zeroinstall/support/basedir.py

   1 """
   2 Support code for the freedesktop.org basedir spec.
   3
   4 This module provides functions for locating configuration files.
   5
   6 @see: U{http://freedesktop.org/wiki/Standards/basedir-spec}
   7
   8 @var home: The value of $HOME (or '/' if not set). If we're running as root and
   9 $HOME isn't owned by root, then this will be root's home from /etc/passwd
  10 instead.
  11 """
  12
  13 # Copyright (C) 2009, Thomas Leonard
  14 # See the README file for details, or visit http://0install.net.
  15
  16 import os
  17
  18 home = os.environ.get('HOME', '/')
  19
  20 try:
  21         _euid = os.geteuid()
  22 except AttributeError:
  23         pass    # Windows?
  24 else:
  25         if _euid == 0:
  26                 # We're running as root. Ensure that $HOME really is root's home,
  27                 # not the user's home, or we're likely to fill it will unreadable
  28                 # root-owned files.
  29                 home_owner = os.stat(home).st_uid
  30                 if home_owner != 0:
  31                         import pwd
  32                         from logging import info
  33                         old_home = home
  34                         home = pwd.getpwuid(0).pw_dir or '/'
  35                         info("$HOME (%s) is owned by user %d, but we are root (0). Using %s instead.", old_home, home_owner, home)
  36                         del old_home
  37                         del home_owner
  38
  39 xdg_data_home = os.environ.get('XDG_DATA_HOME',
  40                         os.path.join(home, '.local', 'share'))
  41
  42 xdg_data_dirs = [xdg_data_home] + \
  43         os.environ.get('XDG_DATA_DIRS', '/usr/local/share:/usr/share').split(':')
  44
  45 xdg_cache_home = os.environ.get('XDG_CACHE_HOME',
  46                         os.path.join(home, '.cache'))
  47
  48 xdg_cache_dirs = [xdg_cache_home] + \
  49         os.environ.get('XDG_CACHE_DIRS', '/var/cache').split(':')
  50
  51 xdg_config_home = os.environ.get('XDG_CONFIG_HOME',
  52                         os.path.join(home, '.config'))
  53
  54 xdg_config_dirs = [xdg_config_home] + \
  55         os.environ.get('XDG_CONFIG_DIRS', '/etc/xdg').split(':')
  56
  57 xdg_data_dirs = filter(lambda x: x, xdg_data_dirs)
  58 xdg_cache_dirs = filter(lambda x: x, xdg_cache_dirs)
  59 xdg_config_dirs = filter(lambda x: x, xdg_config_dirs)
  60
  61 def save_config_path(*resource):
  62         """Ensure $XDG_CONFIG_HOME/<resource>/ exists, and return its path.
  63         'resource' should normally be the name of your application. Use this
  64         when SAVING configuration settings. Use the xdg_config_dirs variable
  65         for loading."""
  66         resource = os.path.join(*resource)
  67         assert not resource.startswith('/')
  68         path = os.path.join(xdg_config_home, resource)
  69         if not os.path.isdir(path):
  70                 os.makedirs(path, 0700)
  71         return path
  72
  73 def load_config_paths(*resource):
  74         """Returns an iterator which gives each directory named 'resource' in the
  75         configuration search path. Information provided by earlier directories should
  76         take precedence over later ones (ie, the user's config dir comes first)."""
  77         resource = os.path.join(*resource)
  78         for config_dir in xdg_config_dirs:
  79                 path = os.path.join(config_dir, resource)
  80                 if os.path.exists(path): yield path
  81
  82 def load_first_config(*resource):
  83         """Returns the first result from load_config_paths, or None if there is nothing
  84         to load."""
  85         for x in load_config_paths(*resource):
  86                 return x
  87         return None
  88
  89 def save_cache_path(*resource):
  90         """Ensure $XDG_CACHE_HOME/<resource>/ exists, and return its path.
  91         'resource' should normally be the name of your application."""
  92         resource = os.path.join(*resource)
  93         assert not resource.startswith('/')
  94         path = os.path.join(xdg_cache_home, resource)
  95         if not os.path.isdir(path):
  96                 os.makedirs(path, 0700)
  97         return path
  98
  99 def load_cache_paths(*resource):
 100         """Returns an iterator which gives each directory named 'resource' in the
 101         cache search path. Information provided by earlier directories should
 102         take precedence over later ones (ie, the user's cache dir comes first)."""
 103         resource = os.path.join(*resource)
 104         for cache_dir in xdg_cache_dirs:
 105                 path = os.path.join(cache_dir, resource)
 106                 if os.path.exists(path): yield path
 107
 108 def load_first_cache(*resource):
 109         """Returns the first result from load_cache_paths, or None if there is nothing
 110         to load."""
 111         for x in load_cache_paths(*resource):
 112                 return x
 113         return None
 114
 115 def load_data_paths(*resource):
 116         """Returns an iterator which gives each directory named 'resource' in the
 117         shared data search path. Information provided by earlier directories should
 118         take precedence over later ones.
 119         @since: 0.28"""
 120         resource = os.path.join(*resource)
 121         for data_dir in xdg_data_dirs:
 122                 path = os.path.join(data_dir, resource)
 123                 if os.path.exists(path): yield path
 124
 125 def load_first_data(*resource):
 126         """Returns the first result from load_data_paths, or None if there is nothing
 127         to load.
 128         @since: 0.28"""
 129         for x in load_data_paths(*resource):
 130                 return x
 131         return None