3 * Copyright 2015 gRPC authors.
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
9 * http://www.apache.org/licenses/LICENSE-2.0
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.
19 #ifndef GRPCPP_IMPL_CODEGEN_COMPLETION_QUEUE_TAG_H
20 #define GRPCPP_IMPL_CODEGEN_COMPLETION_QUEUE_TAG_H
22 // IWYU pragma: private
27 /// An interface allowing implementors to process and filter event tags.
28 class CompletionQueueTag {
30 virtual ~CompletionQueueTag() {}
32 /// FinalizeResult must be called before informing user code that the
33 /// operation bound to the underlying core completion queue tag has
34 /// completed. In practice, this means:
36 /// 1. For the sync API - before returning from Pluck
37 /// 2. For the CQ-based async API - before returning from Next
38 /// 3. For the callback-based API - before invoking the user callback
40 /// This is the method that translates from core-side tag/status to
41 /// C++ API-observable tag/status.
43 /// The return value is the status of the operation (returning status is the
44 /// general behavior of this function). If this function returns false, the
45 /// tag is dropped and not returned from the completion queue: this concept is
46 /// for events that are observed at core but not requested by the user
47 /// application (e.g., server shutdown, for server unimplemented method
48 /// responses, or for cases where a server-side RPC doesn't have a completion
49 /// notification registered using AsyncNotifyWhenDone)
50 virtual bool FinalizeResult(void** tag, bool* status) = 0;
52 } // namespace internal
56 #endif // GRPCPP_IMPL_CODEGEN_COMPLETION_QUEUE_TAG_H