Lib/site.py

   1 """Append module search paths for third-party packages to sys.path.
   2
   3 ****************************************************************
   4 * This module is automatically imported during initialization. *
   5 ****************************************************************
   6
   7 In earlier versions of Python (up to 1.5a3), scripts or modules that
   8 needed to use site-specific modules would place ``import site''
   9 somewhere near the top of their code.  Because of the automatic
  10 import, this is no longer necessary (but code that does it still
  11 works).
  12
  13 This will append site-specific paths to to the module search path.  On
  14 Unix, it starts with sys.prefix and sys.exec_prefix (if different) and
  15 appends lib/python<version>/site-packages as well as lib/site-python.
  16 On other platforms (mainly Mac and Windows), it uses just sys.prefix
  17 \(and sys.exec_prefix, if different, but this is unlikely).  The
  18 resulting directories, if they exist, are appended to sys.path, and
  19 also inspected for path configuration files.
  20
  21 A path configuration file is a file whose name has the form
  22 <package>.pth; its contents are additional directories (one per line)
  23 to be added to sys.path.  Non-existing directories (or
  24 non-directories) are never added to sys.path; no directory is added to
  25 sys.path more than once.  Blank lines and lines beginning with
  26 \code{#} are skipped. Lines starting with \code{import} are executed.
  27
  28 For example, suppose sys.prefix and sys.exec_prefix are set to
  29 /usr/local and there is a directory /usr/local/lib/python1.5/site-packages
  30 with three subdirectories, foo, bar and spam, and two path
  31 configuration files, foo.pth and bar.pth.  Assume foo.pth contains the
  32 following:
  33
  34   # foo package configuration
  35   foo
  36   bar
  37   bletch
  38
  39 and bar.pth contains:
  40
  41   # bar package configuration
  42   bar
  43
  44 Then the following directories are added to sys.path, in this order:
  45
  46   /usr/local/lib/python1.5/site-packages/bar
  47   /usr/local/lib/python1.5/site-packages/foo
  48
  49 Note that bletch is omitted because it doesn't exist; bar precedes foo
  50 because bar.pth comes alphabetically before foo.pth; and spam is
  51 omitted because it is not mentioned in either path configuration file.
  52
  53 After these path manipulations, an attempt is made to import a module
  54 named sitecustomize, which can perform arbitrary additional
  55 site-specific customizations.  If this import fails with an
  56 ImportError exception, it is silently ignored.
  57
  58 """
  59
  60 import sys, os
  61
  62 if os.sep==".":
  63     endsep = "/"
  64 else:
  65     endsep = "."
  66
  67
  68 def makepath(*paths):
  69     dir = os.path.abspath(os.path.join(*paths))
  70     return dir, os.path.normcase(dir)
  71
  72 for m in sys.modules.values():
  73     if hasattr(m, "__file__") and m.__file__:
  74         m.__file__ = os.path.abspath(m.__file__)
  75 del m
  76
  77 # This ensures that the initial path provided by the interpreter contains
  78 # only absolute pathnames, even if we're running from the build directory.
  79 L = []
  80 dirs_in_sys_path = {}
  81 for dir in sys.path:
  82     dir, dircase = makepath(dir)
  83     if not dirs_in_sys_path.has_key(dircase):
  84         L.append(dir)
  85         dirs_in_sys_path[dircase] = 1
  86 sys.path[:] = L
  87 del dir, L
  88
  89 # Append ./build/lib.<platform> in case we're running in the build dir
  90 # (especially for Guido :-)
  91 if os.name == "posix" and os.path.basename(sys.path[-1]) == "Modules":
  92     from distutils.util import get_platform
  93     s = "build/lib.%s-%.3s" % (get_platform(), sys.version)
  94     s = os.path.join(os.path.dirname(sys.path[-1]), s)
  95     sys.path.append(s)
  96     del get_platform, s
  97
  98 def addsitedir(sitedir):
  99     sitedir, sitedircase = makepath(sitedir)
 100     if not dirs_in_sys_path.has_key(sitedircase):
 101         sys.path.append(sitedir)        # Add path component
 102     try:
 103         names = os.listdir(sitedir)
 104     except os.error:
 105         return
 106     names.sort()
 107     for name in names:
 108         if name[-4:] == endsep + "pth":
 109             addpackage(sitedir, name)
 110
 111 def addpackage(sitedir, name):
 112     fullname = os.path.join(sitedir, name)
 113     try:
 114         f = open(fullname)
 115     except IOError:
 116         return
 117     while 1:
 118         dir = f.readline()
 119         if not dir:
 120             break
 121         if dir[0] == '#':
 122             continue
 123         if dir.startswith("import"):
 124             exec dir
 125             continue
 126         if dir[-1] == '\n':
 127             dir = dir[:-1]
 128         dir, dircase = makepath(sitedir, dir)
 129         if not dirs_in_sys_path.has_key(dircase) and os.path.exists(dir):
 130             sys.path.append(dir)
 131             dirs_in_sys_path[dircase] = 1
 132
 133 prefixes = [sys.prefix]
 134 if sys.exec_prefix != sys.prefix:
 135     prefixes.append(sys.exec_prefix)
 136 for prefix in prefixes:
 137     if prefix:
 138         if os.sep == '/':
 139             sitedirs = [os.path.join(prefix,
 140                                      "lib",
 141                                      "python" + sys.version[:3],
 142                                      "site-packages"),
 143                         os.path.join(prefix, "lib", "site-python")]
 144         elif os.sep == ':':
 145             sitedirs = [os.path.join(prefix, "lib", "site-packages")]
 146         else:
 147             sitedirs = [prefix]
 148         for sitedir in sitedirs:
 149             if os.path.isdir(sitedir):
 150                 addsitedir(sitedir)
 151
 152 del dirs_in_sys_path
 153
 154 # Define new built-ins 'quit' and 'exit'.
 155 # These are simply strings that display a hint on how to exit.
 156 if os.sep == ':':
 157     exit = 'Use Cmd-Q to quit.'
 158 elif os.sep == '\\':
 159     exit = 'Use Ctrl-Z plus Return to exit.'
 160 else:
 161     exit = 'Use Ctrl-D (i.e. EOF) to exit.'
 162 import __builtin__
 163 __builtin__.quit = __builtin__.exit = exit
 164 del exit
 165
 166 # interactive prompt objects for printing the license text, a list of
 167 # contributors and the copyright notice.
 168 class _Printer:
 169     MAXLINES = 23
 170
 171     def __init__(self, name, data, files=(), dirs=()):
 172         self.__name = name
 173         self.__data = data
 174         self.__files = files
 175         self.__dirs = dirs
 176         self.__lines = None
 177
 178     def __setup(self):
 179         if self.__lines:
 180             return
 181         data = None
 182         for dir in self.__dirs:
 183             for file in self.__files:
 184                 file = os.path.join(dir, file)
 185                 try:
 186                     fp = open(file)
 187                     data = fp.read()
 188                     fp.close()
 189                     break
 190                 except IOError:
 191                     pass
 192             if data:
 193                 break
 194         if not data:
 195             data = self.__data
 196         self.__lines = data.split('\n')
 197         self.__linecnt = len(self.__lines)
 198
 199     def __repr__(self):
 200         self.__setup()
 201         if len(self.__lines) <= self.MAXLINES:
 202             return "\n".join(self.__lines)
 203         else:
 204             return "Type %s() to see the full %s text" % ((self.__name,)*2)
 205
 206     def __call__(self):
 207         self.__setup()
 208         prompt = 'Hit Return for more, or q (and Return) to quit: '
 209         lineno = 0
 210         while 1:
 211             try:
 212                 for i in range(lineno, lineno + self.MAXLINES):
 213                     print self.__lines[i]
 214             except IndexError:
 215                 break
 216             else:
 217                 lineno += self.MAXLINES
 218                 key = None
 219                 while key is None:
 220                     key = raw_input(prompt)
 221                     if key not in ('', 'q'):
 222                         key = None
 223                 if key == 'q':
 224                     break
 225
 226 __builtin__.copyright = _Printer("copyright", sys.copyright)
 227 if sys.platform[:4] == 'java':
 228     __builtin__.credits = _Printer(
 229         "credits",
 230         "Jython is maintained by the Jython developers (www.jython.org).")
 231 else:
 232     __builtin__.credits = _Printer("credits", """\
 233 Thanks to CWI, CNRI, BeOpen.com, Digital Creations and a cast of thousands
 234 for supporting Python development.  See www.python.org for more information.""")
 235 here = os.path.dirname(os.__file__)
 236 __builtin__.license = _Printer(
 237     "license", "See http://www.pythonlabs.com/products/python2.0/license.html",
 238     ["LICENSE.txt", "LICENSE"],
 239     [os.path.join(here, os.pardir), here, os.curdir])
 240
 241
 242 # Set the string encoding used by the Unicode implementation.  The
 243 # default is 'ascii', but if you're willing to experiment, you can
 244 # change this.
 245
 246 encoding = "ascii" # Default value set by _PyUnicode_Init()
 247
 248 if 0:
 249     # Enable to support locale aware default string encodings.
 250     import locale
 251     loc = locale.getdefaultlocale()
 252     if loc[1]:
 253         encoding = loc[1]
 254
 255 if 0:
 256     # Enable to switch off string to Unicode coercion and implicit
 257     # Unicode to string conversion.
 258     encoding = "undefined"
 259
 260 if encoding != "ascii":
 261     sys.setdefaultencoding(encoding)
 262
 263 #
 264 # Run custom site specific code, if available.
 265 #
 266 try:
 267     import sitecustomize
 268 except ImportError:
 269     pass
 270
 271 #
 272 # Remove sys.setdefaultencoding() so that users cannot change the
 273 # encoding after initialization.  The test for presence is needed when
 274 # this module is run as a script, because this code is executed twice.
 275 #
 276 if hasattr(sys, "setdefaultencoding"):
 277     del sys.setdefaultencoding
 278
 279 def _test():
 280     print "sys.path = ["
 281     for dir in sys.path:
 282         print "    %s," % `dir`
 283     print "]"
 284
 285 if __name__ == '__main__':
 286     _test()