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/*
*
* Copyright 2016 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.
*
*/
#ifndef GRPC_CORE_LIB_BACKOFF_BACKOFF_H
#define GRPC_CORE_LIB_BACKOFF_BACKOFF_H
#include "src/core/lib/iomgr/exec_ctx.h"
namespace grpc_core {
/// Implementation of the backoff mechanism described in
/// doc/connection-backoff.md
class BackOff {
public:
class Options;
/// Initialize backoff machinery - does not need to be destroyed
explicit BackOff(const Options& options);
/// Returns the time at which the next attempt should start.
grpc_millis NextAttemptTime();
/// Reset the backoff, so the next value returned by NextAttemptTime()
/// will be the time of the second attempt (rather than the Nth).
void Reset();
void SetRandomSeed(unsigned int seed);
class Options {
public:
Options& set_initial_backoff(grpc_millis initial_backoff) {
initial_backoff_ = initial_backoff;
return *this;
}
Options& set_multiplier(double multiplier) {
multiplier_ = multiplier;
return *this;
}
Options& set_jitter(double jitter) {
jitter_ = jitter;
return *this;
}
Options& set_max_backoff(grpc_millis max_backoff) {
max_backoff_ = max_backoff;
return *this;
}
/// how long to wait after the first failure before retrying
grpc_millis initial_backoff() const { return initial_backoff_; }
/// factor with which to multiply backoff after a failed retry
double multiplier() const { return multiplier_; }
/// amount to randomize backoffs
double jitter() const { return jitter_; }
/// maximum time between retries
grpc_millis max_backoff() const { return max_backoff_; }
private:
grpc_millis initial_backoff_;
double multiplier_;
double jitter_;
grpc_millis max_backoff_;
}; // class Options
private:
const Options options_;
uint32_t rng_state_;
bool initial_;
/// current delay before retries
grpc_millis current_backoff_;
};
} // namespace grpc_core
#endif /* GRPC_CORE_LIB_BACKOFF_BACKOFF_H */
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