Fixes to handling GenericMessage in framing.

Author: arobenko

include/comms/MessageBase.h

@@ -184,7 +184,13 @@ class MessageBase : public details::MessageImplBuilderT<TMessage, TOptions...>
     static constexpr bool hasCustomName()
     {
         return ImplOptions::HasName;
-    }     
+    }  
+    
+    /// @brief Compile type inquiry whether the class provides @ref doGetId() member function.
+    static constexpr bool hasDoGetId()
+    {
+        return ImplOptions::HasStaticMsgId || ImplOptions::HasDoGetId;
+    }        
 
 #ifdef FOR_DOXYGEN_DOC_ONLY
 

include/comms/frame/MsgIdLayer.h

@@ -601,9 +601,10 @@ class MsgIdLayer : public comms::frame::details::MsgIdLayerBase<TField, TMessage
         using MsgType = typename std::decay<decltype(msg)>::type;
         static_assert(comms::isMessageBase<MsgType>(),
             "The message class is expected to inherit from comms::MessageBase");
-        static_assert(MsgType::hasStaticMsgId(),
+        static_assert(MsgType::hasDoGetId(),
             "The message class must expose direct ID retrieval functionality, "
-            "use comms::option::app::StaticNumIdImpl option to define it.");        
+            "use comms::option::app::StaticNumIdImpl option to define it or "
+            "comms::option::app::HasDoGetId option to mark the class as providing one");        
         return msg.doGetId();
     }
 

include/comms/frame/details/FrameLayerDetails.h

@@ -52,7 +52,7 @@ struct FrameLayerHasDoGetIdHelper;
 template <typename T>
 struct FrameLayerHasDoGetIdHelper<T, true>
 {
-    static const bool Value = T::hasStaticMsgId();
+    static const bool Value = T::hasDoGetId();
 };
 
 template <typename T>

test/CMakeLists.txt

@@ -58,6 +58,7 @@ if (TARGET cxxtest::cxxtest)
     test_func ("CustomSyncPrefixLayer")
     test_func ("Dispatch")
     test_func ("MsgFactory")
+    test_func ("GenericMessage")
 else ()
     message (Warning "Testing is enabled, but cxxtest hasn't been found!")
 endif ()

test/CustomMsgIdLayer.th

@@ -210,7 +210,7 @@ private:
             >;
     public:
         COMMS_FRAME_LAYERS_NAMES_OUTER(id, payload);
-    };    
+    };   
 };
 
 void CustomMsgIdLayerTestSuite::test1()

test/GenericMessage.th

@@ -0,0 +1,94 @@
+//
+// Copyright 2025 - 2025 (C). Alex Robenko. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#include "CommsTestCommon.h"
+
+#include "comms/CompileControl.h"
+#include "comms/GenericMessage.h"
+#include "comms/frame/MsgIdLayer.h"
+#include "comms/frame/MsgDataLayer.h"
+
+CC_DISABLE_WARNINGS()
+#include "cxxtest/TestSuite.h"
+CC_ENABLE_WARNINGS()
+
+class GenericMessageTestSuite : public CxxTest::TestSuite
+{
+public:
+    void test1();
+
+private:
+    using BeFieldBase = comms::Field<comms::option::BigEndian>;
+    using BeIdField1 = comms::field::EnumValue<BeFieldBase, MessageType, comms::option::def::FixedLength<1U>>;
+
+    template <typename... TOpts>
+    using BeMsgBase = 
+        comms::Message<
+            comms::option::BigEndian,
+            TOpts...
+        >;
+
+    using BePolymorphicMsgBase = 
+        BeMsgBase<
+            comms::option::MsgIdType<MessageType>,
+            comms::option::IdInfoInterface,
+            comms::option::ReadIterator<const char*>,
+            comms::option::WriteIterator<char*>,
+            comms::option::ValidCheckInterface,
+            comms::option::LengthInfoInterface        
+        >;
+
+
+    template <typename TIdField, typename TMessage, template<class> class TAllMessages = AllTestMessages>
+    class SimpleFrame : public
+        comms::frame::MsgIdLayer<
+            TIdField,
+            TMessage,
+            TAllMessages<TMessage>,
+            comms::frame::MsgDataLayer<>,
+            comms::option::SupportGenericMessage<comms::GenericMessage<TMessage> >
+        >
+    {
+        using Base =
+            comms::frame::MsgIdLayer<
+                TIdField,
+                TMessage,
+                TAllMessages<TMessage>,
+                comms::frame::MsgDataLayer<>,
+                comms::option::SupportGenericMessage<comms::GenericMessage<TMessage> >
+            >;
+    public:
+        COMMS_FRAME_LAYERS_NAMES_OUTER(id, payload);
+    };    
+};
+
+void GenericMessageTestSuite::test1()
+{
+    using Msg = comms::GenericMessage<BePolymorphicMsgBase>;
+    using TestFrame = SimpleFrame<BeIdField1, BePolymorphicMsgBase>;
+
+    TestFrame frame;
+    Msg msg(MessageType5);
+
+    static const char Buf[] = {
+        MessageType5, 0x01, 0x02, 0x03,
+    };
+
+    static const std::size_t BufSize = std::extent<decltype(Buf)>::value;    
+
+    auto iter = comms::readIteratorFor(msg, Buf);
+    auto es = frame.read(msg, iter, BufSize);
+    TS_ASSERT_EQUALS(es, comms::ErrorStatus::Success);
+
+    std::vector<char> outBuf;
+    outBuf.reserve(BufSize);
+    auto outIter = std::back_inserter(outBuf);
+    es = frame.write(msg, outIter, outBuf.max_size());
+    TS_ASSERT_EQUALS(es, comms::ErrorStatus::Success);   
+    TS_ASSERT_EQUALS(outBuf.size(), BufSize);
+    TS_ASSERT(std::equal(outBuf.begin(), outBuf.end(), std::begin(Buf)));
+}