framework-res: add python script to remove unused resources

This script can be used when importing framework-res from AOSP

res/remove_unused_resources.py

@@ -0,0 +1,46 @@
+#!/usr/bin/python3
+'''
+AOSPs framework-res contains a lot of drawables which are only for the systemUI. Only resources reachable
+from public.xml are part of the Android API and should be kept. This script removes all other resources.
+'''
+
+import glob
+import re
+import os
+
+# find all xml files and parse them for resource references
+xml_files = []
+resources = []
+xml_files_new = glob.glob("res/values/public*.xml")
+xml_files_new += glob.glob("res/values*/themes*.xml")
+xml_files_new += glob.glob("res/values*/styles*.xml")
+xml_files_new += glob.glob("res/values*/colors*.xml")
+xml_files_new += glob.glob("res/xml*/*.xml")
+xml_files_new += glob.glob("AndroidManifest.xml")
+while len(xml_files_new) > 0:
+	xml_files += xml_files_new
+	xml_files_old = xml_files_new
+	xml_files_new = []
+	for f in xml_files_old:
+		with open(f, "r") as x:
+			str = x.read()
+			resources_new = []
+			for pattern in ['name="(.*?)"', '"@drawable/(.*?)"', '>@drawable/(.*?)<', '@drawable/(.*?)\n', '"@layout/(.*?)"', '>@layout/(.*?)<', '>@android:layout/(.*?)<', '"@color/(.*?)"', '"@anim/(.*?)"', '"@android:drawable/(.*?)"', '"@\\*android:drawable/(.*?)"']:
+				for m in re.finditer(pattern, str):
+					resources_new.append(m.group(1))
+			resources += resources_new
+			for name in resources_new:
+				matches = glob.glob("res/**/" + name + ".xml")
+				for m in matches:
+					if not m in xml_files:
+						xml_files_new.append(m)
+
+# remove unused layouts
+for f in glob.glob("res/layout*/*"):
+	if not os.path.basename(f).split(".")[0] in resources:
+		os.remove(f)
+
+# remove unused drawables
+for f in glob.glob("res/drawable*/*"):
+	if not os.path.basename(f).split(".")[0] in resources:
+		os.remove(f)