TCP - split decoder API to progress and buffer.

This may be more intuituve to understand.

Author: BonnyAD9

src/plugins/input/tcp/src/Connection.cpp

@@ -105,7 +105,8 @@ bool Connection::receive(ipx_ctx_t *ctx) {
         );
     }
 
-    auto &buffer = m_decoder->decode();
+    m_decoder->progress();
+    auto &buffer = m_decoder->buffer();
     buffer.process_decoded([=](ByteVector &&msg) { send_msg(ctx, std::move(msg)); });
     return !buffer.is_eof_reached();
 }

src/plugins/input/tcp/src/Decoder.hpp

@@ -17,11 +17,14 @@ namespace tcp_in {
 /** Interface for IPFIX message decoders. */
 class Decoder {
 public:
+    /** Reads all available data from TCP stream and returns buffer with decoded messages. */
+    virtual void progress() = 0;
+
     /**
-     * @brief Reads all available data from TCP stream and returns buffer with decoded messages.
-     * @returns Buffer with decoded messages.
+     * @brief Retrieves decode buffer with decoded data.
+     * @return Buffer with decoded data.
      */
-    virtual DecodeBuffer &decode() = 0;
+    virtual DecodeBuffer &buffer() = 0;
 
     /** Gets the name of the decoder. */
     virtual const char *get_name() const = 0;

src/plugins/input/tcp/src/IpfixDecoder.cpp

@@ -24,7 +24,7 @@
 
 namespace tcp_in {
 
-DecodeBuffer &IpfixDecoder::decode() {
+void IpfixDecoder::progress() {
     while (!m_decoded.enough_data()) {
         // Read the header of the message.
         if (!read_header()) {
@@ -42,8 +42,6 @@ DecodeBuffer &IpfixDecoder::decode() {
     if (m_decoded.is_eof_reached() && m_part_readed.size() != 0) {
         throw std::runtime_error("Received incomplete message.");
     }
-
-    return m_decoded;
 }
 
 bool IpfixDecoder::read_header() {

src/plugins/input/tcp/src/IpfixDecoder.hpp

@@ -31,7 +31,9 @@ class IpfixDecoder : public Decoder {
      */
     IpfixDecoder(int fd) : m_fd(fd), m_decoded(), m_part_readed(), m_msg_size(0) {}
 
-    virtual DecodeBuffer &decode() override;
+    virtual void progress() override;
+
+    virtual DecodeBuffer &buffer() override { return m_decoded; };
 
     virtual const char *get_name() const override {
         return "IPFIX";

src/plugins/input/tcp/src/Lz4Decoder.cpp

@@ -52,7 +52,7 @@ Lz4Decoder::Lz4Decoder(int fd) :
     }
 }
 
-DecodeBuffer &Lz4Decoder::decode() {
+void Lz4Decoder::progress() {
     while (!m_decoded.enough_data()) {
         // Read the header.
         if (!read_header()) {
@@ -73,8 +73,6 @@ DecodeBuffer &Lz4Decoder::decode() {
     if (m_decoded.is_eof_reached() && m_compressed.size() != 0) {
         throw std::runtime_error("Incomplete compressed message received");
     }
-
-    return m_decoded;
 }
 
 bool Lz4Decoder::read_header() {

src/plugins/input/tcp/src/Lz4Decoder.hpp

@@ -43,11 +43,12 @@ class Lz4Decoder : public Decoder {
 
     /**
      * @brief Decodes the next blocks of data until there is no data or when enough data is readed
-     * @return decoded data
      * @throws when fails to read from file descriptor
      * @throws when fails to decompress the data
      */
-    virtual DecodeBuffer &decode() override;
+    virtual void progress() override;
+
+    virtual DecodeBuffer &buffer() override { return m_decoded; }
 
     virtual const char *get_name() const override {
         return "LZ4";

src/plugins/input/tcp/src/tls/TlsDecoder.cpp

@@ -27,11 +27,11 @@ TlsDecoder::TlsDecoder(SslCtx &ctx, int fd) :
     m_handshake_complete = m_ssl.accept();
 }
 
-DecodeBuffer &TlsDecoder::decode() {
+void TlsDecoder::progress() {
     if (!m_handshake_complete) {
         m_handshake_complete = m_ssl.accept();
         if (!m_handshake_complete) {
-            return m_decoded;
+            return;
         }
     }
 
@@ -45,18 +45,16 @@ DecodeBuffer &TlsDecoder::decode() {
             case ReadResult::READ:
                 break;
             case ReadResult::WAIT:
-                return m_decoded;
+                return;
             case ReadResult::FINISHED:
                 // FIXME: properly check that the shutdown is complete.
                 m_ssl.shutdown();
                 // Intentional falltrough
             case ReadResult::CLOSED:
                 m_decoded.signal_eof();
-                return m_decoded;
+                return;
         }
     }
-
-    return m_decoded;
 }
 
 } // namespace tls

src/plugins/input/tcp/src/tls/TlsDecoder.hpp

@@ -36,9 +36,10 @@ class TlsDecoder : public Decoder {
 
     /**
      * @brief Reads all available data from TLS stream and returns buffer with decoded messages.
-     * @returns Buffer with decoded messages.
      */
-    virtual DecodeBuffer &decode() override;
+    virtual void progress() override;
+
+    virtual DecodeBuffer &buffer() override { return m_decoded; }
 
     /**
      * @brief Gets the name of the decoder.