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