jdk-24/test/jdk/java/nio/channels/FileChannel/directio/DirectIOTest.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
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 * 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 8164900
 * @summary Test for ExtendedOpenOption.DIRECT flag
 * @requires (os.family == "linux" | os.family == "solaris"
 *         | os.family == "aix")
 * @library /test/lib
 * @build jdk.test.lib.Platform
 * @run main/native DirectIOTest
 */

import java.io.*;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.channels.*;
import java.nio.channels.FileChannel;
import java.nio.file.Paths;
import java.nio.file.Path;
import java.nio.file.Files;
import jdk.test.lib.Platform;
import java.nio.file.FileStore;
import java.nio.file.StandardOpenOption;
import com.sun.nio.file.ExtendedOpenOption;

public class DirectIOTest {

    private static final int SIZE = 4096;

    private static void testWrite(Path p) throws Exception {
        try (FileChannel fc = FileChannel.open(p, StandardOpenOption.WRITE,
             ExtendedOpenOption.DIRECT)) {
            FileStore fs = Files.getFileStore(p);
            int alignment = (int)fs.getBlockSize();
            ByteBuffer src = ByteBuffer.allocateDirect(SIZE + alignment - 1)
                                       .alignedSlice(alignment);
            for (int j = 0; j < SIZE; j++) {
                src.put((byte)0);
            }
            src.flip();
            fc.write(src);
        }
    }

    private static void testRead(Path p) throws Exception {
        try (FileChannel fc = FileChannel.open(p, ExtendedOpenOption.DIRECT)) {
            FileStore fs = Files.getFileStore(p);
            int alignment = (int)fs.getBlockSize();
            ByteBuffer dest = ByteBuffer.allocateDirect(SIZE + alignment - 1)
                                        .alignedSlice(alignment);
            fc.read(dest);
        }
    }

    public static Path createTempFile() throws IOException {
        return Files.createTempFile(
            Paths.get(System.getProperty("test.dir", ".")), "test", null);
    }

    public static boolean isDirectIOSupportedByFS(Path p) throws Exception {
        boolean supported = true;
        if (Platform.isSolaris()) {
            String fsType = Files.getFileStore(p).type();
            if (!fsType.equals("nfs") && !fsType.equals("ufs")) {
                // print a message and return without failing
                System.out.format("Skipping test: file system type %s of "
                    + "FileStore of %s is neither nfs nor ufs.%n", fsType, p);
                supported = false;
            }
        }
        return supported;
    }

    private static boolean isFileInCache(Path p) {
        String path = p.toString();
        return isFileInCache0(SIZE, path);
    }

    private static native boolean isFileInCache0(int size, String path);

    public static void main(String[] args) throws Exception {
        Path p = createTempFile();

        if (!isDirectIOSupportedByFS(p)) {
            Files.delete(p);
            return;
        }

        System.loadLibrary("DirectIO");

        try {
            testWrite(p);
            if (isFileInCache(p)) {
                throw new RuntimeException("DirectIO is not working properly with "
                    + "write. File still exists in cache!");
            }
            testRead(p);
            if (isFileInCache(p)) {
                throw new RuntimeException("DirectIO is not working properly with "
                    + "read. File still exists in cache!");
            }
        } finally {
            Files.delete(p);
        }
    }
}