Add new convert-repo script
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Add new convert-repo script
This is the beginnings of a generalized framework for converting
repositories. Currently hardwired to convert from git to hg.
manifest hash: dc3b72de2c45bfdaffcc1cf71da530228793facd
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#!/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
from mercurial import hg, ui
class convert_git:
def __init__(self, path):
self.path = path
def getheads(self):
h = file(self.path + "/.git/HEAD").read()[:-1]
return [h]
def getfile(self, name, rev):
a = file(self.path + ("/.git/objects/%s/%s"
% (rev[:2], rev[2:]))).read()
b = zlib.decompress(a)
if sha.sha(b).hexdigest() != rev: raise "bad hash"
head, text = b.split('\0', 1)
return text
def getchanges(self, version):
path = os.getcwd()
os.chdir(self.path)
fh = os.popen("git-diff-tree -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.getfile("", version) # 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 == "parent": parents.append(v)
return (parents, author, date, message)
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)
hg.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):
p1, p2 = "0"*40, "0"*40
if len(parents) > 0: p1 = parents[0]
if len(parents) > 1: p2 = parents[1]
if len(parents) > 2: raise "the dreaded octopus merge!"
self.repo.rawcommit(files, text, author, dest,
hg.bin(p1), hg.bin(p2))
return hg.hex(self.repo.changelog.tip())
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 = parents.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)
gitpath, hgpath, mapfile = sys.argv[1:]
c = convert(convert_git(gitpath), convert_mercurial(hgpath), mapfile)
c.convert()