PlatformDependent Class — netty Architecture

Source Code

common/src/main/java/io/netty/util/internal/PlatformDependent.java lines 87–1910

public final class PlatformDependent {

    private static final InternalLogger logger = InternalLoggerFactory.getInstance(PlatformDependent.class);

    private static Pattern MAX_DIRECT_MEMORY_SIZE_ARG_PATTERN;
    private static final boolean MAYBE_SUPER_USER;

    private static final boolean CAN_ENABLE_TCP_NODELAY_BY_DEFAULT = !isAndroid();

    private static final Throwable UNSAFE_UNAVAILABILITY_CAUSE = unsafeUnavailabilityCause0();
    private static final boolean DIRECT_BUFFER_PREFERRED;
    private static final boolean EXPLICIT_NO_PREFER_DIRECT;
    private static final long MAX_DIRECT_MEMORY = estimateMaxDirectMemory();

    private static final int MPSC_CHUNK_SIZE =  1024;
    private static final int MIN_MAX_MPSC_CAPACITY =  MPSC_CHUNK_SIZE * 2;
    private static final int MAX_ALLOWED_MPSC_CAPACITY = Pow2.MAX_POW2;

    private static final long BYTE_ARRAY_BASE_OFFSET = byteArrayBaseOffset0();

    private static final File TMPDIR = tmpdir0();

    private static final int BIT_MODE = bitMode0();
    private static final String NORMALIZED_ARCH = normalizeArch(SystemPropertyUtil.get("os.arch", ""));
    private static final String NORMALIZED_OS = normalizeOs(SystemPropertyUtil.get("os.name", ""));

    private static final Set<String> LINUX_OS_CLASSIFIERS;

    private static final boolean IS_WINDOWS = isWindows0();
    private static final boolean IS_OSX = isOsx0();
    private static final boolean IS_J9_JVM = isJ9Jvm0();
    private static final boolean IS_IVKVM_DOT_NET = isIkvmDotNet0();

    private static final int ADDRESS_SIZE = addressSize0();
    private static final boolean USE_DIRECT_BUFFER_NO_CLEANER;
    private static final AtomicLong DIRECT_MEMORY_COUNTER;
    private static final long DIRECT_MEMORY_LIMIT;
    private static final Cleaner CLEANER;
    private static final Cleaner DIRECT_CLEANER;
    private static final Cleaner LEGACY_CLEANER;
    private static final boolean HAS_ALLOCATE_UNINIT_ARRAY;
    private static final String LINUX_ID_PREFIX = "ID=";
    private static final String LINUX_ID_LIKE_PREFIX = "ID_LIKE=";
    public static final boolean BIG_ENDIAN_NATIVE_ORDER = ByteOrder.nativeOrder() == ByteOrder.BIG_ENDIAN;

    private static final boolean JFR;
    private static final boolean VAR_HANDLE;

    private static final Cleaner NOOP = new Cleaner() {
        @Override
        public CleanableDirectBuffer allocate(int capacity) {
            return new CleanableDirectBuffer() {
                private final ByteBuffer byteBuffer = ByteBuffer.allocateDirect(capacity);

                @Override
                public ByteBuffer buffer() {
                    return byteBuffer;
                }

                @Override
                public void clean() {
                    // NOOP
                }
            };
        }

        @Override
        public void freeDirectBuffer(ByteBuffer buffer) {
            // NOOP
        }
    };

    static {
        // Here is how the system property is used:
        //
        // * <  0  - Don't use cleaner, and inherit max direct memory from java. In this case the
        //           "practical max direct memory" would be 2 * max memory as defined by the JDK.
        // * == 0  - Use cleaner, Netty will not enforce max memory, and instead will defer to JDK.
        // * >  0  - Don't use cleaner. This will limit Netty's total direct memory
        //           (note: that JDK's direct memory limit is independent of this).
        long maxDirectMemory = SystemPropertyUtil.getLong("io.netty.maxDirectMemory", -1);