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 '#' are skipped. Lines starting with '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
  63 def makepath(*paths):
  64     dir = os.path.abspath(os.path.join(*paths))
  65     return dir, os.path.normcase(dir)
  66
  67 for m in sys.modules.values():
  68     if hasattr(m, "__file__") and m.__file__:
  69         m.__file__ = os.path.abspath(m.__file__)
  70 del m
  71
  72 # This ensures that the initial path provided by the interpreter contains
  73 # only absolute pathnames, even if we're running from the build directory.
  74 L = []
  75 _dirs_in_sys_path = {}
  76 for dir in sys.path:
  77     # Filter out paths that don't exist, but leave in the empty string
  78     # since it's a special case. We also need to special-case the Mac,
  79     # as file names are allowed on sys.path there.
  80     if sys.platform != 'mac':
  81         if dir and not os.path.isdir(dir):
  82             continue
  83     else:
  84         if dir and not os.path.exists(dir):
  85             continue
  86     dir, dircase = makepath(dir)
  87     if not _dirs_in_sys_path.has_key(dircase):
  88         L.append(dir)
  89         _dirs_in_sys_path[dircase] = 1
  90 sys.path[:] = L
  91 del dir, L
  92
  93 # Append ./build/lib.<platform> in case we're running in the build dir
  94 # (especially for Guido :-)
  95 if os.name == "posix" and os.path.basename(sys.path[-1]) == "Modules":
  96     from distutils.util import get_platform
  97     s = "build/lib.%s-%.3s" % (get_platform(), sys.version)
  98     s = os.path.join(os.path.dirname(sys.path[-1]), s)
  99     sys.path.append(s)
 100     del get_platform, s
 101
 102 def _init_pathinfo():
 103     global _dirs_in_sys_path
 104     _dirs_in_sys_path = d = {}
 105     for dir in sys.path:
 106         if dir and not os.path.isdir(dir):
 107             continue
 108         dir, dircase = makepath(dir)
 109         d[dircase] = 1
 110
 111 def addsitedir(sitedir):
 112     global _dirs_in_sys_path
 113     if _dirs_in_sys_path is None:
 114         _init_pathinfo()
 115         reset = 1
 116     else:
 117         reset = 0
 118     sitedir, sitedircase = makepath(sitedir)
 119     if not _dirs_in_sys_path.has_key(sitedircase):
 120         sys.path.append(sitedir)        # Add path component
 121     try:
 122         names = os.listdir(sitedir)
 123     except os.error:
 124         return
 125     names.sort()
 126     for name in names:
 127         if name[-4:] == os.extsep + "pth":
 128             addpackage(sitedir, name)
 129     if reset:
 130         _dirs_in_sys_path = None
 131
 132 def addpackage(sitedir, name):
 133     global _dirs_in_sys_path
 134     if _dirs_in_sys_path is None:
 135         _init_pathinfo()
 136         reset = 1
 137     else:
 138         reset = 0
 139     fullname = os.path.join(sitedir, name)
 140     try:
 141         f = open(fullname)
 142     except IOError:
 143         return
 144     while 1:
 145         dir = f.readline()
 146         if not dir:
 147             break
 148         if dir[0] == '#':
 149             continue
 150         if dir.startswith("import"):
 151             exec dir
 152             continue
 153         if dir[-1] == '\n':
 154             dir = dir[:-1]
 155         dir, dircase = makepath(sitedir, dir)
 156         if not _dirs_in_sys_path.has_key(dircase) and os.path.exists(dir):
 157             sys.path.append(dir)
 158             _dirs_in_sys_path[dircase] = 1
 159     if reset:
 160         _dirs_in_sys_path = None
 161
 162 prefixes = [sys.prefix]
 163 if sys.exec_prefix != sys.prefix:
 164     prefixes.append(sys.exec_prefix)
 165 for prefix in prefixes:
 166     if prefix:
 167         if os.sep == '/':
 168             sitedirs = [os.path.join(prefix,
 169                                      "lib",
 170                                      "python" + sys.version[:3],
 171                                      "site-packages"),
 172                         os.path.join(prefix, "lib", "site-python")]
 173         else:
 174             sitedirs = [prefix, os.path.join(prefix, "lib", "site-packages")]
 175         for sitedir in sitedirs:
 176             if os.path.isdir(sitedir):
 177                 addsitedir(sitedir)
 178
 179 _dirs_in_sys_path = None
 180
 181
 182 # Define new built-ins 'quit' and 'exit'.
 183 # These are simply strings that display a hint on how to exit.
 184 if os.sep == ':':
 185     exit = 'Use Cmd-Q to quit.'
 186 elif os.sep == '\\':
 187     exit = 'Use Ctrl-Z plus Return to exit.'
 188 else:
 189     exit = 'Use Ctrl-D (i.e. EOF) to exit.'
 190 import __builtin__
 191 __builtin__.quit = __builtin__.exit = exit
 192 del exit
 193
 194 # interactive prompt objects for printing the license text, a list of
 195 # contributors and the copyright notice.
 196 class _Printer:
 197     MAXLINES = 23
 198
 199     def __init__(self, name, data, files=(), dirs=()):
 200         self.__name = name
 201         self.__data = data
 202         self.__files = files
 203         self.__dirs = dirs
 204         self.__lines = None
 205
 206     def __setup(self):
 207         if self.__lines:
 208             return
 209         data = None
 210         for dir in self.__dirs:
 211             for file in self.__files:
 212                 file = os.path.join(dir, file)
 213                 try:
 214                     fp = open(file)
 215                     data = fp.read()
 216                     fp.close()
 217                     break
 218                 except IOError:
 219                     pass
 220             if data:
 221                 break
 222         if not data:
 223             data = self.__data
 224         self.__lines = data.split('\n')
 225         self.__linecnt = len(self.__lines)
 226
 227     def __repr__(self):
 228         self.__setup()
 229         if len(self.__lines) <= self.MAXLINES:
 230             return "\n".join(self.__lines)
 231         else:
 232             return "Type %s() to see the full %s text" % ((self.__name,)*2)
 233
 234     def __call__(self):
 235         self.__setup()
 236         prompt = 'Hit Return for more, or q (and Return) to quit: '
 237         lineno = 0
 238         while 1:
 239             try:
 240                 for i in range(lineno, lineno + self.MAXLINES):
 241                     print self.__lines[i]
 242             except IndexError:
 243                 break
 244             else:
 245                 lineno += self.MAXLINES
 246                 key = None
 247                 while key is None:
 248                     key = raw_input(prompt)
 249                     if key not in ('', 'q'):
 250                         key = None
 251                 if key == 'q':
 252                     break
 253
 254 __builtin__.copyright = _Printer("copyright", sys.copyright)
 255 if sys.platform[:4] == 'java':
 256     __builtin__.credits = _Printer(
 257         "credits",
 258         "Jython is maintained by the Jython developers (www.jython.org).")
 259 else:
 260     __builtin__.credits = _Printer("credits", """\
 261 Thanks to CWI, CNRI, BeOpen.com, Digital Creations and a cast of thousands
 262 for supporting Python development.  See www.python.org for more information.""")
 263 here = os.path.dirname(os.__file__)
 264 __builtin__.license = _Printer(
 265     "license", "See http://www.python.org/%.3s/license.html" % sys.version,
 266     ["LICENSE.txt", "LICENSE"],
 267     [os.path.join(here, os.pardir), here, os.curdir])
 268
 269
 270 # Define new built-in 'help'.
 271 # This is a wrapper around pydoc.help (with a twist).
 272
 273 class _Helper:
 274     def __repr__(self):
 275         return "Type help() for interactive help, " \
 276                "or help(object) for help about object."
 277     def __call__(self, *args, **kwds):
 278         import pydoc
 279         return pydoc.help(*args, **kwds)
 280
 281 __builtin__.help = _Helper()
 282
 283
 284 # Set the string encoding used by the Unicode implementation.  The
 285 # default is 'ascii', but if you're willing to experiment, you can
 286 # change this.
 287
 288 encoding = "ascii" # Default value set by _PyUnicode_Init()
 289
 290 if 0:
 291     # Enable to support locale aware default string encodings.
 292     import locale
 293     loc = locale.getdefaultlocale()
 294     if loc[1]:
 295         encoding = loc[1]
 296
 297 if 0:
 298     # Enable to switch off string to Unicode coercion and implicit
 299     # Unicode to string conversion.
 300     encoding = "undefined"
 301
 302 if encoding != "ascii":
 303     # On Non-Unicode builds this will raise an AttributeError...
 304     sys.setdefaultencoding(encoding) # Needs Python Unicode build !
 305
 306 #
 307 # Run custom site specific code, if available.
 308 #
 309 try:
 310     import sitecustomize
 311 except ImportError:
 312     pass
 313
 314 #
 315 # Remove sys.setdefaultencoding() so that users cannot change the
 316 # encoding after initialization.  The test for presence is needed when
 317 # this module is run as a script, because this code is executed twice.
 318 #
 319 if hasattr(sys, "setdefaultencoding"):
 320     del sys.setdefaultencoding
 321
 322 def _test():
 323     print "sys.path = ["
 324     for dir in sys.path:
 325         print "    %s," % `dir`
 326     print "]"
 327
 328 if __name__ == '__main__':
 329     _test()