/*

 * Copyright (c) 2012, 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

 *

 * 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 org.openjdk.tests.separate;

import java.io.*;

import java.util.*;

public class ClassToInterfaceConverter implements ClassFilePreprocessor {

    private String whichClass;

    public ClassToInterfaceConverter(String className) {

        this.whichClass = className;

    }

    private boolean utf8Matches(ClassFile.CpEntry entry, String v) {

        if (!(entry instanceof ClassFile.CpUtf8)) {

            return false;

        }

        ClassFile.CpUtf8 utf8 = (ClassFile.CpUtf8)entry;

        if (v.length() != utf8.bytes.length) {

            return false;

        }

        for (int i = 0; i < v.length(); ++i) {

            if (v.charAt(i) != utf8.bytes[i]) {

                return false;

            }

        }

        return true;

    }

    private void convertToInterface(ClassFile cf) {

        cf.access_flags = 0x0601; // ACC_INTERFACE | ACC_ABSTRACT | ACC_PUBLIC

        ArrayList<ClassFile.Method> new_methods = new ArrayList<>();

        // Find <init> method and delete it

        for (int i = 0; i < cf.methods.size(); ++i) {

            ClassFile.Method method = cf.methods.get(i);

            ClassFile.CpEntry name = cf.constant_pool.get(method.name_index);

            if (!utf8Matches(name, "<init>")) {

                new_methods.add(method);

            }

        }

        cf.methods = new_methods;

    }

    public byte[] preprocess(String classname, byte[] bytes) {

        ClassFile cf = new ClassFile(bytes);

        ClassFile.CpEntry entry = cf.constant_pool.get(cf.this_class);

        ClassFile.CpEntry name = cf.constant_pool.get(

            ((ClassFile.CpClass)entry).name_index);

        if (utf8Matches(name, whichClass)) {

            convertToInterface(cf);

            return cf.toByteArray();

        } else {

            return bytes; // unmodified

        }

    }

/*

    public static void main(String argv[]) throws Exception {

        File input = new File(argv[0]);

        byte[] buffer = new byte[(int)input.length()];

        new FileInputStream(input).read(buffer);

        ClassFilePreprocessor cfp = new ClassToInterfaceConverter("Hello");

        byte[] cf = cfp.preprocess(argv[0], buffer);

        new FileOutputStream(argv[0] + ".mod").write(cf);

    }

*/

}