/*

 * 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.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * 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

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 */

/*

 * This file is available under and governed by the GNU General Public

 * License version 2 only, as published by the Free Software Foundation.

 * However, the following notice accompanied the original version of this

 * file:

 *

 * ASM: a very small and fast Java bytecode manipulation framework

 * Copyright (c) 2000-2011 INRIA, France Telecom

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. Neither the name of the copyright holders nor the names of its

 *    contributors may be used to endorse or promote products derived from

 *    this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE

 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF

 * THE POSSIBILITY OF SUCH DAMAGE.

 */

package jdk.internal.org.objectweb.asm.commons;

import java.util.ArrayList;

import java.util.List;

import jdk.internal.org.objectweb.asm.Attribute;

import jdk.internal.org.objectweb.asm.ByteVector;

import jdk.internal.org.objectweb.asm.ClassReader;

import jdk.internal.org.objectweb.asm.ClassWriter;

import jdk.internal.org.objectweb.asm.Label;

/**

 * A ModuleHashes attribute. This attribute is specific to the OpenJDK and may change in the future.

 *

 * @author Remi Forax

 */

public final class ModuleHashesAttribute extends Attribute {

    /** The name of the hashing algorithm. */

    public String algorithm;

    /** A list of module names. */

    public List<String> modules;

    /** The hash of the modules in {@link #modules}. The two lists must have the same size. */

    public List<byte[]> hashes;

    /**

      * Constructs a new {@link ModuleHashesAttribute}.

      *

      * @param algorithm the name of the hashing algorithm.

      * @param modules a list of module names.

      * @param hashes the hash of the modules in 'modules'. The two lists must have the same size.

      */

    public ModuleHashesAttribute(

            final String algorithm, final List<String> modules, final List<byte[]> hashes) {

        super("ModuleHashes");

        this.algorithm = algorithm;

        this.modules = modules;

        this.hashes = hashes;

    }

    /**

      * Constructs an empty {@link ModuleHashesAttribute}. This object can be passed as a prototype to

      * the {@link ClassReader#accept(org.objectweb.asm.ClassVisitor, Attribute[], int)} method.

      */

    public ModuleHashesAttribute() {

        this(null, null, null);

    }

    @Override

    protected Attribute read(

            final ClassReader classReader,

            final int offset,

            final int length,

            final char[] charBuffer,

            final int codeAttributeOffset,

            final Label[] labels) {

        int currentOffset = offset;

        String hashAlgorithm = classReader.readUTF8(currentOffset, charBuffer);

        currentOffset += 2;

        int numModules = classReader.readUnsignedShort(currentOffset);

        currentOffset += 2;

        ArrayList<String> moduleList = new ArrayList<>(numModules);

        ArrayList<byte[]> hashList = new ArrayList<>(numModules);

        for (int i = 0; i < numModules; ++i) {

            String module = classReader.readModule(currentOffset, charBuffer);

            currentOffset += 2;

            moduleList.add(module);

            int hashLength = classReader.readUnsignedShort(currentOffset);

            currentOffset += 2;

            byte[] hash = new byte[hashLength];

            for (int j = 0; j < hashLength; ++j) {

                hash[j] = (byte) (classReader.readByte(currentOffset) & 0xFF);

                currentOffset += 1;

            }

            hashList.add(hash);

        }

        return new ModuleHashesAttribute(hashAlgorithm, moduleList, hashList);

    }

    @Override

    protected ByteVector write(

            final ClassWriter classWriter,

            final byte[] code,

            final int codeLength,

            final int maxStack,

            final int maxLocals) {

        ByteVector byteVector = new ByteVector();

        byteVector.putShort(classWriter.newUTF8(algorithm));

        if (modules == null) {

            byteVector.putShort(0);

        } else {

            int numModules = modules.size();

            byteVector.putShort(numModules);

            for (int i = 0; i < numModules; ++i) {

                String module = modules.get(i);

                byte[] hash = hashes.get(i);

                byteVector

                        .putShort(classWriter.newModule(module))

                        .putShort(hash.length)

                        .putByteArray(hash, 0, hash.length);

            }

        }

        return byteVector;

    }

}