contrib/convert-repo

Fix 3-way-merge of original parent, workdir and new parent.

The dirstate has to match what is in the repository (what would be
checked out with 'hg update -C'), because the resulting file may be
identical to the new parent, or it may be completely different.
Previously the dirstate wasn't updated, so if you changed the file to
look like the original parent, it might be considered unmodified
relative to the new parent.

#!/usr/bin/env python
#
# This is a generalized framework for converting between SCM
# repository formats.
#
# In its current form, it's hardcoded to convert incrementally between
# git and Mercurial.
#
# To use, you must first import the first git version into Mercurial,
# and establish a mapping between the git commit hash and the hash in
# Mercurial for that version. This mapping is kept in a simple text
# file with lines like so:
#
# <git hash> <mercurial hash>
#
# To convert the rest of the repo, run:
#
# convert-repo <git-dir> <hg-dir> <mapfile>
#
# This updates the mapfile on each commit copied, so it can be
# interrupted and can be run repeatedly to copy new commits.

import sys, os, zlib, sha, time
from mercurial import hg, ui, util

class convert_git:
    def __init__(self, path):
        self.path = path

    def getheads(self):
        h = file(self.path + "/.git/HEAD").read()[:-1]
        return [h]

    def catfile(self, rev, type):
        if rev == "0" * 40: raise IOError()
        path = os.getcwd()
        os.chdir(self.path)
        fh = os.popen("git-cat-file %s %s 2>/dev/null" % (type, rev))
        os.chdir(path)
        return fh.read()

    def getfile(self, name, rev):
        return self.catfile(rev, "blob")

    def getchanges(self, version):
        path = os.getcwd()
        os.chdir(self.path)
        fh = os.popen("git-diff-tree --root -m -r %s" % (version))
        os.chdir(path)

        changes = []
        for l in fh:
            if "\t" not in l: continue
            m, f = l[:-1].split("\t")
            m = m.split()
            h = m[3]
            p = (m[1] == "100755")
            changes.append((f, h, p))
        return changes

    def getcommit(self, version):
        c = self.catfile(version, "commit") # read the commit hash
        end = c.find("\n\n")
        message = c[end+2:]
        l = c[:end].splitlines()
        manifest = l[0].split()[1]
        parents = []
        for e in l[1:]:
            n,v = e.split(" ", 1)
            if n == "author":
                p = v.split()
                date = " ".join(p[-2:])
                author = " ".join(p[:-2])
                if author[0] == "<": author = author[1:-1]
            if n == "committer":
                p = v.split()
                date = " ".join(p[-2:])
                committer = " ".join(p[:-2])
                if committer[0] == "<": committer = committer[1:-1]
                message += "\ncommitter: %s %s\n" % (committer, date)
            if n == "parent": parents.append(v)
        return (parents, author, date, message)

    def gettags(self):
        tags = {}
        for f in os.listdir(self.path + "/.git/refs/tags"):
            try:
                h = file(self.path + "/.git/refs/tags/" + f).read().strip()
                p, a, d, m = self.getcommit(h)
                if not p: p = [h] # git is ugly, don't blame me
                tags[f] = p[0]
            except:
                pass
        return tags

class convert_mercurial:
    def __init__(self, path):
        self.path = path
        u = ui.ui()
        self.repo = hg.repository(u, path)

    def getheads(self):
        h = self.repo.changelog.heads()
        h = [ hg.hex(x) for x in h ]
        return h

    def putfile(self, f, e, data):
        self.repo.wfile(f, "w").write(data)
        if self.repo.dirstate.state(f) == '?':
            self.repo.dirstate.update([f], "a")

        util.set_exec(self.repo.wjoin(f), e)

    def delfile(self, f):
        try:
            os.unlink(self.repo.wjoin(f))
            #self.repo.remove([f])
        except:
            pass

    def putcommit(self, files, parents, author, dest, text):
        seen = {}
        pl = []
        for p in parents:
            if p not in seen:
                pl.append(p)
                seen[p] = 1
        parents = pl

        if len(parents) < 2: parents.append("0" * 40)
        if len(parents) < 2: parents.append("0" * 40)
        p2 = parents.pop(0)

        while parents:
            p1 = p2
            p2 = parents.pop(0)
            self.repo.rawcommit(files, text, author, dest,
                                hg.bin(p1), hg.bin(p2))
            text = "(octopus merge fixup)\n"

        return hg.hex(self.repo.changelog.tip())

    def puttags(self, tags):
        try:
            old = self.repo.wfile(".hgtags").read()
            oldlines = old.splitlines(1)
            oldlines.sort()
        except:
            oldlines = []

        k = tags.keys()
        k.sort()
        newlines = []
        for tag in k:
            newlines.append("%s %s\n" % (tags[tag], tag))

        newlines.sort()

        if newlines != oldlines:
            print "updating tags"
            f = self.repo.wfile(".hgtags", "w")
            f.write("".join(newlines))
            f.close()
            if not oldlines: self.repo.add([".hgtags"])
            date = "%s 0" % time.mktime(time.gmtime())
            self.repo.rawcommit([".hgtags"], "update tags", "convert-repo",
                                date, self.repo.changelog.tip(), hg.nullid)

class convert:
    def __init__(self, source, dest, mapfile):
        self.source = source
        self.dest = dest
        self.mapfile = mapfile
        self.commitcache = {}

        self.map = {}
        for l in file(self.mapfile):
            sv, dv = l[:-1].split()
            self.map[sv] = dv

    def walktree(self, heads):
        visit = heads
        known = {}
        parents = {}
        while visit:
            n = visit.pop(0)
            if n in known or n in self.map: continue
            known[n] = 1
            self.commitcache[n] = self.source.getcommit(n)
            cp = self.commitcache[n][0]
            for p in cp:
                parents.setdefault(n, []).append(p)
                visit.append(p)

        return parents

    def toposort(self, parents):
        visit = parents.keys()
        seen = {}
        children = {}

        while visit:
            n = visit.pop(0)
            if n in seen: continue
            seen[n] = 1
            pc = 0
            if n in parents:
                for p in parents[n]:
                    if p not in self.map: pc += 1
                    visit.append(p)
                    children.setdefault(p, []).append(n)
            if not pc: root = n

        s = []
        removed = {}
        visit = children.keys()
        while visit:
            n = visit.pop(0)
            if n in removed: continue
            dep = 0
            if n in parents:
                for p in parents[n]:
                    if p in self.map: continue
                    if p not in removed:
                        # we're still dependent
                        visit.append(n)
                        dep = 1
                        break

            if not dep:
                # all n's parents are in the list
                removed[n] = 1
                s.append(n)
                if n in children:
                    for c in children[n]:
                        visit.insert(0, c)

        return s

    def copy(self, rev):
        p, a, d, t = self.commitcache[rev]
        files = self.source.getchanges(rev)

        for f,v,e in files:
            try:
                data = self.source.getfile(f, v)
            except IOError, inst:
                self.dest.delfile(f)
            else:
                self.dest.putfile(f, e, data)

        r = [self.map[v] for v in p]
        f = [f for f,v,e in files]
        self.map[rev] = self.dest.putcommit(f, r, a, d, t)
        file(self.mapfile, "a").write("%s %s\n" % (rev, self.map[rev]))

    def convert(self):
        heads = self.source.getheads()
        parents = self.walktree(heads)
        t = self.toposort(parents)
        num = len(t)

        for c in t:
            num -= 1
            if c in self.map: continue
            desc = self.commitcache[c][3].splitlines()[0]
            print num, desc
            self.copy(c)

        tags = self.source.gettags()
        ctags = {}
        for k in tags:
            v = tags[k]
            if v in self.map:
                ctags[k] = self.map[v]

        self.dest.puttags(ctags)

gitpath, hgpath, mapfile = sys.argv[1:]

c = convert(convert_git(gitpath), convert_mercurial(hgpath), mapfile)
c.convert()