/* * * Copyright 2015 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_COMPLETION_QUEUE_TAG_H #define GRPCPP_IMPL_CODEGEN_COMPLETION_QUEUE_TAG_H namespace grpc { namespace internal { /// An interface allowing implementors to process and filter event tags. class CompletionQueueTag { public: virtual ~CompletionQueueTag() {} /// FinalizeResult must be called before informing user code that the /// operation bound to the underlying core completion queue tag has /// completed. In practice, this means: /// /// 1. For the sync API - before returning from Pluck /// 2. For the CQ-based async API - before returning from Next /// 3. For the callback-based API - before invoking the user callback /// /// This is the method that translates from core-side tag/status to /// C++ API-observable tag/status. /// /// The return value is the status of the operation (returning status is the /// general behavior of this function). If this function returns false, the /// tag is dropped and not returned from the completion queue: this concept is /// for events that are observed at core but not requested by the user /// application (e.g., server shutdown, for server unimplemented method /// responses, or for cases where a server-side RPC doesn't have a completion /// notification registered using AsyncNotifyWhenDone) virtual bool FinalizeResult(void** tag, bool* status) = 0; }; } // namespace internal } // namespace grpc #endif // GRPCPP_IMPL_CODEGEN_COMPLETION_QUEUE_TAG_H