HeaderParser Class — netty Architecture

Source Code

codec-stomp/src/main/java/io/netty/handler/codec/stomp/StompSubframeDecoder.java lines 337–440

    private static final class HeaderParser extends Utf8LineParser {

        private final boolean validateHeaders;

        private String name;
        private boolean valid;

        private boolean shouldUnescape;
        private boolean unescapeInProgress;

        HeaderParser(AppendableCharSequence charSeq, int maxLineLength, boolean validateHeaders) {
            super(charSeq, maxLineLength);
            this.validateHeaders = validateHeaders;
        }

        boolean parseHeader(StompHeadersSubframe headersSubframe, ByteBuf buf) {
            shouldUnescape = shouldUnescape(headersSubframe.command());
            AppendableCharSequence value = super.parse(buf);
            if (value == null || (name == null && value.length() == 0)) {
                return false;
            }

            if (valid) {
                headersSubframe.headers().add(name, value.toString());
            } else if (validateHeaders) {
                if (StringUtil.isNullOrEmpty(name)) {
                    throw new IllegalArgumentException("received an invalid header line '" + value + '\'');
                }
                String line = name + ':' + value;
                throw new IllegalArgumentException("a header value or name contains a prohibited character ':'"
                                                   + ", " + line);
            }
            return true;
        }

        @Override
        public boolean process(byte nextByte) throws Exception {
            if (nextByte == StompConstants.COLON) {
                if (name == null) {
                    AppendableCharSequence charSeq = charSequence();
                    if (charSeq.length() != 0) {
                        name = charSeq.substring(0, charSeq.length());
                        charSeq.reset();
                        valid = true;
                        return true;
                    } else {
                        name = StringUtil.EMPTY_STRING;
                    }
                } else {
                    valid = false;
                }
            }

            return super.process(nextByte);
        }

        @Override
        protected void appendTo(AppendableCharSequence charSeq, char chr) {
            if (!shouldUnescape) {
                super.appendTo(charSeq, chr);
                return;
            }

            if (chr == '\\') {
                if (unescapeInProgress) {
                    super.appendTo(charSeq, chr);
                    unescapeInProgress = false;
                } else {
                    unescapeInProgress = true;
                }
                return;
            }

            if (unescapeInProgress) {
                if (chr == 'c') {
                    charSeq.append(':');
                } else if (chr == 'r') {
                    charSeq.append('\r');
                } else if (chr == 'n') {
                    charSeq.append('\n');
                } else {