feat: add meta proto service for service discovery

infra/syntax/CppFormatter.cpp

@@ -652,4 +652,18 @@ namespace application
 
     void Undef::PrintSource(google::protobuf::io::Printer& printer, const std::string& scope) const
     {}
+
+    StaticAssert::StaticAssert(const std::string& condition, const std::string& message)
+        : Entity(true, false)
+        , condition(condition)
+        , message(message)
+    {}
+
+    void StaticAssert::PrintHeader(google::protobuf::io::Printer& printer) const
+    {
+        printer.Print("static_assert($condition$, \"$message$\");\n", "condition", condition, "message", message);
+    }
+
+    void StaticAssert::PrintSource(google::protobuf::io::Printer& printer, const std::string& scope) const
+    {}
 }

infra/syntax/CppFormatter.hpp

@@ -387,6 +387,20 @@ namespace application
     private:
         std::string name;
     };
+
+    class StaticAssert
+        : public Entity
+    {
+    public:
+        explicit StaticAssert(const std::string& condition, const std::string& message);
+
+        void PrintHeader(google::protobuf::io::Printer& printer) const override;
+        void PrintSource(google::protobuf::io::Printer& printer, const std::string& scope) const override;
+
+    private:
+        std::string condition;
+        std::string message;
+    };
 }
 
 #endif

infra/syntax/test/TestCppFormatter.cpp

@@ -731,3 +731,18 @@ TEST_F(CppFormatterTest, Undef_prints_no_source)
     declaration.PrintSource(*printer, "scope");
     ExpectPrinted("");
 }
+
+TEST_F(CppFormatterTest, StaticAssert_prints_header)
+{
+    application::StaticAssert declaration("condition", "message");
+    declaration.PrintHeader(*printer);
+    ExpectPrinted(R"(static_assert(condition, "message");
+)");
+}
+
+TEST_F(CppFormatterTest, StaticAssert_prints_no_source)
+{
+    application::StaticAssert declaration("condition", "message");
+    declaration.PrintSource(*printer, "scope");
+    ExpectPrinted("");
+}

protobuf/CMakeLists.txt

@@ -3,3 +3,4 @@ add_subdirectory(echo)
 add_subdirectory(protoc_echo_plugin)
 add_subdirectory(protoc_echo_plugin_csharp)
 add_subdirectory(protoc_echo_plugin_java)
+add_subdirectory(meta_services)

protobuf/echo/Echo.cpp

@@ -2,6 +2,20 @@
 
 namespace services
 {
+    ServiceId::ServiceId(uint32_t id)
+        : id(id)
+    {}
+
+    Service::Service(Echo& echo, uint32_t serviceId)
+        : ServiceId(serviceId)
+        , infra::Observer<Service, Echo>(echo)
+    {}
+
+    uint32_t ServiceIdAccess::GetId(const ServiceId& serviceId)
+    {
+        return serviceId.id;
+    }
+
     void Service::MethodDone()
     {
         Rpc().ServiceDone();

protobuf/echo/Echo.hpp

@@ -10,20 +10,46 @@
 #include "protobuf/echo/EchoErrorPolicy.hpp"
 #include "protobuf/echo/Proto.hpp"
 #include "protobuf/echo/Serialization.hpp"
+#include <cstdint>
 
 namespace services
 {
     class Echo;
+    class ServiceId;
     class Service;
     class ServiceProxy;
 
-    class Service
-        : public infra::Observer<Service, Echo>
+    class ServiceIdAccess
+    {
+    public:
+        static uint32_t GetId(const ServiceId& serviceId);
+    };
+
+    class ServiceId
     {
+        friend class ServiceIdAccess;
+
     public:
-        using infra::Observer<Service, Echo>::Observer;
+        ServiceId(uint32_t id);
 
-        virtual bool AcceptsService(uint32_t id) const = 0;
+        virtual bool AcceptsService(uint32_t id) const
+        {
+            return id == this->id;
+        }
+
+    public:
+        static constexpr uint32_t reservedServiceId = 0;
+
+    private:
+        const uint32_t id;
+    };
+
+    class Service
+        : public ServiceId
+        , public infra::Observer<Service, Echo>
+    {
+    public:
+        Service(Echo& echo, uint32_t serviceId);
 
         void MethodDone();
         virtual infra::SharedPtr<MethodDeserializer> StartMethod(uint32_t serviceId, uint32_t methodId, uint32_t size, const EchoErrorPolicy& errorPolicy) = 0;

protobuf/echo/ServiceForwarder.cpp

@@ -1,9 +1,11 @@
 #include "protobuf/echo/ServiceForwarder.hpp"
+#include "protobuf/echo/Echo.hpp"
+#include <cstdint>
 
 namespace services
 {
-    ServiceForwarderBase::ServiceForwarderBase(Echo& echo, Echo& forwardTo)
-        : Service(echo)
+    ServiceForwarderBase::ServiceForwarderBase(Echo& echo, uint32_t id, Echo& forwardTo)
+        : Service(echo, id)
         , ServiceProxy(forwardTo, 0)
     {}
 
@@ -83,18 +85,16 @@ namespace services
             contentsReader = nullptr;
     }
 
+    ServiceForwarderAll::ServiceForwarderAll(Echo& echo, Echo& forwardTo)
+        : ServiceForwarderBase(echo, ServiceId::reservedServiceId, forwardTo)
+    {}
+
     bool ServiceForwarderAll::AcceptsService(uint32_t id) const
     {
         return true;
     }
 
     ServiceForwarder::ServiceForwarder(Echo& echo, uint32_t id, Echo& forwardTo)
-        : ServiceForwarderBase(echo, forwardTo)
-        , serviceId(id)
+        : ServiceForwarderBase(echo, id, forwardTo)
     {}
-
-    bool ServiceForwarder::AcceptsService(uint32_t id) const
-    {
-        return serviceId == id;
-    }
 }

protobuf/echo/ServiceForwarder.hpp

@@ -2,6 +2,7 @@
 #define PROTOBUF_ECHO_SERVICE_FORWARDER_HPP
 
 #include "protobuf/echo/Echo.hpp"
+#include <cstdint>
 
 namespace services
 {
@@ -12,7 +13,7 @@ namespace services
         , private MethodSerializer
     {
     public:
-        ServiceForwarderBase(Echo& echo, Echo& forwardTo);
+        ServiceForwarderBase(Echo& echo, uint32_t id, Echo& forwardTo);
 
         // Implementation of Service
         infra::SharedPtr<MethodDeserializer> StartMethod(uint32_t serviceId, uint32_t methodId, uint32_t size, const EchoErrorPolicy& errorPolicy) override;
@@ -44,21 +45,19 @@ namespace services
         : public ServiceForwarderBase
     {
     public:
-        using ServiceForwarderBase::ServiceForwarderBase;
+        ServiceForwarderAll(Echo& echo, Echo& forwardTo);
 
         bool AcceptsService(uint32_t id) const override;
+
+    private:
+        static constexpr uint8_t invalidServiceId = 0;
     };
 
     class ServiceForwarder
         : public ServiceForwarderBase
     {
     public:
         ServiceForwarder(Echo& echo, uint32_t id, Echo& forwardTo);
-
-        bool AcceptsService(uint32_t id) const override;
-
-    private:
-        uint32_t serviceId;
     };
 }
 

protobuf/echo/test_doubles/ServiceStub.cpp

@@ -1,4 +1,5 @@
 #include "protobuf/echo/test_doubles/ServiceStub.hpp"
+#include <cstdint>
 
 namespace services
 {
@@ -50,15 +51,10 @@ namespace services
         return value;
     }
 
-    ServiceStub::ServiceStub(Echo& echo)
-        : Service(echo)
+    ServiceStub::ServiceStub(Echo& echo, uint32_t serviceId)
+        : Service(echo, serviceId)
     {}
 
-    bool ServiceStub::AcceptsService(uint32_t id) const
-    {
-        return id == serviceId;
-    }
-
     infra::SharedPtr<MethodDeserializer> ServiceStub::StartMethod(uint32_t serviceId, uint32_t methodId, uint32_t size, const services::EchoErrorPolicy& errorPolicy)
     {
         switch (methodId)
@@ -84,8 +80,9 @@ namespace services
         }
     }
 
-    ServiceStubProxy::ServiceStubProxy(services::Echo& echo)
+    ServiceStubProxy::ServiceStubProxy(services::Echo& echo, uint32_t serviceId)
         : services::ServiceProxy(echo, maxMessageSize)
+        , serviceId(serviceId)
     {}
 
     void ServiceStubProxy::Method(uint32_t value)

protobuf/echo/test_doubles/ServiceStub.hpp

@@ -3,6 +3,7 @@
 
 #include "protobuf/echo/Echo.hpp"
 #include "gmock/gmock.h"
+#include <cstdint>
 
 namespace services
 {
@@ -64,9 +65,7 @@ namespace services
         : public services::Service
     {
     public:
-        ServiceStub(Echo& echo);
-
-        bool AcceptsService(uint32_t id) const override;
+        ServiceStub(Echo& echo, uint32_t serviceId = defaultServiceId);
 
         MOCK_METHOD(void, Method, (uint32_t value));
         MOCK_METHOD(void, MethodNoParameter, ());
@@ -76,7 +75,7 @@ namespace services
         infra::SharedPtr<MethodDeserializer> StartMethod(uint32_t serviceId, uint32_t methodId, uint32_t size, const services::EchoErrorPolicy& errorPolicy) override;
 
     public:
-        static const uint32_t serviceId = 1;
+        static constexpr uint32_t defaultServiceId = 1;
         static const uint32_t idMethod = 1;
         static const uint32_t idMethodNoParameter = 3;
         static const uint32_t idMethodBytes = 4;
@@ -90,20 +89,23 @@ namespace services
         : public services::ServiceProxy
     {
     public:
-        ServiceStubProxy(services::Echo& echo);
+        ServiceStubProxy(services::Echo& echo, uint32_t serviceId = defaultServiceId);
 
     public:
         void Method(uint32_t value);
         void MethodNoParameter();
 
     public:
-        static constexpr uint32_t serviceId = 1;
+        static constexpr uint32_t defaultServiceId = 1;
         static constexpr uint32_t idMethod = 1;
         static const uint32_t idMethodNoParameter = 3;
         static constexpr uint32_t maxMessageSize = 18;
 
     public:
         using MethodTypeList = infra::List<Message, EmptyMessage>;
+
+    private:
+        const uint32_t serviceId;
     };
 }
 

protobuf/meta_services/CMakeLists.txt

@@ -0,0 +1,20 @@
+add_library(protobuf.meta_services ${EMIL_EXCLUDE_FROM_ALL} STATIC)
+
+target_include_directories(protobuf.meta_services PUBLIC
+    "$<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}/../..>"
+    "$<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>"
+)
+
+protocol_buffer_csharp(protobuf.meta_services ServiceDiscovery.proto)
+protocol_buffer_java(protobuf.meta_services ServiceDiscovery.proto)
+protocol_buffer_echo_all(protobuf.meta_services ServiceDiscovery.proto)
+
+target_sources(protobuf.meta_services PRIVATE
+    PeerServiceDiscoverer.cpp
+    PeerServiceDiscoverer.hpp
+    ServiceDiscoveryEcho.cpp
+    ServiceDiscoveryEcho.hpp
+)
+
+add_subdirectory(test)
+