Object() — netty Function Reference

Source Code

codec-base/src/main/java/io/netty/handler/codec/LengthFieldBasedFrameDecoder.java lines 397–444

    protected Object decode(ChannelHandlerContext ctx, ByteBuf in) throws Exception {
        long frameLength = 0;
        if (frameLengthInt == -1) { // new frame

            if (discardingTooLongFrame) {
                discardingTooLongFrame(in);
            }

            if (in.readableBytes() < lengthFieldEndOffset) {
                return null;
            }

            int actualLengthFieldOffset = in.readerIndex() + lengthFieldOffset;
            frameLength = getUnadjustedFrameLength(in, actualLengthFieldOffset, lengthFieldLength, byteOrder);

            if (frameLength < 0) {
                failOnNegativeLengthField(in, frameLength, lengthFieldEndOffset);
            }

            frameLength += lengthAdjustment + lengthFieldEndOffset;

            if (frameLength < lengthFieldEndOffset) {
                failOnFrameLengthLessThanLengthFieldEndOffset(in, frameLength, lengthFieldEndOffset);
            }

            if (frameLength > maxFrameLength) {
                exceededFrameLength(in, frameLength);
                return null;
            }
            // never overflows because it's less than maxFrameLength
            frameLengthInt = (int) frameLength;
        }
        if (in.readableBytes() < frameLengthInt) { // frameLengthInt exist , just check buf
            return null;
        }
        if (initialBytesToStrip > frameLengthInt) {
            failOnFrameLengthLessThanInitialBytesToStrip(in, frameLength, initialBytesToStrip);
        }
        in.skipBytes(initialBytesToStrip);

        // extract frame
        int readerIndex = in.readerIndex();
        int actualFrameLength = frameLengthInt - initialBytesToStrip;
        ByteBuf frame = extractFrame(ctx, in, readerIndex, actualFrameLength);
        in.readerIndex(readerIndex + actualFrameLength);
        frameLengthInt = -1; // start processing the next frame
        return frame;
    }