/*

 * Copyright (c) 2010, 2014, 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.  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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package jdk.nashorn.internal.runtime;

import java.io.ByteArrayOutputStream;

import java.io.IOException;

import java.io.ObjectOutputStream;

import java.util.zip.Deflater;

import java.util.zip.DeflaterOutputStream;

import jdk.nashorn.internal.ir.FunctionNode;

import jdk.nashorn.internal.runtime.options.Options;

/**

 * This static utility class performs serialization of FunctionNode ASTs to a byte array.

 * The format is a standard Java serialization stream, deflated.

 */

final class AstSerializer {

    // Experimentally, we concluded that compression level 4 gives a good tradeoff between serialization speed

    // and size.

    private static final int COMPRESSION_LEVEL = Options.getIntProperty("nashorn.serialize.compression", 4);

    static byte[] serialize(final FunctionNode fn) {

        final ByteArrayOutputStream out = new ByteArrayOutputStream();

        final Deflater deflater = new Deflater(COMPRESSION_LEVEL);

        try (final ObjectOutputStream oout = new ObjectOutputStream(new DeflaterOutputStream(out, deflater))) {

            oout.writeObject(fn);

        } catch (final IOException e) {

            throw new AssertionError("Unexpected exception serializing function", e);

        } finally {

            deflater.end();

        }

        return out.toByteArray();

    }

}