Google Cloud Pub/Sub C++ Client  1.32.1
A C++ Client Library for Google Cloud Pub/Sub
application_callback.h
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1 // Copyright 2020 Google LLC
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14 
15 #ifndef GOOGLE_CLOUD_CPP_GOOGLE_CLOUD_PUBSUB_APPLICATION_CALLBACK_H
16 #define GOOGLE_CLOUD_CPP_GOOGLE_CLOUD_PUBSUB_APPLICATION_CALLBACK_H
17 
18 #include "google/cloud/pubsub/version.h"
19 #include <functional>
20 
21 namespace google {
22 namespace cloud {
23 namespace pubsub {
24 inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
25 class Message;
26 class AckHandler;
27 
28 /**
29  * Defines the interface for application-level callbacks.
30  *
31  * Applications provide a callable compatible with this type to receive
32  * messages. They acknowledge (or reject) messages using `AckHandler`. This is
33  * a move-only type to support asynchronously acknowledgments.
34  */
35 using ApplicationCallback = std::function<void(Message, AckHandler)>;
36 
37 } // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
38 } // namespace pubsub
39 } // namespace cloud
40 } // namespace google
41 
42 #endif // GOOGLE_CLOUD_CPP_GOOGLE_CLOUD_PUBSUB_APPLICATION_CALLBACK_H