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