gRPC callbackService support added (#8666)

* grpc callbackService support added

Signed-off-by: shankeleven <shashanksati11@gmail.com>

* tests: regenerate C++ gRPC golden with --grpc-callback-api (CallbackService & async_ reactor APIs); update formatting and method placement

---------

Signed-off-by: shankeleven <shashanksati11@gmail.com>
Co-authored-by: Wouter van Oortmerssen <aardappel@gmail.com>

tests/monster_test.grpc.fb.cc

@@ -1,5 +1,5 @@
 // Generated by the gRPC C++ plugin.
-// If you make any local change, they will be lost.
+// FlatBuffers modified generator: native gRPC callback client API enabled when --grpc-callback-api.
 // source: monster_test
 
 #include "monster_test_generated.h"
@@ -13,6 +13,9 @@
 #include <grpcpp/impl/codegen/rpc_service_method.h>
 #include <grpcpp/impl/codegen/service_type.h>
 #include <grpcpp/impl/codegen/sync_stream.h>
+#include <grpcpp/impl/codegen/callback_common.h>
+#include <grpcpp/impl/codegen/server_callback_handlers.h>
+#include <grpcpp/support/client_callback.h>
 namespace MyGame {
 namespace Example {
 
@@ -39,6 +42,14 @@ MonsterStorage::Stub::Stub(const std::shared_ptr< ::grpc::ChannelInterface>& cha
   return ::grpc::internal::BlockingUnaryCall(channel_.get(), rpcmethod_Store_, context, request, response);
 }
 
+void MonsterStorage::Stub::async_Store(::grpc::ClientContext* context, const flatbuffers::grpc::Message<Monster>& request, flatbuffers::grpc::Message<Stat>* response, std::function<void(::grpc::Status)> on_done) {
+  ::grpc::internal::CallbackUnaryCall(channel_.get(), rpcmethod_Store_, context, &request, response, std::move(on_done));
+}
+
+void MonsterStorage::Stub::async_Store(::grpc::ClientContext* context, const flatbuffers::grpc::Message<Monster>& request, flatbuffers::grpc::Message<Stat>* response, ::grpc::ClientUnaryReactor* reactor) {
+  ::grpc::internal::ClientCallbackUnaryFactory::Create(channel_.get(), rpcmethod_Store_, context, &request, response, reactor);
+}
+
 ::grpc::ClientAsyncResponseReader< flatbuffers::grpc::Message<Stat>>* MonsterStorage::Stub::AsyncStoreRaw(::grpc::ClientContext* context, const flatbuffers::grpc::Message<Monster>& request, ::grpc::CompletionQueue* cq) {
   return ::grpc::internal::ClientAsyncResponseReaderFactory< flatbuffers::grpc::Message<Stat>>::Create(channel_.get(), cq, rpcmethod_Store_, context, request, true);
 }
@@ -51,6 +62,10 @@ MonsterStorage::Stub::Stub(const std::shared_ptr< ::grpc::ChannelInterface>& cha
   return ::grpc::internal::ClientReaderFactory< flatbuffers::grpc::Message<Monster>>::Create(channel_.get(), rpcmethod_Retrieve_, context, request);
 }
 
+void MonsterStorage::Stub::async_Retrieve(::grpc::ClientContext* context, const flatbuffers::grpc::Message<Stat>& request, ::grpc::ClientReadReactor< flatbuffers::grpc::Message<Monster> >* reactor) {
+  ::grpc::internal::ClientCallbackReaderFactory< flatbuffers::grpc::Message<Monster> >::Create(channel_.get(), rpcmethod_Retrieve_, context, &request, reactor);
+}
+
 ::grpc::ClientAsyncReader< flatbuffers::grpc::Message<Monster>>* MonsterStorage::Stub::AsyncRetrieveRaw(::grpc::ClientContext* context, const flatbuffers::grpc::Message<Stat>& request, ::grpc::CompletionQueue* cq, void* tag) {
   return ::grpc::internal::ClientAsyncReaderFactory< flatbuffers::grpc::Message<Monster>>::Create(channel_.get(), cq, rpcmethod_Retrieve_, context, request, true, tag);
 }
@@ -63,6 +78,10 @@ MonsterStorage::Stub::Stub(const std::shared_ptr< ::grpc::ChannelInterface>& cha
   return ::grpc::internal::ClientWriterFactory< flatbuffers::grpc::Message<Monster>>::Create(channel_.get(), rpcmethod_GetMaxHitPoint_, context, response);
 }
 
+void MonsterStorage::Stub::async_GetMaxHitPoint(::grpc::ClientContext* context, flatbuffers::grpc::Message<Stat>* response, ::grpc::ClientWriteReactor< flatbuffers::grpc::Message<Monster> >* reactor) {
+  ::grpc::internal::ClientCallbackWriterFactory< flatbuffers::grpc::Message<Monster> >::Create(channel_.get(), rpcmethod_GetMaxHitPoint_, context, response, reactor);
+}
+
 ::grpc::ClientAsyncWriter< flatbuffers::grpc::Message<Monster>>* MonsterStorage::Stub::AsyncGetMaxHitPointRaw(::grpc::ClientContext* context, flatbuffers::grpc::Message<Stat>* response, ::grpc::CompletionQueue* cq, void* tag) {
   return ::grpc::internal::ClientAsyncWriterFactory< flatbuffers::grpc::Message<Monster>>::Create(channel_.get(), cq, rpcmethod_GetMaxHitPoint_, context, response, true, tag);
 }
@@ -75,6 +94,10 @@ MonsterStorage::Stub::Stub(const std::shared_ptr< ::grpc::ChannelInterface>& cha
   return ::grpc::internal::ClientReaderWriterFactory< flatbuffers::grpc::Message<Monster>, flatbuffers::grpc::Message<Stat>>::Create(channel_.get(), rpcmethod_GetMinMaxHitPoints_, context);
 }
 
+void MonsterStorage::Stub::async_GetMinMaxHitPoints(::grpc::ClientContext* context, ::grpc::ClientBidiReactor< flatbuffers::grpc::Message<Monster>, flatbuffers::grpc::Message<Stat> >* reactor) {
+  ::grpc::internal::ClientCallbackReaderWriterFactory< flatbuffers::grpc::Message<Monster>, flatbuffers::grpc::Message<Stat> >::Create(channel_.get(), rpcmethod_GetMinMaxHitPoints_, context, reactor);
+}
+
 ::grpc::ClientAsyncReaderWriter< flatbuffers::grpc::Message<Monster>, flatbuffers::grpc::Message<Stat>>* MonsterStorage::Stub::AsyncGetMinMaxHitPointsRaw(::grpc::ClientContext* context, ::grpc::CompletionQueue* cq, void* tag) {
   return ::grpc::internal::ClientAsyncReaderWriterFactory< flatbuffers::grpc::Message<Monster>, flatbuffers::grpc::Message<Stat>>::Create(channel_.get(), cq, rpcmethod_GetMinMaxHitPoints_, context, true, tag);
 }
@@ -125,6 +148,57 @@ MonsterStorage::Service::~Service() {
   return ::grpc::Status(::grpc::StatusCode::UNIMPLEMENTED, "");
 }
 
+#if defined(GRPC_CALLBACK_API_NONEXPERIMENTAL)
+MonsterStorage::CallbackService::CallbackService() {
+  AddMethod(new ::grpc::internal::RpcServiceMethod(
+      MonsterStorage_method_names[0],
+      ::grpc::internal::RpcMethod::NORMAL_RPC,
+      new ::grpc::internal::CallbackUnaryHandler<flatbuffers::grpc::Message<Monster>, flatbuffers::grpc::Message<Stat>>(
+        [this](::grpc::CallbackServerContext* ctx, const flatbuffers::grpc::Message<Monster>* req, flatbuffers::grpc::Message<Stat>* resp) {
+          return this->Store(ctx, req, resp);
+        })));
+  AddMethod(new ::grpc::internal::RpcServiceMethod(
+      MonsterStorage_method_names[1],
+      ::grpc::internal::RpcMethod::SERVER_STREAMING,
+      new ::grpc::internal::CallbackServerStreamingHandler<flatbuffers::grpc::Message<Stat>, flatbuffers::grpc::Message<Monster>>(
+        [this](::grpc::CallbackServerContext* ctx, const flatbuffers::grpc::Message<Stat>* req) {
+          return this->Retrieve(ctx, req);
+        })));
+  AddMethod(new ::grpc::internal::RpcServiceMethod(
+      MonsterStorage_method_names[2],
+      ::grpc::internal::RpcMethod::CLIENT_STREAMING,
+      new ::grpc::internal::CallbackClientStreamingHandler<flatbuffers::grpc::Message<Monster>, flatbuffers::grpc::Message<Stat>>(
+        [this](::grpc::CallbackServerContext* ctx, flatbuffers::grpc::Message<Stat>* resp) {
+          return this->GetMaxHitPoint(ctx, resp);
+        })));
+  AddMethod(new ::grpc::internal::RpcServiceMethod(
+      MonsterStorage_method_names[3],
+      ::grpc::internal::RpcMethod::BIDI_STREAMING,
+      new ::grpc::internal::CallbackBidiHandler<flatbuffers::grpc::Message<Monster>, flatbuffers::grpc::Message<Stat>>(
+        [this](::grpc::CallbackServerContext* ctx) {
+          return this->GetMinMaxHitPoints(ctx);
+        })));
+}
+
+MonsterStorage::CallbackService::~CallbackService() {}
+
+::grpc::ServerUnaryReactor* MonsterStorage::CallbackService::Store(::grpc::CallbackServerContext* /*context*/, const flatbuffers::grpc::Message<Monster>* /*request*/, flatbuffers::grpc::Message<Stat>* /*response*/) {
+  return nullptr; // user must override
+}
+
+::grpc::ServerWriteReactor<flatbuffers::grpc::Message<Monster>>* MonsterStorage::CallbackService::Retrieve(::grpc::CallbackServerContext* /*context*/, const flatbuffers::grpc::Message<Stat>* /*request*/) {
+  return nullptr; // user must override
+}
+
+::grpc::ServerReadReactor<flatbuffers::grpc::Message<Monster>>* MonsterStorage::CallbackService::GetMaxHitPoint(::grpc::CallbackServerContext* /*context*/, flatbuffers::grpc::Message<Stat>* /*response*/) {
+  return nullptr; // user must override
+}
+
+::grpc::ServerBidiReactor<flatbuffers::grpc::Message<Monster>, flatbuffers::grpc::Message<Stat>>* MonsterStorage::CallbackService::GetMinMaxHitPoints(::grpc::CallbackServerContext* /*context*/) {
+  return nullptr; // user must override
+}
+
+#endif // GRPC_CALLBACK_API_NONEXPERIMENTAL
 
 }  // namespace MyGame
 }  // namespace Example

tests/monster_test.grpc.fb.h

@@ -16,6 +16,9 @@
 #include <grpcpp/impl/codegen/status.h>
 #include <grpcpp/impl/codegen/stub_options.h>
 #include <grpcpp/impl/codegen/sync_stream.h>
+#include <grpcpp/impl/codegen/callback_common.h>
+#include <grpcpp/impl/codegen/server_callback_handlers.h>
+#include <grpcpp/support/client_callback.h>
 
 namespace grpc {
 class CompletionQueue;
@@ -81,11 +84,16 @@ class MonsterStorage final {
     virtual ::grpc::ClientReaderWriterInterface< flatbuffers::grpc::Message<Monster>, flatbuffers::grpc::Message<Stat>>* GetMinMaxHitPointsRaw(::grpc::ClientContext* context) = 0;
     virtual ::grpc::ClientAsyncReaderWriterInterface< flatbuffers::grpc::Message<Monster>, flatbuffers::grpc::Message<Stat>>* AsyncGetMinMaxHitPointsRaw(::grpc::ClientContext* context, ::grpc::CompletionQueue* cq, void* tag) = 0;
     virtual ::grpc::ClientAsyncReaderWriterInterface< flatbuffers::grpc::Message<Monster>, flatbuffers::grpc::Message<Stat>>* PrepareAsyncGetMinMaxHitPointsRaw(::grpc::ClientContext* context, ::grpc::CompletionQueue* cq) = 0;
+  class CallbackService;
   };
   class Stub final : public StubInterface {
    public:
     Stub(const std::shared_ptr< ::grpc::ChannelInterface>& channel);
     ::grpc::Status Store(::grpc::ClientContext* context, const flatbuffers::grpc::Message<Monster>& request, flatbuffers::grpc::Message<Stat>* response) override;
+    // Callback unary (function form). Request/response must outlive callback.
+    void async_Store(::grpc::ClientContext* context, const flatbuffers::grpc::Message<Monster>& request, flatbuffers::grpc::Message<Stat>* response, std::function<void(::grpc::Status)> on_done);
+    // Callback unary (reactor form).
+    void async_Store(::grpc::ClientContext* context, const flatbuffers::grpc::Message<Monster>& request, flatbuffers::grpc::Message<Stat>* response, ::grpc::ClientUnaryReactor* reactor);
     std::unique_ptr< ::grpc::ClientAsyncResponseReader< flatbuffers::grpc::Message<Stat>>> AsyncStore(::grpc::ClientContext* context, const flatbuffers::grpc::Message<Monster>& request, ::grpc::CompletionQueue* cq) {
       return std::unique_ptr< ::grpc::ClientAsyncResponseReader< flatbuffers::grpc::Message<Stat>>>(AsyncStoreRaw(context, request, cq));
     }
@@ -95,6 +103,8 @@ class MonsterStorage final {
     std::unique_ptr< ::grpc::ClientReader< flatbuffers::grpc::Message<Monster>>> Retrieve(::grpc::ClientContext* context, const flatbuffers::grpc::Message<Stat>& request) {
       return std::unique_ptr< ::grpc::ClientReader< flatbuffers::grpc::Message<Monster>>>(RetrieveRaw(context, request));
     }
+    // Server streaming callback reactor entry.
+    void async_Retrieve(::grpc::ClientContext* context, const flatbuffers::grpc::Message<Stat>& request, ::grpc::ClientReadReactor< flatbuffers::grpc::Message<Monster> >* reactor);
     std::unique_ptr< ::grpc::ClientAsyncReader< flatbuffers::grpc::Message<Monster>>> AsyncRetrieve(::grpc::ClientContext* context, const flatbuffers::grpc::Message<Stat>& request, ::grpc::CompletionQueue* cq, void* tag) {
       return std::unique_ptr< ::grpc::ClientAsyncReader< flatbuffers::grpc::Message<Monster>>>(AsyncRetrieveRaw(context, request, cq, tag));
     }
@@ -104,6 +114,8 @@ class MonsterStorage final {
     std::unique_ptr< ::grpc::ClientWriter< flatbuffers::grpc::Message<Monster>>> GetMaxHitPoint(::grpc::ClientContext* context, flatbuffers::grpc::Message<Stat>* response) {
       return std::unique_ptr< ::grpc::ClientWriter< flatbuffers::grpc::Message<Monster>>>(GetMaxHitPointRaw(context, response));
     }
+    // Client streaming callback reactor entry.
+    void async_GetMaxHitPoint(::grpc::ClientContext* context, flatbuffers::grpc::Message<Stat>* response, ::grpc::ClientWriteReactor< flatbuffers::grpc::Message<Monster> >* reactor);
     std::unique_ptr< ::grpc::ClientAsyncWriter< flatbuffers::grpc::Message<Monster>>> AsyncGetMaxHitPoint(::grpc::ClientContext* context, flatbuffers::grpc::Message<Stat>* response, ::grpc::CompletionQueue* cq, void* tag) {
       return std::unique_ptr< ::grpc::ClientAsyncWriter< flatbuffers::grpc::Message<Monster>>>(AsyncGetMaxHitPointRaw(context, response, cq, tag));
     }
@@ -113,6 +125,8 @@ class MonsterStorage final {
     std::unique_ptr< ::grpc::ClientReaderWriter< flatbuffers::grpc::Message<Monster>, flatbuffers::grpc::Message<Stat>>> GetMinMaxHitPoints(::grpc::ClientContext* context) {
       return std::unique_ptr< ::grpc::ClientReaderWriter< flatbuffers::grpc::Message<Monster>, flatbuffers::grpc::Message<Stat>>>(GetMinMaxHitPointsRaw(context));
     }
+    // Bidirectional streaming callback reactor entry.
+    void async_GetMinMaxHitPoints(::grpc::ClientContext* context, ::grpc::ClientBidiReactor< flatbuffers::grpc::Message<Monster>, flatbuffers::grpc::Message<Stat> >* reactor);
     std::unique_ptr<  ::grpc::ClientAsyncReaderWriter< flatbuffers::grpc::Message<Monster>, flatbuffers::grpc::Message<Stat>>> AsyncGetMinMaxHitPoints(::grpc::ClientContext* context, ::grpc::CompletionQueue* cq, void* tag) {
       return std::unique_ptr< ::grpc::ClientAsyncReaderWriter< flatbuffers::grpc::Message<Monster>, flatbuffers::grpc::Message<Stat>>>(AsyncGetMinMaxHitPointsRaw(context, cq, tag));
     }
@@ -343,6 +357,23 @@ class MonsterStorage final {
   typedef   WithStreamedUnaryMethod_Store<  WithSplitStreamingMethod_Retrieve<  Service   >   >   StreamedService;
 };
 
+#if defined(GRPC_CALLBACK_API_NONEXPERIMENTAL)
+class MonsterStorage::CallbackService : public ::grpc::Service {
+ public:
+  CallbackService();
+  virtual ~CallbackService();
+  virtual ::grpc::ServerUnaryReactor* Store(::grpc::CallbackServerContext* context, const flatbuffers::grpc::Message<Monster>* request, flatbuffers::grpc::Message<Stat>* response);
+  virtual ::grpc::ServerWriteReactor<flatbuffers::grpc::Message<Monster>>* Retrieve(::grpc::CallbackServerContext* context, const flatbuffers::grpc::Message<Stat>* request);
+  virtual ::grpc::ServerReadReactor<flatbuffers::grpc::Message<Monster>>* GetMaxHitPoint(::grpc::CallbackServerContext* context, flatbuffers::grpc::Message<Stat>* response);
+  virtual ::grpc::ServerBidiReactor<flatbuffers::grpc::Message<Monster>, flatbuffers::grpc::Message<Stat>>* GetMinMaxHitPoints(::grpc::CallbackServerContext* context);
+};
+#else
+// Callback API requested but not available in this gRPC version.
+#endif // GRPC_CALLBACK_API_NONEXPERIMENTAL
+
+// FlatBuffers: Callback API code generated.
+#define FLATBUFFERS_GENERATED_GRPC_CALLBACK_API 1
+
 }  // namespace Example
 }  // namespace MyGame
 

tests/monster_test_callback.grpc.fb.cc

@@ -0,0 +1,2 @@
+// Callback variant source references primary generated implementation.
+#include "monster_test_callback.grpc.fb.h"

tests/monster_test_callback.grpc.fb.h

@@ -0,0 +1,4 @@
+// Callback variant copy of monster_test.grpc.fb.h generated with
+// --grpc-callback-api (kept separate as a golden for callback API feature
+// evolution)
+#include "monster_test.grpc.fb.h"

tests/monster_test_generated.grpc.fb.cc

@@ -1,8 +1,9 @@
 // Generated by the gRPC C++ plugin.
-// If you make any local change, they will be lost.
+// FlatBuffers modified generator: native gRPC callback client API enabled when --grpc-callback-api.
 // source: monster_test
 
-#include "monster_test_generated.grpc.fb.h"
+#include "monster_test_generated.h"
+#include "monster_test.grpc.fb.h"
 
 #include <grpcpp/impl/codegen/async_stream.h>
 #include <grpcpp/impl/codegen/async_unary_call.h>

tests/monster_test_generated.grpc.fb.h

@@ -201,7 +201,7 @@ class MonsterStorage final {
       BaseClassMustBeDerivedFromService(this);
     }
     // disable synchronous version of this method
-    ::grpc::Status GetMaxHitPoint(::grpc::ServerContext* /*context*/, ::grpc::ServerReader< flatbuffers::grpc::Message<Monster>>* /*reader*/, flatbuffers::grpc::Message<Stat>* response) final override {
+    ::grpc::Status GetMaxHitPoint(::grpc::ServerContext* /*context*/, ::grpc::ServerReader< flatbuffers::grpc::Message<Monster>>* /*reader*/, flatbuffers::grpc::Message<Stat>* /*response*/) final override {
       abort();
       return ::grpc::Status(::grpc::StatusCode::UNIMPLEMENTED, "");
     }

tests/monster_test_suffix/ext_only/monster_test.grpc.fb.cc

@@ -1,5 +1,5 @@
 // Generated by the gRPC C++ plugin.
-// If you make any local change, they will be lost.
+// FlatBuffers modified generator: native gRPC callback client API enabled when --grpc-callback-api.
 // source: monster_test
 
 #include "monster_test_generated.hpp"

tests/monster_test_suffix/filesuffix_only/monster_test.grpc.fb.cc

@@ -1,5 +1,5 @@
 // Generated by the gRPC C++ plugin.
-// If you make any local change, they will be lost.
+// FlatBuffers modified generator: native gRPC callback client API enabled when --grpc-callback-api.
 // source: monster_test
 
 #include "monster_test_suffix.h"

tests/monster_test_suffix/monster_test.grpc.fb.cc

@@ -1,5 +1,5 @@
 // Generated by the gRPC C++ plugin.
-// If you make any local change, they will be lost.
+// FlatBuffers modified generator: native gRPC callback client API enabled when --grpc-callback-api.
 // source: monster_test
 
 #include "monster_test_suffix.hpp"