feat(mw::com): Implement Field Notifier support for Generic Skeleton

score/mw/com/design/skeleton_proxy/generic_skeleton/generic_skeleton_model.puml

@@ -32,15 +32,18 @@ abstract class "SkeletonBinding" {
 
 class "mw::com::impl::GenericSkeleton" #yellow {
   using EventMapView = ServiceElementMapView<GenericSkeletonEvent>
+  using FieldMapView = ServiceElementMapView<GenericSkeletonField>
   ..
   +Create(const InstanceIdentifier&, const GenericSkeletonServiceElementInfo&): Result<GenericSkeleton>
   +Create(const InstanceSpecifier&, const GenericSkeletonServiceElementInfo&): Result<GenericSkeleton>
   +GetEvents() : EventMapView
+  +GetFields(): FieldMapView
   +OfferService(): Result<void>
   +StopOfferService(): void
   ..
   -GenericSkeleton(const InstanceIdentifier&, std::unique_ptr<SkeletonBinding>)
   -events_ : std::unique_ptr<ServiceElementMapViewFactory<GenericSkeletonEvent>::map_type> events_
+  -fields_ : std::unique_ptr<ServiceElementMapViewFactory<GenericSkeletonField>::map_type>
 }
 
 class "lola::Skeleton" {
@@ -110,14 +113,38 @@ class "ServiceElementMapView<ElementType>" {
   +empty() : bool
 }
 
+abstract class "score::mw::com::impl::SkeletonFieldBase" {
+  #skeleton_event_dispatch_ : std::unique_ptr<impl::SkeletonEventBase>
+  +PrepareOffer(): Result<void>
+  -{abstract} IsInitialValueSaved(): bool
+  -{abstract} DoDeferredUpdate(): Result<void>
+  -{abstract} IsSetHandlerMissing(): bool
+}
+
+class "mw::com::impl::GenericSkeletonField" #LightGreen {
+  -initial_field_value_ : std::vector<uint8_t>
+  -has_initial_value_ : bool
+  -has_getter_ : bool
+  -has_setter_ : bool
+  -has_notifier_ : bool
+  -is_set_handler_registered_ : bool
+  .. Notifier API ..
+  +Update(raw_value: span<const uint8_t>): Result<void>
+  +Update(SampleAllocateePtr<void> sample): Result<void>
+  +Allocate(): Result<SampleAllocateePtr<void>>
+  .. Method Handlers (Stubs) ..
+  +RegisterSetHandler(std::function<void(span<uint8_t>)> handler): Result<void>
+}
+
 abstract class "mw::com::impl::SkeletonEventBase" #yellow {
-  +SkeletonEventBase(SkeletonBase&, const std::string_view, std::unique_ptr<SkeletonEventBindingBase>)
+  +SkeletonEventBase(const std::string_view, std::unique_ptr<SkeletonEventBindingBase>)
   +OfferService(): Result<void>
   +StopOfferService(): void
 }
 
 class "mw::com::impl::GenericSkeletonEvent" #yellow {
   +GenericSkeletonEvent(SkeletonBase&, const std::string_view, std::unique_ptr<GenericSkeletonEventBinding>)
+  +GenericSkeletonEvent(SkeletonBase&, const std::string_view, std::unique_ptr<GenericSkeletonEventBinding>, FieldOnlyConstructorEnabler)
   +Send(SampleAllocateePtr<void> sample): Result<void>
   +Allocate(): Result<SampleAllocateePtr<void>>
   +GetSizeInfo() const : DataTypeMetaInfo
@@ -175,6 +202,9 @@ class "DummySkeleton" <<generated>>  {
 "score::mw::com::impl::SkeletonBase" *--> "SkeletonBinding"
 "score::mw::com::impl::SkeletonBase" <|-- "DummySkeleton"
 "score::mw::com::impl::SkeletonBase" <|-- "mw::com::impl::GenericSkeleton"
+"mw::com::impl::GenericSkeleton" *-- "ServiceElementMapView"
+"score::mw::com::impl::SkeletonFieldBase" <|-- "mw::com::impl::GenericSkeletonField"
+"SkeletonFieldBase" "1" *-- "1" "mw::com::impl::SkeletonEventBase" : skeleton_event_dispatch_
 "SkeletonBindingFactory" ..> "SkeletonBinding" : creates
 "SkeletonBinding" <|-- "lola::Skeleton"
 
@@ -200,5 +230,6 @@ class "DummySkeleton" <<generated>>  {
 "mw::com::impl::GenericSkeleton" ..> "ServiceElementMapViewFactory<ElementType>" : uses
 "ServiceElementMapViewFactory<ElementType>" ..> "ServiceElementMapView<ElementType>" : creates
 "ServiceElementMapView<ElementType>" o-- "mw::com::impl::GenericSkeletonEvent" : "0..n"
+"mw::com::impl::GenericSkeleton" *--> "mw::com::impl::GenericSkeletonField" : "0..n"
 
 @enduml

score/mw/com/impl/BUILD

@@ -68,6 +68,7 @@ cc_library(
         ":generic_proxy",
         ":generic_proxy_event",
         ":generic_skeleton",
+        ":generic_skeleton_field",
         ":proxy_event",
         ":proxy_field",
         ":skeleton_event",
@@ -173,6 +174,7 @@ cc_library(
     deps = [
         ":data_type_meta_info",
         ":generic_skeleton_event",
+        ":generic_skeleton_field",
         ":instance_identifier",
         ":instance_specifier",
         ":service_element_map_view",
@@ -209,6 +211,27 @@ cc_library(
     ],
 )
 
+cc_library(
+    name = "generic_skeleton_field",
+    srcs = ["generic_skeleton_field.cpp"],
+    hdrs = ["generic_skeleton_field.h"],
+    features = COMPILER_WARNING_FEATURES,
+    tags = ["FFI"],
+    visibility = [
+        "//score/mw/com:__subpackages__",
+    ],
+    deps = [
+        ":error",
+        ":generic_skeleton_event",
+        ":skeleton_base",
+        ":skeleton_field_base",
+        "//score/mw/com/impl/plumbing:sample_allocatee_ptr",
+        "@score_baselibs//score/language/futurecpp",
+        "@score_baselibs//score/mw/log",
+        "@score_baselibs//score/result",
+    ],
+)
+
 cc_library(
     name = "generic_skeleton_event_binding",
     hdrs = [
@@ -1401,6 +1424,24 @@ cc_unit_test(
     ],
 )
 
+cc_unit_test(
+    name = "generic_skeleton_field_test",
+    srcs = ["generic_skeleton_field_test.cpp"],
+    deps = [
+        ":generic_skeleton",
+        ":generic_skeleton_field",
+        ":runtime_mock",
+        ":service_discovery_client_mock",
+        ":service_discovery_mock",
+        "//score/mw/com/impl/bindings/mock_binding:generic_skeleton_event",
+        "//score/mw/com/impl/plumbing:generic_skeleton_event_binding_factory",
+        "//score/mw/com/impl/plumbing:generic_skeleton_event_binding_factory_mock",
+        "//score/mw/com/impl/test:binding_factory_resources",
+        "//score/mw/com/impl/test:dummy_instance_identifier_builder",
+        "//score/mw/com/impl/test:runtime_mock_guard",
+    ],
+)
+
 cc_unit_test(
     name = "traits_test",
     srcs = [

score/mw/com/impl/generic_skeleton.cpp

@@ -52,6 +52,27 @@ std::string_view GetEventName(const InstanceIdentifier& identifier, std::string_
 
     return std::visit(visitor, service_type_deployment.binding_info_);
 }
+
+// Helper to fetch the stable field name from the Configuration
+std::string_view GetFieldName(const InstanceIdentifier& identifier, std::string_view search_name)
+{
+    const auto& service_type_deployment = InstanceIdentifierView{identifier}.GetServiceTypeDeployment();
+
+    auto visitor = score::cpp::overload(
+        [&](const LolaServiceTypeDeployment& deployment) -> std::string_view {
+            const auto it = deployment.fields_.find(std::string{search_name});
+            if (it != deployment.fields_.end())
+            {
+                return it->first;  // Return the stable address of the Key from the Config Map
+            }
+            return {};
+        },
+        [](const score::cpp::blank&) noexcept -> std::string_view {
+            return {};
+        });
+
+    return std::visit(visitor, service_type_deployment.binding_info_);
+}
 }  // namespace
 
 Result<GenericSkeleton> GenericSkeleton::Create(const InstanceSpecifier& specifier,
@@ -134,6 +155,61 @@ Result<GenericSkeleton> GenericSkeleton::Create(const InstanceIdentifier& identi
         }
     }
 
+    // 3. Create fields directly in the map
+    for (const auto& info : in.fields)
+    {
+        // Check for duplicates
+        if (skeleton.fields_->find(info.name) != skeleton.fields_->cend())
+        {
+            score::mw::log::LogError("GenericSkeleton") << "Duplicate field name provided: " << info.name;
+            return MakeUnexpected(ComErrc::kServiceElementAlreadyExists);
+        }
+
+        std::string_view stable_name = GetFieldName(identifier, info.name);
+
+        if (stable_name.empty())
+        {
+            score::mw::log::LogError("GenericSkeleton") << "Field name not found in configuration: " << info.name;
+            return MakeUnexpected(ComErrc::kBindingFailure);
+        }
+
+        // Validate & convert the public DataTypeMetaInfo into the internal DataTypeSizeInfo.
+        auto data_type_size_info_result = MakeDataTypeSizeInfo(info.data_type_meta_info);
+        if (!data_type_size_info_result.has_value())
+        {
+            score::mw::log::LogError("GenericSkeleton")
+                << "Invalid data type meta-info provided for field: " << info.name;
+            return MakeUnexpected(ComErrc::kInvalidConfiguration);
+        }
+
+        auto event_binding_result =
+            GenericSkeletonEventBindingFactory::Create(skeleton, info.name, data_type_size_info_result.value());
+
+        if (!event_binding_result.has_value())
+        {
+            return MakeUnexpected(ComErrc::kBindingFailure);
+        }
+
+        // Use the hidden constructor tag so the event doesn't register itself in the events_ map
+        auto generic_event =
+            std::make_unique<GenericSkeletonEvent>(skeleton,
+                                                   stable_name,
+                                                   std::move(event_binding_result).value(),
+                                                   GenericSkeletonEvent::FieldOnlyConstructorEnabler{});
+
+        const auto emplace_result = skeleton.fields_->emplace(
+            std::piecewise_construct,
+            std::forward_as_tuple(stable_name),
+            std::forward_as_tuple(
+                skeleton, stable_name, std::move(generic_event), info.has_getter, info.has_setter, info.has_notifier));
+
+        if (!emplace_result.second)
+        {
+            score::mw::log::LogError("GenericSkeleton") << "Failed to emplace field in map: " << info.name;
+            return MakeUnexpected(ComErrc::kBindingFailure);
+        }
+    }
+
     return skeleton;
 }
 
@@ -142,6 +218,11 @@ ServiceElementMapView<GenericSkeletonEvent> GenericSkeleton::GetEvents() const n
     return ServiceElementMapViewFactory<GenericSkeletonEvent>::Create(*events_);
 }
 
+GenericSkeleton::FieldMapView GenericSkeleton::GetFields() const noexcept
+{
+    return ServiceElementMapViewFactory<GenericSkeletonField>::Create(*fields_);
+}
+
 Result<void> GenericSkeleton::OfferService() noexcept
 {
     return SkeletonBase::OfferService();
@@ -154,7 +235,8 @@ void GenericSkeleton::StopOfferService() noexcept
 
 GenericSkeleton::GenericSkeleton(const InstanceIdentifier& identifier, std::unique_ptr<SkeletonBinding> binding)
     : SkeletonBase(std::move(binding), identifier),
-      events_(std::make_unique<std::map<std::string_view, GenericSkeletonEvent>>())
+      events_(std::make_unique<std::map<std::string_view, GenericSkeletonEvent>>()),
+      fields_(std::make_unique<std::map<std::string_view, GenericSkeletonField>>())
 {
 }
 

score/mw/com/impl/generic_skeleton.h

@@ -15,6 +15,7 @@
 
 #include "score/mw/com/impl/data_type_meta_info.h"
 #include "score/mw/com/impl/generic_skeleton_event.h"
+#include "score/mw/com/impl/generic_skeleton_field.h"
 #include "score/mw/com/impl/instance_identifier.h"
 #include "score/mw/com/impl/instance_specifier.h"
 #include "score/mw/com/impl/service_element_map_view.h"
@@ -35,9 +36,19 @@ struct EventInfo
     DataTypeMetaInfo data_type_meta_info;
 };
 
+struct FieldInfo
+{
+    std::string_view name;
+    DataTypeMetaInfo data_type_meta_info;
+    bool has_getter{false};
+    bool has_setter{false};
+    bool has_notifier{false};
+};
+
 struct GenericSkeletonServiceElementInfo
 {
     score::cpp::span<const EventInfo> events{};
+    score::cpp::span<const FieldInfo> fields{};
 };
 
 /// @brief Represents a type-erased, runtime-configurable skeleton for a service instance.
@@ -49,14 +60,13 @@ class GenericSkeleton : public SkeletonBase
 {
   public:
     using EventMapView = ServiceElementMapView<GenericSkeletonEvent>;
-    /// \brief Creates a GenericSkeleton and all its service elements (events + fields) atomically.
+    using FieldMapView = ServiceElementMapView<GenericSkeletonField>;
+    /// @brief Creates a GenericSkeleton and all its service elements (events + fields) atomically.
     ///
     /// \contract
     /// - Empty spans are allowed for `in.events` and/or `in.fields`
     /// - Each provided name must exist in the binding deployment for this instance (events/fields respectively).
     /// - All element names must be unique across all element kinds within this skeleton.
-    /// - For each field, `initial_value_bytes` must be non-empty and
-    ///   `initial_value_bytes.size()` must be <= `size_info.size`.
     /// - On error, no partially-created elements are left behind.
     [[nodiscard]] static Result<GenericSkeleton> Create(const InstanceIdentifier& identifier,
                                                         const GenericSkeletonServiceElementInfo& in);
@@ -72,8 +82,12 @@ class GenericSkeleton : public SkeletonBase
     /// \note The returned view is valid as long as the GenericSkeleton lives.
     [[nodiscard]] EventMapView GetEvents() const noexcept;
 
-    /// \brief Offers the service instance.
-    /// \return A blank result, or an error if offering fails.
+    /// @brief Returns a read-only view to the name-keyed map of fields.
+    /// @note The returned view is valid as long as the GenericSkeleton lives.
+    [[nodiscard]] FieldMapView GetFields() const noexcept;
+
+    /// @brief Offers the service instance.
+    /// @return A blank result, or an error if offering fails.
     [[nodiscard]] Result<void> OfferService() noexcept;
 
     /// \brief Stops offering the service instance.
@@ -88,6 +102,8 @@ class GenericSkeleton : public SkeletonBase
     /// GenericSkeleton. This is required as we hand out views to this map (see GetEvents()), which need to be valid
     /// even after the GenericSkeleton instance has been moved.
     std::unique_ptr<ServiceElementMapViewFactory<GenericSkeletonEvent>::map_type> events_;
+    /// @brief This map owns all GenericSkeletonField instances.
+    std::unique_ptr<ServiceElementMapViewFactory<GenericSkeletonField>::map_type> fields_;
 };
 }  // namespace score::mw::com::impl
 

score/mw/com/impl/generic_skeleton_event.cpp

@@ -43,6 +43,29 @@ GenericSkeletonEvent::GenericSkeletonEvent(SkeletonBase& skeleton_base,
     }
 }
 
+GenericSkeletonEvent::GenericSkeletonEvent(SkeletonBase& skeleton_base,
+                                           const std::string_view event_name,
+                                           std::unique_ptr<GenericSkeletonEventBinding> binding,
+                                           FieldOnlyConstructorEnabler /*tag*/)
+    : SkeletonEventBase(event_name, std::move(binding))
+{
+    // Intentionally omitting SkeletonBaseView{skeleton_base}.RegisterEvent(event_name, *this);
+
+    if (binding_ != nullptr)
+    {
+        const SkeletonBaseView skeleton_base_view{skeleton_base};
+        const auto& instance_identifier = skeleton_base_view.GetAssociatedInstanceIdentifier();
+        auto* const binding_ptr = static_cast<GenericSkeletonEventBinding*>(binding_.get());
+        if (binding_ptr)
+        {
+            const auto binding_type = binding_ptr->GetBindingType();
+            auto tracing_data =
+                tracing::GenerateSkeletonTracingStructFromEventConfig(instance_identifier, binding_type, event_name);
+            binding_ptr->SetSkeletonEventTracingData(tracing_data);
+        }
+    }
+}
+
 Result<void> GenericSkeletonEvent::Send(SampleAllocateePtr<void> sample) noexcept
 {
     if (!service_offered_flag_.IsSet())

score/mw/com/impl/generic_skeleton_event.h

@@ -31,10 +31,20 @@ class SkeletonBase;
 class GenericSkeletonEvent : public SkeletonEventBase
 {
   public:
+    struct FieldOnlyConstructorEnabler
+    {
+        explicit FieldOnlyConstructorEnabler() = default;
+    };
+
     GenericSkeletonEvent(SkeletonBase& skeleton_base,
                          const std::string_view event_name,
                          std::unique_ptr<GenericSkeletonEventBinding> binding);
 
+    GenericSkeletonEvent(SkeletonBase& skeleton_base,
+                         const std::string_view event_name,
+                         std::unique_ptr<GenericSkeletonEventBinding> binding,
+                         FieldOnlyConstructorEnabler tag);
+
     Result<void> Send(SampleAllocateePtr<void> sample) noexcept;
 
     Result<SampleAllocateePtr<void>> Allocate() noexcept;