258 151,147,535 82.842667 392.335349 netbeans zstd 22 1,162,707,029 151,150,220 82.565695 402.840655 mozilla zlib 1 2,775,497,186 298,527,987 147.867662 751.263721 mozilla zlib 6 2,596,856,420 286,597,671 170.572118 987.056093 mozilla zlib 9 2,587,542,494 287,018,264 163.622338 739.803002 mozilla zstd 1 2,723,159,348 286,617,532 91.700995 570.042751 mozilla zstd 3 2,665,055,001 286,152,013 95.240155 561.412805 mozilla zstd 5 2,607,819,817 288,060,030 101.978048 505.152906 mozilla zstd 10 2,558,761,085 283,967,648 104.113481 497.771202 mozilla zstd 15 2,526,216,060 275,581,300 105.853099 591.930683 mozilla zstd 20 2,485,114,806 266,478,859 95.268795 576.515389 mozilla zstd 22 2,484,869,080 266,456,505 94.429282 572.785537
author Pierre-Yves David <pierre-yves.david@octobus.net>
date Wed, 27 Mar 2019 18:35:59 +0100
parents db26dbbee74d
children 1ce46f0ee218
line wrap: on
line source

# logcmdutil.py - utility for log-like commands
#
# Copyright 2005-2007 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.

from __future__ import absolute_import

import itertools
import os
import posixpath

from .i18n import _
from .node import (
    nullid,
    wdirid,
    wdirrev,
)

from . import (
    dagop,
    error,
    formatter,
    graphmod,
    match as matchmod,
    mdiff,
    patch,
    pathutil,
    pycompat,
    revset,
    revsetlang,
    scmutil,
    smartset,
    templatekw,
    templater,
    util,
)
from .utils import (
    dateutil,
    stringutil,
)

def getlimit(opts):
    """get the log limit according to option -l/--limit"""
    limit = opts.get('limit')
    if limit:
        try:
            limit = int(limit)
        except ValueError:
            raise error.Abort(_('limit must be a positive integer'))
        if limit <= 0:
            raise error.Abort(_('limit must be positive'))
    else:
        limit = None
    return limit

def diffordiffstat(ui, repo, diffopts, node1, node2, match,
                   changes=None, stat=False, fp=None, graphwidth=0,
                   prefix='', root='', listsubrepos=False, hunksfilterfn=None):
    '''show diff or diffstat.'''
    ctx1 = repo[node1]
    ctx2 = repo[node2]
    if root:
        relroot = pathutil.canonpath(repo.root, repo.getcwd(), root)
    else:
        relroot = ''
    copysourcematch = None
    def compose(f, g):
        return lambda x: f(g(x))
    def pathfn(f):
        return posixpath.join(prefix, f)
    if relroot != '':
        # XXX relative roots currently don't work if the root is within a
        # subrepo
        uipathfn = scmutil.getuipathfn(repo, legacyrelativevalue=True)
        uirelroot = uipathfn(pathfn(relroot))
        relroot += '/'
        for matchroot in match.files():
            if not matchroot.startswith(relroot):
                ui.warn(_('warning: %s not inside relative root %s\n') %
                        (uipathfn(pathfn(matchroot)), uirelroot))

        relrootmatch = scmutil.match(ctx2, pats=[relroot], default='path')
        match = matchmod.intersectmatchers(match, relrootmatch)
        copysourcematch = relrootmatch

        checkroot = (repo.ui.configbool('devel', 'all-warnings') or
                     repo.ui.configbool('devel', 'check-relroot'))
        def relrootpathfn(f):
            if checkroot and not f.startswith(relroot):
                raise AssertionError(
                    "file %s doesn't start with relroot %s" % (f, relroot))
            return f[len(relroot):]
        pathfn = compose(relrootpathfn, pathfn)

    if stat:
        diffopts = diffopts.copy(context=0, noprefix=False)
        width = 80
        if not ui.plain():
            width = ui.termwidth() - graphwidth
        # If an explicit --root was given, don't respect ui.relative-paths
        if not relroot:
            pathfn = compose(scmutil.getuipathfn(repo), pathfn)

    chunks = ctx2.diff(ctx1, match, changes, opts=diffopts, pathfn=pathfn,
                       copysourcematch=copysourcematch,
                       hunksfilterfn=hunksfilterfn)

    if fp is not None or ui.canwritewithoutlabels():
        out = fp or ui
        if stat:
            chunks = [patch.diffstat(util.iterlines(chunks), width=width)]
        for chunk in util.filechunkiter(util.chunkbuffer(chunks)):
            out.write(chunk)
    else:
        if stat:
            chunks = patch.diffstatui(util.iterlines(chunks), width=width)
        else:
            chunks = patch.difflabel(lambda chunks, **kwargs: chunks, chunks,
                                     opts=diffopts)
        if ui.canbatchlabeledwrites():
            def gen():
                for chunk, label in chunks:
                    yield ui.label(chunk, label=label)
            for chunk in util.filechunkiter(util.chunkbuffer(gen())):
                ui.write(chunk)
        else:
            for chunk, label in chunks:
                ui.write(chunk, label=label)

    for subpath, sub in scmutil.itersubrepos(ctx1, ctx2):
        tempnode2 = node2
        try:
            if node2 is not None:
                tempnode2 = ctx2.substate[subpath][1]
        except KeyError:
            # A subrepo that existed in node1 was deleted between node1 and
            # node2 (inclusive). Thus, ctx2's substate won't contain that
            # subpath. The best we can do is to ignore it.
            tempnode2 = None
        submatch = matchmod.subdirmatcher(subpath, match)
        subprefix = repo.wvfs.reljoin(prefix, subpath)
        if listsubrepos or match.exact(subpath) or any(submatch.files()):
            sub.diff(ui, diffopts, tempnode2, submatch, changes=changes,
                     stat=stat, fp=fp, prefix=subprefix)

class changesetdiffer(object):
    """Generate diff of changeset with pre-configured filtering functions"""

    def _makefilematcher(self, ctx):
        return scmutil.matchall(ctx.repo())

    def _makehunksfilter(self, ctx):
        return None

    def showdiff(self, ui, ctx, diffopts, graphwidth=0, stat=False):
        repo = ctx.repo()
        node = ctx.node()
        prev = ctx.p1().node()
        diffordiffstat(ui, repo, diffopts, prev, node,
                       match=self._makefilematcher(ctx), stat=stat,
                       graphwidth=graphwidth,
                       hunksfilterfn=self._makehunksfilter(ctx))

def changesetlabels(ctx):
    labels = ['log.changeset', 'changeset.%s' % ctx.phasestr()]
    if ctx.obsolete():
        labels.append('changeset.obsolete')
    if ctx.isunstable():
        labels.append('changeset.unstable')
        for instability in ctx.instabilities():
            labels.append('instability.%s' % instability)
    return ' '.join(labels)

class changesetprinter(object):
    '''show changeset information when templating not requested.'''

    def __init__(self, ui, repo, differ=None, diffopts=None, buffered=False):
        self.ui = ui
        self.repo = repo
        self.buffered = buffered
        self._differ = differ or changesetdiffer()
        self._diffopts = patch.diffallopts(ui, diffopts)
        self._includestat = diffopts and diffopts.get('stat')
        self._includediff = diffopts and diffopts.get('patch')
        self.header = {}
        self.hunk = {}
        self.lastheader = None
        self.footer = None
        self._columns = templatekw.getlogcolumns()

    def flush(self, ctx):
        rev = ctx.rev()
        if rev in self.header:
            h = self.header[rev]
            if h != self.lastheader:
                self.lastheader = h
                self.ui.write(h)
            del self.header[rev]
        if rev in self.hunk:
            self.ui.write(self.hunk[rev])
            del self.hunk[rev]

    def close(self):
        if self.footer:
            self.ui.write(self.footer)

    def show(self, ctx, copies=None, **props):
        props = pycompat.byteskwargs(props)
        if self.buffered:
            self.ui.pushbuffer(labeled=True)
            self._show(ctx, copies, props)
            self.hunk[ctx.rev()] = self.ui.popbuffer()
        else:
            self._show(ctx, copies, props)

    def _show(self, ctx, copies, props):
        '''show a single changeset or file revision'''
        changenode = ctx.node()
        graphwidth = props.get('graphwidth', 0)

        if self.ui.quiet:
            self.ui.write("%s\n" % scmutil.formatchangeid(ctx),
                          label='log.node')
            return

        columns = self._columns
        self.ui.write(columns['changeset'] % scmutil.formatchangeid(ctx),
                      label=changesetlabels(ctx))

        # branches are shown first before any other names due to backwards
        # compatibility
        branch = ctx.branch()
        # don't show the default branch name
        if branch != 'default':
            self.ui.write(columns['branch'] % branch, label='log.branch')

        for nsname, ns in self.repo.names.iteritems():
            # branches has special logic already handled above, so here we just
            # skip it
            if nsname == 'branches':
                continue
            # we will use the templatename as the color name since those two
            # should be the same
            for name in ns.names(self.repo, changenode):
                self.ui.write(ns.logfmt % name,
                              label='log.%s' % ns.colorname)
        if self.ui.debugflag:
            self.ui.write(columns['phase'] % ctx.phasestr(), label='log.phase')
        for pctx in scmutil.meaningfulparents(self.repo, ctx):
            label = 'log.parent changeset.%s' % pctx.phasestr()
            self.ui.write(columns['parent'] % scmutil.formatchangeid(pctx),
                          label=label)

        if self.ui.debugflag:
            mnode = ctx.manifestnode()
            if mnode is None:
                mnode = wdirid
                mrev = wdirrev
            else:
                mrev = self.repo.manifestlog.rev(mnode)
            self.ui.write(columns['manifest']
                          % scmutil.formatrevnode(self.ui, mrev, mnode),
                          label='ui.debug log.manifest')
        self.ui.write(columns['user'] % ctx.user(), label='log.user')
        self.ui.write(columns['date'] % dateutil.datestr(ctx.date()),
                      label='log.date')

        if ctx.isunstable():
            instabilities = ctx.instabilities()
            self.ui.write(columns['instability'] % ', '.join(instabilities),
                          label='log.instability')

        elif ctx.obsolete():
            self._showobsfate(ctx)

        self._exthook(ctx)

        if self.ui.debugflag:
            files = ctx.p1().status(ctx)[:3]
            for key, value in zip(['files', 'files+', 'files-'], files):
                if value:
                    self.ui.write(columns[key] % " ".join(value),
                                  label='ui.debug log.files')
        elif ctx.files() and self.ui.verbose:
            self.ui.write(columns['files'] % " ".join(ctx.files()),
                          label='ui.note log.files')
        if copies and self.ui.verbose:
            copies = ['%s (%s)' % c for c in copies]
            self.ui.write(columns['copies'] % ' '.join(copies),
                          label='ui.note log.copies')

        extra = ctx.extra()
        if extra and self.ui.debugflag:
            for key, value in sorted(extra.items()):
                self.ui.write(columns['extra']
                              % (key, stringutil.escapestr(value)),
                              label='ui.debug log.extra')

        description = ctx.description().strip()
        if description:
            if self.ui.verbose:
                self.ui.write(_("description:\n"),
                              label='ui.note log.description')
                self.ui.write(description,
                              label='ui.note log.description')
                self.ui.write("\n\n")
            else:
                self.ui.write(columns['summary'] % description.splitlines()[0],
                              label='log.summary')
        self.ui.write("\n")

        self._showpatch(ctx, graphwidth)

    def _showobsfate(self, ctx):
        # TODO: do not depend on templater
        tres = formatter.templateresources(self.repo.ui, self.repo)
        t = formatter.maketemplater(self.repo.ui, '{join(obsfate, "\n")}',
                                    defaults=templatekw.keywords,
                                    resources=tres)
        obsfate = t.renderdefault({'ctx': ctx}).splitlines()

        if obsfate:
            for obsfateline in obsfate:
                self.ui.write(self._columns['obsolete'] % obsfateline,
                              label='log.obsfate')

    def _exthook(self, ctx):
        '''empty method used by extension as a hook point
        '''

    def _showpatch(self, ctx, graphwidth=0):
        if self._includestat:
            self._differ.showdiff(self.ui, ctx, self._diffopts,
                                  graphwidth, stat=True)
        if self._includestat and self._includediff:
            self.ui.write("\n")
        if self._includediff:
            self._differ.showdiff(self.ui, ctx, self._diffopts,
                                  graphwidth, stat=False)
        if self._includestat or self._includediff:
            self.ui.write("\n")

class changesetformatter(changesetprinter):
    """Format changeset information by generic formatter"""

    def __init__(self, ui, repo, fm, differ=None, diffopts=None,
                 buffered=False):
        changesetprinter.__init__(self, ui, repo, differ, diffopts, buffered)
        self._diffopts = patch.difffeatureopts(ui, diffopts, git=True)
        self._fm = fm

    def close(self):
        self._fm.end()

    def _show(self, ctx, copies, props):
        '''show a single changeset or file revision'''
        fm = self._fm
        fm.startitem()
        fm.context(ctx=ctx)
        fm.data(rev=scmutil.intrev(ctx),
                node=fm.hexfunc(scmutil.binnode(ctx)))

        if self.ui.quiet:
            return

        fm.data(branch=ctx.branch(),
                phase=ctx.phasestr(),
                user=ctx.user(),
                date=fm.formatdate(ctx.date()),
                desc=ctx.description(),
                bookmarks=fm.formatlist(ctx.bookmarks(), name='bookmark'),
                tags=fm.formatlist(ctx.tags(), name='tag'),
                parents=fm.formatlist([fm.hexfunc(c.node())
                                       for c in ctx.parents()], name='node'))

        if self.ui.debugflag:
            fm.data(manifest=fm.hexfunc(ctx.manifestnode() or wdirid),
                    extra=fm.formatdict(ctx.extra()))

            files = ctx.p1().status(ctx)
            fm.data(modified=fm.formatlist(files[0], name='file'),
                    added=fm.formatlist(files[1], name='file'),
                    removed=fm.formatlist(files[2], name='file'))

        elif self.ui.verbose:
            fm.data(files=fm.formatlist(ctx.files(), name='file'))
            if copies:
                fm.data(copies=fm.formatdict(copies,
                                             key='name', value='source'))

        if self._includestat:
            self.ui.pushbuffer()
            self._differ.showdiff(self.ui, ctx, self._diffopts, stat=True)
            fm.data(diffstat=self.ui.popbuffer())
        if self._includediff:
            self.ui.pushbuffer()
            self._differ.showdiff(self.ui, ctx, self._diffopts, stat=False)
            fm.data(diff=self.ui.popbuffer())

class changesettemplater(changesetprinter):
    '''format changeset information.

    Note: there are a variety of convenience functions to build a
    changesettemplater for common cases. See functions such as:
    maketemplater, changesetdisplayer, buildcommittemplate, or other
    functions that use changesest_templater.
    '''

    # Arguments before "buffered" used to be positional. Consider not
    # adding/removing arguments before "buffered" to not break callers.
    def __init__(self, ui, repo, tmplspec, differ=None, diffopts=None,
                 buffered=False):
        changesetprinter.__init__(self, ui, repo, differ, diffopts, buffered)
        # tres is shared with _graphnodeformatter()
        self._tresources = tres = formatter.templateresources(ui, repo)
        self.t = formatter.loadtemplater(ui, tmplspec,
                                         defaults=templatekw.keywords,
                                         resources=tres,
                                         cache=templatekw.defaulttempl)
        self._counter = itertools.count()

        self._tref = tmplspec.ref
        self._parts = {'header': '', 'footer': '',
                       tmplspec.ref: tmplspec.ref,
                       'docheader': '', 'docfooter': '',
                       'separator': ''}
        if tmplspec.mapfile:
            # find correct templates for current mode, for backward
            # compatibility with 'log -v/-q/--debug' using a mapfile
            tmplmodes = [
                (True, ''),
                (self.ui.verbose, '_verbose'),
                (self.ui.quiet, '_quiet'),
                (self.ui.debugflag, '_debug'),
            ]
            for mode, postfix in tmplmodes:
                for t in self._parts:
                    cur = t + postfix
                    if mode and cur in self.t:
                        self._parts[t] = cur
        else:
            partnames = [p for p in self._parts.keys() if p != tmplspec.ref]
            m = formatter.templatepartsmap(tmplspec, self.t, partnames)
            self._parts.update(m)

        if self._parts['docheader']:
            self.ui.write(self.t.render(self._parts['docheader'], {}))

    def close(self):
        if self._parts['docfooter']:
            if not self.footer:
                self.footer = ""
            self.footer += self.t.render(self._parts['docfooter'], {})
        return super(changesettemplater, self).close()

    def _show(self, ctx, copies, props):
        '''show a single changeset or file revision'''
        props = props.copy()
        props['ctx'] = ctx
        props['index'] = index = next(self._counter)
        props['revcache'] = {'copies': copies}
        graphwidth = props.get('graphwidth', 0)

        # write separator, which wouldn't work well with the header part below
        # since there's inherently a conflict between header (across items) and
        # separator (per item)
        if self._parts['separator'] and index > 0:
            self.ui.write(self.t.render(self._parts['separator'], {}))

        # write header
        if self._parts['header']:
            h = self.t.render(self._parts['header'], props)
            if self.buffered:
                self.header[ctx.rev()] = h
            else:
                if self.lastheader != h:
                    self.lastheader = h
                    self.ui.write(h)

        # write changeset metadata, then patch if requested
        key = self._parts[self._tref]
        self.ui.write(self.t.render(key, props))
        self._showpatch(ctx, graphwidth)

        if self._parts['footer']:
            if not self.footer:
                self.footer = self.t.render(self._parts['footer'], props)

def templatespec(tmpl, mapfile):
    if pycompat.ispy3:
        assert not isinstance(tmpl, str), 'tmpl must not be a str'
    if mapfile:
        return formatter.templatespec('changeset', tmpl, mapfile)
    else:
        return formatter.templatespec('', tmpl, None)

def _lookuptemplate(ui, tmpl, style):
    """Find the template matching the given template spec or style

    See formatter.lookuptemplate() for details.
    """

    # ui settings
    if not tmpl and not style: # template are stronger than style
        tmpl = ui.config('ui', 'logtemplate')
        if tmpl:
            return templatespec(templater.unquotestring(tmpl), None)
        else:
            style = util.expandpath(ui.config('ui', 'style'))

    if not tmpl and style:
        mapfile = style
        if not os.path.split(mapfile)[0]:
            mapname = (templater.templatepath('map-cmdline.' + mapfile)
                       or templater.templatepath(mapfile))
            if mapname:
                mapfile = mapname
        return templatespec(None, mapfile)

    if not tmpl:
        return templatespec(None, None)

    return formatter.lookuptemplate(ui, 'changeset', tmpl)

def maketemplater(ui, repo, tmpl, buffered=False):
    """Create a changesettemplater from a literal template 'tmpl'
    byte-string."""
    spec = templatespec(tmpl, None)
    return changesettemplater(ui, repo, spec, buffered=buffered)

def changesetdisplayer(ui, repo, opts, differ=None, buffered=False):
    """show one changeset using template or regular display.

    Display format will be the first non-empty hit of:
    1. option 'template'
    2. option 'style'
    3. [ui] setting 'logtemplate'
    4. [ui] setting 'style'
    If all of these values are either the unset or the empty string,
    regular display via changesetprinter() is done.
    """
    postargs = (differ, opts, buffered)
    if opts.get('template') in {'cbor', 'json'}:
        fm = ui.formatter('log', opts)
        return changesetformatter(ui, repo, fm, *postargs)

    spec = _lookuptemplate(ui, opts.get('template'), opts.get('style'))

    if not spec.ref and not spec.tmpl and not spec.mapfile:
        return changesetprinter(ui, repo, *postargs)

    return changesettemplater(ui, repo, spec, *postargs)

def _makematcher(repo, revs, pats, opts):
    """Build matcher and expanded patterns from log options

    If --follow, revs are the revisions to follow from.

    Returns (match, pats, slowpath) where
    - match: a matcher built from the given pats and -I/-X opts
    - pats: patterns used (globs are expanded on Windows)
    - slowpath: True if patterns aren't as simple as scanning filelogs
    """
    # pats/include/exclude are passed to match.match() directly in
    # _matchfiles() revset but walkchangerevs() builds its matcher with
    # scmutil.match(). The difference is input pats are globbed on
    # platforms without shell expansion (windows).
    wctx = repo[None]
    match, pats = scmutil.matchandpats(wctx, pats, opts)
    slowpath = match.anypats() or (not match.always() and opts.get('removed'))
    if not slowpath:
        follow = opts.get('follow') or opts.get('follow_first')
        startctxs = []
        if follow and opts.get('rev'):
            startctxs = [repo[r] for r in revs]
        for f in match.files():
            if follow and startctxs:
                # No idea if the path was a directory at that revision, so
                # take the slow path.
                if any(f not in c for c in startctxs):
                    slowpath = True
                    continue
            elif follow and f not in wctx:
                # If the file exists, it may be a directory, so let it
                # take the slow path.
                if os.path.exists(repo.wjoin(f)):
                    slowpath = True
                    continue
                else:
                    raise error.Abort(_('cannot follow file not in parent '
                                        'revision: "%s"') % f)
            filelog = repo.file(f)
            if not filelog:
                # A zero count may be a directory or deleted file, so
                # try to find matching entries on the slow path.
                if follow:
                    raise error.Abort(
                        _('cannot follow nonexistent file: "%s"') % f)
                slowpath = True

        # We decided to fall back to the slowpath because at least one
        # of the paths was not a file. Check to see if at least one of them
        # existed in history - in that case, we'll continue down the
        # slowpath; otherwise, we can turn off the slowpath
        if slowpath:
            for path in match.files():
                if path == '.' or path in repo.store:
                    break
            else:
                slowpath = False

    return match, pats, slowpath

def _fileancestors(repo, revs, match, followfirst):
    fctxs = []
    for r in revs:
        ctx = repo[r]
        fctxs.extend(ctx[f].introfilectx() for f in ctx.walk(match))

    # When displaying a revision with --patch --follow FILE, we have
    # to know which file of the revision must be diffed. With
    # --follow, we want the names of the ancestors of FILE in the
    # revision, stored in "fcache". "fcache" is populated as a side effect
    # of the graph traversal.
    fcache = {}
    def filematcher(ctx):
        return scmutil.matchfiles(repo, fcache.get(ctx.rev(), []))

    def revgen():
        for rev, cs in dagop.filectxancestors(fctxs, followfirst=followfirst):
            fcache[rev] = [c.path() for c in cs]
            yield rev
    return smartset.generatorset(revgen(), iterasc=False), filematcher

def _makenofollowfilematcher(repo, pats, opts):
    '''hook for extensions to override the filematcher for non-follow cases'''
    return None

_opt2logrevset = {
    'no_merges':        ('not merge()', None),
    'only_merges':      ('merge()', None),
    '_matchfiles':      (None, '_matchfiles(%ps)'),
    'date':             ('date(%s)', None),
    'branch':           ('branch(%s)', '%lr'),
    '_patslog':         ('filelog(%s)', '%lr'),
    'keyword':          ('keyword(%s)', '%lr'),
    'prune':            ('ancestors(%s)', 'not %lr'),
    'user':             ('user(%s)', '%lr'),
}

def _makerevset(repo, match, pats, slowpath, opts):
    """Return a revset string built from log options and file patterns"""
    opts = dict(opts)
    # follow or not follow?
    follow = opts.get('follow') or opts.get('follow_first')

    # branch and only_branch are really aliases and must be handled at
    # the same time
    opts['branch'] = opts.get('branch', []) + opts.get('only_branch', [])
    opts['branch'] = [repo.lookupbranch(b) for b in opts['branch']]

    if slowpath:
        # See walkchangerevs() slow path.
        #
        # pats/include/exclude cannot be represented as separate
        # revset expressions as their filtering logic applies at file
        # level. For instance "-I a -X b" matches a revision touching
        # "a" and "b" while "file(a) and not file(b)" does
        # not. Besides, filesets are evaluated against the working
        # directory.
        matchargs = ['r:', 'd:relpath']
        for p in pats:
            matchargs.append('p:' + p)
        for p in opts.get('include', []):
            matchargs.append('i:' + p)
        for p in opts.get('exclude', []):
            matchargs.append('x:' + p)
        opts['_matchfiles'] = matchargs
    elif not follow:
        opts['_patslog'] = list(pats)

    expr = []
    for op, val in sorted(opts.iteritems()):
        if not val:
            continue
        if op not in _opt2logrevset:
            continue
        revop, listop = _opt2logrevset[op]
        if revop and '%' not in revop:
            expr.append(revop)
        elif not listop:
            expr.append(revsetlang.formatspec(revop, val))
        else:
            if revop:
                val = [revsetlang.formatspec(revop, v) for v in val]
            expr.append(revsetlang.formatspec(listop, val))

    if expr:
        expr = '(' + ' and '.join(expr) + ')'
    else:
        expr = None
    return expr

def _initialrevs(repo, opts):
    """Return the initial set of revisions to be filtered or followed"""
    follow = opts.get('follow') or opts.get('follow_first')
    if opts.get('rev'):
        revs = scmutil.revrange(repo, opts['rev'])
    elif follow and repo.dirstate.p1() == nullid:
        revs = smartset.baseset()
    elif follow:
        revs = repo.revs('.')
    else:
        revs = smartset.spanset(repo)
        revs.reverse()
    return revs

def getrevs(repo, pats, opts):
    """Return (revs, differ) where revs is a smartset

    differ is a changesetdiffer with pre-configured file matcher.
    """
    follow = opts.get('follow') or opts.get('follow_first')
    followfirst = opts.get('follow_first')
    limit = getlimit(opts)
    revs = _initialrevs(repo, opts)
    if not revs:
        return smartset.baseset(), None
    match, pats, slowpath = _makematcher(repo, revs, pats, opts)
    filematcher = None
    if follow:
        if slowpath or match.always():
            revs = dagop.revancestors(repo, revs, followfirst=followfirst)
        else:
            revs, filematcher = _fileancestors(repo, revs, match, followfirst)
        revs.reverse()
    if filematcher is None:
        filematcher = _makenofollowfilematcher(repo, pats, opts)
    if filematcher is None:
        def filematcher(ctx):
            return match

    expr = _makerevset(repo, match, pats, slowpath, opts)
    if opts.get('graph') and opts.get('rev'):
        # User-specified revs might be unsorted, but don't sort before
        # _makerevset because it might depend on the order of revs
        if not (revs.isdescending() or revs.istopo()):
            revs.sort(reverse=True)
    if expr:
        matcher = revset.match(None, expr)
        revs = matcher(repo, revs)
    if limit is not None:
        revs = revs.slice(0, limit)

    differ = changesetdiffer()
    differ._makefilematcher = filematcher
    return revs, differ

def _parselinerangeopt(repo, opts):
    """Parse --line-range log option and return a list of tuples (filename,
    (fromline, toline)).
    """
    linerangebyfname = []
    for pat in opts.get('line_range', []):
        try:
            pat, linerange = pat.rsplit(',', 1)
        except ValueError:
            raise error.Abort(_('malformatted line-range pattern %s') % pat)
        try:
            fromline, toline = map(int, linerange.split(':'))
        except ValueError:
            raise error.Abort(_("invalid line range for %s") % pat)
        msg = _("line range pattern '%s' must match exactly one file") % pat
        fname = scmutil.parsefollowlinespattern(repo, None, pat, msg)
        linerangebyfname.append(
            (fname, util.processlinerange(fromline, toline)))
    return linerangebyfname

def getlinerangerevs(repo, userrevs, opts):
    """Return (revs, differ).

    "revs" are revisions obtained by processing "line-range" log options and
    walking block ancestors of each specified file/line-range.

    "differ" is a changesetdiffer with pre-configured file matcher and hunks
    filter.
    """
    wctx = repo[None]

    # Two-levels map of "rev -> file ctx -> [line range]".
    linerangesbyrev = {}
    for fname, (fromline, toline) in _parselinerangeopt(repo, opts):
        if fname not in wctx:
            raise error.Abort(_('cannot follow file not in parent '
                                'revision: "%s"') % fname)
        fctx = wctx.filectx(fname)
        for fctx, linerange in dagop.blockancestors(fctx, fromline, toline):
            rev = fctx.introrev()
            if rev not in userrevs:
                continue
            linerangesbyrev.setdefault(
                rev, {}).setdefault(
                    fctx.path(), []).append(linerange)

    def nofilterhunksfn(fctx, hunks):
        return hunks

    def hunksfilter(ctx):
        fctxlineranges = linerangesbyrev.get(ctx.rev())
        if fctxlineranges is None:
            return nofilterhunksfn

        def filterfn(fctx, hunks):
            lineranges = fctxlineranges.get(fctx.path())
            if lineranges is not None:
                for hr, lines in hunks:
                    if hr is None: # binary
                        yield hr, lines
                        continue
                    if any(mdiff.hunkinrange(hr[2:], lr)
                           for lr in lineranges):
                        yield hr, lines
            else:
                for hunk in hunks:
                    yield hunk

        return filterfn

    def filematcher(ctx):
        files = list(linerangesbyrev.get(ctx.rev(), []))
        return scmutil.matchfiles(repo, files)

    revs = sorted(linerangesbyrev, reverse=True)

    differ = changesetdiffer()
    differ._makefilematcher = filematcher
    differ._makehunksfilter = hunksfilter
    return revs, differ

def _graphnodeformatter(ui, displayer):
    spec = ui.config('ui', 'graphnodetemplate')
    if not spec:
        return templatekw.getgraphnode  # fast path for "{graphnode}"

    spec = templater.unquotestring(spec)
    if isinstance(displayer, changesettemplater):
        # reuse cache of slow templates
        tres = displayer._tresources
    else:
        tres = formatter.templateresources(ui)
    templ = formatter.maketemplater(ui, spec, defaults=templatekw.keywords,
                                    resources=tres)
    def formatnode(repo, ctx):
        props = {'ctx': ctx, 'repo': repo}
        return templ.renderdefault(props)
    return formatnode

def displaygraph(ui, repo, dag, displayer, edgefn, getrenamed=None, props=None):
    props = props or {}
    formatnode = _graphnodeformatter(ui, displayer)
    state = graphmod.asciistate()
    styles = state['styles']

    # only set graph styling if HGPLAIN is not set.
    if ui.plain('graph'):
        # set all edge styles to |, the default pre-3.8 behaviour
        styles.update(dict.fromkeys(styles, '|'))
    else:
        edgetypes = {
            'parent': graphmod.PARENT,
            'grandparent': graphmod.GRANDPARENT,
            'missing': graphmod.MISSINGPARENT
        }
        for name, key in edgetypes.items():
            # experimental config: experimental.graphstyle.*
            styles[key] = ui.config('experimental', 'graphstyle.%s' % name,
                                    styles[key])
            if not styles[key]:
                styles[key] = None

        # experimental config: experimental.graphshorten
        state['graphshorten'] = ui.configbool('experimental', 'graphshorten')

    for rev, type, ctx, parents in dag:
        char = formatnode(repo, ctx)
        copies = None
        if getrenamed and ctx.rev():
            copies = []
            for fn in ctx.files():
                rename = getrenamed(fn, ctx.rev())
                if rename:
                    copies.append((fn, rename))
        edges = edgefn(type, char, state, rev, parents)
        firstedge = next(edges)
        width = firstedge[2]
        displayer.show(ctx, copies=copies,
                       graphwidth=width, **pycompat.strkwargs(props))
        lines = displayer.hunk.pop(rev).split('\n')
        if not lines[-1]:
            del lines[-1]
        displayer.flush(ctx)
        for type, char, width, coldata in itertools.chain([firstedge], edges):
            graphmod.ascii(ui, state, type, char, lines, coldata)
            lines = []
    displayer.close()

def displaygraphrevs(ui, repo, revs, displayer, getrenamed):
    revdag = graphmod.dagwalker(repo, revs)
    displaygraph(ui, repo, revdag, displayer, graphmod.asciiedges, getrenamed)

def displayrevs(ui, repo, revs, displayer, getrenamed):
    for rev in revs:
        ctx = repo[rev]
        copies = None
        if getrenamed is not None and rev:
            copies = []
            for fn in ctx.files():
                rename = getrenamed(fn, rev)
                if rename:
                    copies.append((fn, rename))
        displayer.show(ctx, copies=copies)
        displayer.flush(ctx)
    displayer.close()

def checkunsupportedgraphflags(pats, opts):
    for op in ["newest_first"]:
        if op in opts and opts[op]:
            raise error.Abort(_("-G/--graph option is incompatible with --%s")
                             % op.replace("_", "-"))

def graphrevs(repo, nodes, opts):
    limit = getlimit(opts)
    nodes.reverse()
    if limit is not None:
        nodes = nodes[:limit]
    return graphmod.nodes(repo, nodes)