git_remote_helpers/fastimport/helpers.py

   1 # Copyright (C) 2008 Canonical Ltd
   2 #
   3 # This program is free software; you can redistribute it and/or modify
   4 # it under the terms of the GNU General Public License as published by
   5 # the Free Software Foundation; either version 2 of the License, or
   6 # (at your option) any later version.
   7 #
   8 # This program is distributed in the hope that it will be useful,
   9 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 # GNU General Public License for more details.
  12 #
  13 # You should have received a copy of the GNU General Public License
  14 # along with this program; if not, write to the Free Software
  15 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  16
  17 """Miscellaneous useful stuff."""
  18
  19 import os
  20
  21 def single_plural(n, single, plural):
  22     """Return a single or plural form of a noun based on number."""
  23     if n == 1:
  24         return single
  25     else:
  26         return plural
  27
  28
  29 def invert_dict(d):
  30     """Invert a dictionary with keys matching each value turned into a list."""
  31     # Based on recipe from ASPN
  32     result = {}
  33     for k, v in d.iteritems():
  34         keys = result.setdefault(v, [])
  35         keys.append(k)
  36     return result
  37
  38
  39 def invert_dictset(d):
  40     """Invert a dictionary with keys matching a set of values, turned into lists."""
  41     # Based on recipe from ASPN
  42     result = {}
  43     for k, c in d.iteritems():
  44         for v in c:
  45             keys = result.setdefault(v, [])
  46             keys.append(k)
  47     return result
  48
  49
  50 def _common_path_and_rest(l1, l2, common=[]):
  51     # From http://code.activestate.com/recipes/208993/
  52     if len(l1) < 1: return (common, l1, l2)
  53     if len(l2) < 1: return (common, l1, l2)
  54     if l1[0] != l2[0]: return (common, l1, l2)
  55     return _common_path_and_rest(l1[1:], l2[1:], common+[l1[0]])
  56
  57
  58 def common_path(path1, path2):
  59     """Find the common bit of 2 paths."""
  60     return ''.join(_common_path_and_rest(path1, path2)[0])
  61
  62
  63 def common_directory(paths):
  64     """Find the deepest common directory of a list of paths.
  65
  66     :return: if no paths are provided, None is returned;
  67       if there is no common directory, '' is returned;
  68       otherwise the common directory with a trailing / is returned.
  69     """
  70     def get_dir_with_slash(path):
  71         if path == '' or path.endswith('/'):
  72             return path
  73         else:
  74             dirname, basename = os.path.split(path)
  75             if dirname == '':
  76                 return dirname
  77             else:
  78                 return dirname + '/'
  79
  80     if not paths:
  81         return None
  82     elif len(paths) == 1:
  83         return get_dir_with_slash(paths[0])
  84     else:
  85         common = common_path(paths[0], paths[1])
  86         for path in paths[2:]:
  87             common = common_path(common, path)
  88         return get_dir_with_slash(common)