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