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/*
*
* Copyright 2015, Google Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
/// An Alarm posts the user provided tag to its associated completion queue upon
/// expiry or cancellation.
#ifndef GRPCXX_ALARM_H
#define GRPCXX_ALARM_H
#include <grpc++/impl/codegen/completion_queue.h>
#include <grpc++/impl/codegen/completion_queue_tag.h>
#include <grpc++/impl/codegen/grpc_library.h>
#include <grpc++/impl/codegen/time.h>
#include <grpc++/impl/grpc_library.h>
#include <grpc/grpc.h>
struct grpc_alarm;
namespace grpc {
class CompletionQueue;
/// A thin wrapper around \a grpc_alarm (see / \a / src/core/surface/alarm.h).
class Alarm : private GrpcLibraryCodegen {
public:
/// Create a completion queue alarm instance associated to \a cq.
///
/// 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).
/// \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(CompletionQueue* cq, const T& deadline, void* tag)
: tag_(tag),
alarm_(grpc_alarm_create(cq->cq(), TimePoint<T>(deadline).raw_time(),
static_cast<void*>(&tag_))) {}
/// Destroy the given completion queue alarm, cancelling it in the process.
~Alarm() { grpc_alarm_destroy(alarm_); }
/// Cancel a completion queue alarm. Calling this function over an alarm that
/// has already fired has no effect.
void Cancel() { grpc_alarm_cancel(alarm_); }
private:
class AlarmEntry : public CompletionQueueTag {
public:
AlarmEntry(void* tag) : tag_(tag) {}
bool FinalizeResult(void** tag, bool* status) GRPC_OVERRIDE {
*tag = tag_;
return true;
}
private:
void* tag_;
};
AlarmEntry tag_;
grpc_alarm* const alarm_; // owned
};
} // namespace grpc
#endif // GRPCXX_ALARM_H
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