view mercurial/repair.py @ 10364:de1e7099d100

dispatch: provide help for disabled extensions and commands

Before a command is declared unknown, each extension in hgext is searched,
starting with hgext.<cmdname>. If there's a matching command, a help message
suggests the appropriate extension and how to enable it.

Every extension could potentially be imported, but for cases like rebase,
relink, etc. only one extension is imported.

For the case of "hg help disabledext", if the extension is in hgext, the
extension description is read and a similar help suggestion is printed.
No extension import occurs.

# repair.py - functions for repository repair for mercurial
#
# Copyright 2005, 2006 Chris Mason <[e-mail]>
# 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.

import changegroup
from node import nullrev, short
from i18n import _
import os

def _bundle(repo, bases, heads, node, suffix, extranodes=None):
    """create a bundle with the specified revisions as a backup"""
    cg = repo.changegroupsubset(bases, heads, 'strip', extranodes)
    backupdir = repo.join("strip-backup")
    if not os.path.isdir(backupdir):
        os.mkdir(backupdir)
    name = os.path.join(backupdir, "%s-%s" % (short(node), suffix))
    repo.ui.warn(_("saving bundle to %s\n") % name)
    return changegroup.writebundle(cg, name, "HG10BZ")

def _collectfiles(repo, striprev):
    """find out the filelogs affected by the strip"""
    files = set()

    for x in xrange(striprev, len(repo)):
        files.update(repo[x].files())

    return sorted(files)

def _collectextranodes(repo, files, link):
    """return the nodes that have to be saved before the strip"""
    def collectone(revlog):
        extra = []
        startrev = count = len(revlog)
        # find the truncation point of the revlog
        for i in xrange(count):
            lrev = revlog.linkrev(i)
            if lrev >= link:
                startrev = i + 1
                break

        # see if any revision after that point has a linkrev less than link
        # (we have to manually save these guys)
        for i in xrange(startrev, count):
            node = revlog.node(i)
            lrev = revlog.linkrev(i)
            if lrev < link:
                extra.append((node, cl.node(lrev)))

        return extra

    extranodes = {}
    cl = repo.changelog
    extra = collectone(repo.manifest)
    if extra:
        extranodes[1] = extra
    for fname in files:
        f = repo.file(fname)
        extra = collectone(f)
        if extra:
            extranodes[fname] = extra

    return extranodes

def strip(ui, repo, node, backup="all"):
    cl = repo.changelog
    # TODO delete the undo files, and handle undo of merge sets
    striprev = cl.rev(node)

    # 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((striprev,))
    saveheads = set()
    savebases = []
    for r in xrange(striprev + 1, len(cl)):
        parents = cl.parentrevs(r)
        if parents[0] in tostrip or parents[1] in tostrip:
            # r is a descendant of striprev
            tostrip.add(r)
            # if this is a merge and one of the parents does not descend
            # from striprev, mark that parent as a savehead.
            if parents[1] != nullrev:
                for p in parents:
                    if p not in tostrip and p > striprev:
                        saveheads.add(p)
        else:
            # if no parents of this revision will be stripped, mark it as
            # a savebase
            if parents[0] < striprev and parents[1] < striprev:
                savebases.append(cl.node(r))

            saveheads.difference_update(parents)
            saveheads.add(r)

    saveheads = [cl.node(r) for r in saveheads]
    files = _collectfiles(repo, striprev)

    extranodes = _collectextranodes(repo, files, striprev)

    # create a changegroup for all the branches we need to keep
    if backup == "all":
        _bundle(repo, [node], cl.heads(), node, 'backup')
    if saveheads or extranodes:
        chgrpfile = _bundle(repo, savebases, saveheads, node, 'temp',
                            extranodes)

    mfst = repo.manifest

    tr = repo.transaction()
    offset = len(tr.entries)

    tr.startgroup()
    cl.strip(striprev, tr)
    mfst.strip(striprev, tr)
    for fn in files:
        repo.file(fn).strip(striprev, tr)
    tr.endgroup()

    try:
        for i in xrange(offset, len(tr.entries)):
            file, troffset, ignore = tr.entries[i]
            repo.sopener(file, 'a').truncate(troffset)
        tr.close()
    except:
        tr.abort()
        raise

    if saveheads or extranodes:
        ui.status(_("adding branch\n"))
        f = open(chgrpfile, "rb")
        gen = changegroup.readbundle(f, chgrpfile)
        repo.addchangegroup(gen, 'strip', 'bundle:' + chgrpfile, True)
        f.close()
        if backup != "strip":
            os.unlink(chgrpfile)

    repo.destroyed()