package com.alibaba.excel.util;

import java.lang.reflect.AccessibleObject;
import java.lang.reflect.Member;
import java.lang.reflect.Modifier;

/**
 * Member utils.
 *
 * @author Jiaju Zhuang
 */
public class MemberUtils {

    private static final int ACCESS_TEST = Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE;


    /**
     * XXX Default access superclass workaround.
     *
     * When a {@code public} class has a default access superclass with {@code public} members,
     * these members are accessible. Calling them from compiled code works fine.
     * Unfortunately, on some JVMs, using reflection to invoke these members
     * seems to (wrongly) prevent access even when the modifier is {@code public}.
     * Calling {@code setAccessible(true)} solves the problem but will only work from
     * sufficiently privileged code. Better workarounds would be gratefully
     * accepted.
     * @param o the AccessibleObject to set as accessible
     * @return a boolean indicating whether the accessibility of the object was set to true.
     */
    static boolean setAccessibleWorkaround(final AccessibleObject o) {
        if (o == null || o.isAccessible()) {
            return false;
        }
        final Member m = (Member) o;
        if (!o.isAccessible() && Modifier.isPublic(m.getModifiers()) && isPackageAccess(m.getDeclaringClass().getModifiers())) {
            try {
                o.setAccessible(true);
                return true;
            } catch (final SecurityException e) { // NOPMD
                // ignore in favor of subsequent IllegalAccessException
            }
        }
        return false;
    }

    /**
     * Returns whether a given set of modifiers implies package access.
     * @param modifiers to test
     * @return {@code true} unless {@code package}/{@code protected}/{@code private} modifier detected
     */
    static boolean isPackageAccess(final int modifiers) {
        return (modifiers & ACCESS_TEST) == 0;
    }
}