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Diffstat (limited to 'include/grpcpp/alarm_impl.h')
-rw-r--r-- | include/grpcpp/alarm_impl.h | 116 |
1 files changed, 116 insertions, 0 deletions
diff --git a/include/grpcpp/alarm_impl.h b/include/grpcpp/alarm_impl.h new file mode 100644 index 0000000000..7844e7c886 --- /dev/null +++ b/include/grpcpp/alarm_impl.h @@ -0,0 +1,116 @@ +/* + * + * 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. + * + */ + +/// An Alarm posts the user provided tag to its associated completion queue upon +/// expiry or cancellation. +#ifndef GRPCPP_ALARM_IMPL_H +#define GRPCPP_ALARM_IMPL_H + +#include <functional> + +#include <grpc/grpc.h> +#include <grpcpp/impl/codegen/completion_queue.h> +#include <grpcpp/impl/codegen/completion_queue_tag.h> +#include <grpcpp/impl/codegen/grpc_library.h> +#include <grpcpp/impl/codegen/time.h> +#include <grpcpp/impl/grpc_library.h> + +namespace grpc_impl { + +/// A thin wrapper around \a grpc_alarm (see / \a / src/core/surface/alarm.h). +class Alarm : private ::grpc::GrpcLibraryCodegen { + public: + /// Create an unset completion queue alarm + Alarm(); + + /// Destroy the given completion queue alarm, cancelling it in the process. + ~Alarm(); + + /// DEPRECATED: Create and set a completion queue alarm instance associated to + /// \a cq. + /// This form is deprecated because it is inherently racy. + /// \internal We rely on the presence of \a cq for grpc initialization. If \a + /// cq were ever to be removed, a reference to a static + /// internal::GrpcLibraryInitializer instance would need to be introduced + /// here. \endinternal. + template <typename T> + Alarm(::grpc::CompletionQueue* cq, const T& deadline, void* tag) : Alarm() { + SetInternal(cq, ::grpc::TimePoint<T>(deadline).raw_time(), tag); + } + + /// Trigger an alarm instance on completion queue \a cq at the specified time. + /// Once the alarm expires (at \a deadline) or it's cancelled (see \a Cancel), + /// an event with tag \a tag will be added to \a cq. If the alarm expired, the + /// event's success bit will be true, false otherwise (ie, upon cancellation). + template <typename T> + void Set(::grpc::CompletionQueue* cq, const T& deadline, void* tag) { + SetInternal(cq, ::grpc::TimePoint<T>(deadline).raw_time(), tag); + } + + /// Alarms aren't copyable. + Alarm(const Alarm&) = delete; + Alarm& operator=(const Alarm&) = delete; + + /// Alarms are movable. + Alarm(Alarm&& rhs) : alarm_(rhs.alarm_) { rhs.alarm_ = nullptr; } + Alarm& operator=(Alarm&& rhs) { + alarm_ = rhs.alarm_; + rhs.alarm_ = nullptr; + return *this; + } + + /// Cancel a completion queue alarm. Calling this function over an alarm that + /// has already fired has no effect. + void Cancel(); + + /// NOTE: class experimental_type is not part of the public API of this class + /// TODO(vjpai): Move these contents to the public API of Alarm when + /// they are no longer experimental + class experimental_type { + public: + explicit experimental_type(Alarm* alarm) : alarm_(alarm) {} + + /// Set an alarm to invoke callback \a f. The argument to the callback + /// states whether the alarm expired at \a deadline (true) or was cancelled + /// (false) + template <typename T> + void Set(const T& deadline, std::function<void(bool)> f) { + alarm_->SetInternal(::grpc::TimePoint<T>(deadline).raw_time(), + std::move(f)); + } + + private: + Alarm* alarm_; + }; + + /// NOTE: The function experimental() is not stable public API. It is a view + /// to the experimental components of this class. It may be changed or removed + /// at any time. + experimental_type experimental() { return experimental_type(this); } + + private: + void SetInternal(::grpc::CompletionQueue* cq, gpr_timespec deadline, + void* tag); + void SetInternal(gpr_timespec deadline, std::function<void(bool)> f); + + ::grpc::internal::CompletionQueueTag* alarm_; +}; + +} // namespace grpc_impl + +#endif // GRPCPP_ALARM_IMPL_H |