# repair.py - functions for repository repair for mercurial

#

# Copyright 2005, 2006 Chris Mason <mason@suse.com>

# Copyright 2007 Matt Mackall

#

# 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 errno

import hashlib

from .i18n import _

from .node import (

    hex,

    short,

)

from . import (

    bundle2,

    changegroup,

    discovery,

    error,

    exchange,

    obsolete,

    obsutil,

    phases,

    pycompat,

    util,

)

from .utils import stringutil

def backupbundle(

    repo, bases, heads, node, suffix, compress=True, obsolescence=True

):

    """create a bundle with the specified revisions as a backup"""

    backupdir = b"strip-backup"

    vfs = repo.vfs

    if not vfs.isdir(backupdir):

        vfs.mkdir(backupdir)

    # Include a hash of all the nodes in the filename for uniqueness

    allcommits = repo.set(b'%ln::%ln', bases, heads)

    allhashes = sorted(c.hex() for c in allcommits)

    totalhash = hashlib.sha1(b''.join(allhashes)).digest()

    name = b"%s/%s-%s-%s.hg" % (

        backupdir,

        short(node),

        hex(totalhash[:4]),

        suffix,

    )

    cgversion = changegroup.localversion(repo)

    comp = None

    if cgversion != b'01':

        bundletype = b"HG20"

        if compress:

            comp = b'BZ'

    elif compress:

        bundletype = b"HG10BZ"

    else:

        bundletype = b"HG10UN"

    outgoing = discovery.outgoing(repo, missingroots=bases, missingheads=heads)

    contentopts = {

        b'cg.version': cgversion,

        b'obsolescence': obsolescence,

        b'phases': True,

    }

    return bundle2.writenewbundle(

        repo.ui,

        repo,

        b'strip',

        name,

        bundletype,

        outgoing,

        contentopts,

        vfs,

        compression=comp,

    )

def _collectfiles(repo, striprev):

    """find out the filelogs affected by the strip"""

    files = set()

    for x in pycompat.xrange(striprev, len(repo)):

        files.update(repo[x].files())

    return sorted(files)

def _collectrevlog(revlog, striprev):

    _, brokenset = revlog.getstrippoint(striprev)

    return [revlog.linkrev(r) for r in brokenset]

def _collectbrokencsets(repo, files, striprev):

    """return the changesets which will be broken by the truncation"""

    s = set()

    for revlog in manifestrevlogs(repo):

        s.update(_collectrevlog(revlog, striprev))

    for fname in files:

        s.update(_collectrevlog(repo.file(fname), striprev))

    return s

def strip(ui, repo, nodelist, backup=True, topic=b'backup'):

    # This function requires the caller to lock the repo, but it operates

    # within a transaction of its own, and thus requires there to be no current

    # transaction when it is called.

    if repo.currenttransaction() is not None:

        raise error.ProgrammingError(b'cannot strip from inside a transaction')

    # Simple way to maintain backwards compatibility for this

    # argument.

    if backup in [b'none', b'strip']:

        backup = False

    repo = repo.unfiltered()

    repo.destroying()

    vfs = repo.vfs

    # load bookmark before changelog to avoid side effect from outdated

    # changelog (see repo._refreshchangelog)

    repo._bookmarks

    cl = repo.changelog

    # TODO handle undo of merge sets

    if isinstance(nodelist, str):

        nodelist = [nodelist]

    striplist = [cl.rev(node) for node in nodelist]

    striprev = min(striplist)

    files = _collectfiles(repo, striprev)

    saverevs = _collectbrokencsets(repo, files, striprev)

    # Some revisions with rev > striprev may not be descendants of striprev.

    # We have to find these revisions and put them in a bundle, so that

    # we can restore them after the truncations.

    # To create the bundle we use repo.changegroupsubset which requires

    # the list of heads and bases of the set of interesting revisions.

    # (head = revision in the set that has no descendant in the set;

    #  base = revision in the set that has no ancestor in the set)

    tostrip = set(striplist)

    saveheads = set(saverevs)

    for r in cl.revs(start=striprev + 1):

        if any(p in tostrip for p in cl.parentrevs(r)):

            tostrip.add(r)

        if r not in tostrip:

            saverevs.add(r)

            saveheads.difference_update(cl.parentrevs(r))

            saveheads.add(r)

    saveheads = [cl.node(r) for r in saveheads]

    # compute base nodes

    if saverevs:

        descendants = set(cl.descendants(saverevs))

        saverevs.difference_update(descendants)

    savebases = [cl.node(r) for r in saverevs]

    stripbases = [cl.node(r) for r in tostrip]

    stripobsidx = obsmarkers = ()

    if repo.ui.configbool(b'devel', b'strip-obsmarkers'):

        obsmarkers = obsutil.exclusivemarkers(repo, stripbases)

    if obsmarkers:

        stripobsidx = [

            i for i, m in enumerate(repo.obsstore) if m in obsmarkers

        ]

    newbmtarget, updatebm = _bookmarkmovements(repo, tostrip)

    backupfile = None

    node = nodelist[-1]

    if backup:

        backupfile = _createstripbackup(repo, stripbases, node, topic)

    # create a changegroup for all the branches we need to keep

    tmpbundlefile = None

    if saveheads:

        # do not compress temporary bundle if we remove it from disk later

        #

        # We do not include obsolescence, it might re-introduce prune markers

        # we are trying to strip.  This is harmless since the stripped markers

        # are already backed up and we did not touched the markers for the

        # saved changesets.

        tmpbundlefile = backupbundle(

            repo,

            savebases,

            saveheads,

            node,

            b'temp',

            compress=False,

            obsolescence=False,

        )

    with ui.uninterruptible():

        try:

            with repo.transaction(b"strip") as tr:

                # TODO this code violates the interface abstraction of the

                # transaction and makes assumptions that file storage is

                # using append-only files. We'll need some kind of storage

                # API to handle stripping for us.

                offset = len(tr._entries)

                tr.startgroup()

                cl.strip(striprev, tr)

                stripmanifest(repo, striprev, tr, files)

                for fn in files:

                    repo.file(fn).strip(striprev, tr)

                tr.endgroup()

                for i in pycompat.xrange(offset, len(tr._entries)):

                    file, troffset, ignore = tr._entries[i]

                    with repo.svfs(file, b'a', checkambig=True) as fp:

                        fp.truncate(troffset)

                    if troffset == 0:

                        repo.store.markremoved(file)

                deleteobsmarkers(repo.obsstore, stripobsidx)

                del repo.obsstore

                repo.invalidatevolatilesets()

                repo._phasecache.filterunknown(repo)

            if tmpbundlefile:

                ui.note(_(b"adding branch\n"))

                f = vfs.open(tmpbundlefile, b"rb")

                gen = exchange.readbundle(ui, f, tmpbundlefile, vfs)

                if not repo.ui.verbose:

                    # silence internal shuffling chatter

                    repo.ui.pushbuffer()

                tmpbundleurl = b'bundle:' + vfs.join(tmpbundlefile)

                txnname = b'strip'

                if not isinstance(gen, bundle2.unbundle20):

                    txnname = b"strip\n%s" % util.hidepassword(tmpbundleurl)

                with repo.transaction(txnname) as tr:

                    bundle2.applybundle(

                        repo, gen, tr, source=b'strip', url=tmpbundleurl

                    )

                if not repo.ui.verbose:

                    repo.ui.popbuffer()

                f.close()

            with repo.transaction(b'repair') as tr:

                bmchanges = [(m, repo[newbmtarget].node()) for m in updatebm]

                repo._bookmarks.applychanges(repo, tr, bmchanges)

            # remove undo files

            for undovfs, undofile in repo.undofiles():

                try:

                    undovfs.unlink(undofile)

                except OSError as e:

                    if e.errno != errno.ENOENT:

                        ui.warn(

                            _(b'error removing %s: %s\n')

                            % (

                                undovfs.join(undofile),

                                stringutil.forcebytestr(e),

                            )

                        )

        except:  # re-raises

            if backupfile:

                ui.warn(

                    _(b"strip failed, backup bundle stored in '%s'\n")

                    % vfs.join(backupfile)

                )

            if tmpbundlefile:

                ui.warn(

                    _(b"strip failed, unrecovered changes stored in '%s'\n")

                    % vfs.join(tmpbundlefile)

                )

                ui.warn(

                    _(

                        b"(fix the problem, then recover the changesets with "

                        b"\"hg unbundle '%s'\")\n"

                    )

                    % vfs.join(tmpbundlefile)

                )

            raise

        else:

            if tmpbundlefile:

                # Remove temporary bundle only if there were no exceptions

                vfs.unlink(tmpbundlefile)

    repo.destroyed()

    # return the backup file path (or None if 'backup' was False) so

    # extensions can use it

    return backupfile

def softstrip(ui, repo, nodelist, backup=True, topic=b'backup'):

    """perform a "soft" strip using the archived phase"""

    tostrip = [c.node() for c in repo.set(b'sort(%ln::)', nodelist)]

    if not tostrip:

        return None

    newbmtarget, updatebm = _bookmarkmovements(repo, tostrip)

    if backup:

        node = tostrip[0]

        backupfile = _createstripbackup(repo, tostrip, node, topic)

    with repo.transaction(b'strip') as tr:

        phases.retractboundary(repo, tr, phases.archived, tostrip)

        bmchanges = [(m, repo[newbmtarget].node()) for m in updatebm]

        repo._bookmarks.applychanges(repo, tr, bmchanges)

    return backupfile

def _bookmarkmovements(repo, tostrip):

    # compute necessary bookmark movement

    bm = repo._bookmarks

    updatebm = []

    for m in bm:

        rev = repo[bm[m]].rev()

        if rev in tostrip:

            updatebm.append(m)

    newbmtarget = None

    # If we need to move bookmarks, compute bookmark

    # targets. Otherwise we can skip doing this logic.

    if updatebm:

        # For a set s, max(parents(s) - s) is the same as max(heads(::s - s)),

        # but is much faster

        newbmtarget = repo.revs(b'max(parents(%ld) - (%ld))', tostrip, tostrip)

        if newbmtarget:

            newbmtarget = repo[newbmtarget.first()].node()

        else:

            newbmtarget = b'.'

    return newbmtarget, updatebm

def _createstripbackup(repo, stripbases, node, topic):

    # backup the changeset we are about to strip

    vfs = repo.vfs

    cl = repo.changelog

    backupfile = backupbundle(repo, stripbases, cl.heads(), node, topic)

    repo.ui.status(_(b"saved backup bundle to %s\n") % vfs.join(backupfile))

    repo.ui.log(

        b"backupbundle", b"saved backup bundle to %s\n", vfs.join(backupfile)

    )

    return backupfile

def safestriproots(ui, repo, nodes):

    """return list of roots of nodes where descendants are covered by nodes"""

    torev = repo.unfiltered().changelog.rev

    revs = set(torev(n) for n in nodes)

    # tostrip = wanted - unsafe = wanted - ancestors(orphaned)

    # orphaned = affected - wanted

    # affected = descendants(roots(wanted))

    # wanted = revs

    revset = b'%ld - ( ::( (roots(%ld):: and not _phase(%s)) -%ld) )'

    tostrip = set(repo.revs(revset, revs, revs, phases.internal, revs))

    notstrip = revs - tostrip

    if notstrip:

        nodestr = b', '.join(sorted(short(repo[n].node()) for n in notstrip))

        ui.warn(

            % nodestr

        )

    return [c.node() for c in repo.set(b'roots(%ld)', tostrip)]

class stripcallback(object):

    """used as a transaction postclose callback"""

    def __init__(self, ui, repo, backup, topic):

        self.ui = ui

        self.repo = repo