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Diffstat (limited to '3rdParty/SCons/scons-2.4.0/engine/SCons/Memoize.py')
-rw-r--r-- | 3rdParty/SCons/scons-2.4.0/engine/SCons/Memoize.py | 245 |
1 files changed, 0 insertions, 245 deletions
diff --git a/3rdParty/SCons/scons-2.4.0/engine/SCons/Memoize.py b/3rdParty/SCons/scons-2.4.0/engine/SCons/Memoize.py deleted file mode 100644 index 77a8e16..0000000 --- a/3rdParty/SCons/scons-2.4.0/engine/SCons/Memoize.py +++ /dev/null @@ -1,245 +0,0 @@ -# -# Copyright (c) 2001 - 2015 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/Memoize.py rel_2.4.0:3365:9259ea1c13d7 2015/09/21 14:03:43 bdbaddog" - -__doc__ = """Memoizer - -A decorator-based implementation to count hits and misses of the computed -values that various methods cache in memory. - -Use of this modules assumes that wrapped methods be coded to cache their -values in a consistent way. In particular, it requires that the class uses a -dictionary named "_memo" to store the cached values. - -Here is an example of wrapping a method that returns a computed value, -with no input parameters: - - @SCons.Memoize.CountMethodCall - def foo(self): - - try: # Memoization - return self._memo['foo'] # Memoization - except KeyError: # Memoization - pass # Memoization - - result = self.compute_foo_value() - - self._memo['foo'] = result # Memoization - - return result - -Here is an example of wrapping a method that will return different values -based on one or more input arguments: - - def _bar_key(self, argument): # Memoization - return argument # Memoization - - @SCons.Memoize.CountDictCall(_bar_key) - def bar(self, argument): - - memo_key = argument # Memoization - try: # Memoization - memo_dict = self._memo['bar'] # Memoization - except KeyError: # Memoization - memo_dict = {} # Memoization - self._memo['dict'] = memo_dict # Memoization - else: # Memoization - try: # Memoization - return memo_dict[memo_key] # Memoization - except KeyError: # Memoization - pass # Memoization - - result = self.compute_bar_value(argument) - - memo_dict[memo_key] = result # Memoization - - return result - -Deciding what to cache is tricky, because different configurations -can have radically different performance tradeoffs, and because the -tradeoffs involved are often so non-obvious. Consequently, deciding -whether or not to cache a given method will likely be more of an art than -a science, but should still be based on available data from this module. -Here are some VERY GENERAL guidelines about deciding whether or not to -cache return values from a method that's being called a lot: - - -- The first question to ask is, "Can we change the calling code - so this method isn't called so often?" Sometimes this can be - done by changing the algorithm. Sometimes the *caller* should - be memoized, not the method you're looking at. - - -- The memoized function should be timed with multiple configurations - to make sure it doesn't inadvertently slow down some other - configuration. - - -- When memoizing values based on a dictionary key composed of - input arguments, you don't need to use all of the arguments - if some of them don't affect the return values. - -""" - -# A flag controlling whether or not we actually use memoization. -use_memoizer = None - -# Global list of counter objects -CounterList = {} - -class Counter(object): - """ - Base class for counting memoization hits and misses. - - We expect that the initialization in a matching decorator will - fill in the correct class name and method name that represents - the name of the function being counted. - """ - def __init__(self, cls_name, method_name): - """ - """ - self.cls_name = cls_name - self.method_name = method_name - self.hit = 0 - self.miss = 0 - def key(self): - return self.cls_name+'.'+self.method_name - def display(self): - fmt = " %7d hits %7d misses %s()" - print fmt % (self.hit, self.miss, self.key()) - def __cmp__(self, other): - try: - return cmp(self.key(), other.key()) - except AttributeError: - return 0 - -class CountValue(Counter): - """ - A counter class for simple, atomic memoized values. - - A CountValue object should be instantiated in a decorator for each of - the class's methods that memoizes its return value by simply storing - the return value in its _memo dictionary. - """ - def count(self, *args, **kw): - """ Counts whether the memoized value has already been - set (a hit) or not (a miss). - """ - obj = args[0] - if self.method_name in obj._memo: - self.hit = self.hit + 1 - else: - self.miss = self.miss + 1 - -class CountDict(Counter): - """ - A counter class for memoized values stored in a dictionary, with - keys based on the method's input arguments. - - A CountDict object is instantiated in a decorator for each of the - class's methods that memoizes its return value in a dictionary, - indexed by some key that can be computed from one or more of - its input arguments. - """ - def __init__(self, cls_name, method_name, keymaker): - """ - """ - Counter.__init__(self, cls_name, method_name) - self.keymaker = keymaker - def count(self, *args, **kw): - """ Counts whether the computed key value is already present - in the memoization dictionary (a hit) or not (a miss). - """ - obj = args[0] - try: - memo_dict = obj._memo[self.method_name] - except KeyError: - self.miss = self.miss + 1 - else: - key = self.keymaker(*args, **kw) - if key in memo_dict: - self.hit = self.hit + 1 - else: - self.miss = self.miss + 1 - -def Dump(title=None): - """ Dump the hit/miss count for all the counters - collected so far. - """ - if title: - print title - for counter in sorted(CounterList): - CounterList[counter].display() - -def EnableMemoization(): - global use_memoizer - use_memoizer = 1 - -def CountMethodCall(fn): - """ Decorator for counting memoizer hits/misses while retrieving - a simple value in a class method. It wraps the given method - fn and uses a CountValue object to keep track of the - caching statistics. - Wrapping gets enabled by calling EnableMemoization(). - """ - if use_memoizer: - def wrapper(self, *args, **kwargs): - global CounterList - key = self.__class__.__name__+'.'+fn.__name__ - if key not in CounterList: - CounterList[key] = CountValue(self.__class__.__name__, fn.__name__) - CounterList[key].count(self, *args, **kwargs) - return fn(self, *args, **kwargs) - wrapper.__name__= fn.__name__ - return wrapper - else: - return fn - -def CountDictCall(keyfunc): - """ Decorator for counting memoizer hits/misses while accessing - dictionary values with a key-generating function. Like - CountMethodCall above, it wraps the given method - fn and uses a CountDict object to keep track of the - caching statistics. The dict-key function keyfunc has to - get passed in the decorator call and gets stored in the - CountDict instance. - Wrapping gets enabled by calling EnableMemoization(). - """ - def decorator(fn): - if use_memoizer: - def wrapper(self, *args, **kwargs): - global CounterList - key = self.__class__.__name__+'.'+fn.__name__ - if key not in CounterList: - CounterList[key] = CountDict(self.__class__.__name__, fn.__name__, keyfunc) - CounterList[key].count(self, *args, **kwargs) - return fn(self, *args, **kwargs) - wrapper.__name__= fn.__name__ - return wrapper - else: - return fn - return decorator - -# Local Variables: -# tab-width:4 -# indent-tabs-mode:nil -# End: -# vim: set expandtab tabstop=4 shiftwidth=4: |