patchfast importer for SCCS files

diff --git a/contrib/fast-import/git-sccsimport.py b/contrib/fast-import/git-sccsimport.py
new file mode 100755
index 0000000..06980d8
--- /dev/null
+++ b/contrib/fast-import/git-sccsimport.py
@@ -0,1 +1,733 @@
+#!/usr/bin/env python
+#
+# git-sccsimport.py -- Imports SCCS files into git
+#
+# Author: James Youngman <jay@gnu.org>
+# Copyright: 2008 James Youngman <jay@gnu.org>
+# License: GNU GPL version 2 or later <http://www.gnu.org/licenses/old-licenses/gpl-2.0.html>
+#
+"""
+A fast git importer for SCCS files.
+
+How to use this program:
+
+Let's assume you have some SCCS files in $PROJECTDIR and want to
+convert them to a git repository in the directory $NEWGIT.
+
+First, make sure the SCCS (or CSSC) binaries are on your $PATH.  Then
+do this:
+
+  cd "$PROJECTDIR"
+  python git-sccsimport.py --init --git-dir="$NEWGIT" --dirs .
+
+Notice that git-sccsimport is being run with its working
+directory as the root of the tree of SCCS files.  This is
+becaue the relative path from your working directory to the
+SCCS file is also used as the name of the file in the resulting
+git repository.
+
+I tried this on a 32M code repository in SCCS and it produced a
+36M git repository. 
+"""
+import datetime
+import errno
+import optparse
+import os
+import os.path
+import re
+import stat
+import subprocess
+import sys
+import time
+
+GET = "get"
+PRS = "prs"
+SCCS_ESCAPE = chr(1)
+TIMEZONE = None
+MAIL_DOMAIN = None
+UNIX_EPOCH = time.mktime(datetime.datetime(1970, 1, 1,
+											0, 0, 0, 0,
+											None).timetuple())
+IMPORT_REF = None
+
+
+# Two checkins separated by more than FUZZY_WINDOW
+# will never be considered part of the same commit.
+FUZZY_WINDOW = 300.0
+
+
+verbose = False
+
+
+class ImportFailure(Exception):
+  pass
+
+class UsageError(Exception):
+  pass
+
+class AbstractClassError(Exception):
+  pass
+
+def Usage(who, retval, f, e):
+  if e:
+	 print >>f, e
+  print >>f, ("usage: %s sccs-file [sccs-file...]"
+			   % (who,))
+  if retval:
+	 sys.exit(retval)
+  return retval
+
+
+def NotImporting(file, sid, reason):
+  if sid:
+	 msg = ("%s: not importing SID %s: %s"
+			% (file, sid, reason))
+  else:
+	 msg = ("%s: not importing this file: %s"
+			% (file, reason))
+  print >> sys.stderr, msg
+
+
+def DiagnoseCommandFailure(command, returncode, errors):
+  if not errors:
+	 errors = ""
+  if returncode < 0:
+	 msg = ("%s %s killed by signal %s" % command, -(returncode))
+  else:
+	 msg = ("%s %s returned exit status %s" % command, returncode)
+  raise ImportFailure, "%s\n%s" % (errors, msg)
+	 
+
+def RunCommand(commandline):
+  try:
+	 if verbose:
+	   msg = ("Running command: %s\n"
+			  % (" ".join(commandline),))
+	   sys.stderr.write(msg)
+	 child = subprocess.Popen(commandline,
+							  close_fds = True,
+							  stdin =subprocess.PIPE,
+							  stdout=subprocess.PIPE,
+							  stderr=subprocess.PIPE)
+	 output, errors = child.communicate(None)
+	 if child.returncode != 0:
+	   # Some stderr output is normal (warnings, etc.)
+	   DiagnoseCommandFailure(commandline[0], child.returncode, errors)
+	 else:
+	   return output
+  except OSError, oe:
+	 msg = ("Failed to run '%s': %s (%s)"
+			% (commandline[0], oe,
+			   errno.errorcode[oe.errno]))
+	 raise ImportFailure, msg
+		 
+
+	 
+
+def GetBody(sfile, seqno, expand_keywords):
+  options = [GET, "-p", "-s", ("-a%d" % seqno)]
+  if not expand_keywords:
+	 options.append("-k")
+  options.append(sfile)
+  return RunCommand(options)
+	 
+
+def FileMode(filename):
+  return stat.S_IMODE(os.stat(filename).st_mode)
+
+
+class SccsFileQueryBase(object):
+  @staticmethod
+  def HeaderLines(filename):
+	 header_end = "^%cT" % (SCCS_ESCAPE,)
+	 result = []
+	 try:
+	   f = open(filename, "rb")
+	   for line in f.readlines():
+		 if line.startswith(header_end):
+		   break
+		 else:
+		   result.append(line)
+	   return result
+	 finally:
+	   f.close()
+
+		 
+
+#class SccsFileQuerySlow(SccsFileQueryBase):
+#	"""Extract information from SCCS files by running prs."""
+#	@staticmethod
+#	def RunPrs(options):
+#	  commandline = [PRS]
+#	  commandline.extend(options)
+#	  return RunCommand(commandline)
+#	
+#	@staticmethod
+#	def FetchDeltaProperties(sid, filename):
+#	  fmt = (":Dy:/:Dm:/:Dd:%(esc)c"  # 0 delta creation date
+#			 ":Th:::Tm:::Ts:%(esc)c"  # 1 delta creation time (24h)
+#			 ":C:%(esc)c"			  # 2 checkin comments
+#			 ":DS:%(esc)c"			  # 3 seqno
+#			 ":DP:%(esc)c"			  # 4 parent seqno
+#			 ":DT:%(esc)c"			  # 5 delta type (R or D)
+#			 ":I:%(esc)c"			  # 6 SID
+#			 ":MR:%(esc)c"			  # 7 MR numbers
+#			 ":P:%(esc)c"			  # 8 Perpetrator (committer)
+#			 % { 'esc': SCCS_ESCAPE })
+#	  cmdline = [("-d%s" % fmt), ("-r%s" % sid), filename]
+#	  propdata = SccsFileQuerySlow.RunPrs(cmdline)
+#	  return propdata.split(SCCS_ESCAPE)
+#
+#	@staticmethod
+#	def IsValidSccsFile(filename):
+#	  try:
+#		output = SccsFileQuerySlow.RunPrs(["-d:F: ", filename])
+#		return True
+#	  except ImportFailure:
+#		return False
+#	  
+#	@staticmethod
+#	def GetRevisionList(filename):
+#	  revisions = SccsFileQuerySlow.RunPrs(["-d:I: ", "-e", filename])
+#	  return revisions.split()
+
+
+class SccsFileQueryFast(SccsFileQueryBase):
+  """Extract information from SCCS files by parsing them directly."""
+  DELTA_RE = re.compile("^%cd D ([.0-9]*)" % (SCCS_ESCAPE,))
+
+  @staticmethod
+  def IsValidSccsFile(filename):
+	 try:
+	   f = open(filename, "rb")
+	   header = f.read(2)
+	   return header[0] == SCCS_ESCAPE and header[1] == 'h'
+	 finally:
+	   f.close()
+
+  @staticmethod
+  def GetRevisionList(filename):
+	 result = []
+	 header_end = "^%cT" % (SCCS_ESCAPE,)
+	 for line in SccsFileQueryBase.HeaderLines(filename):
+	   m = SccsFileQueryFast.DELTA_RE.match(line)
+	   if m:
+		 result.append(m.group(1))
+	 return result
+
+  @staticmethod
+  def FetchDeltaProperties(sid, filename):
+	 found = False
+	 props = []
+	 comments = []
+	 comment_leader = "%cc" % (SCCS_ESCAPE,)
+	 for line in SccsFileQueryBase.HeaderLines(filename):
+	   if not found:
+		 m = SccsFileQueryFast.DELTA_RE.match(line)
+		 if m and (sid == m.group(1)):
+		   found = True
+		   fields = line.split()
+		   props = [ fields[3],
+					 fields[4],
+					 None, # checkin comment
+					 fields[6],
+					 fields[7],
+					 'D',
+					 fields[2],
+					 "",	   # MR list
+					 fields[5],
+					 "yodel"
+					 ]
+		   continue
+		 else:
+		   if found:
+			 if line.startswith(comment_leader):
+			   comments.append(line[3:])
+			 else:
+			   break
+	 if found:
+	   props[2] = "\n".join(comments)
+	   # print >> sys.stderr, "props: %s" % (props,)
+	   return props
+	 else:
+	   return None
+
+
+def SccsFileQuery():
+  """Factory method for objects that query SccsFileQuery objects"""
+  return SccsFileQueryFast()
+
+
+class Delta(object):
+  """Represents the properties of an SCCS delta that we
+  import into git."""
+  def __init__(self, sccsfile, sid, qif, *args, **kwargs):
+	 super(Delta, self).__init__(*args, **kwargs)
+	 self._sccsfile = sccsfile
+	 self._sid		= sid
+	 self._qif = qif
+	 self.FetchDeltaProperties()
+
+  def __repr__(self):
+	 return 'Delta(%s, "%s")' % (repr(self._sccsfile), self._sid)
+
+  def FetchDeltaProperties(self):
+	 """Query the properties of this delta from the SCCS file."""
+	 props = self._qif.FetchDeltaProperties(self._sid,
+											self._sccsfile._filename)
+	 assert len(props)>1, "%s %s %s" % (self._sccsfile._filename, self._sid, props)
+	 self.SetTimestamp(props[0], props[1])
+	 (self._comment, self._seqno, self._parent_seqno, self._type,
+	  sidcheck, mrlist, self._comitter, _) = props[2:]
+		 
+	 self._seqno = int(self._seqno)
+	 self._parent_seqno = int(self._parent_seqno)
+	 if self._comment == "\n":
+		 self._comment = None
+	 assert sidcheck==self._sid
+	 self._mrs = mrlist.split()
+
+  def SameFuzzyCommit(self, other):
+	 #print >>sys.stderr, ("SameFuzzyCommit: comparing\n1: %s with\n2: %s"
+	 #					   % (self, other))
+	 if self._comment != other._comment:
+	   return False
+	 elif self._comitter != other._comitter:
+	   return False
+	 elif self._mrs != other._mrs:
+	   return False
+	 else:
+	   delta = abs(other._timestamp - self._timestamp)
+	   if delta > FUZZY_WINDOW:
+		 return False
+	   else:
+		 return True
+
+  def SetTimestamp(self, checkin_date, checkin_time):
+	   try:
+		 year, month, monthday = [int(f) for f in checkin_date.split("/")]
+	   except ValueError:
+		 raise ImportFailure, ("Unexpected date format: %s"
+							   % (checkin_date,))
+	   try:
+		 h,m,s = [int(f) for f in checkin_time.split(":")]
+	   except ValueError:
+		 raise ImportFailure, ("Unexpected time format: %s"
+							   % (checkin_time,))
+	   microsec = 0
+
+	   if year < 100:
+		 # Apply the y2k rule (see the "Year 2000 Issues" section
+		 # of the CSSC documentation).
+		 if year < 69:
+		   year += 2000
+		 else:
+		   year += 1900
+
+	   dt = datetime.datetime(year, month, monthday,
+							  h, m, s,
+							  microsec, TIMEZONE)
+	   epoch_offset = time.mktime(dt.timetuple())
+	   # We subtract UNIX_EPOCH to take account of the fact
+	   # that the system epoch may in fact not be the same as the Unix
+	   # epoch.	 git fast-import requires the timestamp to be measured in
+	   # seconds since the Unix epoch.
+	   self._timestamp = epoch_offset - UNIX_EPOCH
+		 
+  def GitTimestamp(self):
+	 n = int(self._timestamp)
+	 return "%d +0000" % (n,)
+
+
+class SccsFile(object):
+  def __init__(self, name, *args, **kwargs):
+	 super(SccsFile, self).__init__(*args, **kwargs)
+	 self._filename = name
+	 qif = SccsFileQuery()
+	 revisions = filter(self.GoodRevision, qif.GetRevisionList(name))
+	 self._deltas = [Delta(self, sid, qif) for sid in revisions]
+	 self._gitname = self.GitFriendlyName(self._GottenName())
+	 if FileMode(self._filename) & 0111:
+	   self._gitmode = "755"
+	 else:
+	   self._gitmode = "644"
+	 
+  gitname = property(lambda self: self._gitname)
+  gitmode = property(lambda self: self._gitmode)
+  filename = property(lambda self: self._filename)
+
+  @staticmethod
+  def IsValidSccsFile(filename):
+	 qif = SccsFileQuery()
+	 return qif.IsValidSccsFile(filename)
+
+  def __repr__(self):
+	 return "SccsFile(r'%s')" % self._filename
+
+  @staticmethod
+  def GitFriendlyName(name):
+	 """git-fastimport does not like leading or trailing slashes,
+	 or . or .. in file names.	This method removes such things."""
+	 if os.path.isabs(name):
+	   raise ImportFailure, "%s is an absolute path name" % (name,)
+	 drive, path = os.path.splitdrive(name)
+	 return os.path.normpath(path)
+
+  def _GottenName(self):
+	 """Convert the name of an SCCS file to the name of the
+	 working file as would be assumed by make.	Specifically,
+	 the s. prefix is stipped, and if the s.file is in a directory
+	 called SCCS, that directory is stripped out of the path also.
+	 """
+	 head, tail = os.path.split(self._filename)
+	 if tail.startswith("s."):
+	   tail = tail[2:]
+	 dirhead, dirtail = os.path.split(head)
+	 if dirtail == "SCCS":
+	   head = dirhead
+	 return os.path.join(head, tail)
+
+
+  def GoodRevision(self, sid):
+	 comps = sid.split(".")
+	 if len(comps) > 1:
+	   return True
+	 else:
+	   NotImporting(self._filename, sid,
+					"SID contains no level component")
+	   return False
+
+		 
+		 
+
+class GitImporter(object):
+  """Handles communications with git-fast-import."""
+  
+  def __init__(self, *args, **kwargs):
+	 super(GitImporter, self).__init__(*args, **kwargs)
+	 self._next_mark = 1
+	 self._command = None
+	 self._importer = None
+	 self._write_to_stdout = False
+
+  def StartImporter(self):
+	 args = ["git","fast-import"]
+	 self._command = " ".join(args)
+	 self._importer = subprocess.Popen(args,
+									   close_fds=True,
+									   stdin=subprocess.PIPE)
+
+  def SendToStdout(self):
+	 self._command = None
+	 self._importer = None
+	 self._write_to_stdout = True
+
+  def GetNextMark(self):
+	 """Get the next unused idnum for a mark statement."""
+	 result = self._next_mark
+	 self._next_mark += 1
+	 return result
+
+  def Write(self, s):
+	 """Write some data to the importer."""
+	 if self._write_to_stdout:
+	   sys.stdout.write(s)
+	 else:
+	   assert self._importer
+	   self._importer.stdin.write(s)
+	   
+  def Done(self):
+	 if self._importer:
+	   self._importer.stdin.close()
+	   returncode = self._importer.wait()
+	   if returncode != 0:
+		 DiagnoseCommandFailure(self._command, returncode, None)
+	   else:
+		 print >>sys.stderr, ("%s completed successfully"
+							  % (self._command,))
+		 
+  def ProgressMsg(self, msg):
+	 """Emit a progress message for the user."""
+	 sys.stderr.write(msg)
+
+  def Progress(self, done, items):
+	 """Inform the user of our current progress."""
+	 percent = (100.0 * float(done)) / float(items)
+	 if done == items:
+	   tail = " done\n"
+	 else:
+	   tail = ""
+	 msg = "\r %3.0f%% (%d/%d)%s" % (percent, done, items, tail)
+	 self.ProgressMsg(msg)
+
+  def GetUserEmailAddress(self, login_name):
+	 """Get an email address corresponding to the given login name."""
+	 if MAIL_DOMAIN:
+	   return "%s@$s" % (login_name,MAIL_DOMAIN)
+	 else:
+	   return login_name
+
+  def WriteData(self, data):
+	 """Emit a data command followd by a blob of data."""
+	 self.Write("data %d\n" % (len(data),))
+	 self.Write(data)
+	 self.Write("\n")
+			 
+  def BeginCommit(self, delta, parent):
+	 """Start a new commit (having the indicated parent)."""
+	 mark = self.GetNextMark()
+	 self.Write("commit %s\nmark :%d\n" % (IMPORT_REF, mark))
+	 ts = delta.GitTimestamp()
+	 self.Write("committer %s <%s> %s\n"
+				% (delta._comitter,
+				   self.GetUserEmailAddress(delta._comitter),
+				   ts))
+	 if delta._comment:
+	   self.WriteData(delta._comment)
+	 else:
+	   self.WriteData("")		   # commit comment is mandatory
+	 if parent:
+	   self.Write("from :%d\n" % (parent,))
+	 return mark
+
+  def Filemodify(self, sfile, body):
+	 """Write a filemodify section of a commit."""
+	 self.Write("M %s inline %s\n" % (sfile.gitmode, sfile.gitname))
+	 self.WriteData(body)
+
+  def CompleteCommit(self):
+	 """Write the final part of a commit."""
+	 self.Write("\n")
+		 
+# TODO: if the fuzzy commit logic puts subsequent deltas into the same
+# commit, the timestamp of the commit is that of the first delta.	One
+# could argue that the timestamp of the last one would be a better
+# choice.
+
+def ImportDeltas(imp, deltas):
+  if not deltas:
+	 raise ImportFailure, "No deltas to import"
+  first_delta_in_commit = None
+  done = 0
+  imp.ProgressMsg("Creating commits...\n")
+  parent = None
+  commit_count = 0
+  for d in deltas:
+	 imp.Progress(done, len(deltas))
+	 done += 1
+	 # Figure out if we need to start a new commit.
+	 if first_delta_in_commit:
+	   if not first_delta_in_commit.SameFuzzyCommit(d):
+		 imp.CompleteCommit()
+		 first_delta_in_commit = None
+	 if first_delta_in_commit is None:
+	   first_delta_in_commit = d
+	   current = imp.BeginCommit(d, parent)
+	   commit_count += 1
+	   parent = current
+	 # We're now in a commit.  Emit the body for this delta.
+	 body = GetBody(d._sccsfile._filename, d._seqno, False)
+	 imp.Filemodify(d._sccsfile, body)
+  # Finished looping over deltas
+  if parent:
+	   imp.CompleteCommit()
+  imp.Progress(done, len(deltas))
+  print >>sys.stderr, ("%d SCCS deltas in %d git commits"
+						% (len(deltas), commit_count))
+
+
+def Import(filenames, stdout):
+  """Import the indicated SCCS files into git."""
+  for filename in filenames:
+	 if not os.access(filename, os.R_OK):
+	   msg = "%s is not readable" % (filename,)
+	   raise ImportFailure, msg
+	 if not os.path.isfile(filename):
+	   msg = "%s is not a file" % (filename,)
+	   raise ImportFailure, msg
+  sccsfiles = []
+  done = 0
+  imp = GitImporter()
+  imp.ProgressMsg("Reading metadata from SCCS files...\n")
+  for filename in filenames:
+	 try:
+	   imp.Progress(done, len(filenames))
+	   if SccsFile.IsValidSccsFile(filename):
+		 sf = SccsFile(filename)
+		 sccsfiles.append(sf)
+	   else:
+		 NotImporting(filename, None, "not a valid SCCS file")
+	   done += 1
+	 except ImportFailure:
+	   msg = ("\nAn import failure occurred while processing %s"
+			  % (filename,))
+	   print >> sys.stderr, msg
+	   raise
+  imp.Progress(done, len(filenames))
+  # Now we have all the metadata; sort the deltas by timestamp
+  # and import the deltas in time order.
+  delta_list = []
+  for sfile in sccsfiles:
+	 for delta in sfile._deltas:
+	   ts = "%15f" % (delta._timestamp,)
+	   t = (ts, delta)
+	   delta_list.append(t)
+  delta_list.sort()
+
+  if stdout:
+	 imp.SendToStdout()
+  else:
+	 imp.StartImporter()
+  try:
+	 ImportDeltas(imp, [d[1] for d in delta_list])
+  finally:
+	 imp.Done()
+
+
+def IsValidGitDir(path):
+  """Returns True IFF path is a valid git repo.
+
+  Copied from git-p4.
+  """
+  if (os.path.exists(path + "/HEAD")
+	   and os.path.exists(path + "/refs")
+	   and os.path.exists(path + "/objects")):
+	 return True;
+  return False
+
+
+def FindGitDir(gitdir, init):
+  """Locate the git repository."""
+  if not gitdir:
+	 gitdir = RunCommand(["git", "rev-parse", "--git-dir"])
+	 if gitdir:
+	   gitdir = gitdir.strip()
+	 else:
+	   cdup = RunCommand(["git", "rev-parse", "--show-cdup"])
+	   if cdup:
+		 gitdir = os.path.abspath(cdup.strip())
+	   else:
+		 gitdir = "."
+  if init:
+	 # Do a sanity check that we're not about to create /.git.
+	 assert gitdir
+	 if not gitdir.endswith("/.git"):
+	   gitdir += "/.git"
+	 if IsValidGitDir(gitdir):
+	   raise ImportFailure, ("Git repository %s was already initialised"
+							 % (gitdir,))
+	 else:
+	   RunCommand(["git", "--git-dir=%s" % (gitdir,), "init"])
+	   
+  if not IsValidGitDir(gitdir):
+	 gitdir += "/.git"
+	 if not IsValidGitDir(gitdir):
+	   raise ImportFailure, ("cannot locate git repository at %s" %
+							 (gitdir,))
+  print >> sys.stderr, "git repository is at", gitdir
+  return gitdir
+
+
+def MakeDirWorklist(dirs):
+  result = []
+  for dirname in dirs:
+	 for root, subdirs, files in os.walk(dirname):
+	   for f in files:
+		 if f.startswith("s."):
+		   physpath = os.path.join(root, f)
+		   if os.access(physpath, os.R_OK):
+			 result.append(physpath)
+  if not result:
+	 print >>sys.stderr, ("Warning: No SCCS files were found in %s"
+						  % (" ".join(dirs)))
+  return result
+
+
+def ParseOptions(argv):
+  global IMPORT_REF
+  global MAIL_DOMAIN
+  global FUZZY_WINDOW
+  global verbose
+  parser = optparse.OptionParser()
+  parser.add_option("--branch",
+					 help="branch to populate",
+					 default="master")
+  parser.add_option("--maildomain",
+					 help="Mail domain for usernames taken from SCCS files")
+  parser.add_option("--fuzzy-commit-window",
+					 default=FUZZY_WINDOW,
+					 help=("Deltas more than this many seconds apart "
+						   "are always considered to be in different commits"))
+  parser.add_option("--git-dir",
+					 help="Directory containing the git repository")
+  parser.add_option("--init", default=False, action="store_true",
+					 help="Initialise the git repository first")
+  parser.add_option("--verbose", default=False, action="store_true",
+					 help="Print verbose status messages")
+  parser.add_option("--stdout", default=False, action="store_true",
+					 help=("Send git-fast-import data to stdout "
+						   "rather than to git-fast-import"))
+  parser.add_option("--dirs",
+					 action="store_true",
+					 help=("Command-line arguments are a list "
+						   "of directories to automatically search "
+						   "rather than a list of SCCS files"))
+  (options, args) = parser.parse_args(argv)
+  verbose = options.verbose
+  if options.maildomain:
+	 MAIL_DOMAIN = options.maildomain
+  try:
+	 FUZZY_WINDOW = float(options.fuzzy_commit_window)
+  except ValueError:
+	 raise UsageError("The argument for the --fuzzy-commit-window option "
+					  "should be a number, but you specified '%s'"
+					  % (options.fuzzy_commit_window,))
+  IMPORT_REF = "refs/heads/%s" % (options.branch,)
+  return options, args
+
+
+def main(argv):
+  progname = argv[0] or "git-sccsimport"
+  try:
+	 options, args = ParseOptions(argv)
+	 print >>sys.stderr, "Positional args:", " ".join(args)
+	 args = args[1:]
+
+	 if not args:
+	   if options.dirs:
+		 raise UsageError("You did not specify any directories to import from")
+	   else:
+		 raise UsageError("You did not specify any SCCS files to import")
+	 
+	 if options.stdout and options.init:
+	   raise UsageError("The --init option is incompatible "
+						"with the --stdout option")
+
+	 if not options.stdout:
+	   try:
+		 os.environ["GIT_DIR"] = FindGitDir(options.git_dir, options.init)
+	   except ImportFailure, init_failure:
+		 if options.init:
+		   action = "initialise"
+		 else:
+		   action = "locate"
+		   print >>sys.stderr, ("Failed to %s the git repository: %s"
+								% (action, init_failure))
+		   return 1
+
+	 if options.dirs:
+	   items = MakeDirWorklist(args)
+	 else:
+	   items = args
+	 print >>sys.stderr, "Importing items:", " ".join(items)
+	 return Import(items, options.stdout)
+
+  except UsageError, usage_err:
+	 return Usage(progname, 1, sys.stderr, usage_err)
+  except ImportFailure, imp_failure:
+	 print >> sys.stderr, "Import failed: %s" % (imp_failure,)
+	 return 1
+
+
+if __name__ == '__main__':
+  sys.exit(main(sys.argv))