Initial import

This is the initial import of 'hg2git' being a converter which feeds a
hg repository into git-fast-import(1).

hg2git.py

@@ -0,0 +1,230 @@
+#!/usr/bin/env python
+
+# Copyright (c) 2007 Rocco Rutte <pdmef@gmx.net>
+# License: GPLv2
+
+"""hg2git.py - A mercurial-to-git filter for git-fast-import(1)
+Usage: hg2git.py <hg repo url> <marks file> <heads file> <tip file>
+"""
+
+from mercurial import repo,hg,cmdutil,util,ui,revlog
+from tempfile import mkstemp
+import re
+import sys
+import os
+
+# silly regex to see if user field has email address
+user_re=re.compile('[^<]+ <[^>]+>$')
+# git branch for hg's default 'HEAD' branch
+cfg_master='master'
+# insert 'checkpoint' command after this many commits
+cfg_checkpoint_count=1000
+
+def usage(ret):
+  sys.stderr.write(__doc__)
+  return ret
+
+def setup_repo(url):
+  myui=ui.ui()
+  return myui,hg.repository(myui,url)
+
+def get_changeset(ui,repo,revision):
+  def get_branch(name):
+    if name=='HEAD':
+      name=cfg_master
+    return name
+  def fixup_user(user):
+    if user_re.match(user)==None:
+      if '@' not in user:
+        return user+' <none@none>'
+      return user+' <'+user+'>'
+    return user
+  node=repo.lookup(revision)
+  (manifest,user,(time,timezone),files,desc,extra)=repo.changelog.read(node)
+  tz="%+03d%02d" % (-timezone / 3600, ((-timezone % 3600) / 60))
+  branch=get_branch(extra.get('branch','master'))
+  return (manifest,fixup_user(user),(time,tz),files,desc,branch,extra)
+
+def gitmode(x):
+  return x and '100755' or '100644'
+
+def wr(msg=''):
+  print msg
+  #map(lambda x: sys.stderr.write('\t[%s]\n' % x),msg.split('\n'))
+
+def checkpoint(count):
+  count=count+1
+  if count%cfg_checkpoint_count==0:
+    sys.stderr.write("Checkpoint after %d commits\n" % count)
+    wr('checkpoint')
+    wr()
+  return count
+
+def get_parent_mark(parent,marks):
+  p=marks.get(str(parent),None)
+  if p==None:
+    # if we didn't see parent previously, assume we saw it in this run
+    p=':%d' % (parent+1)
+  return p
+
+def export_commit(ui,repo,revision,marks,heads,last,max,count):
+  sys.stderr.write('Exporting revision %d (tip %d) as [:%d]\n' % (revision,max,revision+1))
+
+  (_,user,(time,timezone),files,desc,branch,_)=get_changeset(ui,repo,revision)
+  parents=repo.changelog.parentrevs(revision)
+
+  # we need this later to write out tags
+  marks[str(revision)]=':%d'%(revision+1)
+
+  wr('commit refs/heads/%s' % branch)
+  wr('mark :%d' % (revision+1))
+  wr('committer %s %d %s' % (user,time,timezone))
+  wr('data %d' % (len(desc)+1)) # wtf?
+  wr(desc)
+  wr()
+
+  src=heads.get(branch,'')
+  link=''
+  if src!='':
+    # if we have a cached head, this is an incremental import: initialize it
+    # and kill reference so we won't init it again
+    wr('from %s' % src)
+    heads[branch]=''
+  elif not heads.has_key(branch) and revision>0:
+    # newly created branch and not the first one: connect to parent
+    tmp=get_parent_mark(parents[0],marks)
+    wr('from %s' % tmp)
+    sys.stderr.write('Link new branch [%s] to parent [%s]\n' %
+        (branch,tmp))
+    link=tmp # avoid making a merge commit for branch fork
+
+  if parents:
+    l=last.get(branch,revision)
+    for p in parents:
+      # 1) as this commit implicitely is the child of the most recent
+      #    commit of this branch, ignore this parent
+      # 2) ignore nonexistent parents
+      # 3) merge otherwise
+      if p==l or p==revision or p<0:
+        continue
+      tmp=get_parent_mark(p,marks)
+      # if we fork off a branch, don't merge via 'merge' as we have
+      # 'from' already above
+      if tmp==link:
+        continue
+      sys.stderr.write('Merging branch [%s] with parent [%s] from [r%d]\n' %
+          (branch,tmp,p))
+      wr('merge %s' % tmp)
+
+  last[branch]=revision
+  heads[branch]=''
+
+  ctx=repo.changectx(str(revision))
+  man=ctx.manifest()
+
+  wr('deleteall')
+
+  for f in man.keys():
+    fctx=ctx.filectx(f)
+    d=fctx.data()
+    wr('M %s inline %s' % (gitmode(man.execf(f)),f))
+    wr('data %d' % len(d)) # had some trouble with size()
+    wr(d)
+
+  wr()
+  return checkpoint(count)
+
+def export_tags(ui,repo,cache,count):
+  l=repo.tagslist()
+  for tag,node in l:
+    if tag=='tip':
+      continue
+    rev=repo.changelog.rev(node)
+    ref=cache.get(str(rev),None)
+    if ref==None:
+      sys.stderr.write('Failed to find reference for creating tag'
+          ' %s at r%d\n' % (tag,rev))
+      continue
+    (_,user,(time,timezone),_,desc,branch,_)=get_changeset(ui,repo,rev)
+    sys.stderr.write('Exporting tag [%s] at [hg r%d] [git %s]\n' % (tag,rev,ref))
+    wr('tag %s' % tag)
+    wr('from %s' % ref)
+    wr('tagger %s %d %s' % (user,time,timezone))
+    msg='hg2git created tag %s for hg revision %d on branch %s on (summary):\n\t%s' % (tag,
+        rev,branch,desc.split('\n')[0])
+    wr('data %d' % (len(msg)+1))
+    wr(msg)
+    wr()
+    count=checkpoint(count)
+  return count
+
+def load_cache(filename):
+  cache={}
+  if not os.path.exists(filename):
+    return cache
+  f=open(filename,'r')
+  l=0
+  for line in f.readlines():
+    l+=1
+    fields=line.split(' ')
+    if fields==None or not len(fields)==2 or fields[0][0]!=':':
+      sys.stderr.write('Invalid file format in [%s], line %d\n' % (filename,l))
+      continue
+    # put key:value in cache, key without ^:
+    cache[fields[0][1:]]=fields[1].split('\n')[0]
+  f.close()
+  return cache
+
+def save_cache(filename,cache):
+  f=open(filename,'w+')
+  map(lambda x: f.write(':%s %s\n' % (str(x),str(cache.get(x)))),cache.keys())
+  f.close()
+
+def verify_heads(ui,repo,cache):
+  def getsha1(branch):
+    f=open(os.getenv('GIT_DIR','/dev/null')+'/refs/heads/'+branch)
+    sha1=f.readlines()[0].split('\n')[0]
+    f.close()
+    return sha1
+
+  for b in cache.keys():
+    sys.stderr.write('Verifying branch [%s]\n' % b)
+    sha1=getsha1(b)
+    c=cache.get(b)
+    if sha1!=c:
+      sys.stderr.write('Warning: Branch [%s] modified outside hg2git:'
+        '\n%s (repo) != %s (cache)\n' % (b,sha1,c))
+  return True
+
+if __name__=='__main__':
+  if len(sys.argv)!=6: sys.exit(usage(1))
+  repourl,m,marksfile,headsfile,tipfile=sys.argv[1:]
+  _max=int(m)
+
+  marks_cache=load_cache(marksfile)
+  heads_cache=load_cache(headsfile)
+  state_cache=load_cache(tipfile)
+
+  ui,repo=setup_repo(repourl)
+
+  if not verify_heads(ui,repo,heads_cache):
+    sys.exit(1)
+
+  tip=repo.changelog.count()
+
+  min=int(state_cache.get('tip',0))
+  max=_max
+  if _max<0:
+    max=tip
+
+  c=int(state_cache.get('count',0))
+  last={}
+  for rev in range(min,max):
+    c=export_commit(ui,repo,rev,marks_cache,heads_cache,last,tip,c)
+
+  c=export_tags(ui,repo,marks_cache,c)
+
+  state_cache['tip']=max
+  state_cache['count']=c
+  state_cache['repo']=repourl
+  save_cache(tipfile,state_cache)