SquirrelJME/SquirrelJME

// -*- Mode: Java; indent-tabs-mode: t; tab-width: 4 -*-
// ---------------------------------------------------------------------------
// 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.jdwp.host;

import cc.squirreljme.jdwp.JDWPClassType;
import cc.squirreljme.jdwp.host.views.JDWPViewObject;
import cc.squirreljme.jdwp.host.views.JDWPViewThread;
import cc.squirreljme.jdwp.host.views.JDWPViewType;

/**
 * General utilities for JDWP Support.
 *
 * @since 2021/04/11
 */
public final class JDWPHostUtils
{
    /** Interface bit. */
    private static final int _INTERFACE_BIT = 
        0x0200;
    
    /**
     * Not used.
     * 
     * @since 2021/04/11
     */
    private JDWPHostUtils()
    {
    }
    
    /**
     * Returns the type that the given class is.
     * 
     * @param __controller The controller.
     * @param __class The class to check.
     * @return The type that the class is.
     * @throws NullPointerException On null arguments.
     * @since 2021/04/11
     */
    public static JDWPClassType classType(JDWPHostController __controller,
        Object __class)
        throws NullPointerException
    {
        if (__controller == null)
            throw new NullPointerException("NARG");
        
        // If null or not valid, treat as an object
        JDWPViewType viewType = __controller.viewType();
        if (__class == null || !viewType.isValid(__class))
        {
            // If this was an object, then get the class of the object
            JDWPViewObject viewObject = __controller.viewObject();
            if (__class != null && viewObject.isValid(__class))
                return JDWPHostUtils.classType(__controller,
                    viewObject.type(__class));
            
            return JDWPClassType.CLASS;
        }
        
        // Array type?
        if (viewType.signature(__class).startsWith("["))
            return JDWPClassType.ARRAY;
        
        // Is this potentially an interface?
        int flags = viewType.flags(__class);
        if ((flags & JDWPHostUtils._INTERFACE_BIT) != 0)
            return JDWPClassType.INTERFACE;
        
        // Just a plain class
        return JDWPClassType.CLASS;
    }
    
    /**
     * Finds the field ID for the given type.
     * 
     * @param __viewType The type view.
     * @param __type The type to look in.
     * @param __fieldName The field name.
     * @param __fieldDesc The field descriptor.
     * @return The field ID for the given field or a negative if not valid.
     * @throws NullPointerException On null arguments.
     * @since 2022/09/24
     */
    public static int findFieldId(JDWPViewType __viewType, Object __type,
        String __fieldName, String __fieldDesc)
        throws NullPointerException
    {
        if (__viewType == null || __type == null || __fieldName == null ||
            __fieldDesc == null)
            throw new NullPointerException("NARG");
        
        // Search through all fields
        for (int fieldId : __viewType.fields(__type))
            if (__fieldName.equals(__viewType.fieldName(__type, fieldId)) &&
                __fieldDesc.equals(__viewType.fieldSignature(__type, fieldId)))
                return fieldId;
        
        // Not found
        return -1;
    }
    
    /**
     * Is this a visible thread?
     * 
     * @param __view The view used.
     * @param __thread The thread.
     * @return If this thread is visible or not.
     * @since 2022/09/24
     */
    public static boolean isVisibleThread(JDWPViewThread __view,
        Object __thread)
    {
        return !__view.isTerminated(__thread) &&
            !__view.isDebugCallback(__thread) &&
            __view.frames(__thread).length > 0;
    }
    
    /**
     * Converts a signature to a runtime name.
     * 
     * @param __signature The signature to convert.
     * @return The runtime name of the signature.
     * @throws NullPointerException On null arguments.
     * @since 2021/04/18
     */
    public static String signatureToRuntime(String __signature)
        throws NullPointerException
    {
        if (__signature == null)
            throw new NullPointerException("NARG");
        
        // If not a class, keep as is!
        if (!__signature.startsWith("L"))
            return __signature;
        
        // Clip off the L; and un-binary name it
        return __signature.substring(1, __signature.length() - 1)
            .replace('/', '.');
    }
}