hgext/narrow/narrowwirepeer.py

match: convert O(n) to O(log n) in exactmatcher.visitchildrenset

When using narrow, during rebase this is called (at least) once per directory in
the set of files in the commit being rebased. Every time it's called, we did the
set arithmetic (now extracted and cached), which was probably pretty cheap but
not necessary to repeat each time, looped over every item in the matcher and
kept things that started with the directory we were querying.

With very large narrowspecs, and a commit that touched a file in a large number
of directories, this was slow. In a pathological repo, the rebase of a single
commit (that touched over 17k files, I believe in approximately as many
directories) with a narrowspec that had >32k entries took 8,246s of profiled
time, with 5,007s of that spent in visitchildrenset (transitively). With this
change, the time spent in visitchildrenset is less than 34s (which is where my
profile cut off). Most of the remaining time was network access due to our
custom remotefilelog-based setup not properly prefetching.

Differential Revision: https://phab.mercurial-scm.org/D10294

# narrowwirepeer.py - passes narrow spec with unbundle command
#
# Copyright 2017 Google, Inc.
#
# 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 mercurial import (
    bundle2,
    error,
    extensions,
    hg,
    narrowspec,
    wireprototypes,
    wireprotov1peer,
    wireprotov1server,
)

from . import narrowbundle2


def uisetup():
    wireprotov1peer.wirepeer.narrow_widen = peernarrowwiden


def reposetup(repo):
    def wirereposetup(ui, peer):
        def wrapped(orig, cmd, *args, **kwargs):
            if cmd == b'unbundle':
                # TODO: don't blindly add include/exclude wireproto
                # arguments to unbundle.
                include, exclude = repo.narrowpats
                kwargs["includepats"] = b','.join(include)
                kwargs["excludepats"] = b','.join(exclude)
            return orig(cmd, *args, **kwargs)

        extensions.wrapfunction(peer, b'_calltwowaystream', wrapped)

    hg.wirepeersetupfuncs.append(wirereposetup)


@wireprotov1server.wireprotocommand(
    b'narrow_widen',
    b'oldincludes oldexcludes'
    b' newincludes newexcludes'
    b' commonheads cgversion'
    b' known ellipses',
    permission=b'pull',
)
def narrow_widen(
    repo,
    proto,
    oldincludes,
    oldexcludes,
    newincludes,
    newexcludes,
    commonheads,
    cgversion,
    known,
    ellipses,
):
    """wireprotocol command to send data when a narrow clone is widen. We will
    be sending a changegroup here.

    The current set of arguments which are required:
    oldincludes: the old includes of the narrow copy
    oldexcludes: the old excludes of the narrow copy
    newincludes: the new includes of the narrow copy
    newexcludes: the new excludes of the narrow copy
    commonheads: list of heads which are common between the server and client
    cgversion(maybe): the changegroup version to produce
    known: list of nodes which are known on the client (used in ellipses cases)
    ellipses: whether to send ellipses data or not
    """

    preferuncompressed = False
    try:

        def splitpaths(data):
            # work around ''.split(',') => ['']
            return data.split(b',') if data else []

        oldincludes = splitpaths(oldincludes)
        newincludes = splitpaths(newincludes)
        oldexcludes = splitpaths(oldexcludes)
        newexcludes = splitpaths(newexcludes)
        # validate the patterns
        narrowspec.validatepatterns(set(oldincludes))
        narrowspec.validatepatterns(set(newincludes))
        narrowspec.validatepatterns(set(oldexcludes))
        narrowspec.validatepatterns(set(newexcludes))

        common = wireprototypes.decodelist(commonheads)
        known = wireprototypes.decodelist(known)
        if ellipses == b'0':
            ellipses = False
        else:
            ellipses = bool(ellipses)
        cgversion = cgversion

        bundler = bundle2.bundle20(repo.ui)
        newmatch = narrowspec.match(
            repo.root, include=newincludes, exclude=newexcludes
        )
        oldmatch = narrowspec.match(
            repo.root, include=oldincludes, exclude=oldexcludes
        )
        if not ellipses:
            bundle2.widen_bundle(
                bundler,
                repo,
                oldmatch,
                newmatch,
                common,
                known,
                cgversion,
                ellipses,
            )
        else:
            narrowbundle2.generate_ellipses_bundle2_for_widening(
                bundler,
                repo,
                oldmatch,
                newmatch,
                cgversion,
                common,
                known,
            )
    except error.Abort as exc:
        bundler = bundle2.bundle20(repo.ui)
        manargs = [(b'message', exc.message)]
        advargs = []
        if exc.hint is not None:
            advargs.append((b'hint', exc.hint))
        bundler.addpart(bundle2.bundlepart(b'error:abort', manargs, advargs))
        preferuncompressed = True

    chunks = bundler.getchunks()
    return wireprototypes.streamres(
        gen=chunks, prefer_uncompressed=preferuncompressed
    )


def peernarrowwiden(remote, **kwargs):
    for ch in ('commonheads', 'known'):
        kwargs[ch] = wireprototypes.encodelist(kwargs[ch])

    for ch in ('oldincludes', 'newincludes', 'oldexcludes', 'newexcludes'):
        kwargs[ch] = b','.join(kwargs[ch])

    kwargs['ellipses'] = b'%i' % bool(kwargs['ellipses'])
    f = remote._callcompressable(b'narrow_widen', **kwargs)
    return bundle2.getunbundler(remote.ui, f)