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/python1.5/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/python1.5/site-packages/bar
  48   /usr/local/lib/python1.5/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             raise SystemExit(code)
 246     __builtin__.quit = Quitter('quit')
 247     __builtin__.exit = Quitter('exit')
 248
 249
 250 class _Printer(object):
 251     """interactive prompt objects for printing the license text, a list of
 252     contributors and the copyright notice."""
 253
 254     MAXLINES = 23
 255
 256     def __init__(self, name, data, files=(), dirs=()):
 257         self.__name = name
 258         self.__data = data
 259         self.__files = files
 260         self.__dirs = dirs
 261         self.__lines = None
 262
 263     def __setup(self):
 264         if self.__lines:
 265             return
 266         data = None
 267         for dir in self.__dirs:
 268             for filename in self.__files:
 269                 filename = os.path.join(dir, filename)
 270                 try:
 271                     fp = file(filename, "rU")
 272                     data = fp.read()
 273                     fp.close()
 274                     break
 275                 except IOError:
 276                     pass
 277             if data:
 278                 break
 279         if not data:
 280             data = self.__data
 281         self.__lines = data.split('\n')
 282         self.__linecnt = len(self.__lines)
 283
 284     def __repr__(self):
 285         self.__setup()
 286         if len(self.__lines) <= self.MAXLINES:
 287             return "\n".join(self.__lines)
 288         else:
 289             return "Type %s() to see the full %s text" % ((self.__name,)*2)
 290
 291     def __call__(self):
 292         self.__setup()
 293         prompt = 'Hit Return for more, or q (and Return) to quit: '
 294         lineno = 0
 295         while 1:
 296             try:
 297                 for i in range(lineno, lineno + self.MAXLINES):
 298                     print self.__lines[i]
 299             except IndexError:
 300                 break
 301             else:
 302                 lineno += self.MAXLINES
 303                 key = None
 304                 while key is None:
 305                     key = raw_input(prompt)
 306                     if key not in ('', 'q'):
 307                         key = None
 308                 if key == 'q':
 309                     break
 310
 311 def setcopyright():
 312     """Set 'copyright' and 'credits' in __builtin__"""
 313     __builtin__.copyright = _Printer("copyright", sys.copyright)
 314     if sys.platform[:4] == 'java':
 315         __builtin__.credits = _Printer(
 316             "credits",
 317             "Jython is maintained by the Jython developers (www.jython.org).")
 318     else:
 319         __builtin__.credits = _Printer("credits", """\
 320     Thanks to CWI, CNRI, BeOpen.com, Zope Corporation and a cast of thousands
 321     for supporting Python development.  See www.python.org for more information.""")
 322     here = os.path.dirname(os.__file__)
 323     __builtin__.license = _Printer(
 324         "license", "See http://www.python.org/%.3s/license.html" % sys.version,
 325         ["LICENSE.txt", "LICENSE"],
 326         [os.path.join(here, os.pardir), here, os.curdir])
 327
 328
 329 class _Helper(object):
 330     """Define the built-in 'help'.
 331     This is a wrapper around pydoc.help (with a twist).
 332
 333     """
 334
 335     def __repr__(self):
 336         return "Type help() for interactive help, " \
 337                "or help(object) for help about object."
 338     def __call__(self, *args, **kwds):
 339         import pydoc
 340         return pydoc.help(*args, **kwds)
 341
 342 def sethelper():
 343     __builtin__.help = _Helper()
 344
 345 def aliasmbcs():
 346     """On Windows, some default encodings are not provided by Python,
 347     while they are always available as "mbcs" in each locale. Make
 348     them usable by aliasing to "mbcs" in such a case."""
 349     if sys.platform == 'win32':
 350         import locale, codecs
 351         enc = locale.getdefaultlocale()[1]
 352         if enc.startswith('cp'):            # "cp***" ?
 353             try:
 354                 codecs.lookup(enc)
 355             except LookupError:
 356                 import encodings
 357                 encodings._cache[enc] = encodings._unknown
 358                 encodings.aliases.aliases[enc] = 'mbcs'
 359
 360 def setencoding():
 361     """Set the string encoding used by the Unicode implementation.  The
 362     default is 'ascii', but if you're willing to experiment, you can
 363     change this."""
 364     encoding = "ascii" # Default value set by _PyUnicode_Init()
 365     if 0:
 366         # Enable to support locale aware default string encodings.
 367         import locale
 368         loc = locale.getdefaultlocale()
 369         if loc[1]:
 370             encoding = loc[1]
 371     if 0:
 372         # Enable to switch off string to Unicode coercion and implicit
 373         # Unicode to string conversion.
 374         encoding = "undefined"
 375     if encoding != "ascii":
 376         # On Non-Unicode builds this will raise an AttributeError...
 377         sys.setdefaultencoding(encoding) # Needs Python Unicode build !
 378
 379
 380 def execsitecustomize():
 381     """Run custom site specific code, if available."""
 382     try:
 383         import sitecustomize
 384     except ImportError:
 385         pass
 386
 387
 388 def main():
 389     abs__file__()
 390     paths_in_sys = removeduppaths()
 391     if (os.name == "posix" and sys.path and
 392         os.path.basename(sys.path[-1]) == "Modules"):
 393         addbuilddir()
 394     paths_in_sys = addsitepackages(paths_in_sys)
 395     if sys.platform == 'os2emx':
 396         setBEGINLIBPATH()
 397     setquit()
 398     setcopyright()
 399     sethelper()
 400     aliasmbcs()
 401     setencoding()
 402     execsitecustomize()
 403     # Remove sys.setdefaultencoding() so that users cannot change the
 404     # encoding after initialization.  The test for presence is needed when
 405     # this module is run as a script, because this code is executed twice.
 406     if hasattr(sys, "setdefaultencoding"):
 407         del sys.setdefaultencoding
 408
 409 main()
 410
 411 def _test():
 412     print "sys.path = ["
 413     for dir in sys.path:
 414         print "    %r," % (dir,)
 415     print "]"
 416
 417 if __name__ == '__main__':
 418     _test()