com.ui4j.bytebuddy.instrumentation.method.bytecode.stack.Removal Maven / Gradle / Ivy
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package com.ui4j.bytebuddy.instrumentation.method.bytecode.stack;
import com.ui4j.bytebuddy.instrumentation.Instrumentation;
import com.ui4j.bytebuddy.instrumentation.type.TypeDescription;
import com.ui4j.bytebuddy.jar.asm.MethodVisitor;
import com.ui4j.bytebuddy.jar.asm.Opcodes;
/**
* Removes a value from the operand stack.
*/
public enum Removal implements StackManipulation {
/**
* A removal of no value. This corresponds a no-op instruction.
*/
ZERO(StackSize.ZERO, Opcodes.NOP) {
@Override
public Size apply(MethodVisitor methodVisitor, Instrumentation.Context instrumentationContext) {
return new Size(0, 0);
}
},
/**
* A removal of a single-sized value.
*/
SINGLE(StackSize.SINGLE, Opcodes.POP),
/**
* A removal of a double-sized value.
*/
DOUBLE(StackSize.DOUBLE, Opcodes.POP2);
/**
* The size impact of the removal onto the operand stack.
*/
private final Size size;
/**
* The opcode to execute for the removal.
*/
private final int opcode;
/**
* Creates a new removal stack manipulation.
*
* @param stackSize The size impact of the removal onto the operand stack.
* @param opcode The opcode to execute for the removal.
*/
private Removal(StackSize stackSize, int opcode) {
size = stackSize.toDecreasingSize();
this.opcode = opcode;
}
/**
* Removes a value from the operand stack dependant of its size.
*
* @param typeDescription The type to remove from the stack.
* @return A stack manipulation that represents the removal.
*/
public static StackManipulation pop(TypeDescription typeDescription) {
switch (typeDescription.getStackSize()) {
case SINGLE:
return SINGLE;
case DOUBLE:
return DOUBLE;
case ZERO:
return ZERO;
default:
throw new AssertionError();
}
}
@Override
public boolean isValid() {
return true;
}
@Override
public Size apply(MethodVisitor methodVisitor, Instrumentation.Context instrumentationContext) {
methodVisitor.visitInsn(opcode);
return size;
}
}