// Converted from echo.idl by brpc/tools/idl2proto
import "idl_options.proto";
option (idl_support) = true;
option cc_generic_services = true;
message EchoRequest {
  required string message = 1; 
}
message EchoResponse {
  required string message = 1; 
}
 
// 对于有多个参数的idl方法，需要定义一个包含所有request或response的消息，作为对应方法的参数。
message MultiRequests {
  required EchoRequest req1 = 1;
  required EchoRequest req2 = 2;
}
message MultiResponses {
  required EchoRequest res1 = 1;
  required EchoRequest res2 = 2;
}
 
service EchoService {
  // 对应idl中的void Echo(EchoRequest req, out EchoResponse res);
  rpc Echo(EchoRequest) returns (EchoResponse);
 
  // 对应idl中的EchoWithMultiArgs(EchoRequest req1, EchoRequest req2, out EchoResponse res1, out EchoResponse res2);
  rpc EchoWithMultiArgs(MultiRequests) returns (MultiResponses);
}

struct EchoRequest {
    string message;
};
 
struct EchoResponse {
    string message;
};
 
service EchoService {
    void Echo(EchoRequest req, out EchoResponse res);
    uint32_t EchoWithMultiArgs(EchoRequest req1, EchoRequest req2, out EchoResponse res1, out EchoResponse res2);
};

protoc --plugin=protoc-gen-mcpack=$BRPC_PATH/bin/protoc-gen-mcpack --cpp_out=. --mcpack_out=. --proto_path=$BRPC_PATH/include --proto_path=PROTOBUF_INCLUDE_PATH

class EchoServiceImpl : public EchoService {
public:
 
    ...
    // 对应idl中的void Echo(EchoRequest req, out EchoResponse res);
    virtual void Echo(google::protobuf::RpcController* cntl_base,
                      const EchoRequest* request,
                      EchoResponse* response,
                      google::protobuf::Closure* done) {
        brpc::ClosureGuard done_guard(done);
        brpc::Controller* cntl = static_cast<brpc::Controller*>(cntl_base);
 
        // 填充response。
        response->set_message(request->message());
 
        // 对应的idl方法没有返回值，不需要像下面方法中那样set_idl_result()。
        // 可以看到这个方法和其他protobuf服务没有差别，所以这个服务也可以被ubrpc之外的协议访问。
    }
 
    virtual void EchoWithMultiArgs(google::protobuf::RpcController* cntl_base,
                                   const MultiRequests* request,
                                   MultiResponses* response,
                                   google::protobuf::Closure* done) {
        brpc::ClosureGuard done_guard(done);
        brpc::Controller* cntl = static_cast<brpc::Controller*>(cntl_base);
 
        // 填充response。response是我们定义的包含所有idl response的消息。
        response->mutable_res1()->set_message(request->req1().message());
        response->mutable_res2()->set_message(request->req2().message());
 
        // 告诉RPC有多个request和response。
        cntl->set_idl_names(brpc::idl_multi_req_multi_res);
 
        // 对应idl方法的返回值。
        cntl->set_idl_result(17);
    }
};

#include <brpc/ubrpc2pb_protocol.h>
...
brpc::ServerOptions option;
option.nshead_service = new brpc::policy::UbrpcCompackAdaptor; // mcpack2用UbrpcMcpack2Adaptor

// 代表一个nshead请求或回复。
struct NsheadMessage {
    nshead_t head;
    butil::IOBuf body;
};
 
// 实现这个类并赋值给ServerOptions.nshead_service来让brpc处理nshead请求。
class NsheadService : public Describable {
public:
    NsheadService();
    NsheadService(const NsheadServiceOptions&);
    virtual ~NsheadService();
 
    // 实现这个方法来处理nshead请求。注意这个方法可能在调用时controller->Failed()已经为true了。
    // 原因可能是Server.Stop()被调用正在退出(错误码是brpc::ELOGOFF)
    // 或触发了ServerOptions.max_concurrency(错误码是brpc::ELIMIT)
    // 在这种情况下，这个方法应该通过返回一个代表错误的response让客户端知道这些错误。
    // Parameters:
    //   server      The server receiving the request.
    //   controller  Contexts of the request.
    //   request     The nshead request received.
    //   response    The nshead response that you should fill in.
    //   done        You must call done->Run() to end the processing, brpc::ClosureGuard is preferred.
    virtual void ProcessNsheadRequest(const Server& server,
                                      Controller* controller,
                                      const NsheadMessage& request,
                                      NsheadMessage* response,
                                      NsheadClosure* done) = 0;
};

class NsheadPbServiceAdaptor : public NsheadService {
public:
    NsheadPbServiceAdaptor() : NsheadService(
        NsheadServiceOptions(false, SendNsheadPbResponseSize)) {}
    virtual ~NsheadPbServiceAdaptor() {}
 
    // Fetch meta from `nshead_req' into `meta'.
    // Params:
    //   server: where the RPC runs.
    //   nshead_req: the nshead request that server received.
    //   controller: If something goes wrong, call controller->SetFailed()
    //   meta: Set meta information into this structure. `full_method_name'
    //         must be set if controller is not SetFailed()-ed
    // FIXME: server is not needed anymore, controller->server() is same
    virtual void ParseNsheadMeta(const Server& server,
                                 const NsheadMessage& nshead_req,
                                 Controller* controller,
                                 NsheadMeta* meta) const = 0;
    // Transform `nshead_req' to `pb_req'.
    // Params:
    //   meta: was set by ParseNsheadMeta()
    //   nshead_req: the nshead request that server received.
    //   controller: you can set attachment into the controller. If something
    //               goes wrong, call controller->SetFailed()
    //   pb_req: the pb request should be set by your implementation.
    virtual void ParseRequestFromIOBuf(const NsheadMeta& meta,
                                       const NsheadMessage& nshead_req,
                                       Controller* controller,
                                       google::protobuf::Message* pb_req) const = 0;
    // Transform `pb_res' (and controller) to `nshead_res'.
    // Params:
    //   meta: was set by ParseNsheadMeta()
    //   controller: If something goes wrong, call controller->SetFailed()
    //   pb_res: the pb response that returned by pb method. [NOTE] `pb_res'
    //           can be NULL or uninitialized when RPC failed (indicated by
    //           Controller::Failed()), in which case you may put error
    //           information into `nshead_res'.
    //   nshead_res: the nshead response that will be sent back to client.
    virtual void SerializeResponseToIOBuf(const NsheadMeta& meta,
                                          Controller* controller,
                                          const google::protobuf::Message* pb_res,
                                          NsheadMessage* nshead_res) const = 0;
};