- Started to work on a caching mechanism.

test/scythercache.py

@@ -0,0 +1,82 @@
+#
+#	Scyther caching mechanism
+#
+#	Uses md5 hashes to store previously calculated results.
+#
+#	(c)2005 Cas Cremers
+#
+#
+import md5
+import commands
+import os
+
+#	scyther should reside in $PATH
+def scythercall (argumentstring, inputfile):
+	clstring = "scyther " + argumentstring + " " + inputfile
+	(status,scout) = commands.getstatusoutput(clstring)
+	return (status,scout)
+
+#	cached results
+#	input:	a large string (consisting of read input files)
+#	argstring:	a smaller string
+def scythercache (argumentstring, inputstring):
+
+	def cacheid():
+		m = md5.new()
+	
+		# # Determine scyther version
+		# (status, scout) = scythercall ("--version", "")
+		# if status == 1 or status < 0:
+		# 	# some problem
+		# 	print "Problem with determining scyther version!"
+		# 	os.exit()
+		# # Add version to hash
+		# m.update (scout)
+
+		# Add inputfile to hash
+		m.update (inputstring)
+
+		# Add arguments to hash
+		m.update (argumentstring)
+
+		# Return a readable ID (good for a filename)
+		return m.hexdigest()
+
+	# Ensure directories for a file
+	def ensureDirectories (filename):
+
+		def ensureDir (plist):
+			if len(plist) > 1:
+				ensureDir (plist[:-1])
+			path = plist.join("/")
+			if not os.path.exists(path):
+				os.mkdir(path)
+
+		dir = os.path.dirname(filename)
+		ensuredir (dir.split("/"))
+
+	# Determine the unique filename for this test
+	id = cacheid()
+	filename = "scythercache/" + id[:2] + "/res-" + id[2:] + ".txt"
+	cachefile = gettempdir() + "/" + filename
+	ensureDirectories(cachefile)
+
+	# Does it already exist?
+	if os.path.exists(cachefile):
+		# Great: return the cached results
+		f = open(cachefile,"r")
+		res = f.read()
+		f.close()
+		return (0,res)
+	else:
+		# Hmm, we need to compute this result
+		h = NamedTemporaryFile()
+		h.write(inputstring)
+		(status, scout) = scythercall (argumentstring, h.name)
+		h.close()
+		f = open(cachefile,"w")
+		f.write(scout)
+		f.close()
+		return (status,scout)
+
+