Source Code for Package SCons.compat

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 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  Other code will not generally reference things in this package through 
 33  the SCons.compat namespace.  The modules included here add things to 
 34  the __builtin__ namespace or the global module list so that the rest 
 35  of our code can use the objects and names imported here regardless of 
 36  Python version. 
 37   
 38  Simply enough, things that go in the __builtin__ name space come from 
 39  our builtins module. 
 40   
 41  The rest of the things here will be in individual compatibility modules 
 42  that are either: 1) suitably modified copies of the future modules that 
 43  we want to use; or 2) backwards compatible re-implementations of the 
 44  specific portions of a future module's API that we want to use. 
 45   
 46  GENERAL WARNINGS:  Implementations of functions in the SCons.compat 
 47  modules are *NOT* guaranteed to be fully compliant with these functions in 
 48  later versions of Python.  We are only concerned with adding functionality 
 49  that we actually use in SCons, so be wary if you lift this code for 
 50  other uses.  (That said, making these more nearly the same as later, 
 51  official versions is still a desirable goal, we just don't need to be 
 52  obsessive about it.) 
 53   
 54  We name the compatibility modules with an initial '_scons_' (for example, 
 55  _scons_subprocess.py is our compatibility module for subprocess) so 
 56  that we can still try to import the real module name and fall back to 
 57  our compatibility module if we get an ImportError.  The import_as() 
 58  function defined below loads the module as the "real" name (without the 
 59  '_scons'), after which all of the "import {module}" statements in the 
 60  rest of our code will find our pre-loaded compatibility module. 
 61  """ 
 62   
 63  __revision__ = "src/engine/SCons/compat/__init__.py 3842 2008/12/20 22:59:52 scons" 
 64   
 65 -def import_as(module, name): 
 66      """ 
 67      Imports the specified module (from our local directory) as the 
 68      specified name. 
 69      """ 
 70      import imp 
 71      import os.path 
 72      dir = os.path.split(__file__)[0] 
 73      file, filename, suffix_mode_type = imp.find_module(module, [dir]) 
 74      imp.load_module(name, file, filename, suffix_mode_type) 
 75   
 76  import builtins 
 77   
 78  try: 
 79      import hashlib 
 80  except ImportError: 
 81      # Pre-2.5 Python has no hashlib module. 
 82      try: 
 83          import_as('_scons_hashlib', 'hashlib') 
 84      except ImportError: 
 85          # If we failed importing our compatibility module, it probably 
 86          # means this version of Python has no md5 module.  Don't do 
 87          # anything and let the higher layer discover this fact, so it 
 88          # can fall back to using timestamp. 
 89          pass 
 90   
 91  try: 
 92      set 
 93  except NameError: 
 94      # Pre-2.4 Python has no native set type 
 95      try: 
 96          # Python 2.2 and 2.3 can use the copy of the 2.[45] sets module 
 97          # that we grabbed. 
 98          import_as('_scons_sets', 'sets') 
 99      except (ImportError, SyntaxError): 
100          # Python 1.5 (ImportError, no __future_ module) and 2.1 
101          # (SyntaxError, no generators in __future__) will blow up 
102          # trying to import the 2.[45] sets module, so back off to a 
103          # custom sets module that can be discarded easily when we 
104          # stop supporting those versions. 
105          import_as('_scons_sets15', 'sets') 
106      import __builtin__ 
107      import sets 
108      __builtin__.set = sets.Set 
109   
110  import fnmatch 
111  try: 
112      fnmatch.filter 
113  except AttributeError: 
114      # Pre-2.2 Python has no fnmatch.filter() function. 
115 -    def filter(names, pat): 
116          """Return the subset of the list NAMES that match PAT""" 
117          import os,posixpath 
118          result=[] 
119          pat = os.path.normcase(pat) 
120          if not fnmatch._cache.has_key(pat): 
121              import re 
122              res = fnmatch.translate(pat) 
123              fnmatch._cache[pat] = re.compile(res) 
124          match = fnmatch._cache[pat].match 
125          if os.path is posixpath: 
126              # normcase on posix is NOP. Optimize it away from the loop. 
127              for name in names: 
128                  if match(name): 
129                      result.append(name) 
130          else: 
131              for name in names: 
132                  if match(os.path.normcase(name)): 
133                      result.append(name) 
134          return result 
135      fnmatch.filter = filter 
136      del filter 
137   
138  try: 
139      import itertools 
140  except ImportError: 
141      # Pre-2.3 Python has no itertools module. 
142      import_as('_scons_itertools', 'itertools') 
143   
144  # If we need the compatibility version of textwrap, it  must be imported 
145  # before optparse, which uses it. 
146  try: 
147      import textwrap 
148  except ImportError: 
149      # Pre-2.3 Python has no textwrap module. 
150      import_as('_scons_textwrap', 'textwrap') 
151   
152  try: 
153      import optparse 
154  except ImportError: 
155      # Pre-2.3 Python has no optparse module. 
156      import_as('_scons_optparse', 'optparse') 
157   
158  import os 
159  try: 
160      os.devnull 
161  except AttributeError: 
162      # Pre-2.4 Python has no os.devnull attribute 
163      import sys 
164      _names = sys.builtin_module_names 
165      if 'posix' in _names: 
166          os.devnull = '/dev/null' 
167      elif 'nt' in _names: 
168          os.devnull = 'nul' 
169      os.path.devnull = os.devnull 
170   
171  import shlex 
172  try: 
173      shlex.split 
174  except AttributeError: 
175      # Pre-2.3 Python has no shlex.split() function. 
176      # 
177      # The full white-space splitting semantics of shlex.split() are 
178      # complicated to reproduce by hand, so just use a compatibility 
179      # version of the shlex module cribbed from Python 2.5 with some 
180      # minor modifications for older Python versions. 
181      del shlex 
182      import_as('_scons_shlex', 'shlex') 
183   
184   
185  import shutil 
186  try: 
187      shutil.move 
188  except AttributeError: 
189      # Pre-2.3 Python has no shutil.move() function. 
190      # 
191      # Cribbed from Python 2.5. 
192      import os 
193   
194 -    def move(src, dst): 
195          """Recursively move a file or directory to another location. 
196   
197          If the destination is on our current filesystem, then simply use 
198          rename.  Otherwise, copy src to the dst and then remove src. 
199          A lot more could be done here...  A look at a mv.c shows a lot of 
200          the issues this implementation glosses over. 
201   
202          """ 
203          try: 
204              os.rename(src, dst) 
205          except OSError: 
206              if os.path.isdir(src): 
207                  if shutil.destinsrc(src, dst): 
208                      raise Error, "Cannot move a directory '%s' into itself '%s'." % (src, dst) 
209                  shutil.copytree(src, dst, symlinks=True) 
210                  shutil.rmtree(src) 
211              else: 
212                  shutil.copy2(src,dst) 
213                  os.unlink(src) 
214      shutil.move = move 
215      del move 
216   
217 -    def destinsrc(src, dst): 
218          src = os.path.abspath(src) 
219          return os.path.abspath(dst)[:len(src)] == src 
220      shutil.destinsrc = destinsrc 
221      del destinsrc 
222   
223   
224  try: 
225      import subprocess 
226  except ImportError: 
227      # Pre-2.4 Python has no subprocess module. 
228      import_as('_scons_subprocess', 'subprocess') 
229   
230  import sys 
231  try: 
232      sys.version_info 
233  except AttributeError: 
234      # Pre-1.6 Python has no sys.version_info 
235      import string 
236      version_string = string.split(sys.version)[0] 
237      version_ints = map(int, string.split(version_string, '.')) 
238      sys.version_info = tuple(version_ints + ['final', 0]) 
239   
240  try: 
241      import UserString 
242  except ImportError: 
243      # Pre-1.6 Python has no UserString module. 
244      import_as('_scons_UserString', 'UserString') 
245