/*

 * 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.

 */

/* @test

 * @bug 4652496

 * @summary Test transferTo with different target channels

 */

import java.nio.channels.FileChannel;

import java.nio.channels.WritableByteChannel;

import java.nio.ByteBuffer;

import java.io.*;

import java.util.Random;

public class TransferToChannel {

    static File file;

    static File outFile;

    static FileChannel in;

    // Chunk size should be larger than FileChannelImpl.TRANSFER_SIZE for good test

    static int CHUNK_SIZE = 1024 * 9;

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

        file = File.createTempFile("readingin", null);

        outFile = File.createTempFile("writingout", null);

        file.deleteOnExit();

        outFile.deleteOnExit();

        generateBigFile(file);

        FileInputStream fis = new FileInputStream(file);

        in = fis.getChannel();

        test1();

        test2();

        in.close();

        file.delete();

        outFile.delete();

    }

    static void test1() throws Exception {

        for (int i=0; i<10; i++) {

            transferFileToUserChannel();

            System.gc();

            System.err.println("Transferred file...");

        }

    }

    static void test2() throws Exception {

        for (int i=0; i<10; i++) {

            transferFileToTrustedChannel();

            System.gc();

            System.err.println("Transferred file...");

        }

    }

    static void transferFileToUserChannel() throws Exception {

        long remainingBytes = in.size();

        long size = remainingBytes;

        WritableByteChannel wbc = new WritableByteChannel() {

                Random rand = new Random(0);

                public int write(ByteBuffer src) throws IOException {

                    int read = src.remaining();

                    byte[] incoming = new byte[read];

                    src.get(incoming);

                    checkData(incoming, read);

                    return read == 0 ? -1 : read;

                }

                public boolean isOpen() {

                    return true;

                }

                public void close() throws IOException {

                }

                void checkData(byte[] incoming, int size) {

                    byte[] expected = new byte[size];

                    rand.nextBytes(expected);

                    for (int i=0; i<size; i++)

                        if (incoming[i] != expected[i])

                            throw new RuntimeException("Data corrupted");

                }

            };

        while (remainingBytes > 0) {

            long bytesTransferred = in.transferTo(size - remainingBytes,

                              Math.min(CHUNK_SIZE, remainingBytes), wbc);

            if (bytesTransferred >= 0)

                remainingBytes -= bytesTransferred;

            else

                throw new Exception("transfer failed");

        }

    }

    static void transferFileToTrustedChannel() throws Exception {

        long remainingBytes = in.size();

        long size = remainingBytes;

        FileOutputStream fos = new FileOutputStream(outFile);

        FileChannel out = fos.getChannel();

        while (remainingBytes > 0) {

            long bytesTransferred = in.transferTo(size - remainingBytes,

                                                  CHUNK_SIZE, out);

            if (bytesTransferred >= 0)

                remainingBytes -= bytesTransferred;

            else

                throw new Exception("transfer failed");

        }

        out.close();

    }

    static void generateBigFile(File file) throws Exception {

        OutputStream out = new BufferedOutputStream(

                           new FileOutputStream(file));

        byte[] randomBytes = new byte[1024];

        Random rand = new Random(0);

        for (int i = 0; i < 1000; i++) {

            rand.nextBytes(randomBytes);

            out.write(randomBytes);

        }

        out.flush();

        out.close();

    }

}