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scons, python: Remove SmartDict from python utilities

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The SmartDict, used by buildEnv, has been added long time ago for
the following reasons: (checking its documentation)

---
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).
---

These are valid reasons, but I believe they should be addressed in
a more standardized way by using a common dictionary.

1) We should simply rely on dict.get

if buildEnv.get('KEY', False/None):

2) We should discourage the use of stringified False or 0.
If we are using a dictionary, can't we just pass those values as
booleans?
The SmartDict is basically converting every value into a
string ("Variable") at every access (__getitem__)
The Variable is a string + some "basic" conversion methods
What is the problem of passing every dict value as a string?

The problem is the ambiguity on the boolean conversion.

If a variable is modelling a boolean, we can return true if
the value is 'yes', 'true'... and false if the value is
'no', 'false' etc. We should raise an exception if it is
something different, like a typo (e.g.) 'Fasle'.
But if the variable is not modelling a boolean, we don't know
how to handle that. How should we convert 'mystring' ?

If we decide to treat 'mystring' as True (which is basically
what a str.__bool__ would return) we will break typoes detection,
as 'Fasle' will now be converted to True, rather than raising
an exception.

Change-Id: I960fbfb1ec0f703e1e372dd752ee75f00632acac
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/37775
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Reviewed-by: Hoa Nguyen <hoanguyen@ucdavis.edu>
Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
This commit is contained in:
Giacomo Travaglini
2020-11-19 11:53:09 +00:00
parent f06dcf9d1f
commit d574381081
4 changed files with 2 additions and 161 deletions
Download Patch File Download Diff File Expand all files Collapse all files

1
src/python/SConscript
View File

@@ -53,7 +53,6 @@ PySource('m5.util', 'm5/util/dot_writer_ruby.py')
PySource('m5.util', 'm5/util/grammar.py')
PySource('m5.util', 'm5/util/jobfile.py')
PySource('m5.util', 'm5/util/multidict.py')
PySource('m5.util', 'm5/util/smartdict.py')
PySource('m5.util', 'm5/util/sorteddict.py')
PySource('m5.util', 'm5/util/terminal.py')
PySource('m5.util', 'm5/util/pybind.py')

1
src/python/m5/util/__init__.py
View File

@@ -52,7 +52,6 @@ from . import jobfile
from .attrdict import attrdict, multiattrdict, optiondict
from .code_formatter import code_formatter
from .multidict import multidict
from .smartdict import SmartDict
from .sorteddict import SortedDict
# panic() should be called when something happens that should never

157
src/python/m5/util/smartdict.py
View File

@@ -1,157 +0,0 @@
# 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 __future__ import print_function
from __future__ import absolute_import
import six
if six.PY3:
long = int
from .convert import *
from .attrdict import attrdict
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 __bool__(self):
return toBool(str(self))
# Python 2.7 uses __nonzero__ instead of __bool__
__nonzero__ = __bool__
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 __bool__(self):
return False
# Python 2.7 uses __nonzero__ instead of __bool__
__nonzero__ = __bool__
class SmartDict(attrdict):
"""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):
for value in dict.values(self):
yield Variable(value)
def items(self):
for key,value in dict.items(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' ]