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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"
#ifdef __cplusplus
extern "C" {
#endif
typedef struct {
/// const: how long to wait after the first failure before retrying
grpc_millis initial_backoff;
/// const: factor with which to multiply backoff after a failed retry
double multiplier;
/// const: amount to randomize backoffs
double jitter;
/// const: minimum time between retries
grpc_millis min_connect_timeout;
/// const: maximum time between retries
grpc_millis max_backoff;
/// current delay before retries
grpc_millis current_backoff;
/// random number generator
uint32_t rng_state;
} grpc_backoff;
typedef struct {
/// Deadline to be used for the current attempt.
grpc_millis current_deadline;
/// Deadline to be used for the next attempt, following the backoff strategy.
grpc_millis next_attempt_start_time;
} grpc_backoff_result;
/// Initialize backoff machinery - does not need to be destroyed
void grpc_backoff_init(grpc_backoff* backoff, grpc_millis initial_backoff,
double multiplier, double jitter,
grpc_millis min_connect_timeout,
grpc_millis max_backoff);
/// Begin retry loop: returns the deadlines to be used for the current attempt
/// and the subsequent retry, if any.
grpc_backoff_result grpc_backoff_begin(grpc_exec_ctx* exec_ctx,
grpc_backoff* backoff);
/// Step a retry loop: returns the deadlines to be used for the current attempt
/// and the subsequent retry, if any.
grpc_backoff_result grpc_backoff_step(grpc_exec_ctx* exec_ctx,
grpc_backoff* backoff);
/// Reset the backoff, so the next grpc_backoff_step will be a
/// grpc_backoff_begin.
void grpc_backoff_reset(grpc_backoff* backoff);
#ifdef __cplusplus
}
#endif
#endif /* GRPC_CORE_LIB_BACKOFF_BACKOFF_H */
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