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) 2006, 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 if os.geteuid() == 0:
  21         # We're running as root. Ensure that $HOME really is root's home,
  22         # not the user's home, or we're likely to fill it will unreadable
  23         # root-owned files.
  24         home_owner = os.stat(home).st_uid
  25         if home_owner != 0:
  26                 import pwd
  27                 from logging import info
  28                 old_home = home
  29                 home = pwd.getpwuid(0).pw_dir or '/'
  30                 info("$HOME (%s) is owned by user %d, but we are root (0). Using %s instead.", old_home, home_owner, home)
  31                 del old_home
  32                 del home_owner
  33
  34 xdg_data_home = os.environ.get('XDG_DATA_HOME',
  35                         os.path.join(home, '.local', 'share'))
  36
  37 xdg_data_dirs = [xdg_data_home] + \
  38         os.environ.get('XDG_DATA_DIRS', '/usr/local/share:/usr/share').split(':')
  39
  40 xdg_cache_home = os.environ.get('XDG_CACHE_HOME',
  41                         os.path.join(home, '.cache'))
  42
  43 xdg_cache_dirs = [xdg_cache_home] + \
  44         os.environ.get('XDG_CACHE_DIRS', '/var/cache').split(':')
  45
  46 xdg_config_home = os.environ.get('XDG_CONFIG_HOME',
  47                         os.path.join(home, '.config'))
  48
  49 xdg_config_dirs = [xdg_config_home] + \
  50         os.environ.get('XDG_CONFIG_DIRS', '/etc/xdg').split(':')
  51
  52 xdg_data_dirs = filter(lambda x: x, xdg_data_dirs)
  53 xdg_cache_dirs = filter(lambda x: x, xdg_cache_dirs)
  54 xdg_config_dirs = filter(lambda x: x, xdg_config_dirs)
  55
  56 def save_config_path(*resource):
  57         """Ensure $XDG_CONFIG_HOME/<resource>/ exists, and return its path.
  58         'resource' should normally be the name of your application. Use this
  59         when SAVING configuration settings. Use the xdg_config_dirs variable
  60         for loading."""
  61         resource = os.path.join(*resource)
  62         assert not resource.startswith('/')
  63         path = os.path.join(xdg_config_home, resource)
  64         if not os.path.isdir(path):
  65                 os.makedirs(path, 0700)
  66         return path
  67
  68 def load_config_paths(*resource):
  69         """Returns an iterator which gives each directory named 'resource' in the
  70         configuration search path. Information provided by earlier directories should
  71         take precedence over later ones (ie, the user's config dir comes first)."""
  72         resource = os.path.join(*resource)
  73         for config_dir in xdg_config_dirs:
  74                 path = os.path.join(config_dir, resource)
  75                 if os.path.exists(path): yield path
  76
  77 def load_first_config(*resource):
  78         """Returns the first result from load_config_paths, or None if there is nothing
  79         to load."""
  80         for x in load_config_paths(*resource):
  81                 return x
  82         return None
  83
  84 def save_cache_path(*resource):
  85         """Ensure $XDG_CACHE_HOME/<resource>/ exists, and return its path.
  86         'resource' should normally be the name of your application."""
  87         resource = os.path.join(*resource)
  88         assert not resource.startswith('/')
  89         path = os.path.join(xdg_cache_home, resource)
  90         if not os.path.isdir(path):
  91                 os.makedirs(path, 0700)
  92         return path
  93
  94 def load_cache_paths(*resource):
  95         """Returns an iterator which gives each directory named 'resource' in the
  96         cache search path. Information provided by earlier directories should
  97         take precedence over later ones (ie, the user's cache dir comes first)."""
  98         resource = os.path.join(*resource)
  99         for cache_dir in xdg_cache_dirs:
 100                 path = os.path.join(cache_dir, resource)
 101                 if os.path.exists(path): yield path
 102
 103 def load_first_cache(*resource):
 104         """Returns the first result from load_cache_paths, or None if there is nothing
 105         to load."""
 106         for x in load_cache_paths(*resource):
 107                 return x
 108         return None
 109
 110 def load_data_paths(*resource):
 111         """Returns an iterator which gives each directory named 'resource' in the
 112         shared data search path. Information provided by earlier directories should
 113         take precedence over later ones.
 114         @since: 0.28"""
 115         resource = os.path.join(*resource)
 116         for data_dir in xdg_data_dirs:
 117                 path = os.path.join(data_dir, resource)
 118                 if os.path.exists(path): yield path
 119
 120 def load_first_data(*resource):
 121         """Returns the first result from load_data_paths, or None if there is nothing
 122         to load.
 123         @since: 0.28"""
 124         for x in load_data_paths(*resource):
 125                 return x
 126         return None