decode() — netty Function Reference

Architecture documentation for the decode() function in JsonObjectDecoder.java from the netty codebase.

Function java CodecBase Serialization calls 3

Entity Profile

CodecBase→ Serialization→ decode() — netty Function Reference

Dependency Diagram

graph TD
  e065d464_9fe4_dd94_1292_774ad1b9001b["decode()"]
  cc9d6d69_638d_e1e7_aa08_bd1cacf4f8cc["JsonObjectDecoder"]
  e065d464_9fe4_dd94_1292_774ad1b9001b -->|defined in| cc9d6d69_638d_e1e7_aa08_bd1cacf4f8cc
  b07845ff_606f_b96b_ccd4_54fa788281c7["reset()"]
  e065d464_9fe4_dd94_1292_774ad1b9001b -->|calls| b07845ff_606f_b96b_ccd4_54fa788281c7
  82cd9175_c986_585e_8ea2_00d1538388bd["decodeByte()"]
  e065d464_9fe4_dd94_1292_774ad1b9001b -->|calls| 82cd9175_c986_585e_8ea2_00d1538388bd
  df843581_4533_d2cc_abd1_ec20eb52805c["initDecoding()"]
  e065d464_9fe4_dd94_1292_774ad1b9001b -->|calls| df843581_4533_d2cc_abd1_ec20eb52805c
  style e065d464_9fe4_dd94_1292_774ad1b9001b fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

codec-base/src/main/java/io/netty/handler/codec/json/JsonObjectDecoder.java lines 89–183

    @Override
    protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
        if (state == ST_CORRUPTED) {
            in.skipBytes(in.readableBytes());
            return;
        }

        if (this.idx > in.readerIndex() && lastReaderIndex != in.readerIndex()) {
            this.idx = in.readerIndex() + (idx - lastReaderIndex);
        }

        // index of next byte to process.
        int idx = this.idx;
        int wrtIdx = in.writerIndex();

        if (wrtIdx > maxObjectLength) {
            // buffer size exceeded maxObjectLength; discarding the complete buffer.
            in.skipBytes(in.readableBytes());
            reset();
            throw new TooLongFrameException(
                            "object length exceeds " + maxObjectLength + ": " + wrtIdx + " bytes discarded");
        }

        for (/* use current idx */; idx < wrtIdx; idx++) {
            byte c = in.getByte(idx);
            if (state == ST_DECODING_NORMAL) {
                decodeByte(c, in, idx);

                // All opening braces/brackets have been closed. That's enough to conclude
                // that the JSON object/array is complete.
                if (openBraces == 0) {
                    ByteBuf json = extractObject(ctx, in, in.readerIndex(), idx + 1 - in.readerIndex());
                    if (json != null) {
                        out.add(json);
                    }

                    // The JSON object/array was extracted => discard the bytes from
                    // the input buffer.
                    in.readerIndex(idx + 1);
                    // Reset the object state to get ready for the next JSON object/text
                    // coming along the byte stream.
                    reset();
                }
            } else if (state == ST_DECODING_ARRAY_STREAM) {
                decodeByte(c, in, idx);

                if (!insideString && (openBraces == 1 && c == ',' || openBraces == 0 && c == ']')) {
                    // skip leading spaces. No range check is needed and the loop will terminate
                    // because the byte at position idx is not a whitespace.
                    for (int i = in.readerIndex(); Character.isWhitespace(in.getByte(i)); i++) {
                        in.skipBytes(1);
                    }

                    // skip trailing spaces.
                    int idxNoSpaces = idx - 1;
                    while (idxNoSpaces >= in.readerIndex() && Character.isWhitespace(in.getByte(idxNoSpaces))) {
                        idxNoSpaces--;
                    }

                    ByteBuf json = extractObject(ctx, in, in.readerIndex(), idxNoSpaces + 1 - in.readerIndex());
                    if (json != null) {
                        out.add(json);
                    }

                    in.readerIndex(idx + 1);

                    if (c == ']') {
                        reset();
                    }
                }
            // JSON object/array detected. Accumulate bytes until all braces/brackets are closed.
            } else if (c == '{' || c == '[') {
                initDecoding(c);

                if (state == ST_DECODING_ARRAY_STREAM) {
                    // Discard the array bracket
                    in.skipBytes(1);
                }
            // Discard leading spaces in front of a JSON object/array.
            } else if (Character.isWhitespace(c)) {
                in.skipBytes(1);