{--
JVM-Bridge -- bridge from FP languages and others to the Java VM
Copyright (C) 2001 Ashley Yakeley <ashley@semantic.org>

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.

This library 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
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
--}

module Foreign.JavaVM.VM.Callback.Finalizer
	(
	finalizerMethod
	) where
	{
	import Foreign.JavaVM.VM.Callback.Field;
	import Foreign.JavaVM.Configure;
	import Platform.JavaVM;
	
	throwableClassName :: ClassName;
	throwableClassName = "java/lang/Throwable";
	
	insFreeFunction :: Bool -> Instruction;
	insFreeFunction deferred = insINVOKESTATIC (MkMemberRef executeFunctionClassName 
		(MkMemberNameType (nameFromRoot deferred "freeFunction") (MkFunctionType [opaqueAddressType] MkVoidType))
		);
	
	freeField :: Bool -> FieldRef -> [Instruction];
	freeField deferred fref = 
		[
		insALOAD 0,	-- this
		insGETFIELD fref,
		insFreeFunction deferred
		];
	
	finalizerFreeFields :: Bool -> ClassName -> [FieldNameType] -> [Instruction];
	finalizerFreeFields _ _ [] = [];
	finalizerFreeFields deferred classname (f:fs) = (freeField deferred (MkMemberRef classname f)) ++
		(finalizerFreeFields deferred classname fs);
	
	finalizerCode :: Bool -> ClassName -> ClassName -> [FieldNameType] -> AttributeDefinition;
	finalizerCode deferred classname superclassname fieldNameTypes = codeAttributeDef []
		(
			[
			insALOAD 0,	-- this
			insINVOKESPECIAL (MkMemberRef superclassname objectFinalizerNameType) -- call superclass finalizer
			] ++
			(finalizerFreeFields deferred classname fieldNameTypes) ++
			[
			insRETURN MkVoidType
			]
		) [] [];
	
	finalizerThrowables :: AttributeDefinition;
	finalizerThrowables = exceptionsAttributeDef [throwableClassName];
	
	finalizerMethod :: Bool -> ClassName -> ClassName -> [MethodNameType] -> MethodDefinition;
	finalizerMethod deferred classname superclassname methods = MkMethodDefinition
		MkProtected MkVirtual False False False False
		objectFinalizerNameType
		[finalizerCode deferred classname superclassname (fmap fieldNameTypeForMethod methods),
		finalizerThrowables];
	}