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