Muxi Yan | 0e00c43 | 2018-01-26 15:39:32 -0800 | [diff] [blame] | 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 | /// An Alarm posts the user provided tag to its associated completion queue upon |
| 20 | /// expiry or cancellation. |
| 21 | #ifndef GRPCPP_ALARM_H |
| 22 | #define GRPCPP_ALARM_H |
| 23 | |
| 24 | #include <grpc/grpc.h> |
| 25 | #include <grpcpp/impl/codegen/completion_queue.h> |
| 26 | #include <grpcpp/impl/codegen/completion_queue_tag.h> |
| 27 | #include <grpcpp/impl/codegen/grpc_library.h> |
| 28 | #include <grpcpp/impl/codegen/time.h> |
| 29 | #include <grpcpp/impl/grpc_library.h> |
| 30 | |
| 31 | namespace grpc { |
| 32 | |
| 33 | /// A thin wrapper around \a grpc_alarm (see / \a / src/core/surface/alarm.h). |
| 34 | class Alarm : private GrpcLibraryCodegen { |
| 35 | public: |
| 36 | /// Create an unset completion queue alarm |
| 37 | Alarm(); |
| 38 | |
| 39 | /// Destroy the given completion queue alarm, cancelling it in the process. |
| 40 | ~Alarm(); |
| 41 | |
| 42 | /// DEPRECATED: Create and set a completion queue alarm instance associated to |
| 43 | /// \a cq. |
| 44 | /// This form is deprecated because it is inherently racy. |
| 45 | /// \internal We rely on the presence of \a cq for grpc initialization. If \a |
| 46 | /// cq were ever to be removed, a reference to a static |
| 47 | /// internal::GrpcLibraryInitializer instance would need to be introduced |
| 48 | /// here. \endinternal. |
| 49 | template <typename T> |
| 50 | Alarm(CompletionQueue* cq, const T& deadline, void* tag) : Alarm() { |
| 51 | SetInternal(cq, TimePoint<T>(deadline).raw_time(), tag); |
| 52 | } |
| 53 | |
| 54 | /// Trigger an alarm instance on completion queue \a cq at the specified time. |
| 55 | /// Once the alarm expires (at \a deadline) or it's cancelled (see \a Cancel), |
| 56 | /// an event with tag \a tag will be added to \a cq. If the alarm expired, the |
| 57 | /// event's success bit will be true, false otherwise (ie, upon cancellation). |
| 58 | template <typename T> |
| 59 | void Set(CompletionQueue* cq, const T& deadline, void* tag) { |
| 60 | SetInternal(cq, TimePoint<T>(deadline).raw_time(), tag); |
| 61 | } |
| 62 | |
| 63 | /// Alarms aren't copyable. |
| 64 | Alarm(const Alarm&) = delete; |
| 65 | Alarm& operator=(const Alarm&) = delete; |
| 66 | |
| 67 | /// Alarms are movable. |
| 68 | Alarm(Alarm&& rhs) : alarm_(rhs.alarm_) { rhs.alarm_ = nullptr; } |
| 69 | Alarm& operator=(Alarm&& rhs) { |
| 70 | alarm_ = rhs.alarm_; |
| 71 | rhs.alarm_ = nullptr; |
| 72 | return *this; |
| 73 | } |
| 74 | |
| 75 | /// Cancel a completion queue alarm. Calling this function over an alarm that |
| 76 | /// has already fired has no effect. |
| 77 | void Cancel(); |
| 78 | |
| 79 | private: |
| 80 | void SetInternal(CompletionQueue* cq, gpr_timespec deadline, void* tag); |
| 81 | |
| 82 | internal::CompletionQueueTag* alarm_; |
| 83 | }; |
| 84 | |
| 85 | } // namespace grpc |
| 86 | |
| 87 | #endif // GRPCPP_ALARM_H |