1 /* 2 * 3 * Copyright 2015 gRPC authors. 4 * 5 * Licensed under the Apache License, Version 2.0 (the "License"); 6 * you may not use this file except in compliance with the License. 7 * You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 * 17 */ 18 19 #ifndef GRPCPP_IMPL_CODEGEN_COMPLETION_QUEUE_TAG_H 20 #define GRPCPP_IMPL_CODEGEN_COMPLETION_QUEUE_TAG_H 21 22 namespace grpc { 23 24 namespace internal { 25 /// An interface allowing implementors to process and filter event tags. 26 class CompletionQueueTag { 27 public: 28 virtual ~CompletionQueueTag() {} 29 30 /// FinalizeResult must be called before informing user code that the 31 /// operation bound to the underlying core completion queue tag has 32 /// completed. In practice, this means: 33 /// 34 /// 1. For the sync API - before returning from Pluck 35 /// 2. For the CQ-based async API - before returning from Next 36 /// 3. For the callback-based API - before invoking the user callback 37 /// 38 /// This is the method that translates from core-side tag/status to 39 /// C++ API-observable tag/status. 40 /// 41 /// The return value is the status of the operation (returning status is the 42 /// general behavior of this function). If this function returns false, the 43 /// tag is dropped and not returned from the completion queue: this concept is 44 /// for events that are observed at core but not requested by the user 45 /// application (e.g., server shutdown, for server unimplemented method 46 /// responses, or for cases where a server-side RPC doesn't have a completion 47 /// notification registered using AsyncNotifyWhenDone) 48 virtual bool FinalizeResult(void** tag, bool* status) = 0; 49 }; 50 } // namespace internal 51 52 } // namespace grpc 53 54 #endif // GRPCPP_IMPL_CODEGEN_COMPLETION_QUEUE_TAG_H 55
