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     """Process a .pth file within the site-packages directory:
 122        For each line in the file, either combine it with sitedir to a path
 123        and add that to known_paths, or execute it if it starts with 'import '.
 124     """
 125     if known_paths is None:
 126         _init_pathinfo()
 127         reset = 1
 128     else:
 129         reset = 0
 130     fullname = os.path.join(sitedir, name)
 131     try:
 132         f = open(fullname, "rU")
 133     except IOError:
 134         return
 135     try:
 136         for line in f:
 137             if line.startswith("#"):
 138                 continue
 139             if line.startswith("import ") or line.startswith("import\t"):
 140                 exec line
 141                 continue
 142             line = line.rstrip()
 143             dir, dircase = makepath(sitedir, line)
 144             if not dircase in known_paths and os.path.exists(dir):
 145                 sys.path.append(dir)
 146                 known_paths.add(dircase)
 147     finally:
 148         f.close()
 149     if reset:
 150         known_paths = None
 151     return known_paths
 152
 153 def addsitedir(sitedir, known_paths=None):
 154     """Add 'sitedir' argument to sys.path if missing and handle .pth files in
 155     'sitedir'"""
 156     if known_paths is None:
 157         known_paths = _init_pathinfo()
 158         reset = 1
 159     else:
 160         reset = 0
 161     sitedir, sitedircase = makepath(sitedir)
 162     if not sitedircase in known_paths:
 163         sys.path.append(sitedir)        # Add path component
 164     try:
 165         names = os.listdir(sitedir)
 166     except os.error:
 167         return
 168     names.sort()
 169     for name in names:
 170         if name.endswith(os.extsep + "pth"):
 171             addpackage(sitedir, name, known_paths)
 172     if reset:
 173         known_paths = None
 174     return known_paths
 175
 176 def addsitepackages(known_paths):
 177     """Add site-packages (and possibly site-python) to sys.path"""
 178     prefixes = [sys.prefix]
 179     if sys.exec_prefix != sys.prefix:
 180         prefixes.append(sys.exec_prefix)
 181     for prefix in prefixes:
 182         if prefix:
 183             if sys.platform in ('os2emx', 'riscos'):
 184                 sitedirs = [os.path.join(prefix, "Lib", "site-packages")]
 185             elif os.sep == '/':
 186                 sitedirs = [os.path.join(prefix,
 187                                          "lib",
 188                                          "python" + sys.version[:3],
 189                                          "site-packages"),
 190                             os.path.join(prefix, "lib", "site-python")]
 191             else:
 192                 sitedirs = [prefix, os.path.join(prefix, "lib", "site-packages")]
 193             if sys.platform == 'darwin':
 194                 # for framework builds *only* we add the standard Apple
 195                 # locations. Currently only per-user, but /Library and
 196                 # /Network/Library could be added too
 197                 if 'Python.framework' in prefix:
 198                     home = os.environ.get('HOME')
 199                     if home:
 200                         sitedirs.append(
 201                             os.path.join(home,
 202                                          'Library',
 203                                          'Python',
 204                                          sys.version[:3],
 205                                          'site-packages'))
 206             for sitedir in sitedirs:
 207                 if os.path.isdir(sitedir):
 208                     addsitedir(sitedir, known_paths)
 209     return None
 210
 211
 212 def setBEGINLIBPATH():
 213     """The OS/2 EMX port has optional extension modules that do double duty
 214     as DLLs (and must use the .DLL file extension) for other extensions.
 215     The library search path needs to be amended so these will be found
 216     during module import.  Use BEGINLIBPATH so that these are at the start
 217     of the library search path.
 218
 219     """
 220     dllpath = os.path.join(sys.prefix, "Lib", "lib-dynload")
 221     libpath = os.environ['BEGINLIBPATH'].split(';')
 222     if libpath[-1]:
 223         libpath.append(dllpath)
 224     else:
 225         libpath[-1] = dllpath
 226     os.environ['BEGINLIBPATH'] = ';'.join(libpath)
 227
 228
 229 def setquit():
 230     """Define new built-ins 'quit' and 'exit'.
 231     These are simply strings that display a hint on how to exit.
 232
 233     """
 234     if os.sep == ':':
 235         eof = 'Cmd-Q'
 236     elif os.sep == '\\':
 237         eof = 'Ctrl-Z plus Return'
 238     else:
 239         eof = 'Ctrl-D (i.e. EOF)'
 240
 241     class Quitter(object):
 242         def __init__(self, name):
 243             self.name = name
 244         def __repr__(self):
 245             return 'Use %s() or %s to exit' % (self.name, eof)
 246         def __call__(self, code=None):
 247             # Shells like IDLE catch the SystemExit, but listen when their
 248             # stdin wrapper is closed.
 249             try:
 250                 sys.stdin.close()
 251             except:
 252                 pass
 253             raise SystemExit(code)
 254     __builtin__.quit = Quitter('quit')
 255     __builtin__.exit = Quitter('exit')
 256
 257
 258 class _Printer(object):
 259     """interactive prompt objects for printing the license text, a list of
 260     contributors and the copyright notice."""
 261
 262     MAXLINES = 23
 263
 264     def __init__(self, name, data, files=(), dirs=()):
 265         self.__name = name
 266         self.__data = data
 267         self.__files = files
 268         self.__dirs = dirs
 269         self.__lines = None
 270
 271     def __setup(self):
 272         if self.__lines:
 273             return
 274         data = None
 275         for dir in self.__dirs:
 276             for filename in self.__files:
 277                 filename = os.path.join(dir, filename)
 278                 try:
 279                     fp = file(filename, "rU")
 280                     data = fp.read()
 281                     fp.close()
 282                     break
 283                 except IOError:
 284                     pass
 285             if data:
 286                 break
 287         if not data:
 288             data = self.__data
 289         self.__lines = data.split('\n')
 290         self.__linecnt = len(self.__lines)
 291
 292     def __repr__(self):
 293         self.__setup()
 294         if len(self.__lines) <= self.MAXLINES:
 295             return "\n".join(self.__lines)
 296         else:
 297             return "Type %s() to see the full %s text" % ((self.__name,)*2)
 298
 299     def __call__(self):
 300         self.__setup()
 301         prompt = 'Hit Return for more, or q (and Return) to quit: '
 302         lineno = 0
 303         while 1:
 304             try:
 305                 for i in range(lineno, lineno + self.MAXLINES):
 306                     print self.__lines[i]
 307             except IndexError:
 308                 break
 309             else:
 310                 lineno += self.MAXLINES
 311                 key = None
 312                 while key is None:
 313                     key = raw_input(prompt)
 314                     if key not in ('', 'q'):
 315                         key = None
 316                 if key == 'q':
 317                     break
 318
 319 def setcopyright():
 320     """Set 'copyright' and 'credits' in __builtin__"""
 321     __builtin__.copyright = _Printer("copyright", sys.copyright)
 322     if sys.platform[:4] == 'java':
 323         __builtin__.credits = _Printer(
 324             "credits",
 325             "Jython is maintained by the Jython developers (www.jython.org).")
 326     else:
 327         __builtin__.credits = _Printer("credits", """\
 328     Thanks to CWI, CNRI, BeOpen.com, Zope Corporation and a cast of thousands
 329     for supporting Python development.  See www.python.org for more information.""")
 330     here = os.path.dirname(os.__file__)
 331     __builtin__.license = _Printer(
 332         "license", "See http://www.python.org/%.3s/license.html" % sys.version,
 333         ["LICENSE.txt", "LICENSE"],
 334         [os.path.join(here, os.pardir), here, os.curdir])
 335
 336
 337 class _Helper(object):
 338     """Define the built-in 'help'.
 339     This is a wrapper around pydoc.help (with a twist).
 340
 341     """
 342
 343     def __repr__(self):
 344         return "Type help() for interactive help, " \
 345                "or help(object) for help about object."
 346     def __call__(self, *args, **kwds):
 347         import pydoc
 348         return pydoc.help(*args, **kwds)
 349
 350 def sethelper():
 351     __builtin__.help = _Helper()
 352
 353 def aliasmbcs():
 354     """On Windows, some default encodings are not provided by Python,
 355     while they are always available as "mbcs" in each locale. Make
 356     them usable by aliasing to "mbcs" in such a case."""
 357     if sys.platform == 'win32':
 358         import locale, codecs
 359         enc = locale.getdefaultlocale()[1]
 360         if enc.startswith('cp'):            # "cp***" ?
 361             try:
 362                 codecs.lookup(enc)
 363             except LookupError:
 364                 import encodings
 365                 encodings._cache[enc] = encodings._unknown
 366                 encodings.aliases.aliases[enc] = 'mbcs'
 367
 368 def setencoding():
 369     """Set the string encoding used by the Unicode implementation.  The
 370     default is 'ascii', but if you're willing to experiment, you can
 371     change this."""
 372     encoding = "ascii" # Default value set by _PyUnicode_Init()
 373     if 0:
 374         # Enable to support locale aware default string encodings.
 375         import locale
 376         loc = locale.getdefaultlocale()
 377         if loc[1]:
 378             encoding = loc[1]
 379     if 0:
 380         # Enable to switch off string to Unicode coercion and implicit
 381         # Unicode to string conversion.
 382         encoding = "undefined"
 383     if encoding != "ascii":
 384         # On Non-Unicode builds this will raise an AttributeError...
 385         sys.setdefaultencoding(encoding) # Needs Python Unicode build !
 386
 387
 388 def execsitecustomize():
 389     """Run custom site specific code, if available."""
 390     try:
 391         import sitecustomize
 392     except ImportError:
 393         pass
 394
 395
 396 def main():
 397     abs__file__()
 398     paths_in_sys = removeduppaths()
 399     if (os.name == "posix" and sys.path and
 400         os.path.basename(sys.path[-1]) == "Modules"):
 401         addbuilddir()
 402     paths_in_sys = addsitepackages(paths_in_sys)
 403     if sys.platform == 'os2emx':
 404         setBEGINLIBPATH()
 405     setquit()
 406     setcopyright()
 407     sethelper()
 408     aliasmbcs()
 409     setencoding()
 410     execsitecustomize()
 411     # Remove sys.setdefaultencoding() so that users cannot change the
 412     # encoding after initialization.  The test for presence is needed when
 413     # this module is run as a script, because this code is executed twice.
 414     if hasattr(sys, "setdefaultencoding"):
 415         del sys.setdefaultencoding
 416
 417 main()
 418
 419 def _test():
 420     print "sys.path = ["
 421     for dir in sys.path:
 422         print "    %r," % (dir,)
 423     print "]"
 424
 425 if __name__ == '__main__':
 426     _test()