view mercurial/verify.py @ 23785:cb99bacb9b4e

branchcache: introduce revbranchcache for caching of revision branch names

It is expensive to retrieve the branch name of a revision. Very expensive when
creating a changectx and calling .branch() every time - slightly less when
using changelog.branchinfo().

Now, to speed things up, provide a way to cache the results on disk in an
efficient format. Each branchname is assigned a number, and for each revision
we store the number of the corresponding branch name. The branch names are
stored in a dedicated file which is strictly append only.

Branch names are usually reused across several revisions, and the total list of
branch names will thus be so small that it is feasible to read the whole set of
names before using the cache. It will however do that it might be more
efficient to use the changelog for retrieving the branch info for a single
revision.

The revision entries are stored in another file. This file is usually append
only, but if the repository has been modified, the file will be truncated and
the relevant parts rewritten on demand.

The entries for each revision are 8 bytes each, and the whole revision file
will thus be 1/8 of 00changelog.i.

Each revision entry contains the first 4 bytes of the corresponding node hash.
This is used as a check sum that always is verified before the entry is used.
That check is relatively expensive but it makes sure history modification is
detected and handled correctly. It will also detect and handle most revision
file corruptions.

This is just a cache. A new format can always be introduced if other
requirements or ideas make that seem like a good idea. Rebuilding the cache is
not really more expensive than it was to run for example 'hg log -b branchname'
before this cache was introduced.

This new method is still unused but promise to make some operations several
times faster once it actually is used.

Abandoning Python 2.4 would make it possible to implement this more efficiently
by using struct classes and pack_into. The Python code could probably also be
micro optimized or it could be implemented very efficiently in C where it would
be easy to control the data access.

# verify.py - repository integrity checking for Mercurial
#
# Copyright 2006, 2007 Matt 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 node import nullid, short
from i18n import _
import os
import revlog, util, error

def verify(repo):
    lock = repo.lock()
    try:
        return _verify(repo)
    finally:
        lock.release()

def _normpath(f):
    # under hg < 2.4, convert didn't sanitize paths properly, so a
    # converted repo may contain repeated slashes
    while '//' in f:
        f = f.replace('//', '/')
    return f

def _verify(repo):
    repo = repo.unfiltered()
    mflinkrevs = {}
    filelinkrevs = {}
    filenodes = {}
    revisions = 0
    badrevs = set()
    errors = [0]
    warnings = [0]
    ui = repo.ui
    cl = repo.changelog
    mf = repo.manifest
    lrugetctx = util.lrucachefunc(repo.changectx)

    if not repo.url().startswith('file:'):
        raise util.Abort(_("cannot verify bundle or remote repos"))

    def err(linkrev, msg, filename=None):
        if linkrev is not None:
            badrevs.add(linkrev)
        else:
            linkrev = '?'
        msg = "%s: %s" % (linkrev, msg)
        if filename:
            msg = "%s@%s" % (filename, msg)
        ui.warn(" " + msg + "\n")
        errors[0] += 1

    def exc(linkrev, msg, inst, filename=None):
        if isinstance(inst, KeyboardInterrupt):
            ui.warn(_("interrupted"))
            raise
        if not str(inst):
            inst = repr(inst)
        err(linkrev, "%s: %s" % (msg, inst), filename)

    def warn(msg):
        ui.warn(msg + "\n")
        warnings[0] += 1

    def checklog(obj, name, linkrev):
        if not len(obj) and (havecl or havemf):
            err(linkrev, _("empty or missing %s") % name)
            return

        d = obj.checksize()
        if d[0]:
            err(None, _("data length off by %d bytes") % d[0], name)
        if d[1]:
            err(None, _("index contains %d extra bytes") % d[1], name)

        if obj.version != revlog.REVLOGV0:
            if not revlogv1:
                warn(_("warning: `%s' uses revlog format 1") % name)
        elif revlogv1:
            warn(_("warning: `%s' uses revlog format 0") % name)

    def checkentry(obj, i, node, seen, linkrevs, f):
        lr = obj.linkrev(obj.rev(node))
        if lr < 0 or (havecl and lr not in linkrevs):
            if lr < 0 or lr >= len(cl):
                msg = _("rev %d points to nonexistent changeset %d")
            else:
                msg = _("rev %d points to unexpected changeset %d")
            err(None, msg % (i, lr), f)
            if linkrevs:
                if f and len(linkrevs) > 1:
                    try:
                        # attempt to filter down to real linkrevs
                        linkrevs = [l for l in linkrevs
                                    if lrugetctx(l)[f].filenode() == node]
                    except Exception:
                        pass
                warn(_(" (expected %s)") % " ".join(map(str, linkrevs)))
            lr = None # can't be trusted

        try:
            p1, p2 = obj.parents(node)
            if p1 not in seen and p1 != nullid:
                err(lr, _("unknown parent 1 %s of %s") %
                    (short(p1), short(node)), f)
            if p2 not in seen and p2 != nullid:
                err(lr, _("unknown parent 2 %s of %s") %
                    (short(p2), short(node)), f)
        except Exception, inst:
            exc(lr, _("checking parents of %s") % short(node), inst, f)

        if node in seen:
            err(lr, _("duplicate revision %d (%d)") % (i, seen[node]), f)
        seen[node] = i
        return lr

    if os.path.exists(repo.sjoin("journal")):
        ui.warn(_("abandoned transaction found - run hg recover\n"))

    revlogv1 = cl.version != revlog.REVLOGV0
    if ui.verbose or not revlogv1:
        ui.status(_("repository uses revlog format %d\n") %
                       (revlogv1 and 1 or 0))

    havecl = len(cl) > 0
    havemf = len(mf) > 0

    ui.status(_("checking changesets\n"))
    refersmf = False
    seen = {}
    checklog(cl, "changelog", 0)
    total = len(repo)
    for i in repo:
        ui.progress(_('checking'), i, total=total, unit=_('changesets'))
        n = cl.node(i)
        checkentry(cl, i, n, seen, [i], "changelog")

        try:
            changes = cl.read(n)
            if changes[0] != nullid:
                mflinkrevs.setdefault(changes[0], []).append(i)
                refersmf = True
            for f in changes[3]:
                filelinkrevs.setdefault(_normpath(f), []).append(i)
        except Exception, inst:
            refersmf = True
            exc(i, _("unpacking changeset %s") % short(n), inst)
    ui.progress(_('checking'), None)

    ui.status(_("checking manifests\n"))
    seen = {}
    if refersmf:
        # Do not check manifest if there are only changelog entries with
        # null manifests.
        checklog(mf, "manifest", 0)
    total = len(mf)
    for i in mf:
        ui.progress(_('checking'), i, total=total, unit=_('manifests'))
        n = mf.node(i)
        lr = checkentry(mf, i, n, seen, mflinkrevs.get(n, []), "manifest")
        if n in mflinkrevs:
            del mflinkrevs[n]
        else:
            err(lr, _("%s not in changesets") % short(n), "manifest")

        try:
            for f, fn in mf.readdelta(n).iteritems():
                if not f:
                    err(lr, _("file without name in manifest"))
                elif f != "/dev/null":
                    filenodes.setdefault(_normpath(f), {}).setdefault(fn, lr)
        except Exception, inst:
            exc(lr, _("reading manifest delta %s") % short(n), inst)
    ui.progress(_('checking'), None)

    ui.status(_("crosschecking files in changesets and manifests\n"))

    total = len(mflinkrevs) + len(filelinkrevs) + len(filenodes)
    count = 0
    if havemf:
        for c, m in sorted([(c, m) for m in mflinkrevs
                            for c in mflinkrevs[m]]):
            count += 1
            if m == nullid:
                continue
            ui.progress(_('crosschecking'), count, total=total)
            err(c, _("changeset refers to unknown manifest %s") % short(m))
        mflinkrevs = None # del is bad here due to scope issues

        for f in sorted(filelinkrevs):
            count += 1
            ui.progress(_('crosschecking'), count, total=total)
            if f not in filenodes:
                lr = filelinkrevs[f][0]
                err(lr, _("in changeset but not in manifest"), f)

    if havecl:
        for f in sorted(filenodes):
            count += 1
            ui.progress(_('crosschecking'), count, total=total)
            if f not in filelinkrevs:
                try:
                    fl = repo.file(f)
                    lr = min([fl.linkrev(fl.rev(n)) for n in filenodes[f]])
                except Exception:
                    lr = None
                err(lr, _("in manifest but not in changeset"), f)

    ui.progress(_('crosschecking'), None)

    ui.status(_("checking files\n"))

    storefiles = set()
    for f, f2, size in repo.store.datafiles():
        if not f:
            err(None, _("cannot decode filename '%s'") % f2)
        elif size > 0 or not revlogv1:
            storefiles.add(_normpath(f))

    files = sorted(set(filenodes) | set(filelinkrevs))
    total = len(files)
    for i, f in enumerate(files):
        ui.progress(_('checking'), i, item=f, total=total)
        try:
            linkrevs = filelinkrevs[f]
        except KeyError:
            # in manifest but not in changelog
            linkrevs = []

        if linkrevs:
            lr = linkrevs[0]
        else:
            lr = None

        try:
            fl = repo.file(f)
        except error.RevlogError, e:
            err(lr, _("broken revlog! (%s)") % e, f)
            continue

        for ff in fl.files():
            try:
                storefiles.remove(ff)
            except KeyError:
                err(lr, _("missing revlog!"), ff)

        checklog(fl, f, lr)
        seen = {}
        rp = None
        for i in fl:
            revisions += 1
            n = fl.node(i)
            lr = checkentry(fl, i, n, seen, linkrevs, f)
            if f in filenodes:
                if havemf and n not in filenodes[f]:
                    err(lr, _("%s not in manifests") % (short(n)), f)
                else:
                    del filenodes[f][n]

            # verify contents
            try:
                l = len(fl.read(n))
                rp = fl.renamed(n)
                if l != fl.size(i):
                    if len(fl.revision(n)) != fl.size(i):
                        err(lr, _("unpacked size is %s, %s expected") %
                            (l, fl.size(i)), f)
            except error.CensoredNodeError:
                if ui.config("censor", "policy", "abort") == "abort":
                    err(lr, _("censored file data"), f)
            except Exception, inst:
                exc(lr, _("unpacking %s") % short(n), inst, f)

            # check renames
            try:
                if rp:
                    if lr is not None and ui.verbose:
                        ctx = lrugetctx(lr)
                        found = False
                        for pctx in ctx.parents():
                            if rp[0] in pctx:
                                found = True
                                break
                        if not found:
                            warn(_("warning: copy source of '%s' not"
                                   " in parents of %s") % (f, ctx))
                    fl2 = repo.file(rp[0])
                    if not len(fl2):
                        err(lr, _("empty or missing copy source revlog %s:%s")
                            % (rp[0], short(rp[1])), f)
                    elif rp[1] == nullid:
                        ui.note(_("warning: %s@%s: copy source"
                                  " revision is nullid %s:%s\n")
                            % (f, lr, rp[0], short(rp[1])))
                    else:
                        fl2.rev(rp[1])
            except Exception, inst:
                exc(lr, _("checking rename of %s") % short(n), inst, f)

        # cross-check
        if f in filenodes:
            fns = [(lr, n) for n, lr in filenodes[f].iteritems()]
            for lr, node in sorted(fns):
                err(lr, _("%s in manifests not found") % short(node), f)
    ui.progress(_('checking'), None)

    for f in storefiles:
        warn(_("warning: orphan revlog '%s'") % f)

    ui.status(_("%d files, %d changesets, %d total revisions\n") %
                   (len(files), len(cl), revisions))
    if warnings[0]:
        ui.warn(_("%d warnings encountered!\n") % warnings[0])
    if errors[0]:
        ui.warn(_("%d integrity errors encountered!\n") % errors[0])
        if badrevs:
            ui.warn(_("(first damaged changeset appears to be %d)\n")
                    % min(badrevs))
        return 1