SCons.compat

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# Source Code for Package SCons.compat

      1  #
      2  # Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 The SCons Foundation
      3  #
      4  # Permission is hereby granted, free of charge, to any person obtaining
      5  # a copy of this software and associated documentation files (the
      6  # "Software"), to deal in the Software without restriction, including
      7  # without limitation the rights to use, copy, modify, merge, publish,
      8  # distribute, sublicense, and/or sell copies of the Software, and to
      9  # permit persons to whom the Software is furnished to do so, subject to
     10  # the following conditions:
     11  #
     12  # The above copyright notice and this permission notice shall be included
     13  # in all copies or substantial portions of the Software.
     14  #
     15  # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
     16  # KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
     17  # WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
     18  # NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
     19  # LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
     20  # OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
     21  # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
     22  #
     23
     24  __doc__ = """
     25  SCons compatibility package for old Python versions
     26
     27  This subpackage holds modules that provide backwards-compatible
     28  implementations of various things that we'd like to use in SCons but which
     29  only show up in later versions of Python than the early, old version(s)
     30  we still support.
     31
     32  This package will be imported by other code:
     33
     34      import SCons.compat
     35
     36  But other code will not generally reference things in this package through
     37  the SCons.compat namespace.  The modules included here add things to
     38  the __builtin__ namespace or the global module list so that the rest
     39  of our code can use the objects and names imported here regardless of
     40  Python version.
     41
     42  Simply enough, things that go in the __builtin__ name space come from
     43  our builtins module.
     44
     45  The rest of the things here will be in individual compatibility modules
     46  that are either: 1) suitably modified copies of the future modules that
     47  we want to use; or 2) backwards compatible re-implementations of the
     48  specific portions of a future module's API that we want to use.
     49
     50  GENERAL WARNINGS:  Implementations of functions in the SCons.compat
     51  modules are *NOT* guaranteed to be fully compliant with these functions in
     52  later versions of Python.  We are only concerned with adding functionality
     53  that we actually use in SCons, so be wary if you lift this code for
     54  other uses.  (That said, making these more nearly the same as later,
     55  official versions is still a desirable goal, we just don't need to be
     56  obsessive about it.)
     57
     58  We name the compatibility modules with an initial '_scons_' (for example,
     59  _scons_subprocess.py is our compatibility module for subprocess) so
     60  that we can still try to import the real module name and fall back to
     61  our compatibility module if we get an ImportError.  The import_as()
     62  function defined below loads the module as the "real" name (without the
     63  '_scons'), after which all of the "import {module}" statements in the
     64  rest of our code will find our pre-loaded compatibility module.
     65  """
     66
     67  __revision__ = "src/engine/SCons/compat/__init__.py 2725 2008/03/31 12:52:02 knight"
     68
     69 -def import_as(module, name):
     70      """
     71      Imports the specified module (from our local directory) as the
     72      specified name.
     73      """
     74      import imp
     75      import os.path
     76      dir = os.path.split(__file__)[0]
     77      file, filename, suffix_mode_type = imp.find_module(module, [dir])
     78      imp.load_module(name, file, filename, suffix_mode_type)
     79
     80  import builtins
     81
     82  try:
     83      import hashlib
     84  except ImportError:
     85      # Pre-2.5 Python has no hashlib module.
     86      try:
     87          import_as('_scons_hashlib', 'hashlib')
     88      except ImportError:
     89          # If we failed importing our compatibility module, it probably
     90          # means this version of Python has no md5 module.  Don't do
     91          # anything and let the higher layer discover this fact, so it
     92          # can fall back to using timestamp.
     93          pass
     94
     95  try:
     96      set
     97  except NameError:
     98      # Pre-2.4 Python has no native set type
     99      try:
    100          # Python 2.2 and 2.3 can use the copy of the 2.[45] sets module
    101          # that we grabbed.
    102          import_as('_scons_sets', 'sets')
    103      except (ImportError, SyntaxError):
    104          # Python 1.5 (ImportError, no __future_ module) and 2.1
    105          # (SyntaxError, no generators in __future__) will blow up
    106          # trying to import the 2.[45] sets module, so back off to a
    107          # custom sets module that can be discarded easily when we
    108          # stop supporting those versions.
    109          import_as('_scons_sets15', 'sets')
    110      import __builtin__
    111      import sets
    112      __builtin__.set = sets.Set
    113
    114  import fnmatch
    115  try:
    116      fnmatch.filter
    117  except AttributeError:
    118      # Pre-2.2 Python has no fnmatch.filter() function.
    119 -    def filter(names, pat):
    120          """Return the subset of the list NAMES that match PAT"""
    121          import os,posixpath
    122          result=[]
    123          pat = os.path.normcase(pat)
    124          if not fnmatch._cache.has_key(pat):
    125              import re
    126              res = fnmatch.translate(pat)
    127              fnmatch._cache[pat] = re.compile(res)
    128          match = fnmatch._cache[pat].match
    129          if os.path is posixpath:
    130              # normcase on posix is NOP. Optimize it away from the loop.
    131              for name in names:
    132                  if match(name):
    133                      result.append(name)
    134          else:
    135              for name in names:
    136                  if match(os.path.normcase(name)):
    137                      result.append(name)
    138          return result
    139      fnmatch.filter = filter
    140      del filter
    141
    142
    143  # If we need the compatibility version of textwrap, it  must be imported
    144  # before optparse, which uses it.
    145  try:
    146      import textwrap
    147  except ImportError:
    148      # Pre-2.3 Python has no textwrap module.
    149      import_as('_scons_textwrap', 'textwrap')
    150
    151  try:
    152      import optparse
    153  except ImportError:
    154      # Pre-2.3 Python has no optparse module.
    155      import_as('_scons_optparse', 'optparse')
    156
    157  import shlex
    158  try:
    159      shlex.split
    160  except AttributeError:
    161      # Pre-2.3 Python has no shlex.split() function.
    162      #
    163      # The full white-space splitting semantics of shlex.split() are
    164      # complicated to reproduce by hand, so just use a compatibility
    165      # version of the shlex module cribbed from Python 2.5 with some
    166      # minor modifications for older Python versions.
    167      del shlex
    168      import_as('_scons_shlex', 'shlex')
    169
    170  try:
    171      import subprocess
    172  except ImportError:
    173      # Pre-2.4 Python has no subprocess module.
    174      import_as('_scons_subprocess', 'subprocess')
    175
    176  import sys
    177  try:
    178      sys.version_info
    179  except AttributeError:
    180      # Pre-1.6 Python has no sys.version_info
    181      import string
    182      version_string = string.split(sys.version)[0]
    183      version_ints = map(int, string.split(version_string, '.'))
    184      sys.version_info = tuple(version_ints + ['final', 0])
    185
    186  try:
    187      import UserString
    188  except ImportError:
    189      # Pre-1.6 Python has no UserString module.
    190      import_as('_scons_UserString', 'UserString')
    191