/brz/remove-bazaar

# repository.py -- For dealing wih git repositories.

# Copyright (C) 2007 James Westby <jw+debian@jameswestby.net>

# 

# This program is free software; you can redistribute it and/or

# modify it under the terms of the GNU General Public License

# as published by the Free Software Foundation; version 2

# of the License.

# 

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU General Public License for more details.

# 

# You should have received a copy of the GNU General Public License

# along with this program; if not, write to the Free Software

# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,

# MA  02110-1301, USA.

import os

from objects import (ShaFile,

                     Commit,

                     Tree,

                     Blob,

                     )

objectdir = 'objects'

symref = 'ref: '

class Repository(object):

  ref_locs = ['', 'refs', 'refs/tags', 'refs/heads', 'refs/remotes']

  def __init__(self, root):

    self._basedir = root

  def basedir(self):

    return self._basedir

  def object_dir(self):

    return os.path.join(self.basedir(), objectdir)

  def _get_ref(self, file):

    f = open(file, 'rb')

    try:

      contents = f.read()

      if contents.startswith(symref):

        ref = contents[len(symref):]

        if ref[-1] == '\n':

          ref = ref[:-1]

        return self.ref(ref)

      assert len(contents) == 41, 'Invalid ref'

      return contents[:-1]

    finally:

      f.close()

  def ref(self, name):

    for dir in self.ref_locs:

      file = os.path.join(self.basedir(), dir, name)

      if os.path.exists(file):

        return self._get_ref(file)

  def head(self):

    return self.ref('HEAD')

  def _get_object(self, sha, cls):

    assert len(sha) == 40, "Incorrect length sha: %s" % str(sha)

    dir = sha[:2]

    file = sha[2:]

    path = os.path.join(self.object_dir(), dir, file)

    if not os.path.exists(path):

      return None

    return cls.from_file(path)

  def get_object(self, sha):

    return self._get_object(sha, ShaFile)

  def get_commit(self, sha):

    return self._get_object(sha, Commit)

  def get_tree(self, sha):

    return self._get_object(sha, Tree)

  def get_blob(self, sha):

    return self._get_object(sha, Blob)