X-Git-Url: https://scm.cri.ensmp.fr/git/Photo.git/blobdiff_plain/b0a7e10b4f32cf74864bb53268ca4d3080f23bc0..6c41809185e322ce2d30e98234f71144f78f06c0:/Products/Photo/cache.py

diff --git a/Products/Photo/cache.py b/Products/Photo/cache.py
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+# -*- coding: utf-8 -*-
+#######################################################################################
+#   Photo is a part of Plinn - http://plinn.org                                       #
+#   Copyright (C) 2008  Benoît PIN <benoit.pin@ensmp.fr>                              #
+#                                                                                     #
+#   This program is free software; you can redistribute it and/or                     #
+#   modify it under the terms of the GNU General Public License                       #
+#   as published by the Free Software Foundation; either version 2                    #
+#   of the License, or (at your option) any later version.                            #
+#                                                                                     #
+#   This program is distributed in the hope that it will be useful,                   #
+#   but WITHOUT ANY WARRANTY; without even the implied warranty of                    #
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the                     #
+#   GNU General Public License for more details.                                      #
+#                                                                                     #
+#   You should have received a copy of the GNU General Public License                 #
+#   along with this program; if not, write to the Free Software                       #
+#   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.   #
+#######################################################################################
+""" Memoization utils
+
+
+
+"""
+
+import inspect
+from BTrees.OOBTree import OOBTree
+
+def memoizedmethod(*indexes, **options) :
+	""" Used as decorator, this function stores result
+		of method m inside self._methodResultsCache or
+		self._v__methodResultsCache if volatile.
+		This decorator may be used inside a class which provides
+		a mapping object named _methodResultsCache and / or
+		_v__methodResultsCache.
+		
+		example :
+		
+		1 - simple metdhod memoization
+		
+		@memoizedmethod()
+		def methodWithNoParameters(self): pass
+		
+		2 - indexed memoisation:
+		Parameters names are passed to memoizedmethod are
+		evaluated to construct an indexed cache.
+		Names must be a subset of the memoized method signature.
+		
+		@memoizedmethod('arg1', 'arg2')
+		def methodWithParameters(self, arg1, arg2=None): pass
+	"""
+	volatile = options.get('volatile', False)
+	cacheVarName = '_methodResultsCache'
+	if volatile==True :
+		cacheVarName = '_v_%s' % cacheVarName
+	
+	def makeMemoizedMethod(m) :
+		methodname = m.__name__
+		
+		if not indexes :
+			def memoizedMethod(self) :
+				if not hasattr(self, cacheVarName) :
+					setattr(self, cacheVarName, OOBTree())
+				cache = getattr(self, cacheVarName)
+				if cache.has_key(methodname) :
+					return cache[methodname]
+				else :
+					res = m(self)
+					cache[methodname] = res
+					return res
+
+			memoizedMethod.__name__ = methodname
+			memoizedMethod.__doc__ = m.__doc__
+			return memoizedMethod
+		
+		else :
+			args, varargs, varkw, defaults = inspect.getargspec(m)
+			args = list(args)
+			if defaults is None :
+				defaults = []
+			mandatoryargs = args[1:-len(defaults)]
+			optargs = args[-len(defaults):]
+			defaultValues = dict(zip([name for name in args[-len(defaults):]], [val for val in defaults]))
+			
+			indexPositions = []
+			for index in indexes :
+				try :
+					indexPositions.append((index, args.index(index)))
+				except ValueError :
+					raise ValueError("%r argument is not in signature of %r" % (index, methodname))
+			
+			if indexPositions :
+				indexPositions.sort(lambda a, b : cmp(a[1], b[1]))
+			
+			indexPositions = tuple(indexPositions)
+				
+			
+			def memoizedMethod(self, *args, **kw) :
+				# test if m if called by ZPublished
+				if len(args) < len(mandatoryargs) and hasattr(self, 'REQUEST') :
+					assert not kw
+					args = list(args)
+					get = lambda name : self.REQUEST[name]
+					for name in mandatoryargs :
+						try :
+							args.append(get(name))
+						except KeyError :
+							exactOrAtLeast = defaults and 'exactly' or 'at least'
+							raise TypeError('%(methodname)s takes %(exactOrAtLeast)s %(mandatoryArgsLength)d argument (%(givenArgsLength)s given)' % \
+											{ 'methodname': methodname
+											, 'exactOrAtLeast': exactOrAtLeast
+											, 'mandatoryArgsLength': len(mandatoryargs)
+											, 'givenArgsLength': len(args)})
+					
+					for name in optargs :
+						get = self.REQUEST.get
+						args.append(get(name, defaultValues[name]))
+
+					args = tuple(args)
+				
+				if not hasattr(self, cacheVarName) :
+					setattr(self, cacheVarName, OOBTree())
+				cache = getattr(self, cacheVarName)
+				if not cache.has_key(methodname) :
+					cache[methodname] = OOBTree()
+				
+				cache = cache[methodname]
+				index = aggregateIndex(indexPositions, args)
+				
+				if cache.has_key(index) :
+					return cache[index]
+				else :
+					res = m(self, *args, **kw)
+					cache[index] = res
+					return res
+
+			memoizedMethod.__name__ = methodname
+			memoizedMethod.__doc__ = m.__doc__
+			return memoizedMethod
+
+	return makeMemoizedMethod
+
+def aggregateIndex(indexPositions, args):
+	'''
+	Returns the index to be used when looking for or inserting
+	a cache entry.
+	view_name is a string.
+	local_keys is a mapping or None.
+	'''
+	
+	agg_index = []
+	
+	for name, pos in indexPositions :
+		val = args[pos-1]
+		agg_index.append((name, str(val)))
+	
+	return tuple(agg_index)