Class GcUtf8String

core/src/main/java/io/questdb/std/str/GcUtf8String.java:38–125

A garbage-collected immutable UTF-8 string over owned native memory, originating from a Java String.

 * A garbage-collected immutable UTF-8 string over owned native memory, originating from a Java String.
 */
public class GcUtf8String implements DirectUtf8Sequence {
    private static final long BUFFER_ADDRESS_OFFSET;
    @SuppressWarnings("FieldCanBeLocal")  // We need to hold a reference to `buffer` or it will be GC'd.
    private final ByteBuffer buffer;  // We use a ByteBuffer here, instead of a ptr, to avoid Closeable requirement.
    @NotNull
    private final String original;
    private final long ptr;
    private final int size;
    private final long zeroPaddedSixPrefix;

    public GcUtf8String(@NotNull String original) {
        // ***** NOTE *****
        // This class causes garbage collection.
        // It should be used with care.
        // It is currently intended to be used for the `dirName` and `tableName` fields
        // of `TableToken` and similar things.
        this.original = original;
        final byte[] bytes = original.getBytes(StandardCharsets.UTF_8);
        this.buffer = ByteBuffer.allocateDirect(bytes.length);
        this.buffer.put(bytes);
        this.buffer.rewind();
        this.ptr = Unsafe.getLong(this.buffer, BUFFER_ADDRESS_OFFSET);
        this.size = bytes.length;
        this.zeroPaddedSixPrefix = Utf8s.zeroPaddedSixPrefix(this);
    }

    @Override
    public @NotNull CharSequence asAsciiCharSequence() {
        return original;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }

        if (o == null || getClass() != o.getClass()) {
            return false;
        }

        final GcUtf8String that = (GcUtf8String) o;
        return original.equals(that.original);
    }

    @Override
    public int hashCode() {
        return original.hashCode();
    }

    @Override
    public boolean isAscii() {
        return original.length() == size;
    }

    @Override
    public long ptr() {
        return ptr;