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/*
*
* Copyright 2016 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_RPC_SERVICE_METHOD_H
#define GRPCPP_IMPL_CODEGEN_RPC_SERVICE_METHOD_H
#include <climits>
#include <functional>
#include <map>
#include <memory>
#include <vector>
#include <grpc/impl/codegen/log.h>
#include <grpcpp/impl/codegen/byte_buffer.h>
#include <grpcpp/impl/codegen/config.h>
#include <grpcpp/impl/codegen/rpc_method.h>
#include <grpcpp/impl/codegen/status.h>
namespace grpc {
class ServerContext;
namespace internal {
/// Base class for running an RPC handler.
class MethodHandler {
public:
virtual ~MethodHandler() {}
struct HandlerParameter {
/// Constructor for HandlerParameter
///
/// \param c : the gRPC Call structure for this server call
/// \param context : the ServerContext structure for this server call
/// \param req : the request payload, if appropriate for this RPC
/// \param req_status : the request status after any interceptors have run
/// \param rpc_requester : used only by the callback API. It is a function
/// called by the RPC Controller to request another RPC (and also
/// to set up the state required to make that request possible)
HandlerParameter(Call* c, ServerContext* context, void* req,
Status req_status, std::function<void()> requester)
: call(c),
server_context(context),
request(req),
status(req_status),
call_requester(std::move(requester)) {}
~HandlerParameter() {}
Call* call;
ServerContext* server_context;
void* request;
Status status;
std::function<void()> call_requester;
};
virtual void RunHandler(const HandlerParameter& param) = 0;
/* Returns a pointer to the deserialized request. \a status reflects the
result of deserialization. This pointer and the status should be filled in
a HandlerParameter and passed to RunHandler. It is illegal to access the
pointer after calling RunHandler. Ownership of the deserialized request is
retained by the handler. Returns nullptr if deserialization failed. */
virtual void* Deserialize(grpc_call* call, grpc_byte_buffer* req,
Status* status) {
GPR_CODEGEN_ASSERT(req == nullptr);
return nullptr;
}
};
/// Server side rpc method class
class RpcServiceMethod : public RpcMethod {
public:
/// Takes ownership of the handler
RpcServiceMethod(const char* name, RpcMethod::RpcType type,
MethodHandler* handler)
: RpcMethod(name, type),
server_tag_(nullptr),
api_type_(ApiType::SYNC),
handler_(handler) {}
enum class ApiType {
SYNC,
ASYNC,
RAW,
CALL_BACK, // not CALLBACK because that is reserved in Windows
RAW_CALL_BACK,
};
void set_server_tag(void* tag) { server_tag_ = tag; }
void* server_tag() const { return server_tag_; }
/// if MethodHandler is nullptr, then this is an async method
MethodHandler* handler() const { return handler_.get(); }
ApiType api_type() const { return api_type_; }
void SetHandler(MethodHandler* handler) { handler_.reset(handler); }
void SetServerApiType(RpcServiceMethod::ApiType type) {
if ((api_type_ == ApiType::SYNC) &&
(type == ApiType::ASYNC || type == ApiType::RAW)) {
// this marks this method as async
handler_.reset();
} else if (api_type_ != ApiType::SYNC) {
// this is not an error condition, as it allows users to declare a server
// like WithRawMethod_foo<AsyncService>. However since it
// overwrites behavior, it should be logged.
gpr_log(
GPR_INFO,
"You are marking method %s as '%s', even though it was "
"previously marked '%s'. This behavior will overwrite the original "
"behavior. If you expected this then ignore this message.",
name(), TypeToString(api_type_), TypeToString(type));
}
api_type_ = type;
}
private:
void* server_tag_;
ApiType api_type_;
std::unique_ptr<MethodHandler> handler_;
const char* TypeToString(RpcServiceMethod::ApiType type) {
switch (type) {
case ApiType::SYNC:
return "sync";
case ApiType::ASYNC:
return "async";
case ApiType::RAW:
return "raw";
case ApiType::CALL_BACK:
return "callback";
case ApiType::RAW_CALL_BACK:
return "raw_callback";
default:
GPR_UNREACHABLE_CODE(return "unknown");
}
}
};
} // namespace internal
} // namespace grpc
#endif // GRPCPP_IMPL_CODEGEN_RPC_SERVICE_METHOD_H
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