| // |
| // |
| // Copyright 2019 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_SUPPORT_MESSAGE_ALLOCATOR_H |
| #define GRPCPP_SUPPORT_MESSAGE_ALLOCATOR_H |
| |
| namespace grpc { |
| |
| // NOTE: This is an API for advanced users who need custom allocators. |
| // Per rpc struct for the allocator. This is the interface to return to user. |
| class RpcAllocatorState { |
| public: |
| virtual ~RpcAllocatorState() = default; |
| // Optionally deallocate request early to reduce the size of working set. |
| // A custom MessageAllocator needs to be registered to make use of this. |
| // This is not abstract because implementing it is optional. |
| virtual void FreeRequest() {} |
| }; |
| |
| // This is the interface returned by the allocator. |
| // grpc library will call the methods to get request/response pointers and to |
| // release the object when it is done. |
| template <typename RequestT, typename ResponseT> |
| class MessageHolder : public RpcAllocatorState { |
| public: |
| // Release this object. For example, if the custom allocator's |
| // AllocateMessasge creates an instance of a subclass with new, the Release() |
| // should do a "delete this;". |
| virtual void Release() = 0; |
| RequestT* request() { return request_; } |
| ResponseT* response() { return response_; } |
| |
| protected: |
| void set_request(RequestT* request) { request_ = request; } |
| void set_response(ResponseT* response) { response_ = response; } |
| |
| private: |
| // NOTE: subclasses should set these pointers. |
| RequestT* request_; |
| ResponseT* response_; |
| }; |
| |
| // A custom allocator can be set via the generated code to a callback unary |
| // method, such as SetMessageAllocatorFor_Echo(custom_allocator). The allocator |
| // needs to be alive for the lifetime of the server. |
| // Implementations need to be thread-safe. |
| template <typename RequestT, typename ResponseT> |
| class MessageAllocator { |
| public: |
| virtual ~MessageAllocator() = default; |
| virtual MessageHolder<RequestT, ResponseT>* AllocateMessages() = 0; |
| }; |
| |
| } // namespace grpc |
| |
| #endif // GRPCPP_SUPPORT_MESSAGE_ALLOCATOR_H |