# 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 = "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('%ln::%ln', bases, heads)

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

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

    name = "%s/%s-%s-%s.hg" % (backupdir, short(node),

                               hex(totalhash[:4]), suffix)

    cgversion = changegroup.localversion(repo)

    comp = None

    if cgversion != '01':

        bundletype = "HG20"

        if compress:

            comp = 'BZ'

    elif compress:

        bundletype = "HG10BZ"

    else:

        bundletype = "HG10UN"

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

    contentopts = {

        'cg.version': cgversion,

        'obsolescence': obsolescence,

        'phases': True,

    }

    return bundle2.writenewbundle(repo.ui, repo, '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 _collectmanifest(repo, striprev):

    return _collectrevlog(repo.manifestlog.getstorage(b''), striprev)

def _collectbrokencsets(repo, files, striprev):

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

    s = set()

    s.update(_collectmanifest(repo, striprev))

    for fname in files:

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

    return s

def strip(ui, repo, nodelist, backup=True, topic='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('cannot strip from inside a transaction')

    # Simple way to maintain backwards compatibility for this

    # argument.

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

        backup = False

    repo = repo.unfiltered()

    repo.destroying()

    vfs = repo.vfs

    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('devel', '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, 'temp',

                                     compress=False, obsolescence=False)

    with ui.uninterruptible():

        try:

            with repo.transaction("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, '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(_("adding branch\n"))

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

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

                if not repo.ui.verbose:

                    # silence internal shuffling chatter

                    repo.ui.pushbuffer()

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

                txnname = 'strip'

                if not isinstance(gen, bundle2.unbundle20):

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

                with repo.transaction(txnname) as tr:

                    bundle2.applybundle(repo, gen, tr, source='strip',

                                        url=tmpbundleurl)

                if not repo.ui.verbose:

                    repo.ui.popbuffer()

                f.close()

            with repo.transaction('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(_('error removing %s: %s\n') %

                                (undovfs.join(undofile),

                                 stringutil.forcebytestr(e)))

        except: # re-raises

            if backupfile:

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

                        % vfs.join(backupfile))

            if tmpbundlefile:

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

                        % vfs.join(tmpbundlefile))

                ui.warn(_("(fix the problem, then recover the changesets with "

                          "\"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 _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 updatebm: # don't compute anything is there is no bookmark to move anyway

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

        # but is much faster

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

        if newbmtarget:

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

        else:

            newbmtarget = '.'

    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(_("saved backup bundle to %s\n") %

                   vfs.join(backupfile))

    repo.ui.log("backupbundle", "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 = '%ld - ( ::( (roots(%ld):: and not _phase(%s)) -%ld) )'

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

    notstrip = revs - tostrip

    if notstrip:

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

        ui.warn(_('warning: orphaned descendants detected, '

                  'not stripping %s\n') % nodestr)

    return [c.node() for c in repo.set('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

        self.backup = backup

        self.topic = topic or 'backup'

        self.nodelist = []

    def addnodes(self, nodes):

        self.nodelist.extend(nodes)

    def __call__(self, tr):

        roots = safestriproots(self.ui, self.repo, self.nodelist)

        if roots:

            strip(self.ui, self.repo, roots, self.backup, self.topic)

def delayedstrip(ui, repo, nodelist, topic=None, backup=True):

    """like strip, but works inside transaction and won't strip irreverent revs

    nodelist must explicitly contain all descendants. Otherwise a warning will

    be printed that some nodes are not stripped.

    Will do a backup if `backup` is True. The last non-None "topic" will be

    used as the backup topic name. The default backup topic name is "backup".

    """

    tr = repo.currenttransaction()

    if not tr:

        nodes = safestriproots(ui, repo, nodelist)

        return strip(ui, repo, nodes, backup=backup, topic=topic)

    # transaction postclose callbacks are called in alphabet order.

    # use '\xff' as prefix so we are likely to be called last.

    callback = tr.getpostclose('\xffstrip')

    if callback is None:

        callback = stripcallback(ui, repo, backup=backup, topic=topic)

        tr.addpostclose('\xffstrip', callback)

    if topic:

        callback.topic = topic

    callback.addnodes(nodelist)

def stripmanifest(repo, striprev, tr, files):

    revlog = repo.manifestlog.getstorage(b'')

    revlog.strip(striprev, tr)

    striptrees(repo, tr, striprev, files)

def striptrees(repo, tr, striprev, files):

    if 'treemanifest' in repo.requirements: # safe but unnecessary

                                            # otherwise

        for unencoded, encoded, size in repo.store.datafiles():

            if (unencoded.startswith('meta/') and

                unencoded.endswith('00manifest.i')):

                dir = unencoded[5:-12]

                repo.manifestlog.getstorage(dir).strip(striprev, tr)

def rebuildfncache(ui, repo):

    """Rebuilds the fncache file from repo history.

    Missing entries will be added. Extra entries will be removed.

    """

    repo = repo.unfiltered()

    if 'fncache' not in repo.requirements:

        ui.warn(_('(not rebuilding fncache because repository does not '

                  'support fncache)\n'))