interceptor.h

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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_INTERCEPTOR_H
#define GRPCPP_IMPL_CODEGEN_INTERCEPTOR_H

#include <grpc/impl/codegen/grpc_types.h>
#include <grpcpp/impl/codegen/byte_buffer.h>
#include <grpcpp/impl/codegen/config.h>
#include <grpcpp/impl/codegen/core_codegen_interface.h>
#include <grpcpp/impl/codegen/metadata_map.h>

namespace grpc {

class ChannelInterface;
class Status;

namespace experimental {

enum class InterceptionHookPoints {
  PRE_SEND_INITIAL_METADATA,
  PRE_SEND_MESSAGE,
  PRE_SEND_STATUS,  // server only
  PRE_SEND_CLOSE,   // client only: WritesDone for stream; after write in unary
  PRE_RECV_INITIAL_METADATA,
  PRE_RECV_MESSAGE,
  PRE_RECV_STATUS,
  POST_RECV_INITIAL_METADATA,
  POST_RECV_MESSAGE,
  POST_RECV_STATUS,  // client only
  POST_RECV_CLOSE,   // server only
  PRE_SEND_CANCEL,
  NUM_INTERCEPTION_HOOKS
};

class InterceptorBatchMethods {
 public:
  virtual ~InterceptorBatchMethods(){};
  virtual bool QueryInterceptionHookPoint(InterceptionHookPoints type) = 0;
  virtual void Proceed() = 0;
  virtual void Hijack() = 0;

  virtual ByteBuffer* GetSendMessage() = 0;

  virtual std::multimap<grpc::string, grpc::string>*
  GetSendInitialMetadata() = 0;

  virtual Status GetSendStatus() = 0;

  virtual void ModifySendStatus(const Status& status) = 0;

  virtual std::multimap<grpc::string, grpc::string>*
  GetSendTrailingMetadata() = 0;

  virtual void* GetRecvMessage() = 0;

  virtual std::multimap<grpc::string_ref, grpc::string_ref>*
  GetRecvInitialMetadata() = 0;

  virtual Status* GetRecvStatus() = 0;

  virtual std::multimap<grpc::string_ref, grpc::string_ref>*
  GetRecvTrailingMetadata() = 0;

  virtual std::unique_ptr<ChannelInterface> GetInterceptedChannel() = 0;
};

class Interceptor {
 public:
  virtual ~Interceptor() {}

  virtual void Intercept(InterceptorBatchMethods* methods) = 0;
};

}  // namespace experimental
}  // namespace grpc

#endif  // GRPCPP_IMPL_CODEGEN_INTERCEPTOR_H