view mercurial/exchangev2.py @ 43299:83bb1e89ab9b

copies: compute the exact set of revision to walk

This change make the code clearer by removing the revision queue. It comes
without very noticeable performance impact. However the simpler code will be
easier to update in later changesets.

revision: large amount; added files: large amount; rename small amount; c3b14617fbd7 9ba6ab77fd29
before: ! wall 1.430082 comb 1.430000 user 1.390000 sys 0.040000 (median of 10)
after:  ! wall 1.405192 comb 1.410000 user 1.390000 sys 0.020000 (median of 10)
revision: large amount; added files: small amount; rename small amount; c3b14617fbd7 f650a9b140d2
before: ! wall 1.971366 comb 1.970000 user 1.950000 sys 0.020000 (median of 10)
after:  ! wall 1.892541 comb 1.890000 user 1.870000 sys 0.020000 (median of 10)
revision: large amount; added files: large amount; rename large amount; 08ea3258278e d9fa043f30c0
before: ! wall 0.252594 comb 0.250000 user 0.240000 sys 0.010000 (median of 38)
after:  ! wall 0.240075 comb 0.240000 user 0.240000 sys 0.000000 (median of 40)
revision: small amount; added files: large amount; rename large amount; df6f7a526b60 a83dc6a2d56f
before: ! wall 0.013100 comb 0.010000 user 0.010000 sys 0.000000 (median of 226)
after:  ! wall 0.013247 comb 0.010000 user 0.010000 sys 0.000000 (median of 223)
revision: small amount; added files: large amount; rename small amount; 4aa4e1f8e19a 169138063d63
before: ! wall 0.001633 comb 0.000000 user 0.000000 sys 0.000000 (median of 1000)
after:  ! wall 0.001670 comb 0.000000 user 0.000000 sys 0.000000 (median of 1000)
revision: small amount; added files: small amount; rename small amount; 4bc173b045a6 964879152e2e
before: ! wall 0.000078 comb 0.000000 user 0.000000 sys 0.000000 (median of 11984)
after:  ! wall 0.000119 comb 0.000000 user 0.000000 sys 0.000000 (median of 7982)
revision: medium amount; added files: large amount; rename medium amount; c95f1ced15f2 2c68e87c3efe
before: ! wall 0.207093 comb 0.210000 user 0.210000 sys 0.000000 (median of 47)
after:  ! wall 0.201551 comb 0.200000 user 0.200000 sys 0.000000 (median of 48)
revision: medium amount; added files: medium amount; rename small amount; d343da0c55a8 d7746d32bf9d
before: ! wall 0.038462 comb 0.040000 user 0.040000 sys 0.000000 (median of 100)
after:  ! wall 0.036578 comb 0.030000 user 0.030000 sys 0.000000 (median of 100)

Differential Revision: https://phab.mercurial-scm.org/D7076

# exchangev2.py - repository exchange for wire protocol version 2
#
# Copyright 2018 Gregory Szorc <[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 collections
import weakref

from .i18n import _
from .node import (
    nullid,
    short,
)
from . import (
    bookmarks,
    error,
    mdiff,
    narrowspec,
    phases,
    pycompat,
    setdiscovery,
)
from .interfaces import repository


def pull(pullop):
    """Pull using wire protocol version 2."""
    repo = pullop.repo
    remote = pullop.remote

    usingrawchangelogandmanifest = _checkuserawstorefiledata(pullop)

    # If this is a clone and it was requested to perform a "stream clone",
    # we obtain the raw files data from the remote then fall back to an
    # incremental pull. This is somewhat hacky and is not nearly robust enough
    # for long-term usage.
    if usingrawchangelogandmanifest:
        with repo.transaction(b'clone'):
            _fetchrawstorefiles(repo, remote)
            repo.invalidate(clearfilecache=True)

    tr = pullop.trmanager.transaction()

    # We don't use the repo's narrow matcher here because the patterns passed
    # to exchange.pull() could be different.
    narrowmatcher = narrowspec.match(
        repo.root,
        # Empty maps to nevermatcher. So always
        # set includes if missing.
        pullop.includepats or {b'path:.'},
        pullop.excludepats,
    )

    if pullop.includepats or pullop.excludepats:
        pathfilter = {}
        if pullop.includepats:
            pathfilter[b'include'] = sorted(pullop.includepats)
        if pullop.excludepats:
            pathfilter[b'exclude'] = sorted(pullop.excludepats)
    else:
        pathfilter = None

    # Figure out what needs to be fetched.
    common, fetch, remoteheads = _pullchangesetdiscovery(
        repo, remote, pullop.heads, abortwhenunrelated=pullop.force
    )

    # And fetch the data.
    pullheads = pullop.heads or remoteheads
    csetres = _fetchchangesets(repo, tr, remote, common, fetch, pullheads)

    # New revisions are written to the changelog. But all other updates
    # are deferred. Do those now.

    # Ensure all new changesets are draft by default. If the repo is
    # publishing, the phase will be adjusted by the loop below.
    if csetres[b'added']:
        phases.registernew(repo, tr, phases.draft, csetres[b'added'])

    # And adjust the phase of all changesets accordingly.
    for phase in phases.phasenames:
        if phase == b'secret' or not csetres[b'nodesbyphase'][phase]:
            continue

        phases.advanceboundary(
            repo,
            tr,
            phases.phasenames.index(phase),
            csetres[b'nodesbyphase'][phase],
        )

    # Write bookmark updates.
    bookmarks.updatefromremote(
        repo.ui,
        repo,
        csetres[b'bookmarks'],
        remote.url(),
        pullop.gettransaction,
        explicit=pullop.explicitbookmarks,
    )

    manres = _fetchmanifests(repo, tr, remote, csetres[b'manifestnodes'])

    # We don't properly support shallow changeset and manifest yet. So we apply
    # depth limiting locally.
    if pullop.depth:
        relevantcsetnodes = set()
        clnode = repo.changelog.node

        for rev in repo.revs(
            b'ancestors(%ln, %s)', pullheads, pullop.depth - 1
        ):
            relevantcsetnodes.add(clnode(rev))

        csetrelevantfilter = lambda n: n in relevantcsetnodes

    else:
        csetrelevantfilter = lambda n: True

    # If obtaining the raw store files, we need to scan the full repo to
    # derive all the changesets, manifests, and linkrevs.
    if usingrawchangelogandmanifest:
        csetsforfiles = []
        mnodesforfiles = []
        manifestlinkrevs = {}

        for rev in repo:
            ctx = repo[rev]
            node = ctx.node()

            if not csetrelevantfilter(node):
                continue

            mnode = ctx.manifestnode()

            csetsforfiles.append(node)
            mnodesforfiles.append(mnode)
            manifestlinkrevs[mnode] = rev

    else:
        csetsforfiles = [n for n in csetres[b'added'] if csetrelevantfilter(n)]
        mnodesforfiles = manres[b'added']
        manifestlinkrevs = manres[b'linkrevs']

    # Find all file nodes referenced by added manifests and fetch those
    # revisions.
    fnodes = _derivefilesfrommanifests(repo, narrowmatcher, mnodesforfiles)
    _fetchfilesfromcsets(
        repo,
        tr,
        remote,
        pathfilter,
        fnodes,
        csetsforfiles,
        manifestlinkrevs,
        shallow=bool(pullop.depth),
    )


def _checkuserawstorefiledata(pullop):
    """Check whether we should use rawstorefiledata command to retrieve data."""

    repo = pullop.repo
    remote = pullop.remote

    # Command to obtain raw store data isn't available.
    if b'rawstorefiledata' not in remote.apidescriptor[b'commands']:
        return False

    # Only honor if user requested stream clone operation.
    if not pullop.streamclonerequested:
        return False

    # Only works on empty repos.
    if len(repo):
        return False

    # TODO This is super hacky. There needs to be a storage API for this. We
    # also need to check for compatibility with the remote.
    if b'revlogv1' not in repo.requirements:
        return False

    return True


def _fetchrawstorefiles(repo, remote):
    with remote.commandexecutor() as e:
        objs = e.callcommand(
            b'rawstorefiledata', {b'files': [b'changelog', b'manifestlog'],}
        ).result()

        # First object is a summary of files data that follows.
        overall = next(objs)

        progress = repo.ui.makeprogress(
            _(b'clone'), total=overall[b'totalsize'], unit=_(b'bytes')
        )
        with progress:
            progress.update(0)

            # Next are pairs of file metadata, data.
            while True:
                try:
                    filemeta = next(objs)
                except StopIteration:
                    break

                for k in (b'location', b'path', b'size'):
                    if k not in filemeta:
                        raise error.Abort(
                            _(b'remote file data missing key: %s') % k
                        )

                if filemeta[b'location'] == b'store':
                    vfs = repo.svfs
                else:
                    raise error.Abort(
                        _(b'invalid location for raw file data: %s')
                        % filemeta[b'location']
                    )

                bytesremaining = filemeta[b'size']

                with vfs.open(filemeta[b'path'], b'wb') as fh:
                    while True:
                        try:
                            chunk = next(objs)
                        except StopIteration:
                            break

                        bytesremaining -= len(chunk)

                        if bytesremaining < 0:
                            raise error.Abort(
                                _(
                                    b'received invalid number of bytes for file '
                                    b'data; expected %d, got extra'
                                )
                                % filemeta[b'size']
                            )

                        progress.increment(step=len(chunk))
                        fh.write(chunk)

                        try:
                            if chunk.islast:
                                break
                        except AttributeError:
                            raise error.Abort(
                                _(
                                    b'did not receive indefinite length bytestring '
                                    b'for file data'
                                )
                            )

                if bytesremaining:
                    raise error.Abort(
                        _(
                            b'received invalid number of bytes for'
                            b'file data; expected %d got %d'
                        )
                        % (
                            filemeta[b'size'],
                            filemeta[b'size'] - bytesremaining,
                        )
                    )


def _pullchangesetdiscovery(repo, remote, heads, abortwhenunrelated=True):
    """Determine which changesets need to be pulled."""

    if heads:
        knownnode = repo.changelog.hasnode
        if all(knownnode(head) for head in heads):
            return heads, False, heads

    # TODO wire protocol version 2 is capable of more efficient discovery
    # than setdiscovery. Consider implementing something better.
    common, fetch, remoteheads = setdiscovery.findcommonheads(
        repo.ui, repo, remote, abortwhenunrelated=abortwhenunrelated
    )

    common = set(common)
    remoteheads = set(remoteheads)

    # If a remote head is filtered locally, put it back in the common set.
    # See the comment in exchange._pulldiscoverychangegroup() for more.

    if fetch and remoteheads:
        nodemap = repo.unfiltered().changelog.nodemap

        common |= {head for head in remoteheads if head in nodemap}

        if set(remoteheads).issubset(common):
            fetch = []

    common.discard(nullid)

    return common, fetch, remoteheads


def _fetchchangesets(repo, tr, remote, common, fetch, remoteheads):
    # TODO consider adding a step here where we obtain the DAG shape first
    # (or ask the server to slice changesets into chunks for us) so that
    # we can perform multiple fetches in batches. This will facilitate
    # resuming interrupted clones, higher server-side cache hit rates due
    # to smaller segments, etc.
    with remote.commandexecutor() as e:
        objs = e.callcommand(
            b'changesetdata',
            {
                b'revisions': [
                    {
                        b'type': b'changesetdagrange',
                        b'roots': sorted(common),
                        b'heads': sorted(remoteheads),
                    }
                ],
                b'fields': {b'bookmarks', b'parents', b'phase', b'revision'},
            },
        ).result()

        # The context manager waits on all response data when exiting. So
        # we need to remain in the context manager in order to stream data.
        return _processchangesetdata(repo, tr, objs)


def _processchangesetdata(repo, tr, objs):
    repo.hook(b'prechangegroup', throw=True, **pycompat.strkwargs(tr.hookargs))

    urepo = repo.unfiltered()
    cl = urepo.changelog

    cl.delayupdate(tr)

    # The first emitted object is a header describing the data that
    # follows.
    meta = next(objs)

    progress = repo.ui.makeprogress(
        _(b'changesets'), unit=_(b'chunks'), total=meta.get(b'totalitems')
    )

    manifestnodes = {}

    def linkrev(node):
        repo.ui.debug(b'add changeset %s\n' % short(node))
        # Linkrev for changelog is always self.
        return len(cl)

    def onchangeset(cl, node):
        progress.increment()

        revision = cl.changelogrevision(node)

        # We need to preserve the mapping of changelog revision to node
        # so we can set the linkrev accordingly when manifests are added.
        manifestnodes[cl.rev(node)] = revision.manifest

    nodesbyphase = {phase: set() for phase in phases.phasenames}
    remotebookmarks = {}

    # addgroup() expects a 7-tuple describing revisions. This normalizes
    # the wire data to that format.
    #
    # This loop also aggregates non-revision metadata, such as phase
    # data.
    def iterrevisions():
        for cset in objs:
            node = cset[b'node']

            if b'phase' in cset:
                nodesbyphase[cset[b'phase']].add(node)

            for mark in cset.get(b'bookmarks', []):
                remotebookmarks[mark] = node

            # TODO add mechanism for extensions to examine records so they
            # can siphon off custom data fields.

            extrafields = {}

            for field, size in cset.get(b'fieldsfollowing', []):
                extrafields[field] = next(objs)

            # Some entries might only be metadata only updates.
            if b'revision' not in extrafields:
                continue

            data = extrafields[b'revision']

            yield (
                node,
                cset[b'parents'][0],
                cset[b'parents'][1],
                # Linknode is always itself for changesets.
                cset[b'node'],
                # We always send full revisions. So delta base is not set.
                nullid,
                mdiff.trivialdiffheader(len(data)) + data,
                # Flags not yet supported.
                0,
            )

    added = cl.addgroup(
        iterrevisions(), linkrev, weakref.proxy(tr), addrevisioncb=onchangeset
    )

    progress.complete()

    return {
        b'added': added,
        b'nodesbyphase': nodesbyphase,
        b'bookmarks': remotebookmarks,
        b'manifestnodes': manifestnodes,
    }


def _fetchmanifests(repo, tr, remote, manifestnodes):
    rootmanifest = repo.manifestlog.getstorage(b'')

    # Some manifests can be shared between changesets. Filter out revisions
    # we already know about.
    fetchnodes = []
    linkrevs = {}
    seen = set()

    for clrev, node in sorted(pycompat.iteritems(manifestnodes)):
        if node in seen:
            continue

        try:
            rootmanifest.rev(node)
        except error.LookupError:
            fetchnodes.append(node)
            linkrevs[node] = clrev

        seen.add(node)

    # TODO handle tree manifests

    # addgroup() expects 7-tuple describing revisions. This normalizes
    # the wire data to that format.
    def iterrevisions(objs, progress):
        for manifest in objs:
            node = manifest[b'node']

            extrafields = {}

            for field, size in manifest.get(b'fieldsfollowing', []):
                extrafields[field] = next(objs)

            if b'delta' in extrafields:
                basenode = manifest[b'deltabasenode']
                delta = extrafields[b'delta']
            elif b'revision' in extrafields:
                basenode = nullid
                revision = extrafields[b'revision']
                delta = mdiff.trivialdiffheader(len(revision)) + revision
            else:
                continue

            yield (
                node,
                manifest[b'parents'][0],
                manifest[b'parents'][1],
                # The value passed in is passed to the lookup function passed
                # to addgroup(). We already have a map of manifest node to
                # changelog revision number. So we just pass in the
                # manifest node here and use linkrevs.__getitem__ as the
                # resolution function.
                node,
                basenode,
                delta,
                # Flags not yet supported.
                0,
            )

            progress.increment()

    progress = repo.ui.makeprogress(
        _(b'manifests'), unit=_(b'chunks'), total=len(fetchnodes)
    )

    commandmeta = remote.apidescriptor[b'commands'][b'manifestdata']
    batchsize = commandmeta.get(b'recommendedbatchsize', 10000)
    # TODO make size configurable on client?

    # We send commands 1 at a time to the remote. This is not the most
    # efficient because we incur a round trip at the end of each batch.
    # However, the existing frame-based reactor keeps consuming server
    # data in the background. And this results in response data buffering
    # in memory. This can consume gigabytes of memory.
    # TODO send multiple commands in a request once background buffering
    # issues are resolved.

    added = []

    for i in pycompat.xrange(0, len(fetchnodes), batchsize):
        batch = [node for node in fetchnodes[i : i + batchsize]]
        if not batch:
            continue

        with remote.commandexecutor() as e:
            objs = e.callcommand(
                b'manifestdata',
                {
                    b'tree': b'',
                    b'nodes': batch,
                    b'fields': {b'parents', b'revision'},
                    b'haveparents': True,
                },
            ).result()

            # Chomp off header object.
            next(objs)

            added.extend(
                rootmanifest.addgroup(
                    iterrevisions(objs, progress),
                    linkrevs.__getitem__,
                    weakref.proxy(tr),
                )
            )

    progress.complete()

    return {
        b'added': added,
        b'linkrevs': linkrevs,
    }


def _derivefilesfrommanifests(repo, matcher, manifestnodes):
    """Determine what file nodes are relevant given a set of manifest nodes.

    Returns a dict mapping file paths to dicts of file node to first manifest
    node.
    """
    ml = repo.manifestlog
    fnodes = collections.defaultdict(dict)

    progress = repo.ui.makeprogress(
        _(b'scanning manifests'), total=len(manifestnodes)
    )

    with progress:
        for manifestnode in manifestnodes:
            m = ml.get(b'', manifestnode)

            # TODO this will pull in unwanted nodes because it takes the storage
            # delta into consideration. What we really want is something that
            # takes the delta between the manifest's parents. And ideally we
            # would ignore file nodes that are known locally. For now, ignore
            # both these limitations. This will result in incremental fetches
            # requesting data we already have. So this is far from ideal.
            md = m.readfast()

            for path, fnode in md.items():
                if matcher(path):
                    fnodes[path].setdefault(fnode, manifestnode)

            progress.increment()

    return fnodes


def _fetchfiles(repo, tr, remote, fnodes, linkrevs):
    """Fetch file data from explicit file revisions."""

    def iterrevisions(objs, progress):
        for filerevision in objs:
            node = filerevision[b'node']

            extrafields = {}

            for field, size in filerevision.get(b'fieldsfollowing', []):
                extrafields[field] = next(objs)

            if b'delta' in extrafields:
                basenode = filerevision[b'deltabasenode']
                delta = extrafields[b'delta']
            elif b'revision' in extrafields:
                basenode = nullid
                revision = extrafields[b'revision']
                delta = mdiff.trivialdiffheader(len(revision)) + revision
            else:
                continue

            yield (
                node,
                filerevision[b'parents'][0],
                filerevision[b'parents'][1],
                node,
                basenode,
                delta,
                # Flags not yet supported.
                0,
            )

            progress.increment()

    progress = repo.ui.makeprogress(
        _(b'files'),
        unit=_(b'chunks'),
        total=sum(len(v) for v in pycompat.itervalues(fnodes)),
    )

    # TODO make batch size configurable
    batchsize = 10000
    fnodeslist = [x for x in sorted(fnodes.items())]

    for i in pycompat.xrange(0, len(fnodeslist), batchsize):
        batch = [x for x in fnodeslist[i : i + batchsize]]
        if not batch:
            continue

        with remote.commandexecutor() as e:
            fs = []
            locallinkrevs = {}

            for path, nodes in batch:
                fs.append(
                    (
                        path,
                        e.callcommand(
                            b'filedata',
                            {
                                b'path': path,
                                b'nodes': sorted(nodes),
                                b'fields': {b'parents', b'revision'},
                                b'haveparents': True,
                            },
                        ),
                    )
                )

                locallinkrevs[path] = {
                    node: linkrevs[manifestnode]
                    for node, manifestnode in pycompat.iteritems(nodes)
                }

            for path, f in fs:
                objs = f.result()

                # Chomp off header objects.
                next(objs)

                store = repo.file(path)
                store.addgroup(
                    iterrevisions(objs, progress),
                    locallinkrevs[path].__getitem__,
                    weakref.proxy(tr),
                )


def _fetchfilesfromcsets(
    repo, tr, remote, pathfilter, fnodes, csets, manlinkrevs, shallow=False
):
    """Fetch file data from explicit changeset revisions."""

    def iterrevisions(objs, remaining, progress):
        while remaining:
            filerevision = next(objs)

            node = filerevision[b'node']

            extrafields = {}

            for field, size in filerevision.get(b'fieldsfollowing', []):
                extrafields[field] = next(objs)

            if b'delta' in extrafields:
                basenode = filerevision[b'deltabasenode']
                delta = extrafields[b'delta']
            elif b'revision' in extrafields:
                basenode = nullid
                revision = extrafields[b'revision']
                delta = mdiff.trivialdiffheader(len(revision)) + revision
            else:
                continue

            if b'linknode' in filerevision:
                linknode = filerevision[b'linknode']
            else:
                linknode = node

            yield (
                node,
                filerevision[b'parents'][0],
                filerevision[b'parents'][1],
                linknode,
                basenode,
                delta,
                # Flags not yet supported.
                0,
            )

            progress.increment()
            remaining -= 1

    progress = repo.ui.makeprogress(
        _(b'files'),
        unit=_(b'chunks'),
        total=sum(len(v) for v in pycompat.itervalues(fnodes)),
    )

    commandmeta = remote.apidescriptor[b'commands'][b'filesdata']
    batchsize = commandmeta.get(b'recommendedbatchsize', 50000)

    shallowfiles = repository.REPO_FEATURE_SHALLOW_FILE_STORAGE in repo.features
    fields = {b'parents', b'revision'}
    clrev = repo.changelog.rev

    # There are no guarantees that we'll have ancestor revisions if
    # a) this repo has shallow file storage b) shallow data fetching is enabled.
    # Force remote to not delta against possibly unknown revisions when these
    # conditions hold.
    haveparents = not (shallowfiles or shallow)

    # Similarly, we may not have calculated linkrevs for all incoming file
    # revisions. Ask the remote to do work for us in this case.
    if not haveparents:
        fields.add(b'linknode')

    for i in pycompat.xrange(0, len(csets), batchsize):
        batch = [x for x in csets[i : i + batchsize]]
        if not batch:
            continue

        with remote.commandexecutor() as e:
            args = {
                b'revisions': [
                    {b'type': b'changesetexplicit', b'nodes': batch,}
                ],
                b'fields': fields,
                b'haveparents': haveparents,
            }

            if pathfilter:
                args[b'pathfilter'] = pathfilter

            objs = e.callcommand(b'filesdata', args).result()

            # First object is an overall header.
            overall = next(objs)

            # We have overall['totalpaths'] segments.
            for i in pycompat.xrange(overall[b'totalpaths']):
                header = next(objs)

                path = header[b'path']
                store = repo.file(path)

                linkrevs = {
                    fnode: manlinkrevs[mnode]
                    for fnode, mnode in pycompat.iteritems(fnodes[path])
                }

                def getlinkrev(node):
                    if node in linkrevs:
                        return linkrevs[node]
                    else:
                        return clrev(node)

                store.addgroup(
                    iterrevisions(objs, header[b'totalitems'], progress),
                    getlinkrev,
                    weakref.proxy(tr),
                    maybemissingparents=shallow,
                )