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Diffstat (limited to 'src/python/m5/smartdict.py')
| -rw-r--r-- | src/python/m5/smartdict.py | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/src/python/m5/smartdict.py b/src/python/m5/smartdict.py new file mode 100644 index 000000000..cd38d7326 --- /dev/null +++ b/src/python/m5/smartdict.py @@ -0,0 +1,152 @@ +# Copyright (c) 2005 The Regents of The University of Michigan +# All rights reserved. +# +# Redistribution and use in source and binary forms, with or without +# modification, are permitted provided that the following conditions are +# met: redistributions of source code must retain the above copyright +# notice, this list of conditions and the following disclaimer; +# redistributions in binary form must reproduce the above copyright +# notice, this list of conditions and the following disclaimer in the +# documentation and/or other materials provided with the distribution; +# neither the name of the copyright holders nor the names of its +# contributors may be used to endorse or promote products derived from +# this software without specific prior written permission. +# +# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +# The SmartDict class fixes a couple of issues with using the content +# of os.environ or similar dicts of strings as Python variables: +# +# 1) Undefined variables should return False rather than raising KeyError. +# +# 2) String values of 'False', '0', etc., should evaluate to False +# (not just the empty string). +# +# #1 is solved by overriding __getitem__, and #2 is solved by using a +# proxy class for values and overriding __nonzero__ on the proxy. +# Everything else is just to (a) make proxies behave like normal +# values otherwise, (b) make sure any dict operation returns a proxy +# rather than a normal value, and (c) coerce values written to the +# dict to be strings. + + +from convert import * + +class Variable(str): + """Intelligent proxy class for SmartDict. Variable will use the + various convert functions to attempt to convert values to useable + types""" + def __int__(self): + return toInteger(str(self)) + def __long__(self): + return toLong(str(self)) + def __float__(self): + return toFloat(str(self)) + def __nonzero__(self): + return toBool(str(self)) + def convert(self, other): + t = type(other) + if t == bool: + return bool(self) + if t == int: + return int(self) + if t == long: + return long(self) + if t == float: + return float(self) + return str(self) + def __lt__(self, other): + return self.convert(other) < other + def __le__(self, other): + return self.convert(other) <= other + def __eq__(self, other): + return self.convert(other) == other + def __ne__(self, other): + return self.convert(other) != other + def __gt__(self, other): + return self.convert(other) > other + def __ge__(self, other): + return self.convert(other) >= other + + def __add__(self, other): + return self.convert(other) + other + def __sub__(self, other): + return self.convert(other) - other + def __mul__(self, other): + return self.convert(other) * other + def __div__(self, other): + return self.convert(other) / other + def __truediv__(self, other): + return self.convert(other) / other + + def __radd__(self, other): + return other + self.convert(other) + def __rsub__(self, other): + return other - self.convert(other) + def __rmul__(self, other): + return other * self.convert(other) + def __rdiv__(self, other): + return other / self.convert(other) + def __rtruediv__(self, other): + return other / self.convert(other) + +class UndefinedVariable(object): + """Placeholder class to represent undefined variables. Will + generally cause an exception whenever it is used, but evaluates to + zero for boolean truth testing such as in an if statement""" + def __nonzero__(self): + return False + +class SmartDict(dict): + """Dictionary class that holds strings, but intelligently converts + those strings to other types depending on their usage""" + + def __getitem__(self, key): + """returns a Variable proxy if the values exists in the database and + returns an UndefinedVariable otherwise""" + + if key in self: + return Variable(dict.get(self, key)) + else: + # Note that this does *not* change the contents of the dict, + # so that even after we call env['foo'] we still get a + # meaningful answer from "'foo' in env" (which + # calls dict.__contains__, which we do not override). + return UndefinedVariable() + + def __setitem__(self, key, item): + """intercept the setting of any variable so that we always + store strings in the dict""" + dict.__setitem__(self, key, str(item)) + + def values(self): + return [ Variable(v) for v in dict.values(self) ] + + def itervalues(self): + for value in dict.itervalues(self): + yield Variable(value) + + def items(self): + return [ (k, Variable(v)) for k,v in dict.items(self) ] + + def iteritems(self): + for key,value in dict.iteritems(self): + yield key, Variable(value) + + def get(self, key, default='False'): + return Variable(dict.get(self, key, str(default))) + + def setdefault(self, key, default='False'): + return Variable(dict.setdefault(self, key, str(default))) + +__all__ = [ 'SmartDict' ] |