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 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 dir = dircase = None  # sys.path may be empty at this point
  77 for dir in sys.path:
  78     # Filter out duplicate paths (on case-insensitive file systems also
  79     # if they only differ in case); turn relative paths into absolute
  80     # paths.
  81     dir, dircase = makepath(dir)
  82     if not dircase in _dirs_in_sys_path:
  83         L.append(dir)
  84         _dirs_in_sys_path[dircase] = 1
  85 sys.path[:] = L
  86 del dir, dircase, L
  87
  88 # Append ./build/lib.<platform> in case we're running in the build dir
  89 # (especially for Guido :-)
  90 # XXX This should not be part of site.py, since it is needed even when
  91 # using the -S option for Python.  See http://www.python.org/sf/586680
  92 if (os.name == "posix" and sys.path and
  93     os.path.basename(sys.path[-1]) == "Modules"):
  94     from distutils.util import get_platform
  95     s = "build/lib.%s-%.3s" % (get_platform(), sys.version)
  96     s = os.path.join(os.path.dirname(sys.path[-1]), s)
  97     sys.path.append(s)
  98     del get_platform, s
  99
 100 def _init_pathinfo():
 101     global _dirs_in_sys_path
 102     _dirs_in_sys_path = d = {}
 103     for dir in sys.path:
 104         if dir and not os.path.isdir(dir):
 105             continue
 106         dir, dircase = makepath(dir)
 107         d[dircase] = 1
 108
 109 def addsitedir(sitedir):
 110     global _dirs_in_sys_path
 111     if _dirs_in_sys_path is None:
 112         _init_pathinfo()
 113         reset = 1
 114     else:
 115         reset = 0
 116     sitedir, sitedircase = makepath(sitedir)
 117     if not sitedircase in _dirs_in_sys_path:
 118         sys.path.append(sitedir)        # Add path component
 119     try:
 120         names = os.listdir(sitedir)
 121     except os.error:
 122         return
 123     names.sort()
 124     for name in names:
 125         if name[-4:] == os.extsep + "pth":
 126             addpackage(sitedir, name)
 127     if reset:
 128         _dirs_in_sys_path = None
 129
 130 def addpackage(sitedir, name):
 131     global _dirs_in_sys_path
 132     if _dirs_in_sys_path is None:
 133         _init_pathinfo()
 134         reset = 1
 135     else:
 136         reset = 0
 137     fullname = os.path.join(sitedir, name)
 138     try:
 139         f = open(fullname)
 140     except IOError:
 141         return
 142     while 1:
 143         dir = f.readline()
 144         if not dir:
 145             break
 146         if dir[0] == '#':
 147             continue
 148         if dir.startswith("import"):
 149             exec dir
 150             continue
 151         dir = dir.rstrip()
 152         dir, dircase = makepath(sitedir, dir)
 153         if not dircase in _dirs_in_sys_path and os.path.exists(dir):
 154             sys.path.append(dir)
 155             _dirs_in_sys_path[dircase] = 1
 156     if reset:
 157         _dirs_in_sys_path = None
 158
 159 prefixes = [sys.prefix]
 160 sitedir = None # make sure sitedir is initialized because of later 'del'
 161 if sys.exec_prefix != sys.prefix:
 162     prefixes.append(sys.exec_prefix)
 163 for prefix in prefixes:
 164     if prefix:
 165         if sys.platform in ('os2emx', 'riscos'):
 166             sitedirs = [os.path.join(prefix, "Lib", "site-packages")]
 167         elif 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         if sys.platform == 'darwin':
 176             # for framework builds *only* we add the standard Apple
 177             # locations. Currently only per-user, but /Library and
 178             # /Network/Library could be added too
 179             if 'Python.framework' in prefix:
 180                 home = os.environ.get('HOME')
 181                 if home:
 182                     sitedirs.append(
 183                         os.path.join(home,
 184                                      'Library',
 185                                      'Python',
 186                                      sys.version[:3],
 187                                      'site-packages'))
 188         for sitedir in sitedirs:
 189             if os.path.isdir(sitedir):
 190                 addsitedir(sitedir)
 191 del prefix, sitedir
 192
 193 _dirs_in_sys_path = None
 194
 195
 196 # the OS/2 EMX port has optional extension modules that do double duty
 197 # as DLLs (and must use the .DLL file extension) for other extensions.
 198 # The library search path needs to be amended so these will be found
 199 # during module import.  Use BEGINLIBPATH so that these are at the start
 200 # of the library search path.
 201 if sys.platform == 'os2emx':
 202     dllpath = os.path.join(sys.prefix, "Lib", "lib-dynload")
 203     libpath = os.environ['BEGINLIBPATH'].split(';')
 204     if libpath[-1]:
 205         libpath.append(dllpath)
 206     else:
 207         libpath[-1] = dllpath
 208     os.environ['BEGINLIBPATH'] = ';'.join(libpath)
 209
 210
 211 # Define new built-ins 'quit' and 'exit'.
 212 # These are simply strings that display a hint on how to exit.
 213 if os.sep == ':':
 214     exit = 'Use Cmd-Q to quit.'
 215 elif os.sep == '\\':
 216     exit = 'Use Ctrl-Z plus Return to exit.'
 217 else:
 218     exit = 'Use Ctrl-D (i.e. EOF) to exit.'
 219 import __builtin__
 220 __builtin__.quit = __builtin__.exit = exit
 221 del exit
 222
 223 # interactive prompt objects for printing the license text, a list of
 224 # contributors and the copyright notice.
 225 class _Printer:
 226     MAXLINES = 23
 227
 228     def __init__(self, name, data, files=(), dirs=()):
 229         self.__name = name
 230         self.__data = data
 231         self.__files = files
 232         self.__dirs = dirs
 233         self.__lines = None
 234
 235     def __setup(self):
 236         if self.__lines:
 237             return
 238         data = None
 239         for dir in self.__dirs:
 240             for file in self.__files:
 241                 file = os.path.join(dir, file)
 242                 try:
 243                     fp = open(file)
 244                     data = fp.read()
 245                     fp.close()
 246                     break
 247                 except IOError:
 248                     pass
 249             if data:
 250                 break
 251         if not data:
 252             data = self.__data
 253         self.__lines = data.split('\n')
 254         self.__linecnt = len(self.__lines)
 255
 256     def __repr__(self):
 257         self.__setup()
 258         if len(self.__lines) <= self.MAXLINES:
 259             return "\n".join(self.__lines)
 260         else:
 261             return "Type %s() to see the full %s text" % ((self.__name,)*2)
 262
 263     def __call__(self):
 264         self.__setup()
 265         prompt = 'Hit Return for more, or q (and Return) to quit: '
 266         lineno = 0
 267         while 1:
 268             try:
 269                 for i in range(lineno, lineno + self.MAXLINES):
 270                     print self.__lines[i]
 271             except IndexError:
 272                 break
 273             else:
 274                 lineno += self.MAXLINES
 275                 key = None
 276                 while key is None:
 277                     key = raw_input(prompt)
 278                     if key not in ('', 'q'):
 279                         key = None
 280                 if key == 'q':
 281                     break
 282
 283 __builtin__.copyright = _Printer("copyright", sys.copyright)
 284 if sys.platform[:4] == 'java':
 285     __builtin__.credits = _Printer(
 286         "credits",
 287         "Jython is maintained by the Jython developers (www.jython.org).")
 288 else:
 289     __builtin__.credits = _Printer("credits", """\
 290 Thanks to CWI, CNRI, BeOpen.com, Zope Corporation and a cast of thousands
 291 for supporting Python development.  See www.python.org for more information.""")
 292 here = os.path.dirname(os.__file__)
 293 __builtin__.license = _Printer(
 294     "license", "See http://www.python.org/%.3s/license.html" % sys.version,
 295     ["LICENSE.txt", "LICENSE"],
 296     [os.path.join(here, os.pardir), here, os.curdir])
 297
 298
 299 # Define new built-in 'help'.
 300 # This is a wrapper around pydoc.help (with a twist).
 301
 302 class _Helper:
 303     def __repr__(self):
 304         return "Type help() for interactive help, " \
 305                "or help(object) for help about object."
 306     def __call__(self, *args, **kwds):
 307         import pydoc
 308         return pydoc.help(*args, **kwds)
 309
 310 __builtin__.help = _Helper()
 311
 312
 313 # On Windows, some default encodings are not provided
 314 # by Python (e.g. "cp932" in Japanese locale), while they
 315 # are always available as "mbcs" in each locale.
 316 # Make them usable by aliasing to "mbcs" in such a case.
 317
 318 if sys.platform == 'win32':
 319     import locale, codecs
 320     enc = locale.getdefaultlocale()[1]
 321     if enc.startswith('cp'):            # "cp***" ?
 322         try:
 323             codecs.lookup(enc)
 324         except LookupError:
 325             import encodings
 326             encodings._cache[enc] = encodings._unknown
 327             encodings.aliases.aliases[enc] = 'mbcs'
 328
 329 # Set the string encoding used by the Unicode implementation.  The
 330 # default is 'ascii', but if you're willing to experiment, you can
 331 # change this.
 332
 333 encoding = "ascii" # Default value set by _PyUnicode_Init()
 334
 335 if 0:
 336     # Enable to support locale aware default string encodings.
 337     import locale
 338     loc = locale.getdefaultlocale()
 339     if loc[1]:
 340         encoding = loc[1]
 341
 342 if 0:
 343     # Enable to switch off string to Unicode coercion and implicit
 344     # Unicode to string conversion.
 345     encoding = "undefined"
 346
 347 if encoding != "ascii":
 348     # On Non-Unicode builds this will raise an AttributeError...
 349     sys.setdefaultencoding(encoding) # Needs Python Unicode build !
 350
 351 #
 352 # Run custom site specific code, if available.
 353 #
 354 try:
 355     import sitecustomize
 356 except ImportError:
 357     pass
 358
 359 #
 360 # Remove sys.setdefaultencoding() so that users cannot change the
 361 # encoding after initialization.  The test for presence is needed when
 362 # this module is run as a script, because this code is executed twice.
 363 #
 364 if hasattr(sys, "setdefaultencoding"):
 365     del sys.setdefaultencoding
 366
 367 def _test():
 368     print "sys.path = ["
 369     for dir in sys.path:
 370         print "    %s," % `dir`
 371     print "]"
 372
 373 if __name__ == '__main__':
 374     _test()