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 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 \code{#} are skipped. Lines starting with \code{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, os
  61
  62 if os.sep==".":
  63     endsep = "/"
  64 else:
  65     endsep = "."
  66
  67
  68 def makepath(*paths):
  69     dir = os.path.abspath(os.path.join(*paths))
  70     return dir, os.path.normcase(dir)
  71
  72 for m in sys.modules.values():
  73     if hasattr(m, "__file__") and m.__file__:
  74         m.__file__ = os.path.abspath(m.__file__)
  75 del m
  76
  77 # This ensures that the initial path provided by the interpreter contains
  78 # only absolute pathnames, even if we're running from the build directory.
  79 L = []
  80 _dirs_in_sys_path = {}
  81 for dir in sys.path:
  82     # Filter out paths that don't exist, but leave in the empty string
  83     # since it's a special case. We also need to special-case the Mac,
  84     # as file names are allowed on sys.path there.
  85     if sys.platform != 'mac':
  86         if dir and not os.path.isdir(dir):
  87             continue
  88     else:
  89         if dir and not os.path.exists(dir):
  90             continue
  91     dir, dircase = makepath(dir)
  92     if not _dirs_in_sys_path.has_key(dircase):
  93         L.append(dir)
  94         _dirs_in_sys_path[dircase] = 1
  95 sys.path[:] = L
  96 del dir, L
  97
  98 # Append ./build/lib.<platform> in case we're running in the build dir
  99 # (especially for Guido :-)
 100 if os.name == "posix" and os.path.basename(sys.path[-1]) == "Modules":
 101     from distutils.util import get_platform
 102     s = "build/lib.%s-%.3s" % (get_platform(), sys.version)
 103     s = os.path.join(os.path.dirname(sys.path[-1]), s)
 104     sys.path.append(s)
 105     del get_platform, s
 106
 107 def _init_pathinfo():
 108     global _dirs_in_sys_path
 109     _dirs_in_sys_path = d = {}
 110     for dir in sys.path:
 111         if dir and not os.path.isdir(dir):
 112             continue
 113         dir, dircase = makepath(dir)
 114         d[dircase] = 1
 115
 116 def addsitedir(sitedir):
 117     global _dirs_in_sys_path
 118     if _dirs_in_sys_path is None:
 119         _init_pathinfo()
 120         reset = 1
 121     else:
 122         reset = 0
 123     sitedir, sitedircase = makepath(sitedir)
 124     if not _dirs_in_sys_path.has_key(sitedircase):
 125         sys.path.append(sitedir)        # Add path component
 126     try:
 127         names = os.listdir(sitedir)
 128     except os.error:
 129         return
 130     names.sort()
 131     for name in names:
 132         if name[-4:] == endsep + "pth":
 133             addpackage(sitedir, name)
 134     if reset:
 135         _dirs_in_sys_path = None
 136
 137 def addpackage(sitedir, name):
 138     global _dirs_in_sys_path
 139     if _dirs_in_sys_path is None:
 140         _init_pathinfo()
 141         reset = 1
 142     else:
 143         reset = 0
 144     fullname = os.path.join(sitedir, name)
 145     try:
 146         f = open(fullname)
 147     except IOError:
 148         return
 149     while 1:
 150         dir = f.readline()
 151         if not dir:
 152             break
 153         if dir[0] == '#':
 154             continue
 155         if dir.startswith("import"):
 156             exec dir
 157             continue
 158         if dir[-1] == '\n':
 159             dir = dir[:-1]
 160         dir, dircase = makepath(sitedir, dir)
 161         if not _dirs_in_sys_path.has_key(dircase) and os.path.exists(dir):
 162             sys.path.append(dir)
 163             _dirs_in_sys_path[dircase] = 1
 164     if reset:
 165         _dirs_in_sys_path = None
 166
 167 prefixes = [sys.prefix]
 168 if sys.exec_prefix != sys.prefix:
 169     prefixes.append(sys.exec_prefix)
 170 for prefix in prefixes:
 171     if prefix:
 172         if os.sep == '/':
 173             sitedirs = [os.path.join(prefix,
 174                                      "lib",
 175                                      "python" + sys.version[:3],
 176                                      "site-packages"),
 177                         os.path.join(prefix, "lib", "site-python")]
 178         else:
 179             sitedirs = [prefix, os.path.join(prefix, "lib", "site-packages")]
 180         for sitedir in sitedirs:
 181             if os.path.isdir(sitedir):
 182                 addsitedir(sitedir)
 183
 184 _dirs_in_sys_path = None
 185
 186
 187 # Define new built-ins 'quit' and 'exit'.
 188 # These are simply strings that display a hint on how to exit.
 189 if os.sep == ':':
 190     exit = 'Use Cmd-Q to quit.'
 191 elif os.sep == '\\':
 192     exit = 'Use Ctrl-Z plus Return to exit.'
 193 else:
 194     exit = 'Use Ctrl-D (i.e. EOF) to exit.'
 195 import __builtin__
 196 __builtin__.quit = __builtin__.exit = exit
 197 del exit
 198
 199 # interactive prompt objects for printing the license text, a list of
 200 # contributors and the copyright notice.
 201 class _Printer:
 202     MAXLINES = 23
 203
 204     def __init__(self, name, data, files=(), dirs=()):
 205         self.__name = name
 206         self.__data = data
 207         self.__files = files
 208         self.__dirs = dirs
 209         self.__lines = None
 210
 211     def __setup(self):
 212         if self.__lines:
 213             return
 214         data = None
 215         for dir in self.__dirs:
 216             for file in self.__files:
 217                 file = os.path.join(dir, file)
 218                 try:
 219                     fp = open(file)
 220                     data = fp.read()
 221                     fp.close()
 222                     break
 223                 except IOError:
 224                     pass
 225             if data:
 226                 break
 227         if not data:
 228             data = self.__data
 229         self.__lines = data.split('\n')
 230         self.__linecnt = len(self.__lines)
 231
 232     def __repr__(self):
 233         self.__setup()
 234         if len(self.__lines) <= self.MAXLINES:
 235             return "\n".join(self.__lines)
 236         else:
 237             return "Type %s() to see the full %s text" % ((self.__name,)*2)
 238
 239     def __call__(self):
 240         self.__setup()
 241         prompt = 'Hit Return for more, or q (and Return) to quit: '
 242         lineno = 0
 243         while 1:
 244             try:
 245                 for i in range(lineno, lineno + self.MAXLINES):
 246                     print self.__lines[i]
 247             except IndexError:
 248                 break
 249             else:
 250                 lineno += self.MAXLINES
 251                 key = None
 252                 while key is None:
 253                     key = raw_input(prompt)
 254                     if key not in ('', 'q'):
 255                         key = None
 256                 if key == 'q':
 257                     break
 258
 259 __builtin__.copyright = _Printer("copyright", sys.copyright)
 260 if sys.platform[:4] == 'java':
 261     __builtin__.credits = _Printer(
 262         "credits",
 263         "Jython is maintained by the Jython developers (www.jython.org).")
 264 else:
 265     __builtin__.credits = _Printer("credits", """\
 266 Thanks to CWI, CNRI, BeOpen.com, Digital Creations and a cast of thousands
 267 for supporting Python development.  See www.python.org for more information.""")
 268 here = os.path.dirname(os.__file__)
 269 __builtin__.license = _Printer(
 270     "license", "See http://www.pythonlabs.com/products/python2.0/license.html",
 271     ["LICENSE.txt", "LICENSE"],
 272     [os.path.join(here, os.pardir), here, os.curdir])
 273
 274
 275 # Define new built-in 'help'.
 276 # This is a wrapper around pydoc.help (with a twist).
 277
 278 class _Helper:
 279     def __repr__(self):
 280         return "Type help() for interactive help, " \
 281                "or help(object) for help about object."
 282     def __call__(self, *args, **kwds):
 283         import pydoc
 284         return pydoc.help(*args, **kwds)
 285
 286 __builtin__.help = _Helper()
 287
 288
 289 # Set the string encoding used by the Unicode implementation.  The
 290 # default is 'ascii', but if you're willing to experiment, you can
 291 # change this.
 292
 293 encoding = "ascii" # Default value set by _PyUnicode_Init()
 294
 295 if 0:
 296     # Enable to support locale aware default string encodings.
 297     import locale
 298     loc = locale.getdefaultlocale()
 299     if loc[1]:
 300         encoding = loc[1]
 301
 302 if 0:
 303     # Enable to switch off string to Unicode coercion and implicit
 304     # Unicode to string conversion.
 305     encoding = "undefined"
 306
 307 if encoding != "ascii":
 308     # On Non-Unicode builds this will raise an AttributeError...
 309     sys.setdefaultencoding(encoding) # Needs Python Unicode build !
 310
 311 #
 312 # Run custom site specific code, if available.
 313 #
 314 try:
 315     import sitecustomize
 316 except ImportError:
 317     pass
 318
 319 #
 320 # Remove sys.setdefaultencoding() so that users cannot change the
 321 # encoding after initialization.  The test for presence is needed when
 322 # this module is run as a script, because this code is executed twice.
 323 #
 324 if hasattr(sys, "setdefaultencoding"):
 325     del sys.setdefaultencoding
 326
 327 def _test():
 328     print "sys.path = ["
 329     for dir in sys.path:
 330         print "    %s," % `dir`
 331     print "]"
 332
 333 if __name__ == '__main__':
 334     _test()