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 * 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.

 *

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 */

/* @test

 * @bug 8072773

 * @build jdk.testlibrary.RandomFactory

 * @run testng/othervm StreamLinesTest

 * @summary Tests streams returned from Files.lines, primarily focused on

 *          testing the file-channel-based stream stream with supported

 *          character sets

 * @key randomness

 */

import org.testng.annotations.DataProvider;

import org.testng.annotations.Test;

import java.io.BufferedReader;

import java.io.BufferedWriter;

import java.io.IOException;

import java.nio.charset.Charset;

import java.nio.charset.StandardCharsets;

import java.nio.file.Files;

import java.nio.file.Path;

import java.nio.file.StandardOpenOption;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.EnumSet;

import java.util.List;

import java.util.Random;

import java.util.function.IntFunction;

import java.util.function.Supplier;

import java.util.stream.OpTestCase;

import java.util.stream.Stream;

import java.util.stream.TestData;

import jdk.testlibrary.RandomFactory;

public class StreamLinesTest extends OpTestCase {

    enum LineSeparator {

        NONE(""),

        N("\n"),

        R("\r"),

        RN("\r\n");

        public final String value;

        LineSeparator(String value) {

            this.value = value;

        }

        public String toString() {

            return name();

        }

    }

    static Path generateTempFileWithLines(IntFunction<String> lineGenerator,

                                          IntFunction<LineSeparator> lineSeparatorGenerator,

                                          int lines, Charset cs, boolean endLineSep) throws IOException {

        Path p = Files.createTempFile("lines", null);

        BufferedWriter bw = Files.newBufferedWriter(p, cs);

        for (int i = 0; i < lines - 1; i++) {

            bw.write(lineGenerator.apply(i));

            bw.write(lineSeparatorGenerator.apply(i).value);

        }

        if (lines > 0) {

            bw.write(lineGenerator.apply(lines - 1));

            if (endLineSep)

                bw.write(lineSeparatorGenerator.apply(lines - 1).value);

        }

        bw.flush();

        bw.close();

        p.toFile().deleteOnExit();

        return p;

    }

    static void writeLineSeparator(Path p,

                                   IntFunction<LineSeparator> lineSeparatorGenerator,

                                   int lines, Charset cs) throws IOException {

        BufferedWriter bw = Files.newBufferedWriter(p, cs, StandardOpenOption.APPEND);

        bw.write(lineSeparatorGenerator.apply(lines - 1).value);

        bw.flush();

        bw.close();

    }

    static List<String> readAllLines(Path path, Charset cs) throws IOException {

        try (BufferedReader reader = Files.newBufferedReader(path, cs)) {

            List<String> result = new ArrayList<>();

            for (; ; ) {

                String line = reader.readLine();

                if (line == null)

                    break;

                result.add(line);

            }

            return result;

        }

    }

    static Object[] of(String description, IntFunction<String> lineGenerator,

                       IntFunction<LineSeparator> separatorGenerator, int n, Charset cs) {

        return new Object[]{description, lineGenerator, separatorGenerator, n, cs};

    }

    private static final Random random = RandomFactory.getRandom();

    @DataProvider

    public static Object[][] lines() {

        List<Object[]> l = new ArrayList<>();

        // Include the three supported optimal-line charsets and one

        // which does not

        List<Charset> charsets = Arrays.asList(StandardCharsets.UTF_8,

                                               StandardCharsets.US_ASCII,

                                               StandardCharsets.ISO_8859_1,

                                               StandardCharsets.UTF_16);

        String[] lines = {"", "A", "AB", "ABC", "ABCD"};

        int[] linesSizes = {0, 1, 2, 3, 4, 16, 256, 1024};

        for (Charset charset : charsets) {

            for (int linesSize : linesSizes) {

                if (linesSize > 0) {

                    for (String line : lines) {

                        for (LineSeparator ls : EnumSet.complementOf(EnumSet.of(LineSeparator.NONE))) {

                            String description = String.format("%d lines of \"%s\" with separator %s", linesSize, line, ls);

                            l.add(of(description,

                                    i -> line,

                                    i -> ls,

                                    linesSize, charset));

                        }

                    }

                } else {

                    l.add(of("Empty file: 0 lines",

                            i -> "",

                            i -> LineSeparator.NONE,

                            0, charset));

                }

            }

        }

        for (Charset charset : charsets) {

            l.add(of("A maximum of 1024 random lines and separators",

                     i -> lines[1 + random.nextInt(lines.length - 1)],

                     i -> LineSeparator.values()[random.nextInt(LineSeparator.values().length)],

                     1024, charset));

        }

        for (Charset charset : charsets) {

            l.add(of("One large line with no separators",

                     i -> "ABCD",

                     i -> LineSeparator.NONE,

                     1024, charset));

        }

        return l.toArray(new Object[][]{});

    }

    @Test(dataProvider = "lines")

    public void test(String description,

                     IntFunction<String> lineGenerator, IntFunction<LineSeparator> separatorGenerator,

                     int lines, Charset cs) throws IOException {

        Path p = generateTempFileWithLines(lineGenerator, separatorGenerator, lines, cs, false);

        Supplier<Stream<String>> ss = () -> {

            try {

                return Files.lines(p, cs);

            }

            catch (IOException e) {

                throw new RuntimeException(e);

            }

        };

        // Test without a separator at the end

        List<String> expected = readAllLines(p, cs);

        withData(TestData.Factory.ofSupplier("Lines with no separator at end", ss))

                .stream(s -> s)

                .expectedResult(expected)

                .exercise();

        // Test with a separator at the end

        writeLineSeparator(p, separatorGenerator, lines, cs);

        expected = readAllLines(p, cs);

        withData(TestData.Factory.ofSupplier("Lines with separator at end", ss))

                .stream(s -> s)

                .expectedResult(expected)

                .exercise();

    }

}