BrotliDecoder Class — netty Architecture

Source Code

codec-compression/src/main/java/io/netty/handler/codec/compression/BrotliDecoder.java lines 33–186

public final class BrotliDecoder extends ByteToMessageDecoder {

    private enum State {
        DONE, NEEDS_MORE_INPUT, ERROR
    }

    static {
        try {
            Brotli.ensureAvailability();
        } catch (Throwable throwable) {
            throw new ExceptionInInitializerError(throwable);
        }
    }

    private final int inputBufferSize;
    private DecoderJNI.Wrapper decoder;
    private boolean destroyed;
    private boolean needsRead;

    /**
     * Creates a new BrotliDecoder with a default 8kB input buffer
     */
    public BrotliDecoder() {
        this(8 * 1024);
    }

    /**
     * Creates a new BrotliDecoder
     * @param inputBufferSize desired size of the input buffer in bytes
     */
    public BrotliDecoder(int inputBufferSize) {
        this.inputBufferSize = ObjectUtil.checkPositive(inputBufferSize, "inputBufferSize");
    }

    private void forwardOutput(ChannelHandlerContext ctx) {
        ByteBuffer nativeBuffer = decoder.pull();
        // nativeBuffer actually wraps brotli's internal buffer so we need to copy its content
        ByteBuf copy = ctx.alloc().buffer(nativeBuffer.remaining());
        copy.writeBytes(nativeBuffer);
        needsRead = false;
        ctx.fireChannelRead(copy);
    }

    private State decompress(ChannelHandlerContext ctx, ByteBuf input) {
        for (;;) {
            switch (decoder.getStatus()) {
                case DONE:
                    return State.DONE;

                case OK:
                    decoder.push(0);
                    break;

                case NEEDS_MORE_INPUT:
                    if (decoder.hasOutput()) {
                        forwardOutput(ctx);
                    }

                    if (!input.isReadable()) {
                        return State.NEEDS_MORE_INPUT;
                    }

                    ByteBuffer decoderInputBuffer = decoder.getInputBuffer();
                    decoderInputBuffer.clear();
                    int readBytes = readBytes(input, decoderInputBuffer);
                    decoder.push(readBytes);
                    break;

                case NEEDS_MORE_OUTPUT:
                    forwardOutput(ctx);
                    break;

                default:
                    return State.ERROR;
            }
        }
    }

    private static int readBytes(ByteBuf in, ByteBuffer dest) {
        int limit = Math.min(in.readableBytes(), dest.remaining());
        ByteBuffer slice = dest.slice();