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+"""SCons.Util
+
+Various utility functions go here.
+
+"""
+
+#
+# Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 The SCons Foundation
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be included
+# in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
+# KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
+# WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+#
+
+__revision__ = "src/engine/SCons/Util.py 4577 2009/12/27 19:43:56 scons"
+
+import copy
+import os
+import os.path
+import re
+import string
+import sys
+import types
+
+from UserDict import UserDict
+from UserList import UserList
+from UserString import UserString
+
+# Don't "from types import ..." these because we need to get at the
+# types module later to look for UnicodeType.
+DictType = types.DictType
+InstanceType = types.InstanceType
+ListType = types.ListType
+StringType = types.StringType
+TupleType = types.TupleType
+
+def dictify(keys, values, result={}):
+ for k, v in zip(keys, values):
+ result[k] = v
+ return result
+
+_altsep = os.altsep
+if _altsep is None and sys.platform == 'win32':
+ # My ActivePython 2.0.1 doesn't set os.altsep! What gives?
+ _altsep = '/'
+if _altsep:
+ def rightmost_separator(path, sep, _altsep=_altsep):
+ rfind = string.rfind
+ return max(rfind(path, sep), rfind(path, _altsep))
+else:
+ rightmost_separator = string.rfind
+
+# First two from the Python Cookbook, just for completeness.
+# (Yeah, yeah, YAGNI...)
+def containsAny(str, set):
+ """Check whether sequence str contains ANY of the items in set."""
+ for c in set:
+ if c in str: return 1
+ return 0
+
+def containsAll(str, set):
+ """Check whether sequence str contains ALL of the items in set."""
+ for c in set:
+ if c not in str: return 0
+ return 1
+
+def containsOnly(str, set):
+ """Check whether sequence str contains ONLY items in set."""
+ for c in str:
+ if c not in set: return 0
+ return 1
+
+def splitext(path):
+ "Same as os.path.splitext() but faster."
+ sep = rightmost_separator(path, os.sep)
+ dot = string.rfind(path, '.')
+ # An ext is only real if it has at least one non-digit char
+ if dot > sep and not containsOnly(path[dot:], "0123456789."):
+ return path[:dot],path[dot:]
+ else:
+ return path,""
+
+def updrive(path):
+ """
+ Make the drive letter (if any) upper case.
+ This is useful because Windows is inconsitent on the case
+ of the drive letter, which can cause inconsistencies when
+ calculating command signatures.
+ """
+ drive, rest = os.path.splitdrive(path)
+ if drive:
+ path = string.upper(drive) + rest
+ return path
+
+class NodeList(UserList):
+ """This class is almost exactly like a regular list of Nodes
+ (actually it can hold any object), with one important difference.
+ If you try to get an attribute from this list, it will return that
+ attribute from every item in the list. For example:
+
+ >>> someList = NodeList([ ' foo ', ' bar ' ])
+ >>> someList.strip()
+ [ 'foo', 'bar' ]
+ """
+ def __nonzero__(self):
+ return len(self.data) != 0
+
+ def __str__(self):
+ return string.join(map(str, self.data))
+
+ def __iter__(self):
+ return iter(self.data)
+
+ def __call__(self, *args, **kwargs):
+ result = map(lambda x, args=args, kwargs=kwargs: apply(x,
+ args,
+ kwargs),
+ self.data)
+ return self.__class__(result)
+
+ def __getattr__(self, name):
+ result = map(lambda x, n=name: getattr(x, n), self.data)
+ return self.__class__(result)
+
+
+_get_env_var = re.compile(r'^\$([_a-zA-Z]\w*|{[_a-zA-Z]\w*})$')
+
+def get_environment_var(varstr):
+ """Given a string, first determine if it looks like a reference
+ to a single environment variable, like "$FOO" or "${FOO}".
+ If so, return that variable with no decorations ("FOO").
+ If not, return None."""
+ mo=_get_env_var.match(to_String(varstr))
+ if mo:
+ var = mo.group(1)
+ if var[0] == '{':
+ return var[1:-1]
+ else:
+ return var
+ else:
+ return None
+
+class DisplayEngine:
+ def __init__(self):
+ self.__call__ = self.print_it
+
+ def print_it(self, text, append_newline=1):
+ if append_newline: text = text + '\n'
+ try:
+ sys.stdout.write(text)
+ except IOError:
+ # Stdout might be connected to a pipe that has been closed
+ # by now. The most likely reason for the pipe being closed
+ # is that the user has press ctrl-c. It this is the case,
+ # then SCons is currently shutdown. We therefore ignore
+ # IOError's here so that SCons can continue and shutdown
+ # properly so that the .sconsign is correctly written
+ # before SCons exits.
+ pass
+
+ def dont_print(self, text, append_newline=1):
+ pass
+
+ def set_mode(self, mode):
+ if mode:
+ self.__call__ = self.print_it
+ else:
+ self.__call__ = self.dont_print
+
+def render_tree(root, child_func, prune=0, margin=[0], visited={}):
+ """
+ Render a tree of nodes into an ASCII tree view.
+ root - the root node of the tree
+ child_func - the function called to get the children of a node
+ prune - don't visit the same node twice
+ margin - the format of the left margin to use for children of root.
+ 1 results in a pipe, and 0 results in no pipe.
+ visited - a dictionary of visited nodes in the current branch if not prune,
+ or in the whole tree if prune.
+ """
+
+ rname = str(root)
+
+ children = child_func(root)
+ retval = ""
+ for pipe in margin[:-1]:
+ if pipe:
+ retval = retval + "| "
+ else:
+ retval = retval + " "
+
+ if visited.has_key(rname):
+ return retval + "+-[" + rname + "]\n"
+
+ retval = retval + "+-" + rname + "\n"
+ if not prune:
+ visited = copy.copy(visited)
+ visited[rname] = 1
+
+ for i in range(len(children)):
+ margin.append(i<len(children)-1)
+ retval = retval + render_tree(children[i], child_func, prune, margin, visited
+)
+ margin.pop()
+
+ return retval
+
+IDX = lambda N: N and 1 or 0
+
+def print_tree(root, child_func, prune=0, showtags=0, margin=[0], visited={}):
+ """
+ Print a tree of nodes. This is like render_tree, except it prints
+ lines directly instead of creating a string representation in memory,
+ so that huge trees can be printed.
+
+ root - the root node of the tree
+ child_func - the function called to get the children of a node
+ prune - don't visit the same node twice
+ showtags - print status information to the left of each node line
+ margin - the format of the left margin to use for children of root.
+ 1 results in a pipe, and 0 results in no pipe.
+ visited - a dictionary of visited nodes in the current branch if not prune,
+ or in the whole tree if prune.
+ """
+
+ rname = str(root)
+
+ if showtags:
+
+ if showtags == 2:
+ print ' E = exists'
+ print ' R = exists in repository only'
+ print ' b = implicit builder'
+ print ' B = explicit builder'
+ print ' S = side effect'
+ print ' P = precious'
+ print ' A = always build'
+ print ' C = current'
+ print ' N = no clean'
+ print ' H = no cache'
+ print ''
+
+ tags = ['[']
+ tags.append(' E'[IDX(root.exists())])
+ tags.append(' R'[IDX(root.rexists() and not root.exists())])
+ tags.append(' BbB'[[0,1][IDX(root.has_explicit_builder())] +
+ [0,2][IDX(root.has_builder())]])
+ tags.append(' S'[IDX(root.side_effect)])
+ tags.append(' P'[IDX(root.precious)])
+ tags.append(' A'[IDX(root.always_build)])
+ tags.append(' C'[IDX(root.is_up_to_date())])
+ tags.append(' N'[IDX(root.noclean)])
+ tags.append(' H'[IDX(root.nocache)])
+ tags.append(']')
+
+ else:
+ tags = []
+
+ def MMM(m):
+ return [" ","| "][m]
+ margins = map(MMM, margin[:-1])
+
+ children = child_func(root)
+
+ if prune and visited.has_key(rname) and children:
+ print string.join(tags + margins + ['+-[', rname, ']'], '')
+ return
+
+ print string.join(tags + margins + ['+-', rname], '')
+
+ visited[rname] = 1
+
+ if children:
+ margin.append(1)
+ idx = IDX(showtags)
+ for C in children[:-1]:
+ print_tree(C, child_func, prune, idx, margin, visited)
+ margin[-1] = 0
+ print_tree(children[-1], child_func, prune, idx, margin, visited)
+ margin.pop()
+
+
+
+# Functions for deciding if things are like various types, mainly to
+# handle UserDict, UserList and UserString like their underlying types.
+#
+# Yes, all of this manual testing breaks polymorphism, and the real
+# Pythonic way to do all of this would be to just try it and handle the
+# exception, but handling the exception when it's not the right type is
+# often too slow.
+
+try:
+ class mystr(str):
+ pass
+except TypeError:
+ # An older Python version without new-style classes.
+ #
+ # The actual implementations here have been selected after timings
+ # coded up in in bench/is_types.py (from the SCons source tree,
+ # see the scons-src distribution), mostly against Python 1.5.2.
+ # Key results from those timings:
+ #
+ # -- Storing the type of the object in a variable (t = type(obj))
+ # slows down the case where it's a native type and the first
+ # comparison will match, but nicely speeds up the case where
+ # it's a different native type. Since that's going to be
+ # common, it's a good tradeoff.
+ #
+ # -- The data show that calling isinstance() on an object that's
+ # a native type (dict, list or string) is expensive enough
+ # that checking up front for whether the object is of type
+ # InstanceType is a pretty big win, even though it does slow
+ # down the case where it really *is* an object instance a
+ # little bit.
+ def is_Dict(obj):
+ t = type(obj)
+ return t is DictType or \
+ (t is InstanceType and isinstance(obj, UserDict))
+
+ def is_List(obj):
+ t = type(obj)
+ return t is ListType \
+ or (t is InstanceType and isinstance(obj, UserList))
+
+ def is_Sequence(obj):
+ t = type(obj)
+ return t is ListType \
+ or t is TupleType \
+ or (t is InstanceType and isinstance(obj, UserList))
+
+ def is_Tuple(obj):
+ t = type(obj)
+ return t is TupleType
+
+ if hasattr(types, 'UnicodeType'):
+ def is_String(obj):
+ t = type(obj)
+ return t is StringType \
+ or t is UnicodeType \
+ or (t is InstanceType and isinstance(obj, UserString))
+ else:
+ def is_String(obj):
+ t = type(obj)
+ return t is StringType \
+ or (t is InstanceType and isinstance(obj, UserString))
+
+ def is_Scalar(obj):
+ return is_String(obj) or not is_Sequence(obj)
+
+ def flatten(obj, result=None):
+ """Flatten a sequence to a non-nested list.
+
+ Flatten() converts either a single scalar or a nested sequence
+ to a non-nested list. Note that flatten() considers strings
+ to be scalars instead of sequences like Python would.
+ """
+ if is_Scalar(obj):
+ return [obj]
+ if result is None:
+ result = []
+ for item in obj:
+ if is_Scalar(item):
+ result.append(item)
+ else:
+ flatten_sequence(item, result)
+ return result
+
+ def flatten_sequence(sequence, result=None):
+ """Flatten a sequence to a non-nested list.
+
+ Same as flatten(), but it does not handle the single scalar
+ case. This is slightly more efficient when one knows that
+ the sequence to flatten can not be a scalar.
+ """
+ if result is None:
+ result = []
+ for item in sequence:
+ if is_Scalar(item):
+ result.append(item)
+ else:
+ flatten_sequence(item, result)
+ return result
+
+ #
+ # Generic convert-to-string functions that abstract away whether or
+ # not the Python we're executing has Unicode support. The wrapper
+ # to_String_for_signature() will use a for_signature() method if the
+ # specified object has one.
+ #
+ if hasattr(types, 'UnicodeType'):
+ UnicodeType = types.UnicodeType
+ def to_String(s):
+ if isinstance(s, UserString):
+ t = type(s.data)
+ else:
+ t = type(s)
+ if t is UnicodeType:
+ return unicode(s)
+ else:
+ return str(s)
+ else:
+ to_String = str
+
+ def to_String_for_signature(obj):
+ try:
+ f = obj.for_signature
+ except AttributeError:
+ return to_String_for_subst(obj)
+ else:
+ return f()
+
+ def to_String_for_subst(s):
+ if is_Sequence( s ):
+ return string.join( map(to_String_for_subst, s) )
+
+ return to_String( s )
+
+else:
+ # A modern Python version with new-style classes, so we can just use
+ # isinstance().
+ #
+ # We are using the following trick to speed-up these
+ # functions. Default arguments are used to take a snapshot of the
+ # the global functions and constants used by these functions. This
+ # transforms accesses to global variable into local variables
+ # accesses (i.e. LOAD_FAST instead of LOAD_GLOBAL).
+
+ DictTypes = (dict, UserDict)
+ ListTypes = (list, UserList)
+ SequenceTypes = (list, tuple, UserList)
+
+ # Empirically, Python versions with new-style classes all have
+ # unicode.
+ #
+ # Note that profiling data shows a speed-up when comparing
+ # explicitely with str and unicode instead of simply comparing
+ # with basestring. (at least on Python 2.5.1)
+ StringTypes = (str, unicode, UserString)
+
+ # Empirically, it is faster to check explicitely for str and
+ # unicode than for basestring.
+ BaseStringTypes = (str, unicode)
+
+ def is_Dict(obj, isinstance=isinstance, DictTypes=DictTypes):
+ return isinstance(obj, DictTypes)
+
+ def is_List(obj, isinstance=isinstance, ListTypes=ListTypes):
+ return isinstance(obj, ListTypes)
+
+ def is_Sequence(obj, isinstance=isinstance, SequenceTypes=SequenceTypes):
+ return isinstance(obj, SequenceTypes)
+
+ def is_Tuple(obj, isinstance=isinstance, tuple=tuple):
+ return isinstance(obj, tuple)
+
+ def is_String(obj, isinstance=isinstance, StringTypes=StringTypes):
+ return isinstance(obj, StringTypes)
+
+ def is_Scalar(obj, isinstance=isinstance, StringTypes=StringTypes, SequenceTypes=SequenceTypes):
+ # Profiling shows that there is an impressive speed-up of 2x
+ # when explicitely checking for strings instead of just not
+ # sequence when the argument (i.e. obj) is already a string.
+ # But, if obj is a not string than it is twice as fast to
+ # check only for 'not sequence'. The following code therefore
+ # assumes that the obj argument is a string must of the time.
+ return isinstance(obj, StringTypes) or not isinstance(obj, SequenceTypes)
+
+ def do_flatten(sequence, result, isinstance=isinstance,
+ StringTypes=StringTypes, SequenceTypes=SequenceTypes):
+ for item in sequence:
+ if isinstance(item, StringTypes) or not isinstance(item, SequenceTypes):
+ result.append(item)
+ else:
+ do_flatten(item, result)
+
+ def flatten(obj, isinstance=isinstance, StringTypes=StringTypes,
+ SequenceTypes=SequenceTypes, do_flatten=do_flatten):
+ """Flatten a sequence to a non-nested list.
+
+ Flatten() converts either a single scalar or a nested sequence
+ to a non-nested list. Note that flatten() considers strings
+ to be scalars instead of sequences like Python would.
+ """
+ if isinstance(obj, StringTypes) or not isinstance(obj, SequenceTypes):
+ return [obj]
+ result = []
+ for item in obj:
+ if isinstance(item, StringTypes) or not isinstance(item, SequenceTypes):
+ result.append(item)
+ else:
+ do_flatten(item, result)
+ return result
+
+ def flatten_sequence(sequence, isinstance=isinstance, StringTypes=StringTypes,
+ SequenceTypes=SequenceTypes, do_flatten=do_flatten):
+ """Flatten a sequence to a non-nested list.
+
+ Same as flatten(), but it does not handle the single scalar
+ case. This is slightly more efficient when one knows that
+ the sequence to flatten can not be a scalar.
+ """
+ result = []
+ for item in sequence:
+ if isinstance(item, StringTypes) or not isinstance(item, SequenceTypes):
+ result.append(item)
+ else:
+ do_flatten(item, result)
+ return result
+
+
+ #
+ # Generic convert-to-string functions that abstract away whether or
+ # not the Python we're executing has Unicode support. The wrapper
+ # to_String_for_signature() will use a for_signature() method if the
+ # specified object has one.
+ #
+ def to_String(s,
+ isinstance=isinstance, str=str,
+ UserString=UserString, BaseStringTypes=BaseStringTypes):
+ if isinstance(s,BaseStringTypes):
+ # Early out when already a string!
+ return s
+ elif isinstance(s, UserString):
+ # s.data can only be either a unicode or a regular
+ # string. Please see the UserString initializer.
+ return s.data
+ else:
+ return str(s)
+
+ def to_String_for_subst(s,
+ isinstance=isinstance, join=string.join, str=str, to_String=to_String,
+ BaseStringTypes=BaseStringTypes, SequenceTypes=SequenceTypes,
+ UserString=UserString):
+
+ # Note that the test cases are sorted by order of probability.
+ if isinstance(s, BaseStringTypes):
+ return s
+ elif isinstance(s, SequenceTypes):
+ l = []
+ for e in s:
+ l.append(to_String_for_subst(e))
+ return join( s )
+ elif isinstance(s, UserString):
+ # s.data can only be either a unicode or a regular
+ # string. Please see the UserString initializer.
+ return s.data
+ else:
+ return str(s)
+
+ def to_String_for_signature(obj, to_String_for_subst=to_String_for_subst,
+ AttributeError=AttributeError):
+ try:
+ f = obj.for_signature
+ except AttributeError:
+ return to_String_for_subst(obj)
+ else:
+ return f()
+
+
+
+# The SCons "semi-deep" copy.
+#
+# This makes separate copies of lists (including UserList objects)
+# dictionaries (including UserDict objects) and tuples, but just copies
+# references to anything else it finds.
+#
+# A special case is any object that has a __semi_deepcopy__() method,
+# which we invoke to create the copy, which is used by the BuilderDict
+# class because of its extra initialization argument.
+#
+# The dispatch table approach used here is a direct rip-off from the
+# normal Python copy module.
+
+_semi_deepcopy_dispatch = d = {}
+
+def _semi_deepcopy_dict(x):
+ copy = {}
+ for key, val in x.items():
+ # The regular Python copy.deepcopy() also deepcopies the key,
+ # as follows:
+ #
+ # copy[semi_deepcopy(key)] = semi_deepcopy(val)
+ #
+ # Doesn't seem like we need to, but we'll comment it just in case.
+ copy[key] = semi_deepcopy(val)
+ return copy
+d[types.DictionaryType] = _semi_deepcopy_dict
+
+def _semi_deepcopy_list(x):
+ return map(semi_deepcopy, x)
+d[types.ListType] = _semi_deepcopy_list
+
+def _semi_deepcopy_tuple(x):
+ return tuple(map(semi_deepcopy, x))
+d[types.TupleType] = _semi_deepcopy_tuple
+
+def _semi_deepcopy_inst(x):
+ if hasattr(x, '__semi_deepcopy__'):
+ return x.__semi_deepcopy__()
+ elif isinstance(x, UserDict):
+ return x.__class__(_semi_deepcopy_dict(x))
+ elif isinstance(x, UserList):
+ return x.__class__(_semi_deepcopy_list(x))
+ else:
+ return x
+d[types.InstanceType] = _semi_deepcopy_inst
+
+def semi_deepcopy(x):
+ copier = _semi_deepcopy_dispatch.get(type(x))
+ if copier:
+ return copier(x)
+ else:
+ return x
+
+
+
+class Proxy:
+ """A simple generic Proxy class, forwarding all calls to
+ subject. So, for the benefit of the python newbie, what does
+ this really mean? Well, it means that you can take an object, let's
+ call it 'objA', and wrap it in this Proxy class, with a statement
+ like this
+
+ proxyObj = Proxy(objA),
+
+ Then, if in the future, you do something like this
+
+ x = proxyObj.var1,
+
+ since Proxy does not have a 'var1' attribute (but presumably objA does),
+ the request actually is equivalent to saying
+
+ x = objA.var1
+
+ Inherit from this class to create a Proxy."""
+
+ def __init__(self, subject):
+ """Wrap an object as a Proxy object"""
+ self.__subject = subject
+
+ def __getattr__(self, name):
+ """Retrieve an attribute from the wrapped object. If the named
+ attribute doesn't exist, AttributeError is raised"""
+ return getattr(self.__subject, name)
+
+ def get(self):
+ """Retrieve the entire wrapped object"""
+ return self.__subject
+
+ def __cmp__(self, other):
+ if issubclass(other.__class__, self.__subject.__class__):
+ return cmp(self.__subject, other)
+ return cmp(self.__dict__, other.__dict__)
+
+# attempt to load the windows registry module:
+can_read_reg = 0
+try:
+ import _winreg
+
+ can_read_reg = 1
+ hkey_mod = _winreg
+
+ RegOpenKeyEx = _winreg.OpenKeyEx
+ RegEnumKey = _winreg.EnumKey
+ RegEnumValue = _winreg.EnumValue
+ RegQueryValueEx = _winreg.QueryValueEx
+ RegError = _winreg.error
+
+except ImportError:
+ try:
+ import win32api
+ import win32con
+ can_read_reg = 1
+ hkey_mod = win32con
+
+ RegOpenKeyEx = win32api.RegOpenKeyEx
+ RegEnumKey = win32api.RegEnumKey
+ RegEnumValue = win32api.RegEnumValue
+ RegQueryValueEx = win32api.RegQueryValueEx
+ RegError = win32api.error
+
+ except ImportError:
+ class _NoError(Exception):
+ pass
+ RegError = _NoError
+
+if can_read_reg:
+ HKEY_CLASSES_ROOT = hkey_mod.HKEY_CLASSES_ROOT
+ HKEY_LOCAL_MACHINE = hkey_mod.HKEY_LOCAL_MACHINE
+ HKEY_CURRENT_USER = hkey_mod.HKEY_CURRENT_USER
+ HKEY_USERS = hkey_mod.HKEY_USERS
+
+ def RegGetValue(root, key):
+ """This utility function returns a value in the registry
+ without having to open the key first. Only available on
+ Windows platforms with a version of Python that can read the
+ registry. Returns the same thing as
+ SCons.Util.RegQueryValueEx, except you just specify the entire
+ path to the value, and don't have to bother opening the key
+ first. So:
+
+ Instead of:
+ k = SCons.Util.RegOpenKeyEx(SCons.Util.HKEY_LOCAL_MACHINE,
+ r'SOFTWARE\Microsoft\Windows\CurrentVersion')
+ out = SCons.Util.RegQueryValueEx(k,
+ 'ProgramFilesDir')
+
+ You can write:
+ out = SCons.Util.RegGetValue(SCons.Util.HKEY_LOCAL_MACHINE,
+ r'SOFTWARE\Microsoft\Windows\CurrentVersion\ProgramFilesDir')
+ """
+ # I would use os.path.split here, but it's not a filesystem
+ # path...
+ p = key.rfind('\\') + 1
+ keyp = key[:p-1] # -1 to omit trailing slash
+ val = key[p:]
+ k = RegOpenKeyEx(root, keyp)
+ return RegQueryValueEx(k,val)
+else:
+ try:
+ e = WindowsError
+ except NameError:
+ # Make sure we have a definition of WindowsError so we can
+ # run platform-independent tests of Windows functionality on
+ # platforms other than Windows. (WindowsError is, in fact, an
+ # OSError subclass on Windows.)
+ class WindowsError(OSError):
+ pass
+ import __builtin__
+ __builtin__.WindowsError = WindowsError
+ else:
+ del e
+
+ HKEY_CLASSES_ROOT = None
+ HKEY_LOCAL_MACHINE = None
+ HKEY_CURRENT_USER = None
+ HKEY_USERS = None
+
+ def RegGetValue(root, key):
+ raise WindowsError
+
+ def RegOpenKeyEx(root, key):
+ raise WindowsError
+
+if sys.platform == 'win32':
+
+ def WhereIs(file, path=None, pathext=None, reject=[]):
+ if path is None:
+ try:
+ path = os.environ['PATH']
+ except KeyError:
+ return None
+ if is_String(path):
+ path = string.split(path, os.pathsep)
+ if pathext is None:
+ try:
+ pathext = os.environ['PATHEXT']
+ except KeyError:
+ pathext = '.COM;.EXE;.BAT;.CMD'
+ if is_String(pathext):
+ pathext = string.split(pathext, os.pathsep)
+ for ext in pathext:
+ if string.lower(ext) == string.lower(file[-len(ext):]):
+ pathext = ['']
+ break
+ if not is_List(reject) and not is_Tuple(reject):
+ reject = [reject]
+ for dir in path:
+ f = os.path.join(dir, file)
+ for ext in pathext:
+ fext = f + ext
+ if os.path.isfile(fext):
+ try:
+ reject.index(fext)
+ except ValueError:
+ return os.path.normpath(fext)
+ continue
+ return None
+
+elif os.name == 'os2':
+
+ def WhereIs(file, path=None, pathext=None, reject=[]):
+ if path is None:
+ try:
+ path = os.environ['PATH']
+ except KeyError:
+ return None
+ if is_String(path):
+ path = string.split(path, os.pathsep)
+ if pathext is None:
+ pathext = ['.exe', '.cmd']
+ for ext in pathext:
+ if string.lower(ext) == string.lower(file[-len(ext):]):
+ pathext = ['']
+ break
+ if not is_List(reject) and not is_Tuple(reject):
+ reject = [reject]
+ for dir in path:
+ f = os.path.join(dir, file)
+ for ext in pathext:
+ fext = f + ext
+ if os.path.isfile(fext):
+ try:
+ reject.index(fext)
+ except ValueError:
+ return os.path.normpath(fext)
+ continue
+ return None
+
+else:
+
+ def WhereIs(file, path=None, pathext=None, reject=[]):
+ import stat
+ if path is None:
+ try:
+ path = os.environ['PATH']
+ except KeyError:
+ return None
+ if is_String(path):
+ path = string.split(path, os.pathsep)
+ if not is_List(reject) and not is_Tuple(reject):
+ reject = [reject]
+ for d in path:
+ f = os.path.join(d, file)
+ if os.path.isfile(f):
+ try:
+ st = os.stat(f)
+ except OSError:
+ # os.stat() raises OSError, not IOError if the file
+ # doesn't exist, so in this case we let IOError get
+ # raised so as to not mask possibly serious disk or
+ # network issues.
+ continue
+ if stat.S_IMODE(st[stat.ST_MODE]) & 0111:
+ try:
+ reject.index(f)
+ except ValueError:
+ return os.path.normpath(f)
+ continue
+ return None
+
+def PrependPath(oldpath, newpath, sep = os.pathsep,
+ delete_existing=1, canonicalize=None):
+ """This prepends newpath elements to the given oldpath. Will only
+ add any particular path once (leaving the first one it encounters
+ and ignoring the rest, to preserve path order), and will
+ os.path.normpath and os.path.normcase all paths to help assure
+ this. This can also handle the case where the given old path
+ variable is a list instead of a string, in which case a list will
+ be returned instead of a string.
+
+ Example:
+ Old Path: "/foo/bar:/foo"
+ New Path: "/biz/boom:/foo"
+ Result: "/biz/boom:/foo:/foo/bar"
+
+ If delete_existing is 0, then adding a path that exists will
+ not move it to the beginning; it will stay where it is in the
+ list.
+
+ If canonicalize is not None, it is applied to each element of
+ newpath before use.
+ """
+
+ orig = oldpath
+ is_list = 1
+ paths = orig
+ if not is_List(orig) and not is_Tuple(orig):
+ paths = string.split(paths, sep)
+ is_list = 0
+
+ if is_String(newpath):
+ newpaths = string.split(newpath, sep)
+ elif not is_List(newpath) and not is_Tuple(newpath):
+ newpaths = [ newpath ] # might be a Dir
+ else:
+ newpaths = newpath
+
+ if canonicalize:
+ newpaths=map(canonicalize, newpaths)
+
+ if not delete_existing:
+ # First uniquify the old paths, making sure to
+ # preserve the first instance (in Unix/Linux,
+ # the first one wins), and remembering them in normpaths.
+ # Then insert the new paths at the head of the list
+ # if they're not already in the normpaths list.
+ result = []
+ normpaths = []
+ for path in paths:
+ if not path:
+ continue
+ normpath = os.path.normpath(os.path.normcase(path))
+ if normpath not in normpaths:
+ result.append(path)
+ normpaths.append(normpath)
+ newpaths.reverse() # since we're inserting at the head
+ for path in newpaths:
+ if not path:
+ continue
+ normpath = os.path.normpath(os.path.normcase(path))
+ if normpath not in normpaths:
+ result.insert(0, path)
+ normpaths.append(normpath)
+ paths = result
+
+ else:
+ newpaths = newpaths + paths # prepend new paths
+
+ normpaths = []
+ paths = []
+ # now we add them only if they are unique
+ for path in newpaths:
+ normpath = os.path.normpath(os.path.normcase(path))
+ if path and not normpath in normpaths:
+ paths.append(path)
+ normpaths.append(normpath)
+
+ if is_list:
+ return paths
+ else:
+ return string.join(paths, sep)
+
+def AppendPath(oldpath, newpath, sep = os.pathsep,
+ delete_existing=1, canonicalize=None):
+ """This appends new path elements to the given old path. Will
+ only add any particular path once (leaving the last one it
+ encounters and ignoring the rest, to preserve path order), and
+ will os.path.normpath and os.path.normcase all paths to help
+ assure this. This can also handle the case where the given old
+ path variable is a list instead of a string, in which case a list
+ will be returned instead of a string.
+
+ Example:
+ Old Path: "/foo/bar:/foo"
+ New Path: "/biz/boom:/foo"
+ Result: "/foo/bar:/biz/boom:/foo"
+
+ If delete_existing is 0, then adding a path that exists
+ will not move it to the end; it will stay where it is in the list.
+
+ If canonicalize is not None, it is applied to each element of
+ newpath before use.
+ """
+
+ orig = oldpath
+ is_list = 1
+ paths = orig
+ if not is_List(orig) and not is_Tuple(orig):
+ paths = string.split(paths, sep)
+ is_list = 0
+
+ if is_String(newpath):
+ newpaths = string.split(newpath, sep)
+ elif not is_List(newpath) and not is_Tuple(newpath):
+ newpaths = [ newpath ] # might be a Dir
+ else:
+ newpaths = newpath
+
+ if canonicalize:
+ newpaths=map(canonicalize, newpaths)
+
+ if not delete_existing:
+ # add old paths to result, then
+ # add new paths if not already present
+ # (I thought about using a dict for normpaths for speed,
+ # but it's not clear hashing the strings would be faster
+ # than linear searching these typically short lists.)
+ result = []
+ normpaths = []
+ for path in paths:
+ if not path:
+ continue
+ result.append(path)
+ normpaths.append(os.path.normpath(os.path.normcase(path)))
+ for path in newpaths:
+ if not path:
+ continue
+ normpath = os.path.normpath(os.path.normcase(path))
+ if normpath not in normpaths:
+ result.append(path)
+ normpaths.append(normpath)
+ paths = result
+ else:
+ # start w/ new paths, add old ones if not present,
+ # then reverse.
+ newpaths = paths + newpaths # append new paths
+ newpaths.reverse()
+
+ normpaths = []
+ paths = []
+ # now we add them only if they are unique
+ for path in newpaths:
+ normpath = os.path.normpath(os.path.normcase(path))
+ if path and not normpath in normpaths:
+ paths.append(path)
+ normpaths.append(normpath)
+ paths.reverse()
+
+ if is_list:
+ return paths
+ else:
+ return string.join(paths, sep)
+
+if sys.platform == 'cygwin':
+ def get_native_path(path):
+ """Transforms an absolute path into a native path for the system. In
+ Cygwin, this converts from a Cygwin path to a Windows one."""
+ return string.replace(os.popen('cygpath -w ' + path).read(), '\n', '')
+else:
+ def get_native_path(path):
+ """Transforms an absolute path into a native path for the system.
+ Non-Cygwin version, just leave the path alone."""
+ return path
+
+display = DisplayEngine()
+
+def Split(arg):
+ if is_List(arg) or is_Tuple(arg):
+ return arg
+ elif is_String(arg):
+ return string.split(arg)
+ else:
+ return [arg]
+
+class CLVar(UserList):
+ """A class for command-line construction variables.
+
+ This is a list that uses Split() to split an initial string along
+ white-space arguments, and similarly to split any strings that get
+ added. This allows us to Do the Right Thing with Append() and
+ Prepend() (as well as straight Python foo = env['VAR'] + 'arg1
+ arg2') regardless of whether a user adds a list or a string to a
+ command-line construction variable.
+ """
+ def __init__(self, seq = []):
+ UserList.__init__(self, Split(seq))
+ def __add__(self, other):
+ return UserList.__add__(self, CLVar(other))
+ def __radd__(self, other):
+ return UserList.__radd__(self, CLVar(other))
+ def __coerce__(self, other):
+ return (self, CLVar(other))
+ def __str__(self):
+ return string.join(self.data)
+
+# A dictionary that preserves the order in which items are added.
+# Submitted by David Benjamin to ActiveState's Python Cookbook web site:
+# http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/107747
+# Including fixes/enhancements from the follow-on discussions.
+class OrderedDict(UserDict):
+ def __init__(self, dict = None):
+ self._keys = []
+ UserDict.__init__(self, dict)
+
+ def __delitem__(self, key):
+ UserDict.__delitem__(self, key)
+ self._keys.remove(key)
+
+ def __setitem__(self, key, item):
+ UserDict.__setitem__(self, key, item)
+ if key not in self._keys: self._keys.append(key)
+
+ def clear(self):
+ UserDict.clear(self)
+ self._keys = []
+
+ def copy(self):
+ dict = OrderedDict()
+ dict.update(self)
+ return dict
+
+ def items(self):
+ return zip(self._keys, self.values())
+
+ def keys(self):
+ return self._keys[:]
+
+ def popitem(self):
+ try:
+ key = self._keys[-1]
+ except IndexError:
+ raise KeyError('dictionary is empty')
+
+ val = self[key]
+ del self[key]
+
+ return (key, val)
+
+ def setdefault(self, key, failobj = None):
+ UserDict.setdefault(self, key, failobj)
+ if key not in self._keys: self._keys.append(key)
+
+ def update(self, dict):
+ for (key, val) in dict.items():
+ self.__setitem__(key, val)
+
+ def values(self):
+ return map(self.get, self._keys)
+
+class Selector(OrderedDict):
+ """A callable ordered dictionary that maps file suffixes to
+ dictionary values. We preserve the order in which items are added
+ so that get_suffix() calls always return the first suffix added."""
+ def __call__(self, env, source, ext=None):
+ if ext is None:
+ try:
+ ext = source[0].suffix
+ except IndexError:
+ ext = ""
+ try:
+ return self[ext]
+ except KeyError:
+ # Try to perform Environment substitution on the keys of
+ # the dictionary before giving up.
+ s_dict = {}
+ for (k,v) in self.items():
+ if k is not None:
+ s_k = env.subst(k)
+ if s_dict.has_key(s_k):
+ # We only raise an error when variables point
+ # to the same suffix. If one suffix is literal
+ # and a variable suffix contains this literal,
+ # the literal wins and we don't raise an error.
+ raise KeyError, (s_dict[s_k][0], k, s_k)
+ s_dict[s_k] = (k,v)
+ try:
+ return s_dict[ext][1]
+ except KeyError:
+ try:
+ return self[None]
+ except KeyError:
+ return None
+
+
+if sys.platform == 'cygwin':
+ # On Cygwin, os.path.normcase() lies, so just report back the
+ # fact that the underlying Windows OS is case-insensitive.
+ def case_sensitive_suffixes(s1, s2):
+ return 0
+else:
+ def case_sensitive_suffixes(s1, s2):
+ return (os.path.normcase(s1) != os.path.normcase(s2))
+
+def adjustixes(fname, pre, suf, ensure_suffix=False):
+ if pre:
+ path, fn = os.path.split(os.path.normpath(fname))
+ if fn[:len(pre)] != pre:
+ fname = os.path.join(path, pre + fn)
+ # Only append a suffix if the suffix we're going to add isn't already
+ # there, and if either we've been asked to ensure the specific suffix
+ # is present or there's no suffix on it at all.
+ if suf and fname[-len(suf):] != suf and \
+ (ensure_suffix or not splitext(fname)[1]):
+ fname = fname + suf
+ return fname
+
+
+
+# From Tim Peters,
+# http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/52560
+# ASPN: Python Cookbook: Remove duplicates from a sequence
+# (Also in the printed Python Cookbook.)
+
+def unique(s):
+ """Return a list of the elements in s, but without duplicates.
+
+ For example, unique([1,2,3,1,2,3]) is some permutation of [1,2,3],
+ unique("abcabc") some permutation of ["a", "b", "c"], and
+ unique(([1, 2], [2, 3], [1, 2])) some permutation of
+ [[2, 3], [1, 2]].
+
+ For best speed, all sequence elements should be hashable. Then
+ unique() will usually work in linear time.
+
+ If not possible, the sequence elements should enjoy a total
+ ordering, and if list(s).sort() doesn't raise TypeError it's
+ assumed that they do enjoy a total ordering. Then unique() will
+ usually work in O(N*log2(N)) time.
+
+ If that's not possible either, the sequence elements must support
+ equality-testing. Then unique() will usually work in quadratic
+ time.
+ """
+
+ n = len(s)
+ if n == 0:
+ return []
+
+ # Try using a dict first, as that's the fastest and will usually
+ # work. If it doesn't work, it will usually fail quickly, so it
+ # usually doesn't cost much to *try* it. It requires that all the
+ # sequence elements be hashable, and support equality comparison.
+ u = {}
+ try:
+ for x in s:
+ u[x] = 1
+ except TypeError:
+ pass # move on to the next method
+ else:
+ return u.keys()
+ del u
+
+ # We can't hash all the elements. Second fastest is to sort,
+ # which brings the equal elements together; then duplicates are
+ # easy to weed out in a single pass.
+ # NOTE: Python's list.sort() was designed to be efficient in the
+ # presence of many duplicate elements. This isn't true of all
+ # sort functions in all languages or libraries, so this approach
+ # is more effective in Python than it may be elsewhere.
+ try:
+ t = list(s)
+ t.sort()
+ except TypeError:
+ pass # move on to the next method
+ else:
+ assert n > 0
+ last = t[0]
+ lasti = i = 1
+ while i < n:
+ if t[i] != last:
+ t[lasti] = last = t[i]
+ lasti = lasti + 1
+ i = i + 1
+ return t[:lasti]
+ del t
+
+ # Brute force is all that's left.
+ u = []
+ for x in s:
+ if x not in u:
+ u.append(x)
+ return u
+
+
+
+# From Alex Martelli,
+# http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/52560
+# ASPN: Python Cookbook: Remove duplicates from a sequence
+# First comment, dated 2001/10/13.
+# (Also in the printed Python Cookbook.)
+
+def uniquer(seq, idfun=None):
+ if idfun is None:
+ def idfun(x): return x
+ seen = {}
+ result = []
+ for item in seq:
+ marker = idfun(item)
+ # in old Python versions:
+ # if seen.has_key(marker)
+ # but in new ones:
+ if marker in seen: continue
+ seen[marker] = 1
+ result.append(item)
+ return result
+
+# A more efficient implementation of Alex's uniquer(), this avoids the
+# idfun() argument and function-call overhead by assuming that all
+# items in the sequence are hashable.
+
+def uniquer_hashables(seq):
+ seen = {}
+ result = []
+ for item in seq:
+ #if not item in seen:
+ if not seen.has_key(item):
+ seen[item] = 1
+ result.append(item)
+ return result
+
+
+
+# Much of the logic here was originally based on recipe 4.9 from the
+# Python CookBook, but we had to dumb it way down for Python 1.5.2.
+class LogicalLines:
+
+ def __init__(self, fileobj):
+ self.fileobj = fileobj
+
+ def readline(self):
+ result = []
+ while 1:
+ line = self.fileobj.readline()
+ if not line:
+ break
+ if line[-2:] == '\\\n':
+ result.append(line[:-2])
+ else:
+ result.append(line)
+ break
+ return string.join(result, '')
+
+ def readlines(self):
+ result = []
+ while 1:
+ line = self.readline()
+ if not line:
+ break
+ result.append(line)
+ return result
+
+
+
+class UniqueList(UserList):
+ def __init__(self, seq = []):
+ UserList.__init__(self, seq)
+ self.unique = True
+ def __make_unique(self):
+ if not self.unique:
+ self.data = uniquer_hashables(self.data)
+ self.unique = True
+ def __lt__(self, other):
+ self.__make_unique()
+ return UserList.__lt__(self, other)
+ def __le__(self, other):
+ self.__make_unique()
+ return UserList.__le__(self, other)
+ def __eq__(self, other):
+ self.__make_unique()
+ return UserList.__eq__(self, other)
+ def __ne__(self, other):
+ self.__make_unique()
+ return UserList.__ne__(self, other)
+ def __gt__(self, other):
+ self.__make_unique()
+ return UserList.__gt__(self, other)
+ def __ge__(self, other):
+ self.__make_unique()
+ return UserList.__ge__(self, other)
+ def __cmp__(self, other):
+ self.__make_unique()
+ return UserList.__cmp__(self, other)
+ def __len__(self):
+ self.__make_unique()
+ return UserList.__len__(self)
+ def __getitem__(self, i):
+ self.__make_unique()
+ return UserList.__getitem__(self, i)
+ def __setitem__(self, i, item):
+ UserList.__setitem__(self, i, item)
+ self.unique = False
+ def __getslice__(self, i, j):
+ self.__make_unique()
+ return UserList.__getslice__(self, i, j)
+ def __setslice__(self, i, j, other):
+ UserList.__setslice__(self, i, j, other)
+ self.unique = False
+ def __add__(self, other):
+ result = UserList.__add__(self, other)
+ result.unique = False
+ return result
+ def __radd__(self, other):
+ result = UserList.__radd__(self, other)
+ result.unique = False
+ return result
+ def __iadd__(self, other):
+ result = UserList.__iadd__(self, other)
+ result.unique = False
+ return result
+ def __mul__(self, other):
+ result = UserList.__mul__(self, other)
+ result.unique = False
+ return result
+ def __rmul__(self, other):
+ result = UserList.__rmul__(self, other)
+ result.unique = False
+ return result
+ def __imul__(self, other):
+ result = UserList.__imul__(self, other)
+ result.unique = False
+ return result
+ def append(self, item):
+ UserList.append(self, item)
+ self.unique = False
+ def insert(self, i):
+ UserList.insert(self, i)
+ self.unique = False
+ def count(self, item):
+ self.__make_unique()
+ return UserList.count(self, item)
+ def index(self, item):
+ self.__make_unique()
+ return UserList.index(self, item)
+ def reverse(self):
+ self.__make_unique()
+ UserList.reverse(self)
+ def sort(self, *args, **kwds):
+ self.__make_unique()
+ #return UserList.sort(self, *args, **kwds)
+ return apply(UserList.sort, (self,)+args, kwds)
+ def extend(self, other):
+ UserList.extend(self, other)
+ self.unique = False
+
+
+
+class Unbuffered:
+ """
+ A proxy class that wraps a file object, flushing after every write,
+ and delegating everything else to the wrapped object.
+ """
+ def __init__(self, file):
+ self.file = file
+ def write(self, arg):
+ try:
+ self.file.write(arg)
+ self.file.flush()
+ except IOError:
+ # Stdout might be connected to a pipe that has been closed
+ # by now. The most likely reason for the pipe being closed
+ # is that the user has press ctrl-c. It this is the case,
+ # then SCons is currently shutdown. We therefore ignore
+ # IOError's here so that SCons can continue and shutdown
+ # properly so that the .sconsign is correctly written
+ # before SCons exits.
+ pass
+ def __getattr__(self, attr):
+ return getattr(self.file, attr)
+
+def make_path_relative(path):
+ """ makes an absolute path name to a relative pathname.
+ """
+ if os.path.isabs(path):
+ drive_s,path = os.path.splitdrive(path)
+
+ import re
+ if not drive_s:
+ path=re.compile("/*(.*)").findall(path)[0]
+ else:
+ path=path[1:]
+
+ assert( not os.path.isabs( path ) ), path
+ return path
+
+
+
+# The original idea for AddMethod() and RenameFunction() come from the
+# following post to the ActiveState Python Cookbook:
+#
+# ASPN: Python Cookbook : Install bound methods in an instance
+# http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/223613
+#
+# That code was a little fragile, though, so the following changes
+# have been wrung on it:
+#
+# * Switched the installmethod() "object" and "function" arguments,
+# so the order reflects that the left-hand side is the thing being
+# "assigned to" and the right-hand side is the value being assigned.
+#
+# * Changed explicit type-checking to the "try: klass = object.__class__"
+# block in installmethod() below so that it still works with the
+# old-style classes that SCons uses.
+#
+# * Replaced the by-hand creation of methods and functions with use of
+# the "new" module, as alluded to in Alex Martelli's response to the
+# following Cookbook post:
+#
+# ASPN: Python Cookbook : Dynamically added methods to a class
+# http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/81732
+
+def AddMethod(object, function, name = None):
+ """
+ Adds either a bound method to an instance or an unbound method to
+ a class. If name is ommited the name of the specified function
+ is used by default.
+ Example:
+ a = A()
+ def f(self, x, y):
+ self.z = x + y
+ AddMethod(f, A, "add")
+ a.add(2, 4)
+ print a.z
+ AddMethod(lambda self, i: self.l[i], a, "listIndex")
+ print a.listIndex(5)
+ """
+ import new
+
+ if name is None:
+ name = function.func_name
+ else:
+ function = RenameFunction(function, name)
+
+ try:
+ klass = object.__class__
+ except AttributeError:
+ # "object" is really a class, so it gets an unbound method.
+ object.__dict__[name] = new.instancemethod(function, None, object)
+ else:
+ # "object" is really an instance, so it gets a bound method.
+ object.__dict__[name] = new.instancemethod(function, object, klass)
+
+def RenameFunction(function, name):
+ """
+ Returns a function identical to the specified function, but with
+ the specified name.
+ """
+ import new
+
+ # Compatibility for Python 1.5 and 2.1. Can be removed in favor of
+ # passing function.func_defaults directly to new.function() once
+ # we base on Python 2.2 or later.
+ func_defaults = function.func_defaults
+ if func_defaults is None:
+ func_defaults = ()
+
+ return new.function(function.func_code,
+ function.func_globals,
+ name,
+ func_defaults)
+
+
+md5 = False
+def MD5signature(s):
+ return str(s)
+
+def MD5filesignature(fname, chunksize=65536):
+ f = open(fname, "rb")
+ result = f.read()
+ f.close()
+ return result
+
+try:
+ import hashlib
+except ImportError:
+ pass
+else:
+ if hasattr(hashlib, 'md5'):
+ md5 = True
+ def MD5signature(s):
+ m = hashlib.md5()
+ m.update(str(s))
+ return m.hexdigest()
+
+ def MD5filesignature(fname, chunksize=65536):
+ m = hashlib.md5()
+ f = open(fname, "rb")
+ while 1:
+ blck = f.read(chunksize)
+ if not blck:
+ break
+ m.update(str(blck))
+ f.close()
+ return m.hexdigest()
+
+def MD5collect(signatures):
+ """
+ Collects a list of signatures into an aggregate signature.
+
+ signatures - a list of signatures
+ returns - the aggregate signature
+ """
+ if len(signatures) == 1:
+ return signatures[0]
+ else:
+ return MD5signature(string.join(signatures, ', '))
+
+
+
+# Wrap the intern() function so it doesn't throw exceptions if ineligible
+# arguments are passed. The intern() function was moved into the sys module in
+# Python 3.
+try:
+ intern
+except NameError:
+ from sys import intern
+
+def silent_intern(x):
+ """
+ Perform intern() on the passed argument and return the result.
+ If the input is ineligible (e.g. a unicode string) the original argument is
+ returned and no exception is thrown.
+ """
+ try:
+ return intern(x)
+ except TypeError:
+ return x
+
+
+
+# From Dinu C. Gherman,
+# Python Cookbook, second edition, recipe 6.17, p. 277.
+# Also:
+# http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/68205
+# ASPN: Python Cookbook: Null Object Design Pattern
+
+# TODO(1.5):
+#class Null(object):
+class Null:
+ """ Null objects always and reliably "do nothing." """
+ def __new__(cls, *args, **kwargs):
+ if not '_inst' in vars(cls):
+ #cls._inst = type.__new__(cls, *args, **kwargs)
+ cls._inst = apply(type.__new__, (cls,) + args, kwargs)
+ return cls._inst
+ def __init__(self, *args, **kwargs):
+ pass
+ def __call__(self, *args, **kwargs):
+ return self
+ def __repr__(self):
+ return "Null(0x%08X)" % id(self)
+ def __nonzero__(self):
+ return False
+ def __getattr__(self, name):
+ return self
+ def __setattr__(self, name, value):
+ return self
+ def __delattr__(self, name):
+ return self
+
+class NullSeq(Null):
+ def __len__(self):
+ return 0
+ def __iter__(self):
+ return iter(())
+ def __getitem__(self, i):
+ return self
+ def __delitem__(self, i):
+ return self
+ def __setitem__(self, i, v):
+ return self
+
+
+del __revision__
+
+# Local Variables:
+# tab-width:4
+# indent-tabs-mode:nil
+# End:
+# vim: set expandtab tabstop=4 shiftwidth=4: