view mercurial/hgweb/webutil.py @ 49000:dd6b67d5c256 stable

rust: fix unsound `OwningDirstateMap`

As per the previous patch, `OwningDirstateMap` is unsound. Self-referential
structs are difficult to implement correctly in Rust since the compiler is
free to move structs around as much as it wants to. They are also very rarely
needed in practice, so the state-of-the-art on how they should be done within
the Rust rules is still a bit new.

The crate `ouroboros` is an attempt at providing a safe way (in the Rust sense)
of declaring self-referential structs. It is getting a lot attention and was
improved very quickly when soundness issues were found in the past: rather than
relying on our own (limited) review circle, we might as well use the de-facto
common crate to fix this problem. This will give us a much better chance of
finding issues should any new ones be discovered as well as the benefit of
fewer `unsafe` APIs of our own.

I was starting to think about how I would present a safe API to the old struct
but soon realized that the callback-based approach was already done in
`ouroboros`, along with a lot more care towards refusing incorrect structs.

In short: we don't return a mutable reference to the `DirstateMap` anymore, we
expect users of its API to pass a `FnOnce` that takes the map as an argument.
This allows our `OwningDirstateMap` to control the input and output lifetimes
of the code that modifies it to prevent such issues.

Changing to `ouroboros` meant changing every API with it, but it is relatively
low churn in the end. It correctly identified the example buggy modification of
`copy_map_insert` outlined in the previous patch as violating the borrow rules.

Differential Revision: https://phab.mercurial-scm.org/D12429

# hgweb/webutil.py - utility library for the web interface.
#
# Copyright 21 May 2005 - (c) 2005 Jake Edge <[e-mail]>
# Copyright 2005-2007 Olivia Mackall <[e-mail]>
#
# 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 copy
import difflib
import os
import re

from ..i18n import _
from ..node import hex, short
from ..pycompat import setattr

from .common import (
    ErrorResponse,
    HTTP_BAD_REQUEST,
    HTTP_NOT_FOUND,
    paritygen,
)

from .. import (
    context,
    diffutil,
    error,
    match,
    mdiff,
    obsutil,
    patch,
    pathutil,
    pycompat,
    scmutil,
    templatefilters,
    templatekw,
    templateutil,
    ui as uimod,
    util,
)

from ..utils import stringutil

archivespecs = util.sortdict(
    (
        (b'zip', (b'application/zip', b'zip', b'.zip', None)),
        (b'gz', (b'application/x-gzip', b'tgz', b'.tar.gz', None)),
        (b'bz2', (b'application/x-bzip2', b'tbz2', b'.tar.bz2', None)),
    )
)


def archivelist(ui, nodeid, url=None):
    allowed = ui.configlist(b'web', b'allow-archive', untrusted=True)
    archives = []

    for typ, spec in pycompat.iteritems(archivespecs):
        if typ in allowed or ui.configbool(
            b'web', b'allow' + typ, untrusted=True
        ):
            archives.append(
                {
                    b'type': typ,
                    b'extension': spec[2],
                    b'node': nodeid,
                    b'url': url,
                }
            )

    return templateutil.mappinglist(archives)


def up(p):
    if p[0:1] != b"/":
        p = b"/" + p
    if p[-1:] == b"/":
        p = p[:-1]
    up = os.path.dirname(p)
    if up == b"/":
        return b"/"
    return up + b"/"


def _navseq(step, firststep=None):
    if firststep:
        yield firststep
        if firststep >= 20 and firststep <= 40:
            firststep = 50
            yield firststep
        assert step > 0
        assert firststep > 0
        while step <= firststep:
            step *= 10
    while True:
        yield 1 * step
        yield 3 * step
        step *= 10


class revnav(object):
    def __init__(self, repo):
        """Navigation generation object

        :repo: repo object we generate nav for
        """
        # used for hex generation
        self._revlog = repo.changelog

    def __nonzero__(self):
        """return True if any revision to navigate over"""
        return self._first() is not None

    __bool__ = __nonzero__

    def _first(self):
        """return the minimum non-filtered changeset or None"""
        try:
            return next(iter(self._revlog))
        except StopIteration:
            return None

    def hex(self, rev):
        return hex(self._revlog.node(rev))

    def gen(self, pos, pagelen, limit):
        """computes label and revision id for navigation link

        :pos: is the revision relative to which we generate navigation.
        :pagelen: the size of each navigation page
        :limit: how far shall we link

        The return is:
            - a single element mappinglist
            - containing a dictionary with a `before` and `after` key
            - values are dictionaries with `label` and `node` keys
        """
        if not self:
            # empty repo
            return templateutil.mappinglist(
                [
                    {
                        b'before': templateutil.mappinglist([]),
                        b'after': templateutil.mappinglist([]),
                    },
                ]
            )

        targets = []
        for f in _navseq(1, pagelen):
            if f > limit:
                break
            targets.append(pos + f)
            targets.append(pos - f)
        targets.sort()

        first = self._first()
        navbefore = [{b'label': b'(%i)' % first, b'node': self.hex(first)}]
        navafter = []
        for rev in targets:
            if rev not in self._revlog:
                continue
            if pos < rev < limit:
                navafter.append(
                    {b'label': b'+%d' % abs(rev - pos), b'node': self.hex(rev)}
                )
            if 0 < rev < pos:
                navbefore.append(
                    {b'label': b'-%d' % abs(rev - pos), b'node': self.hex(rev)}
                )

        navafter.append({b'label': b'tip', b'node': b'tip'})

        # TODO: maybe this can be a scalar object supporting tomap()
        return templateutil.mappinglist(
            [
                {
                    b'before': templateutil.mappinglist(navbefore),
                    b'after': templateutil.mappinglist(navafter),
                },
            ]
        )


class filerevnav(revnav):
    def __init__(self, repo, path):
        """Navigation generation object

        :repo: repo object we generate nav for
        :path: path of the file we generate nav for
        """
        # used for iteration
        self._changelog = repo.unfiltered().changelog
        # used for hex generation
        self._revlog = repo.file(path)

    def hex(self, rev):
        return hex(self._changelog.node(self._revlog.linkrev(rev)))


# TODO: maybe this can be a wrapper class for changectx/filectx list, which
# yields {'ctx': ctx}
def _ctxsgen(context, ctxs):
    for s in ctxs:
        d = {
            b'node': s.hex(),
            b'rev': s.rev(),
            b'user': s.user(),
            b'date': s.date(),
            b'description': s.description(),
            b'branch': s.branch(),
        }
        if util.safehasattr(s, b'path'):
            d[b'file'] = s.path()
        yield d


def _siblings(siblings=None, hiderev=None):
    if siblings is None:
        siblings = []
    siblings = [s for s in siblings if s.node() != s.repo().nullid]
    if len(siblings) == 1 and siblings[0].rev() == hiderev:
        siblings = []
    return templateutil.mappinggenerator(_ctxsgen, args=(siblings,))


def difffeatureopts(req, ui, section):
    diffopts = diffutil.difffeatureopts(
        ui, untrusted=True, section=section, whitespace=True
    )

    for k in (
        b'ignorews',
        b'ignorewsamount',
        b'ignorewseol',
        b'ignoreblanklines',
    ):
        v = req.qsparams.get(k)
        if v is not None:
            v = stringutil.parsebool(v)
            setattr(diffopts, k, v if v is not None else True)

    return diffopts


def annotate(req, fctx, ui):
    diffopts = difffeatureopts(req, ui, b'annotate')
    return fctx.annotate(follow=True, diffopts=diffopts)


def parents(ctx, hide=None):
    if isinstance(ctx, context.basefilectx):
        introrev = ctx.introrev()
        if ctx.changectx().rev() != introrev:
            return _siblings([ctx.repo()[introrev]], hide)
    return _siblings(ctx.parents(), hide)


def children(ctx, hide=None):
    return _siblings(ctx.children(), hide)


def renamelink(fctx):
    r = fctx.renamed()
    if r:
        return templateutil.mappinglist([{b'file': r[0], b'node': hex(r[1])}])
    return templateutil.mappinglist([])


def nodetagsdict(repo, node):
    return templateutil.hybridlist(repo.nodetags(node), name=b'name')


def nodebookmarksdict(repo, node):
    return templateutil.hybridlist(repo.nodebookmarks(node), name=b'name')


def nodebranchdict(repo, ctx):
    branches = []
    branch = ctx.branch()
    # If this is an empty repo, ctx.node() == nullid,
    # ctx.branch() == 'default'.
    try:
        branchnode = repo.branchtip(branch)
    except error.RepoLookupError:
        branchnode = None
    if branchnode == ctx.node():
        branches.append(branch)
    return templateutil.hybridlist(branches, name=b'name')


def nodeinbranch(repo, ctx):
    branches = []
    branch = ctx.branch()
    try:
        branchnode = repo.branchtip(branch)
    except error.RepoLookupError:
        branchnode = None
    if branch != b'default' and branchnode != ctx.node():
        branches.append(branch)
    return templateutil.hybridlist(branches, name=b'name')


def nodebranchnodefault(ctx):
    branches = []
    branch = ctx.branch()
    if branch != b'default':
        branches.append(branch)
    return templateutil.hybridlist(branches, name=b'name')


def _nodenamesgen(context, f, node, name):
    for t in f(node):
        yield {name: t}


def showtag(repo, t1, node=None):
    if node is None:
        node = repo.nullid
    args = (repo.nodetags, node, b'tag')
    return templateutil.mappinggenerator(_nodenamesgen, args=args, name=t1)


def showbookmark(repo, t1, node=None):
    if node is None:
        node = repo.nullid
    args = (repo.nodebookmarks, node, b'bookmark')
    return templateutil.mappinggenerator(_nodenamesgen, args=args, name=t1)


def branchentries(repo, stripecount, limit=0):
    tips = []
    heads = repo.heads()
    parity = paritygen(stripecount)
    sortkey = lambda item: (not item[1], item[0].rev())

    def entries(context):
        count = 0
        if not tips:
            for tag, hs, tip, closed in repo.branchmap().iterbranches():
                tips.append((repo[tip], closed))
        for ctx, closed in sorted(tips, key=sortkey, reverse=True):
            if limit > 0 and count >= limit:
                return
            count += 1
            if closed:
                status = b'closed'
            elif ctx.node() not in heads:
                status = b'inactive'
            else:
                status = b'open'
            yield {
                b'parity': next(parity),
                b'branch': ctx.branch(),
                b'status': status,
                b'node': ctx.hex(),
                b'date': ctx.date(),
            }

    return templateutil.mappinggenerator(entries)


def cleanpath(repo, path):
    path = path.lstrip(b'/')
    auditor = pathutil.pathauditor(repo.root, realfs=False)
    return pathutil.canonpath(repo.root, b'', path, auditor=auditor)


def changectx(repo, req):
    changeid = b"tip"
    if b'node' in req.qsparams:
        changeid = req.qsparams[b'node']
        ipos = changeid.find(b':')
        if ipos != -1:
            changeid = changeid[(ipos + 1) :]

    return scmutil.revsymbol(repo, changeid)


def basechangectx(repo, req):
    if b'node' in req.qsparams:
        changeid = req.qsparams[b'node']
        ipos = changeid.find(b':')
        if ipos != -1:
            changeid = changeid[:ipos]
            return scmutil.revsymbol(repo, changeid)

    return None


def filectx(repo, req):
    if b'file' not in req.qsparams:
        raise ErrorResponse(HTTP_NOT_FOUND, b'file not given')
    path = cleanpath(repo, req.qsparams[b'file'])
    if b'node' in req.qsparams:
        changeid = req.qsparams[b'node']
    elif b'filenode' in req.qsparams:
        changeid = req.qsparams[b'filenode']
    else:
        raise ErrorResponse(HTTP_NOT_FOUND, b'node or filenode not given')
    try:
        fctx = scmutil.revsymbol(repo, changeid)[path]
    except error.RepoError:
        fctx = repo.filectx(path, fileid=changeid)

    return fctx


def linerange(req):
    linerange = req.qsparams.getall(b'linerange')
    if not linerange:
        return None
    if len(linerange) > 1:
        raise ErrorResponse(HTTP_BAD_REQUEST, b'redundant linerange parameter')
    try:
        fromline, toline = map(int, linerange[0].split(b':', 1))
    except ValueError:
        raise ErrorResponse(HTTP_BAD_REQUEST, b'invalid linerange parameter')
    try:
        return util.processlinerange(fromline, toline)
    except error.ParseError as exc:
        raise ErrorResponse(HTTP_BAD_REQUEST, pycompat.bytestr(exc))


def formatlinerange(fromline, toline):
    return b'%d:%d' % (fromline + 1, toline)


def _succsandmarkersgen(context, mapping):
    repo = context.resource(mapping, b'repo')
    itemmappings = templatekw.showsuccsandmarkers(context, mapping)
    for item in itemmappings.tovalue(context, mapping):
        item[b'successors'] = _siblings(
            repo[successor] for successor in item[b'successors']
        )
        yield item


def succsandmarkers(context, mapping):
    return templateutil.mappinggenerator(_succsandmarkersgen, args=(mapping,))


# teach templater succsandmarkers is switched to (context, mapping) API
succsandmarkers._requires = {b'repo', b'ctx'}


def _whyunstablegen(context, mapping):
    repo = context.resource(mapping, b'repo')
    ctx = context.resource(mapping, b'ctx')

    entries = obsutil.whyunstable(repo, ctx)
    for entry in entries:
        if entry.get(b'divergentnodes'):
            entry[b'divergentnodes'] = _siblings(entry[b'divergentnodes'])
        yield entry


def whyunstable(context, mapping):
    return templateutil.mappinggenerator(_whyunstablegen, args=(mapping,))


whyunstable._requires = {b'repo', b'ctx'}


def commonentry(repo, ctx):
    node = scmutil.binnode(ctx)
    return {
        # TODO: perhaps ctx.changectx() should be assigned if ctx is a
        # filectx, but I'm not pretty sure if that would always work because
        # fctx.parents() != fctx.changectx.parents() for example.
        b'ctx': ctx,
        b'rev': ctx.rev(),
        b'node': hex(node),
        b'author': ctx.user(),
        b'desc': ctx.description(),
        b'date': ctx.date(),
        b'extra': ctx.extra(),
        b'phase': ctx.phasestr(),
        b'obsolete': ctx.obsolete(),
        b'succsandmarkers': succsandmarkers,
        b'instabilities': templateutil.hybridlist(
            ctx.instabilities(), name=b'instability'
        ),
        b'whyunstable': whyunstable,
        b'branch': nodebranchnodefault(ctx),
        b'inbranch': nodeinbranch(repo, ctx),
        b'branches': nodebranchdict(repo, ctx),
        b'tags': nodetagsdict(repo, node),
        b'bookmarks': nodebookmarksdict(repo, node),
        b'parent': lambda context, mapping: parents(ctx),
        b'child': lambda context, mapping: children(ctx),
    }


def changelistentry(web, ctx):
    """Obtain a dictionary to be used for entries in a changelist.

    This function is called when producing items for the "entries" list passed
    to the "shortlog" and "changelog" templates.
    """
    repo = web.repo
    rev = ctx.rev()
    n = scmutil.binnode(ctx)
    showtags = showtag(repo, b'changelogtag', n)
    files = listfilediffs(ctx.files(), n, web.maxfiles)

    entry = commonentry(repo, ctx)
    entry.update(
        {
            b'allparents': lambda context, mapping: parents(ctx),
            b'parent': lambda context, mapping: parents(ctx, rev - 1),
            b'child': lambda context, mapping: children(ctx, rev + 1),
            b'changelogtag': showtags,
            b'files': files,
        }
    )
    return entry


def changelistentries(web, revs, maxcount, parityfn):
    """Emit up to N records for an iterable of revisions."""
    repo = web.repo

    count = 0
    for rev in revs:
        if count >= maxcount:
            break

        count += 1

        entry = changelistentry(web, repo[rev])
        entry[b'parity'] = next(parityfn)

        yield entry


def symrevorshortnode(req, ctx):
    if b'node' in req.qsparams:
        return templatefilters.revescape(req.qsparams[b'node'])
    else:
        return short(scmutil.binnode(ctx))


def _listfilesgen(context, ctx, stripecount):
    parity = paritygen(stripecount)
    filesadded = ctx.filesadded()
    for blockno, f in enumerate(ctx.files()):
        if f not in ctx:
            status = b'removed'
        elif f in filesadded:
            status = b'added'
        else:
            status = b'modified'
        template = b'filenolink' if status == b'removed' else b'filenodelink'
        yield context.process(
            template,
            {
                b'node': ctx.hex(),
                b'file': f,
                b'blockno': blockno + 1,
                b'parity': next(parity),
                b'status': status,
            },
        )


def changesetentry(web, ctx):
    '''Obtain a dictionary to be used to render the "changeset" template.'''

    showtags = showtag(web.repo, b'changesettag', scmutil.binnode(ctx))
    showbookmarks = showbookmark(
        web.repo, b'changesetbookmark', scmutil.binnode(ctx)
    )
    showbranch = nodebranchnodefault(ctx)

    basectx = basechangectx(web.repo, web.req)
    if basectx is None:
        basectx = ctx.p1()

    style = web.config(b'web', b'style')
    if b'style' in web.req.qsparams:
        style = web.req.qsparams[b'style']

    diff = diffs(web, ctx, basectx, None, style)

    parity = paritygen(web.stripecount)
    diffstatsgen = diffstatgen(web.repo.ui, ctx, basectx)
    diffstats = diffstat(ctx, diffstatsgen, parity)

    return dict(
        diff=diff,
        symrev=symrevorshortnode(web.req, ctx),
        basenode=basectx.hex(),
        changesettag=showtags,
        changesetbookmark=showbookmarks,
        changesetbranch=showbranch,
        files=templateutil.mappedgenerator(
            _listfilesgen, args=(ctx, web.stripecount)
        ),
        diffsummary=lambda context, mapping: diffsummary(diffstatsgen),
        diffstat=diffstats,
        archives=web.archivelist(ctx.hex()),
        **pycompat.strkwargs(commonentry(web.repo, ctx))
    )


def _listfilediffsgen(context, files, node, max):
    for f in files[:max]:
        yield context.process(b'filedifflink', {b'node': hex(node), b'file': f})
    if len(files) > max:
        yield context.process(b'fileellipses', {})


def listfilediffs(files, node, max):
    return templateutil.mappedgenerator(
        _listfilediffsgen, args=(files, node, max)
    )


def _prettyprintdifflines(context, lines, blockno, lineidprefix):
    for lineno, l in enumerate(lines, 1):
        difflineno = b"%d.%d" % (blockno, lineno)
        if l.startswith(b'+'):
            ltype = b"difflineplus"
        elif l.startswith(b'-'):
            ltype = b"difflineminus"
        elif l.startswith(b'@'):
            ltype = b"difflineat"
        else:
            ltype = b"diffline"
        yield context.process(
            ltype,
            {
                b'line': l,
                b'lineno': lineno,
                b'lineid': lineidprefix + b"l%s" % difflineno,
                b'linenumber': b"% 8s" % difflineno,
            },
        )


def _diffsgen(
    context,
    repo,
    ctx,
    basectx,
    files,
    style,
    stripecount,
    linerange,
    lineidprefix,
):
    if files:
        m = match.exact(files)
    else:
        m = match.always()

    diffopts = patch.diffopts(repo.ui, untrusted=True)
    parity = paritygen(stripecount)

    diffhunks = patch.diffhunks(repo, basectx, ctx, m, opts=diffopts)
    for blockno, (fctx1, fctx2, header, hunks) in enumerate(diffhunks, 1):
        if style != b'raw':
            header = header[1:]
        lines = [h + b'\n' for h in header]
        for hunkrange, hunklines in hunks:
            if linerange is not None and hunkrange is not None:
                s1, l1, s2, l2 = hunkrange
                if not mdiff.hunkinrange((s2, l2), linerange):
                    continue
            lines.extend(hunklines)
        if lines:
            l = templateutil.mappedgenerator(
                _prettyprintdifflines, args=(lines, blockno, lineidprefix)
            )
            yield {
                b'parity': next(parity),
                b'blockno': blockno,
                b'lines': l,
            }


def diffs(web, ctx, basectx, files, style, linerange=None, lineidprefix=b''):
    args = (
        web.repo,
        ctx,
        basectx,
        files,
        style,
        web.stripecount,
        linerange,
        lineidprefix,
    )
    return templateutil.mappinggenerator(
        _diffsgen, args=args, name=b'diffblock'
    )


def _compline(type, leftlineno, leftline, rightlineno, rightline):
    lineid = leftlineno and (b"l%d" % leftlineno) or b''
    lineid += rightlineno and (b"r%d" % rightlineno) or b''
    llno = b'%d' % leftlineno if leftlineno else b''
    rlno = b'%d' % rightlineno if rightlineno else b''
    return {
        b'type': type,
        b'lineid': lineid,
        b'leftlineno': leftlineno,
        b'leftlinenumber': b"% 6s" % llno,
        b'leftline': leftline or b'',
        b'rightlineno': rightlineno,
        b'rightlinenumber': b"% 6s" % rlno,
        b'rightline': rightline or b'',
    }


def _getcompblockgen(context, leftlines, rightlines, opcodes):
    for type, llo, lhi, rlo, rhi in opcodes:
        type = pycompat.sysbytes(type)
        len1 = lhi - llo
        len2 = rhi - rlo
        count = min(len1, len2)
        for i in pycompat.xrange(count):
            yield _compline(
                type=type,
                leftlineno=llo + i + 1,
                leftline=leftlines[llo + i],
                rightlineno=rlo + i + 1,
                rightline=rightlines[rlo + i],
            )
        if len1 > len2:
            for i in pycompat.xrange(llo + count, lhi):
                yield _compline(
                    type=type,
                    leftlineno=i + 1,
                    leftline=leftlines[i],
                    rightlineno=None,
                    rightline=None,
                )
        elif len2 > len1:
            for i in pycompat.xrange(rlo + count, rhi):
                yield _compline(
                    type=type,
                    leftlineno=None,
                    leftline=None,
                    rightlineno=i + 1,
                    rightline=rightlines[i],
                )


def _getcompblock(leftlines, rightlines, opcodes):
    args = (leftlines, rightlines, opcodes)
    return templateutil.mappinggenerator(
        _getcompblockgen, args=args, name=b'comparisonline'
    )


def _comparegen(context, contextnum, leftlines, rightlines):
    '''Generator function that provides side-by-side comparison data.'''
    s = difflib.SequenceMatcher(None, leftlines, rightlines)
    if contextnum < 0:
        l = _getcompblock(leftlines, rightlines, s.get_opcodes())
        yield {b'lines': l}
    else:
        for oc in s.get_grouped_opcodes(n=contextnum):
            l = _getcompblock(leftlines, rightlines, oc)
            yield {b'lines': l}


def compare(contextnum, leftlines, rightlines):
    args = (contextnum, leftlines, rightlines)
    return templateutil.mappinggenerator(
        _comparegen, args=args, name=b'comparisonblock'
    )


def diffstatgen(ui, ctx, basectx):
    '''Generator function that provides the diffstat data.'''

    diffopts = patch.diffopts(ui, {b'noprefix': False})
    stats = patch.diffstatdata(util.iterlines(ctx.diff(basectx, opts=diffopts)))
    maxname, maxtotal, addtotal, removetotal, binary = patch.diffstatsum(stats)
    while True:
        yield stats, maxname, maxtotal, addtotal, removetotal, binary


def diffsummary(statgen):
    '''Return a short summary of the diff.'''

    stats, maxname, maxtotal, addtotal, removetotal, binary = next(statgen)
    return _(b' %d files changed, %d insertions(+), %d deletions(-)\n') % (
        len(stats),
        addtotal,
        removetotal,
    )


def _diffstattmplgen(context, ctx, statgen, parity):
    stats, maxname, maxtotal, addtotal, removetotal, binary = next(statgen)
    files = ctx.files()

    def pct(i):
        if maxtotal == 0:
            return 0
        return (float(i) / maxtotal) * 100

    fileno = 0
    for filename, adds, removes, isbinary in stats:
        template = b'diffstatlink' if filename in files else b'diffstatnolink'
        total = adds + removes
        fileno += 1
        yield context.process(
            template,
            {
                b'node': ctx.hex(),
                b'file': filename,
                b'fileno': fileno,
                b'total': total,
                b'addpct': pct(adds),
                b'removepct': pct(removes),
                b'parity': next(parity),
            },
        )


def diffstat(ctx, statgen, parity):
    '''Return a diffstat template for each file in the diff.'''
    args = (ctx, statgen, parity)
    return templateutil.mappedgenerator(_diffstattmplgen, args=args)


class sessionvars(templateutil.wrapped):
    def __init__(self, vars, start=b'?'):
        self._start = start
        self._vars = vars

    def __getitem__(self, key):
        return self._vars[key]

    def __setitem__(self, key, value):
        self._vars[key] = value

    def __copy__(self):
        return sessionvars(copy.copy(self._vars), self._start)

    def contains(self, context, mapping, item):
        item = templateutil.unwrapvalue(context, mapping, item)
        return item in self._vars

    def getmember(self, context, mapping, key):
        key = templateutil.unwrapvalue(context, mapping, key)
        return self._vars.get(key)

    def getmin(self, context, mapping):
        raise error.ParseError(_(b'not comparable'))

    def getmax(self, context, mapping):
        raise error.ParseError(_(b'not comparable'))

    def filter(self, context, mapping, select):
        # implement if necessary
        raise error.ParseError(_(b'not filterable'))

    def itermaps(self, context):
        separator = self._start
        for key, value in sorted(pycompat.iteritems(self._vars)):
            yield {
                b'name': key,
                b'value': pycompat.bytestr(value),
                b'separator': separator,
            }
            separator = b'&'

    def join(self, context, mapping, sep):
        # could be '{separator}{name}={value|urlescape}'
        raise error.ParseError(_(b'not displayable without template'))

    def show(self, context, mapping):
        return self.join(context, mapping, b'')

    def tobool(self, context, mapping):
        return bool(self._vars)

    def tovalue(self, context, mapping):
        return self._vars


class wsgiui(uimod.ui):
    # default termwidth breaks under mod_wsgi
    def termwidth(self):
        return 80


def getwebsubs(repo):
    websubtable = []
    websubdefs = repo.ui.configitems(b'websub')
    # we must maintain interhg backwards compatibility
    websubdefs += repo.ui.configitems(b'interhg')
    for key, pattern in websubdefs:
        # grab the delimiter from the character after the "s"
        unesc = pattern[1:2]
        delim = stringutil.reescape(unesc)

        # identify portions of the pattern, taking care to avoid escaped
        # delimiters. the replace format and flags are optional, but
        # delimiters are required.
        match = re.match(
            br'^s%s(.+)(?:(?<=\\\\)|(?<!\\))%s(.*)%s([ilmsux])*$'
            % (delim, delim, delim),
            pattern,
        )
        if not match:
            repo.ui.warn(
                _(b"websub: invalid pattern for %s: %s\n") % (key, pattern)
            )
            continue

        # we need to unescape the delimiter for regexp and format
        delim_re = re.compile(br'(?<!\\)\\%s' % delim)
        regexp = delim_re.sub(unesc, match.group(1))
        format = delim_re.sub(unesc, match.group(2))

        # the pattern allows for 6 regexp flags, so set them if necessary
        flagin = match.group(3)
        flags = 0
        if flagin:
            for flag in pycompat.sysstr(flagin.upper()):
                flags |= re.__dict__[flag]

        try:
            regexp = re.compile(regexp, flags)
            websubtable.append((regexp, format))
        except re.error:
            repo.ui.warn(
                _(b"websub: invalid regexp for %s: %s\n") % (key, regexp)
            )
    return websubtable


def getgraphnode(repo, ctx):
    return templatekw.getgraphnodecurrent(
        repo, ctx, {}
    ) + templatekw.getgraphnodesymbol(ctx)