Example usage for org.objectweb.asm.tree AbstractInsnNode getPrevious

Introduction

In this page you can find the example usage for org.objectweb.asm.tree AbstractInsnNode getPrevious.

Prototype

public AbstractInsnNode getPrevious()

Source Link

Document

Returns the previous instruction in the list to which this instruction belongs, if any.

Usage

From source file:vazkii.quark.base.asm.ClassTransformer.java

License:Creative Commons License

private static byte[] transformBlockPistonBase(byte[] basicClass) {
    log("Transforming BlockPistonBase");
    MethodSignature sig1 = new MethodSignature("doMove", "func_176319_a", "a",
            "(Lnet/minecraft/world/World;Lnet/minecraft/util/math/BlockPos;Lnet/minecraft/util/EnumFacing;Z)Z");
    MethodSignature sig2 = new MethodSignature("canPush", "func_185646_a", "a",
            "(Lnet/minecraft/block/state/IBlockState;Lnet/minecraft/world/World;Lnet/minecraft/util/math/BlockPos;Lnet/minecraft/util/EnumFacing;ZLnet/minecraft/util/EnumFacing;)Z");

    byte[] transClass = transform(basicClass, Pair.of(sig1, combine((AbstractInsnNode node) -> { // Filter
        return node.getOpcode() == Opcodes.ASTORE && ((VarInsnNode) node).var == 11;
    }, (MethodNode method, AbstractInsnNode node) -> { // Action
        InsnList newInstructions = new InsnList();

        newInstructions.add(new VarInsnNode(Opcodes.ALOAD, 1));
        newInstructions.add(new VarInsnNode(Opcodes.ALOAD, 2));
        newInstructions.add(new VarInsnNode(Opcodes.ALOAD, 6));
        newInstructions.add(new VarInsnNode(Opcodes.ALOAD, 8));
        newInstructions.add(new VarInsnNode(Opcodes.ALOAD, 11));
        newInstructions.add(new VarInsnNode(Opcodes.ILOAD, 4));
        newInstructions.add(new MethodInsnNode(Opcodes.INVOKESTATIC, ASM_HOOKS, "breakStuffWithSpikes",
                "(Lnet/minecraft/world/World;Lnet/minecraft/util/math/BlockPos;Ljava/util/List;Ljava/util/List;Lnet/minecraft/util/EnumFacing;Z)Z"));

        // recalculate the list and array sizes
        LabelNode label = new LabelNode();
        newInstructions.add(new JumpInsnNode(Opcodes.IFEQ, label));

        newInstructions.add(new VarInsnNode(Opcodes.ALOAD, 6));
        newInstructions.add(new MethodInsnNode(Opcodes.INVOKEINTERFACE, "java/util/List", "size", "()I"));
        newInstructions.add(new VarInsnNode(Opcodes.ALOAD, 8));
        newInstructions.add(new MethodInsnNode(Opcodes.INVOKEINTERFACE, "java/util/List", "size", "()I"));
        newInstructions.add(new InsnNode(Opcodes.IADD));
        newInstructions.add(new VarInsnNode(Opcodes.ISTORE, 9));
        newInstructions.add(new VarInsnNode(Opcodes.ILOAD, 9));

        AbstractInsnNode newNode = node.getPrevious();
        while (true) {
            if (newNode.getOpcode() == Opcodes.ANEWARRAY) {
                newInstructions.add(new TypeInsnNode(Opcodes.ANEWARRAY, ((TypeInsnNode) newNode).desc));
                break;
            }//ww  w  . j  a  v a 2  s  . co  m
            newNode = newNode.getPrevious();
        }

        newInstructions.add(new VarInsnNode(Opcodes.ASTORE, 10));
        newInstructions.add(label);

        method.instructions.insert(node, newInstructions);
        return true;
    })));

    transClass = transform(transClass, Pair.of(sig2, combine((AbstractInsnNode node) -> { // Filter
        return node.getOpcode() == Opcodes.INVOKEVIRTUAL
                && ((MethodInsnNode) node).name.equals("hasTileEntity");
    }, (MethodNode method, AbstractInsnNode node) -> { // Action
        InsnList newInstructions = new InsnList();

        newInstructions.add(new VarInsnNode(Opcodes.ALOAD, 0));
        newInstructions.add(new MethodInsnNode(Opcodes.INVOKESTATIC, ASM_HOOKS, "shouldPistonMoveTE",
                "(ZLnet/minecraft/block/state/IBlockState;)Z"));

        method.instructions.insert(node, newInstructions);
        return true;
    })));

    return transClass;
}