SquirrelJME/SquirrelJME

// -*- Mode: Java; indent-tabs-mode: t; tab-width: 4 -*-
// ---------------------------------------------------------------------------
// Multi-Phasic Applications: SquirrelJME
//     Copyright (C) Stephanie Gawroriski <xer@multiphasicapps.net>
// ---------------------------------------------------------------------------
// SquirrelJME is under the Mozilla Public License Version 2.0.
// See license.mkd for licensing and copyright information.
// ---------------------------------------------------------------------------

package cc.squirreljme.debugger;

import cc.squirreljme.runtime.cldc.debug.Debugging;
import net.multiphasicapps.classfile.ByteCode;
import net.multiphasicapps.classfile.ClassName;
import net.multiphasicapps.classfile.Method;
import net.multiphasicapps.classfile.MethodNameAndType;

/**
 * Java method viewer using SquirrelJME's {@link Method}.
 *
 * @since 2024/01/21
 */
public class JavaMethodViewer
    implements MethodViewer
{
    /** The method to view. */
    protected final Method method;
    
    /** Cached instructions. */
    private volatile InstructionViewer[] _instructions;
    
    /**
     * Initializes the method viewer.
     *
     * @param __method The method to view.
     * @throws NullPointerException On null arguments.
     * @since 2024/01/21
     */
    public JavaMethodViewer(Method __method)
        throws NullPointerException
    {
        if (__method == null)
            throw new NullPointerException("NARG");
        
        this.method = __method;
    }
    
    /**
     * {@inheritDoc}
     * @since 2024/01/21
     */
    @Override
    public ClassName inClass()
    {
        return this.method.inClass();
    }
    
    /**
     * {@inheritDoc}
     * @since 2024/01/21
     */
    @Override
    public boolean isAbstract()
    {
        return this.method.flags().isAbstract();
    }
    
    /**
     * {@inheritDoc}
     * @since 2024/01/21
     */
    @Override
    public boolean isNative()
    {
        return this.method.flags().isNative();
    }
    
    /**
     * {@inheritDoc}
     * @since 2024/01/21
     */
    @Override
    public MethodNameAndType methodNameAndType()
    {
        return this.method.nameAndType();
    }
    
    /**
     * {@inheritDoc}
     * @since 2024/01/21
     */
    @Override
    public InstructionViewer[] instructions()
    {
        // Cannot be native or abstract
        if (this.isAbstract() || this.isNative())
            return null;
        
        // Did we already wrap everything?
        InstructionViewer[] result = this._instructions;
        if (result != null)
            return result.clone();
        
        // Get the byte code for the method
        ByteCode byteCode = this.method.byteCode();
        
        // Get the instructions and wrap them all
        int count = byteCode.instructionCount();
        result = new InstructionViewer[count];
        for (int i = 0; i < count; i++)
            result[i] = new JavaInstructionViewer(byteCode.getByIndex(i));
        
        // Cache for later and return the result
        this._instructions = result;
        return result.clone();
    }
}