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/*
*
* Copyright 2018 gRPC authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
#ifndef GRPCPP_IMPL_CODEGEN_SERVER_CALLBACK_H
#define GRPCPP_IMPL_CODEGEN_SERVER_CALLBACK_H
#include <functional>
#include <grpcpp/impl/codegen/call.h>
#include <grpcpp/impl/codegen/call_op_set.h>
#include <grpcpp/impl/codegen/callback_common.h>
#include <grpcpp/impl/codegen/config.h>
#include <grpcpp/impl/codegen/core_codegen_interface.h>
#include <grpcpp/impl/codegen/server_context.h>
#include <grpcpp/impl/codegen/server_interface.h>
#include <grpcpp/impl/codegen/status.h>
namespace grpc {
// forward declarations
namespace internal {
template <class ServiceType, class RequestType, class ResponseType>
class CallbackUnaryHandler;
} // namespace internal
namespace experimental {
// For unary RPCs, the exposed controller class is only an interface
// and the actual implementation is an internal class.
class ServerCallbackRpcController {
public:
virtual ~ServerCallbackRpcController() {}
// The method handler must call this function when it is done so that
// the library knows to free its resources
virtual void Finish(Status s) = 0;
// Allow the method handler to push out the initial metadata before
// the response and status are ready
virtual void SendInitialMetadata(std::function<void(bool)>) = 0;
};
} // namespace experimental
namespace internal {
template <class ServiceType, class RequestType, class ResponseType>
class CallbackUnaryHandler : public MethodHandler {
public:
CallbackUnaryHandler(
std::function<void(ServerContext*, const RequestType*, ResponseType*,
experimental::ServerCallbackRpcController*)>
func,
ServiceType* service)
: func_(func) {}
void RunHandler(const HandlerParameter& param) final {
// Arena allocate a controller structure (that includes request/response)
g_core_codegen_interface->grpc_call_ref(param.call->call());
auto* controller = new (g_core_codegen_interface->grpc_call_arena_alloc(
param.call->call(), sizeof(ServerCallbackRpcControllerImpl)))
ServerCallbackRpcControllerImpl(
param.server_context, param.call,
static_cast<RequestType*>(param.request),
std::move(param.call_requester));
Status status = param.status;
if (status.ok()) {
// Call the actual function handler and expect the user to call finish
CatchingCallback(std::move(func_), param.server_context,
controller->request(), controller->response(),
controller);
} else {
// if deserialization failed, we need to fail the call
controller->Finish(status);
}
}
void* Deserialize(grpc_call* call, grpc_byte_buffer* req,
Status* status) final {
ByteBuffer buf;
buf.set_buffer(req);
auto* request = new (g_core_codegen_interface->grpc_call_arena_alloc(
call, sizeof(RequestType))) RequestType();
*status = SerializationTraits<RequestType>::Deserialize(&buf, request);
buf.Release();
if (status->ok()) {
return request;
}
request->~RequestType();
return nullptr;
}
private:
std::function<void(ServerContext*, const RequestType*, ResponseType*,
experimental::ServerCallbackRpcController*)>
func_;
// The implementation class of ServerCallbackRpcController is a private member
// of CallbackUnaryHandler since it is never exposed anywhere, and this allows
// it to take advantage of CallbackUnaryHandler's friendships.
class ServerCallbackRpcControllerImpl
: public experimental::ServerCallbackRpcController {
public:
void Finish(Status s) override {
finish_tag_.Set(
call_.call(),
[this](bool) {
grpc_call* call = call_.call();
auto call_requester = std::move(call_requester_);
this->~ServerCallbackRpcControllerImpl(); // explicitly call
// destructor
g_core_codegen_interface->grpc_call_unref(call);
call_requester();
},
&finish_buf_);
if (!ctx_->sent_initial_metadata_) {
finish_buf_.SendInitialMetadata(&ctx_->initial_metadata_,
ctx_->initial_metadata_flags());
if (ctx_->compression_level_set()) {
finish_buf_.set_compression_level(ctx_->compression_level());
}
ctx_->sent_initial_metadata_ = true;
}
// The response is dropped if the status is not OK.
if (s.ok()) {
finish_buf_.ServerSendStatus(&ctx_->trailing_metadata_,
finish_buf_.SendMessage(resp_));
} else {
finish_buf_.ServerSendStatus(&ctx_->trailing_metadata_, s);
}
finish_buf_.set_core_cq_tag(&finish_tag_);
call_.PerformOps(&finish_buf_);
}
void SendInitialMetadata(std::function<void(bool)> f) override {
GPR_CODEGEN_ASSERT(!ctx_->sent_initial_metadata_);
meta_tag_.Set(call_.call(), std::move(f), &meta_buf_);
meta_buf_.SendInitialMetadata(&ctx_->initial_metadata_,
ctx_->initial_metadata_flags());
if (ctx_->compression_level_set()) {
meta_buf_.set_compression_level(ctx_->compression_level());
}
ctx_->sent_initial_metadata_ = true;
meta_buf_.set_core_cq_tag(&meta_tag_);
call_.PerformOps(&meta_buf_);
}
private:
template <class SrvType, class ReqType, class RespType>
friend class CallbackUnaryHandler;
ServerCallbackRpcControllerImpl(ServerContext* ctx, Call* call,
RequestType* req,
std::function<void()> call_requester)
: ctx_(ctx),
call_(*call),
req_(req),
call_requester_(std::move(call_requester)) {}
~ServerCallbackRpcControllerImpl() { req_->~RequestType(); }
RequestType* request() { return req_; }
ResponseType* response() { return &resp_; }
CallOpSet<CallOpSendInitialMetadata> meta_buf_;
CallbackWithSuccessTag meta_tag_;
CallOpSet<CallOpSendInitialMetadata, CallOpSendMessage,
CallOpServerSendStatus>
finish_buf_;
CallbackWithSuccessTag finish_tag_;
ServerContext* ctx_;
Call call_;
RequestType* req_;
ResponseType resp_;
std::function<void()> call_requester_;
};
};
} // namespace internal
} // namespace grpc
#endif // GRPCPP_IMPL_CODEGEN_SERVER_CALLBACK_H
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