feat(tcp): TCPStreamer DataSources, in-process TCPStreamService, stream multiplexing and TCPStreamJoin

Add TCPStreamer/TCPStreamerClient (TCP transport behind the UDPSServerI/UDPSClientI
seam), an optional single in-process TCPStreamService serving many streams over
worker threads, multiplexed SUBSCRIBE (comma list, stream index in fragmentIdx),
and TCPStreamJoin, which merges several streams into one sample-and-hold stream
paced by a master. StreamHub takes a comma list of streams over one connection.
Includes GTests, E2E scenarios s58-s73 and docs.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Source/Components/DataSources/UDPStreamer/UDPStreamer.cpp

@@ -84,6 +84,7 @@ UDPStreamer::UDPStreamer()
     : MemoryDataSourceI(), EmbeddedServiceMethodBinderI(), executor(*this) {
   port = UDPS_DEFAULT_PORT;
   maxPayloadSize = UDPS_DEFAULT_MAX_PAYLOAD;
+  server = new UDPSServer();
   cpuMask = 0xFFFFFFFFu;
   stackSize = THREADS_DEFAULT_STACKSIZE;
   publishMode = UDPStreamerPublishStrict;
@@ -135,7 +136,11 @@ UDPStreamer::~UDPStreamer() {
     }
   }
 
-  (void)server.Stop();
+  if (server != NULL_PTR(UDPSServerI *)) {
+    (void)server->Stop();
+    delete server;
+    server = NULL_PTR(UDPSServerI *);
+  }
 
   HeapI *heapAccum = GlobalObjectsDatabase::Instance()->GetStandardHeap();
   if (accumBuffer != NULL_PTR(uint8 *)) {
@@ -192,7 +197,7 @@ bool UDPStreamer::Initialise(StructuredDataI &data) {
 
   if (ok) {
     if (!data.Read("MaxPayloadSize", maxPayloadSize)) {
-      maxPayloadSize = UDPS_DEFAULT_MAX_PAYLOAD;
+      maxPayloadSize = DefaultMaxPayloadSize();
       REPORT_ERROR(ErrorManagement::Information,
                    "MaxPayloadSize not specified; using default %u.",
                    maxPayloadSize);
@@ -286,38 +291,58 @@ bool UDPStreamer::Initialise(StructuredDataI &data) {
   }
 
   if (ok) {
-    // Build server config with already-resolved Port and MaxPayloadSize so
-    // UDPSServer::Initialise() always sees them, even when defaults were used.
-    ConfigurationDatabase serverCfg;
-    (void)serverCfg.Write("Port", static_cast<uint32>(port));
-    (void)serverCfg.Write("MaxPayloadSize", maxPayloadSize);
-    // Forward optional multicast / timeout params if present in caller's data.
-    StreamString mcGroup;
-    if (data.Read("MulticastGroup", mcGroup) && (mcGroup.Size() > 0u)) {
-      (void)serverCfg.Write("MulticastGroup", mcGroup.Buffer());
-      uint32 dp = 0u;
-      if (data.Read("DataPort", dp)) {
-        (void)serverCfg.Write("DataPort", dp);
-      }
-      StreamString iface;
-      if (data.Read("Interface", iface)) {
-        (void)serverCfg.Write("Interface", iface);
-      } else {
-        ok = false;
-        REPORT_ERROR(ErrorManagement::InitialisationError,
-                     "Missing mandatory interface for multicasting");
-      }
-    }
-    uint32 clientTimeout = 0u;
-    if (data.Read("ClientTimeout", clientTimeout)) {
-      (void)serverCfg.Write("ClientTimeout", clientTimeout);
-    }
-    ok = server.Initialise(serverCfg);
+    ok = InitialiseTransport(data);
   }
 
   return ok;
 }
 
+uint32 UDPStreamer::DefaultMaxPayloadSize() const {
+  return UDPS_DEFAULT_MAX_PAYLOAD;
+}
+
+bool UDPStreamer::InitialiseTransport(StructuredDataI &data) {
+  bool ok = true;
+  // Build server config with already-resolved Port and MaxPayloadSize so
+  // UDPSServer::Initialise() always sees them, even when defaults were used.
+  ConfigurationDatabase serverCfg;
+  (void)serverCfg.Write("Port", static_cast<uint32>(port));
+  (void)serverCfg.Write("MaxPayloadSize", maxPayloadSize);
+  // Forward optional multicast / timeout params if present in caller's data.
+  StreamString mcGroup;
+  if (data.Read("MulticastGroup", mcGroup) && (mcGroup.Size() > 0u)) {
+    (void)serverCfg.Write("MulticastGroup", mcGroup.Buffer());
+    uint32 dp = 0u;
+    if (data.Read("DataPort", dp)) {
+      (void)serverCfg.Write("DataPort", dp);
+    }
+    StreamString iface;
+    if (data.Read("Interface", iface)) {
+      (void)serverCfg.Write("Interface", iface);
+    } else {
+      ok = false;
+      REPORT_ERROR(ErrorManagement::InitialisationError,
+                   "Missing mandatory interface for multicasting");
+    }
+  }
+  uint32 clientTimeout = 0u;
+  if (data.Read("ClientTimeout", clientTimeout)) {
+    (void)serverCfg.Write("ClientTimeout", clientTimeout);
+  }
+  ok = server->Initialise(serverCfg);
+
+  return ok;
+}
+
+void UDPStreamer::SetServer(UDPSServerI *newServer) {
+  if (server != NULL_PTR(UDPSServerI *)) {
+    delete server;
+  }
+  server = newServer;
+}
+
+UDPSServerI *UDPStreamer::Transport() const { return server; }
+
 bool UDPStreamer::SetConfiguredDatabase(StructuredDataI &data) {
   bool ok = MemoryDataSourceI::SetConfiguredDatabase(data);
   if (!ok) {
@@ -804,7 +829,7 @@ bool UDPStreamer::PrepareNextState(const char8 *const currentStateName,
                                    const char8 *const nextStateName) {
   bool ok = true;
 
-  ok = server.Start();
+  ok = server->Start();
 
   /* Build the CONFIG payload and cache it in the server so any CONNECT client
    * receives it immediately.  The config is static for the lifetime of this
@@ -818,7 +843,7 @@ bool UDPStreamer::PrepareNextState(const char8 *const currentStateName,
     if (cfgBuf != NULL_PTR(uint8 *)) {
       uint32 cfgPayloadSize = 0u;
       if (BuildConfigPayload(cfgBuf, configBufSize, cfgPayloadSize)) {
-        (void)server.SendConfig(cfgBuf, cfgPayloadSize);
+        (void)server->SendConfig(cfgBuf, cfgPayloadSize);
       } else {
         REPORT_ERROR(ErrorManagement::Warning,
                      "Could not build initial CONFIG payload.");
@@ -992,7 +1017,7 @@ ErrorManagement::ErrorType UDPStreamer::Execute(ExecutionInfo &info) {
 
     /* --- Poll for incoming control commands (CONNECT / DISCONNECT / ACK) ---
      */
-    server.ServiceClients();
+    server->ServiceClients();
 
     /* Synchronise() already gates publication to the correct rate (size/time
      * for Accumulate, every-Nth for Decimate, every call for Strict).  The
@@ -1015,12 +1040,12 @@ ErrorManagement::ErrorType UDPStreamer::Execute(ExecutionInfo &info) {
       }
       bufMutex.FastUnLock();
 
-      if ((fill > 0u) && server.HasClients()) {
+      if ((fill > 0u) && server->HasClients()) {
         SerializeAccumulated(scratchBuffer, scratchTimestamps, fill);
         uint32 sendBytes =
             UDPS_TIMESTAMP_BYTES + 4u + fill * singleCycleWireBytes;
         packetCounter++;
-        if (!server.SendData(packetCounter, wireBuffer, sendBytes)) {
+        if (!server->SendData(packetCounter, wireBuffer, sendBytes)) {
           REPORT_ERROR(ErrorManagement::Warning,
                        "Failed to send Accumulate DATA packet (counter=%u).",
                        packetCounter);
@@ -1040,11 +1065,11 @@ ErrorManagement::ErrorType UDPStreamer::Execute(ExecutionInfo &info) {
       }
       bufMutex.FastUnLock();
 
-      if (pending && server.HasClients()) {
+      if (pending && server->HasClients()) {
         QuantizeAndSerialize(scratchBuffer, ts);
 
         packetCounter++;
-        if (!server.SendData(packetCounter, wireBuffer, totalWireBytes)) {
+        if (!server->SendData(packetCounter, wireBuffer, totalWireBytes)) {
           REPORT_ERROR(ErrorManagement::Warning,
                        "Failed to send DATA packet (counter=%u).",
                        packetCounter);
@@ -1056,7 +1081,7 @@ ErrorManagement::ErrorType UDPStreamer::Execute(ExecutionInfo &info) {
   }
 
   if (info.GetStage() == ExecutionInfo::TerminationStage) {
-    (void)server.Stop();
+    (void)server->Stop();
     REPORT_ERROR(ErrorManagement::Information,
                  "UDPStreamer background thread terminated.");
   }
@@ -1367,9 +1392,9 @@ uint16 UDPStreamer::GetPort() const { return port; }
 
 uint32 UDPStreamer::GetMaxPayloadSize() const { return maxPayloadSize; }
 
-bool UDPStreamer::IsClientConnected() const { return server.HasClients(); }
+bool UDPStreamer::IsClientConnected() const { return server->HasClients(); }
 
-bool UDPStreamer::IsMulticast() const { return server.IsMulticast(); }
+bool UDPStreamer::IsMulticast() const { return server->IsMulticast(); }
 
 uint32 UDPStreamer::GetDroppedPublications() const { return droppedPublications; }
 

Source/Components/DataSources/UDPStreamer/UDPStreamer.h

@@ -39,6 +39,7 @@
 #include "SingleThreadService.h"
 #include "StreamString.h"
 #include "UDPSServer.h"
+#include "UDPSTransportI.h"
 
 /*---------------------------------------------------------------------------*/
 /*                           Class declaration                               */
@@ -333,6 +334,33 @@ public:
      */
     uint32 GetDroppedPublications() const;
 
+protected:
+    /**
+     * @brief MaxPayloadSize used when the configuration does not specify one.
+     * @details Transport specific (a datagram budget for UDP, a frame budget for
+     * TCP), hence overridable. Called from Initialise(), not the constructor.
+     */
+    virtual uint32 DefaultMaxPayloadSize() const;
+
+    /**
+     * @brief Configures the transport from the already-resolved Port and
+     * MaxPayloadSize plus whatever transport keys @p data carries.
+     * @details The default implementation configures the UDPSServer (unicast /
+     * multicast). A subclass that installs another transport with SetServer()
+     * overrides this to configure it instead.
+     */
+    virtual bool InitialiseTransport(StructuredDataI &data);
+
+    /**
+     * @brief Replaces the transport. Takes ownership; only valid before Start().
+     */
+    void SetServer(UDPSServerI *newServer);
+
+    /**
+     * @brief The transport currently in use (owned by this object).
+     */
+    UDPSServerI *Transport() const;
+
 private:
     /**
      * @brief Serializes the CONFIG payload into buf and sets payloadSize.
@@ -417,8 +445,8 @@ private:
     uint8  *wireBuffer;      /**< Pre-allocated buffer for the serialized DATA payload */
     uint32  totalWireBytes;  /**< Total bytes of all signals after quantization + 8-byte timestamp prefix */
 
-    /* Networking — handled by UDPSServer */
-    UDPSServer      server;          /**< Multi-client session manager (unicast and multicast) */
+    /* Networking — handled by a UDPSServerI (UDPSServer by default) */
+    UDPSServerI    *server;          /**< Owned transport; see SetServer() */
 
     /* Thread management */
     SingleThreadService executor;    /**< Background thread service */

Source/Components/DataSources/UDPStreamer/depends.x86-linux

@@ -135,4 +135,6 @@
  /home/martino/workspace/MARTe2/Source/Core/FileSystem/L1Portability/BasicUDPSocket.h \
  /home/martino/workspace/MARTe2/Source/Core/BareMetal/L1Portability/Sleep.h \
  /home/martino/workspace/MARTe2/Source/Core/FileSystem/L1Portability/InternetHost.h \
- ../../../..//Common/UDP/UDPSProtocol.h
+ ../../../..//Common/UDP/UDPSProtocol.h \
+ ../../../..//Source/Components/Interfaces/UDPStream/UDPSTransportI.h \
+ ../../../..//Source/Components/Interfaces/UDPStream/UDPSTransportI.h

Source/Components/DataSources/UDPStreamer/dependsRaw.x86-linux

@@ -135,4 +135,6 @@ UDPStreamer.o: UDPStreamer.cpp \
  /home/martino/workspace/MARTe2/Source/Core/FileSystem/L1Portability/BasicUDPSocket.h \
  /home/martino/workspace/MARTe2/Source/Core/BareMetal/L1Portability/Sleep.h \
  /home/martino/workspace/MARTe2/Source/Core/FileSystem/L1Portability/InternetHost.h \
- ../../../..//Common/UDP/UDPSProtocol.h
+ ../../../..//Common/UDP/UDPSProtocol.h \
+ ../../../..//Source/Components/Interfaces/UDPStream/UDPSTransportI.h \
+ ../../../..//Source/Components/Interfaces/UDPStream/UDPSTransportI.h