/*

 * Copyright (c) 2009, 2019, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

package shared;

import java.lang.reflect.Method;

import java.lang.reflect.Modifier;

public abstract class Checker {

    protected Class staticTargetClass;

    protected Class dynamicTargetClass;

    protected String methodName;

    public abstract String check (Class callSite);

    public Checker(Class staticTargetClass, Class dynamicTargetClass) {

        if (!staticTargetClass.isAssignableFrom(dynamicTargetClass)) {

            throw new RuntimeException("Dynamic target class should be a subclass of the static target class.");

        }

        // **********************************************

        // NB!!! All classes are assumed to be PUBLIC !!!

        // **********************************************

        Class klass = dynamicTargetClass;

        while (klass != Object.class) {

            if (!Modifier.isPublic(klass.getModifiers())) {

                throw new AssertionError("Class "+klass.getName()+" isn't public.");

            }

            klass = klass.getSuperclass();

        }

        this.methodName = Utils.TARGET_METHOD_NAME;

        this.staticTargetClass = staticTargetClass;

        this.dynamicTargetClass = dynamicTargetClass;

    }

    protected Method getMethodInHierarchy (Class klass) {

        return getMethodInHierarchy(klass, methodName);

    }

    protected Method getMethodInHierarchy (Class klass, String name) {

        while (klass != null) {

            Method method = getDeclaredMethod (klass, name);

            if ( method != null) {

// TODO: why doesn't this check work in VM?

//                int modifiers = method.getModifiers();

//

//                if (Modifier.isPrivate(modifiers)) {

//                    if (klass == initialClass) {

//                        return method;

//                    }

//                } else {

//                    return method;

//                }

                return method;

            }

            klass = klass.getSuperclass();

        }

        return null;

    }

    protected Method getMethod (Class klass) {

        return getMethod (klass, methodName);

    }

    protected Method getDeclaredMethod (Class klass) {

        return getDeclaredMethod (klass, methodName);

    }

    static protected Method getMethod (Class klass, String name) {

        return findMethod (klass.getMethods(), name);

    }

    static protected Method getDeclaredMethod (Class klass, String name) {

        return findMethod (klass.getDeclaredMethods(), name);

    }

    static protected Method findMethod (Method[] methods, String name) {

        for (Method method : methods) {

            if (name.equals(method.getName())) {

                return method;

            }

        }

        return null;

    }

    static public String getClassPackageName(Class klass) {

        String name = klass.getName();

        return getClassPackageName(name);

    }

    static public String getClassPackageName(String name) {

        int lastDotIndex = name.lastIndexOf('.');

        if (lastDotIndex > -1) {

            return name.substring(0, lastDotIndex);

        } else {

            return "";

        }

    }

    public static String abbreviateResult(String result) {

        // Abbreviate exception names

        result = result.replaceAll("java.lang.NullPointerException", "NPE");

        result = result.replaceAll("java.lang.IllegalAccessError", "IAE");

        result = result.replaceAll("java.lang.IllegalAccessException", "IAExc");

        result = result.replaceAll("java.lang.NoSuchMethodError", "NSME");

        result = result.replaceAll("java.lang.AbstractMethodError", "AME");

        result = result.replaceAll("java.lang.IncompatibleClassChangeError", "ICCE");

        result = result.replaceAll("java.lang.VerifyError", "VE");

        result = result.replaceAll("java.lang.ClassFormatError", "CFE");

        return result;

    }

    // Check access possibility from particular call site

    protected boolean checkAccess(Class klass, Class callerClass) {

        int modifiers = klass.getModifiers();

        return checkAccess(modifiers, klass, callerClass);

    }

    protected boolean checkAccess(Method m, Class callerClass) {

        int modifiers = m.getModifiers();

        Class declaringClass = m.getDeclaringClass();

        return checkAccess(modifiers, declaringClass, callerClass);

    }

    protected boolean checkAccess(int modifiers, Class klass, Class callerClass) {

        if ( Modifier.isPublic(modifiers) ) {

            return true;

        } else if ( Modifier.isProtected(modifiers) ) {

            if (klass.isAssignableFrom(callerClass)) {

                return true;

            } else if (getClassPackageName(klass).equals(getClassPackageName(callerClass))) {

                return true;

            }

        } else if ( Modifier.isPrivate(modifiers)) {

            if (klass == callerClass) {

                return true;

            }

        } else if (getClassPackageName(klass).equals(getClassPackageName(callerClass))) {

            return true;

        } else {

            // if method isn't accessible, IllegalAccessException is thrown

            return false;

        }

        return false;

    }

}