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 (including Mac OSX), it starts with sys.prefix and
  15 sys.exec_prefix (if different) and appends
  16 lib/python<version>/site-packages as well as lib/site-python.
  17 On other platforms (such as Windows), it tries each of the
  18 prefixes directly, as well as with lib/site-packages appended.  The
  19 resulting directories, if they exist, are appended to sys.path, and
  20 also inspected for path configuration files.
  21
  22 A path configuration file is a file whose name has the form
  23 <package>.pth; its contents are additional directories (one per line)
  24 to be added to sys.path.  Non-existing directories (or
  25 non-directories) are never added to sys.path; no directory is added to
  26 sys.path more than once.  Blank lines and lines beginning with
  27 '#' are skipped. Lines starting with 'import' are executed.
  28
  29 For example, suppose sys.prefix and sys.exec_prefix are set to
  30 /usr/local and there is a directory /usr/local/lib/python2.5/site-packages
  31 with three subdirectories, foo, bar and spam, and two path
  32 configuration files, foo.pth and bar.pth.  Assume foo.pth contains the
  33 following:
  34
  35   # foo package configuration
  36   foo
  37   bar
  38   bletch
  39
  40 and bar.pth contains:
  41
  42   # bar package configuration
  43   bar
  44
  45 Then the following directories are added to sys.path, in this order:
  46
  47   /usr/local/lib/python2.5/site-packages/bar
  48   /usr/local/lib/python2.5/site-packages/foo
  49
  50 Note that bletch is omitted because it doesn't exist; bar precedes foo
  51 because bar.pth comes alphabetically before foo.pth; and spam is
  52 omitted because it is not mentioned in either path configuration file.
  53
  54 After these path manipulations, an attempt is made to import a module
  55 named sitecustomize, which can perform arbitrary additional
  56 site-specific customizations.  If this import fails with an
  57 ImportError exception, it is silently ignored.
  58
  59 """
  60
  61 import sys
  62 import os
  63 import __builtin__
  64
  65
  66 def makepath(*paths):
  67     dir = os.path.abspath(os.path.join(*paths))
  68     return dir, os.path.normcase(dir)
  69
  70 def abs__file__():
  71     """Set all module' __file__ attribute to an absolute path"""
  72     for m in sys.modules.values():
  73         if hasattr(m, '__loader__'):
  74             continue   # don't mess with a PEP 302-supplied __file__
  75         try:
  76             m.__file__ = os.path.abspath(m.__file__)
  77         except AttributeError:
  78             continue
  79
  80 def removeduppaths():
  81     """ Remove duplicate entries from sys.path along with making them
  82     absolute"""
  83     # This ensures that the initial path provided by the interpreter contains
  84     # only absolute pathnames, even if we're running from the build directory.
  85     L = []
  86     known_paths = set()
  87     for dir in sys.path:
  88         # Filter out duplicate paths (on case-insensitive file systems also
  89         # if they only differ in case); turn relative paths into absolute
  90         # paths.
  91         dir, dircase = makepath(dir)
  92         if not dircase in known_paths:
  93             L.append(dir)
  94             known_paths.add(dircase)
  95     sys.path[:] = L
  96     return known_paths
  97
  98 # XXX This should not be part of site.py, since it is needed even when
  99 # using the -S option for Python.  See http://www.python.org/sf/586680
 100 def addbuilddir():
 101     """Append ./build/lib.<platform> in case we're running in the build dir
 102     (especially for Guido :-)"""
 103     from distutils.util import get_platform
 104     s = "build/lib.%s-%.3s" % (get_platform(), sys.version)
 105     s = os.path.join(os.path.dirname(sys.path[-1]), s)
 106     sys.path.append(s)
 107
 108 def _init_pathinfo():
 109     """Return a set containing all existing directory entries from sys.path"""
 110     d = set()
 111     for dir in sys.path:
 112         try:
 113             if os.path.isdir(dir):
 114                 dir, dircase = makepath(dir)
 115                 d.add(dircase)
 116         except TypeError:
 117             continue
 118     return d
 119
 120 def addpackage(sitedir, name, known_paths):
 121     """Add a new path to known_paths by combining sitedir and 'name' or execute
 122     sitedir if it starts with 'import'"""
 123     if known_paths is None:
 124         _init_pathinfo()
 125         reset = 1
 126     else:
 127         reset = 0
 128     fullname = os.path.join(sitedir, name)
 129     try:
 130         f = open(fullname, "rU")
 131     except IOError:
 132         return
 133     try:
 134         for line in f:
 135             if line.startswith("#"):
 136                 continue
 137             if line.startswith("import"):
 138                 exec line
 139                 continue
 140             line = line.rstrip()
 141             dir, dircase = makepath(sitedir, line)
 142             if not dircase in known_paths and os.path.exists(dir):
 143                 sys.path.append(dir)
 144                 known_paths.add(dircase)
 145     finally:
 146         f.close()
 147     if reset:
 148         known_paths = None
 149     return known_paths
 150
 151 def addsitedir(sitedir, known_paths=None):
 152     """Add 'sitedir' argument to sys.path if missing and handle .pth files in
 153     'sitedir'"""
 154     if known_paths is None:
 155         known_paths = _init_pathinfo()
 156         reset = 1
 157     else:
 158         reset = 0
 159     sitedir, sitedircase = makepath(sitedir)
 160     if not sitedircase in known_paths:
 161         sys.path.append(sitedir)        # Add path component
 162     try:
 163         names = os.listdir(sitedir)
 164     except os.error:
 165         return
 166     names.sort()
 167     for name in names:
 168         if name.endswith(os.extsep + "pth"):
 169             addpackage(sitedir, name, known_paths)
 170     if reset:
 171         known_paths = None
 172     return known_paths
 173
 174 def addsitepackages(known_paths):
 175     """Add site-packages (and possibly site-python) to sys.path"""
 176     prefixes = [sys.prefix]
 177     if sys.exec_prefix != sys.prefix:
 178         prefixes.append(sys.exec_prefix)
 179     for prefix in prefixes:
 180         if prefix:
 181             if sys.platform in ('os2emx', 'riscos'):
 182                 sitedirs = [os.path.join(prefix, "Lib", "site-packages")]
 183             elif os.sep == '/':
 184                 sitedirs = [os.path.join(prefix,
 185                                          "lib",
 186                                          "python" + sys.version[:3],
 187                                          "site-packages"),
 188                             os.path.join(prefix, "lib", "site-python")]
 189             else:
 190                 sitedirs = [prefix, os.path.join(prefix, "lib", "site-packages")]
 191             if sys.platform == 'darwin':
 192                 # for framework builds *only* we add the standard Apple
 193                 # locations. Currently only per-user, but /Library and
 194                 # /Network/Library could be added too
 195                 if 'Python.framework' in prefix:
 196                     home = os.environ.get('HOME')
 197                     if home:
 198                         sitedirs.append(
 199                             os.path.join(home,
 200                                          'Library',
 201                                          'Python',
 202                                          sys.version[:3],
 203                                          'site-packages'))
 204             for sitedir in sitedirs:
 205                 if os.path.isdir(sitedir):
 206                     addsitedir(sitedir, known_paths)
 207     return None
 208
 209
 210 def setBEGINLIBPATH():
 211     """The OS/2 EMX port has optional extension modules that do double duty
 212     as DLLs (and must use the .DLL file extension) for other extensions.
 213     The library search path needs to be amended so these will be found
 214     during module import.  Use BEGINLIBPATH so that these are at the start
 215     of the library search path.
 216
 217     """
 218     dllpath = os.path.join(sys.prefix, "Lib", "lib-dynload")
 219     libpath = os.environ['BEGINLIBPATH'].split(';')
 220     if libpath[-1]:
 221         libpath.append(dllpath)
 222     else:
 223         libpath[-1] = dllpath
 224     os.environ['BEGINLIBPATH'] = ';'.join(libpath)
 225
 226
 227 def setquit():
 228     """Define new built-ins 'quit' and 'exit'.
 229     These are simply strings that display a hint on how to exit.
 230
 231     """
 232     if os.sep == ':':
 233         eof = 'Cmd-Q'
 234     elif os.sep == '\\':
 235         eof = 'Ctrl-Z plus Return'
 236     else:
 237         eof = 'Ctrl-D (i.e. EOF)'
 238
 239     class Quitter(object):
 240         def __init__(self, name):
 241             self.name = name
 242         def __repr__(self):
 243             return 'Use %s() or %s to exit' % (self.name, eof)
 244         def __call__(self, code=None):
 245             # Shells like IDLE catch the SystemExit, but listen when their
 246             # stdin wrapper is closed.
 247             try:
 248                 sys.stdin.close()
 249             except:
 250                 pass
 251             raise SystemExit(code)
 252     __builtin__.quit = Quitter('quit')
 253     __builtin__.exit = Quitter('exit')
 254
 255
 256 class _Printer(object):
 257     """interactive prompt objects for printing the license text, a list of
 258     contributors and the copyright notice."""
 259
 260     MAXLINES = 23
 261
 262     def __init__(self, name, data, files=(), dirs=()):
 263         self.__name = name
 264         self.__data = data
 265         self.__files = files
 266         self.__dirs = dirs
 267         self.__lines = None
 268
 269     def __setup(self):
 270         if self.__lines:
 271             return
 272         data = None
 273         for dir in self.__dirs:
 274             for filename in self.__files:
 275                 filename = os.path.join(dir, filename)
 276                 try:
 277                     fp = file(filename, "rU")
 278                     data = fp.read()
 279                     fp.close()
 280                     break
 281                 except IOError:
 282                     pass
 283             if data:
 284                 break
 285         if not data:
 286             data = self.__data
 287         self.__lines = data.split('\n')
 288         self.__linecnt = len(self.__lines)
 289
 290     def __repr__(self):
 291         self.__setup()
 292         if len(self.__lines) <= self.MAXLINES:
 293             return "\n".join(self.__lines)
 294         else:
 295             return "Type %s() to see the full %s text" % ((self.__name,)*2)
 296
 297     def __call__(self):
 298         self.__setup()
 299         prompt = 'Hit Return for more, or q (and Return) to quit: '
 300         lineno = 0
 301         while 1:
 302             try:
 303                 for i in range(lineno, lineno + self.MAXLINES):
 304                     print self.__lines[i]
 305             except IndexError:
 306                 break
 307             else:
 308                 lineno += self.MAXLINES
 309                 key = None
 310                 while key is None:
 311                     key = raw_input(prompt)
 312                     if key not in ('', 'q'):
 313                         key = None
 314                 if key == 'q':
 315                     break
 316
 317 def setcopyright():
 318     """Set 'copyright' and 'credits' in __builtin__"""
 319     __builtin__.copyright = _Printer("copyright", sys.copyright)
 320     if sys.platform[:4] == 'java':
 321         __builtin__.credits = _Printer(
 322             "credits",
 323             "Jython is maintained by the Jython developers (www.jython.org).")
 324     else:
 325         __builtin__.credits = _Printer("credits", """\
 326     Thanks to CWI, CNRI, BeOpen.com, Zope Corporation and a cast of thousands
 327     for supporting Python development.  See www.python.org for more information.""")
 328     here = os.path.dirname(os.__file__)
 329     __builtin__.license = _Printer(
 330         "license", "See http://www.python.org/%.3s/license.html" % sys.version,
 331         ["LICENSE.txt", "LICENSE"],
 332         [os.path.join(here, os.pardir), here, os.curdir])
 333
 334
 335 class _Helper(object):
 336     """Define the built-in 'help'.
 337     This is a wrapper around pydoc.help (with a twist).
 338
 339     """
 340
 341     def __repr__(self):
 342         return "Type help() for interactive help, " \
 343                "or help(object) for help about object."
 344     def __call__(self, *args, **kwds):
 345         import pydoc
 346         return pydoc.help(*args, **kwds)
 347
 348 def sethelper():
 349     __builtin__.help = _Helper()
 350
 351 def aliasmbcs():
 352     """On Windows, some default encodings are not provided by Python,
 353     while they are always available as "mbcs" in each locale. Make
 354     them usable by aliasing to "mbcs" in such a case."""
 355     if sys.platform == 'win32':
 356         import locale, codecs
 357         enc = locale.getdefaultlocale()[1]
 358         if enc.startswith('cp'):            # "cp***" ?
 359             try:
 360                 codecs.lookup(enc)
 361             except LookupError:
 362                 import encodings
 363                 encodings._cache[enc] = encodings._unknown
 364                 encodings.aliases.aliases[enc] = 'mbcs'
 365
 366 def setencoding():
 367     """Set the string encoding used by the Unicode implementation.  The
 368     default is 'ascii', but if you're willing to experiment, you can
 369     change this."""
 370     encoding = "ascii" # Default value set by _PyUnicode_Init()
 371     if 0:
 372         # Enable to support locale aware default string encodings.
 373         import locale
 374         loc = locale.getdefaultlocale()
 375         if loc[1]:
 376             encoding = loc[1]
 377     if 0:
 378         # Enable to switch off string to Unicode coercion and implicit
 379         # Unicode to string conversion.
 380         encoding = "undefined"
 381     if encoding != "ascii":
 382         # On Non-Unicode builds this will raise an AttributeError...
 383         sys.setdefaultencoding(encoding) # Needs Python Unicode build !
 384
 385
 386 def execsitecustomize():
 387     """Run custom site specific code, if available."""
 388     try:
 389         import sitecustomize
 390     except ImportError:
 391         pass
 392
 393
 394 def main():
 395     abs__file__()
 396     paths_in_sys = removeduppaths()
 397     if (os.name == "posix" and sys.path and
 398         os.path.basename(sys.path[-1]) == "Modules"):
 399         addbuilddir()
 400     paths_in_sys = addsitepackages(paths_in_sys)
 401     if sys.platform == 'os2emx':
 402         setBEGINLIBPATH()
 403     setquit()
 404     setcopyright()
 405     sethelper()
 406     aliasmbcs()
 407     setencoding()
 408     execsitecustomize()
 409     # Remove sys.setdefaultencoding() so that users cannot change the
 410     # encoding after initialization.  The test for presence is needed when
 411     # this module is run as a script, because this code is executed twice.
 412     if hasattr(sys, "setdefaultencoding"):
 413         del sys.setdefaultencoding
 414
 415 main()
 416
 417 def _test():
 418     print "sys.path = ["
 419     for dir in sys.path:
 420         print "    %r," % (dir,)
 421     print "]"
 422
 423 if __name__ == '__main__':
 424     _test()