mercurial/repair.py

hgweb: be sure to drain request data even in early error conditions

Thanks to Mads Kiilerich with noticing this. The hg client can only read data
after all the sent data has been read, so we have to read all the request data
even if we're not going to do anything with it (in error conditions). This
is not easy to fix in the client, because we're using Python's httplib, which
is strictly stateful. Abstracted the draining into a separate method.

# 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, incorporated herein by reference.

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

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 = {}

    for x in xrange(striprev, len(repo)):
        for name in repo[x].files():
            if name in files:
                continue
            files[name] = 1

    files = files.keys()
    files.sort()
    return 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(0, count):
            node = revlog.node(i)
            lrev = revlog.linkrev(node)
            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(node)
            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 = {striprev: 1}
    saveheads = {}
    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[r] = 1
            # 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[p] = 1
        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))

            for p in parents:
                if p in saveheads:
                    del saveheads[p]
            saveheads[r] = 1

    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)

    cl.strip(striprev)
    repo.manifest.strip(striprev)
    for name in files:
        f = repo.file(name)
        f.strip(striprev)

    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)