6024e5c395
clang 20.0.0 (based on r547379) from build 12806354. Bug: http://b/379133546 Test: N/A Change-Id: I2eb8938af55d809de674be63cb30cf27e801862b Upstream-Commit: ad834e67b1105d15ef907f6255d4c96e8e733f57
66 lines
2.1 KiB
C++
66 lines
2.1 KiB
C++
//===- llvm/Support/ExponentialBackoff.h ------------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines a helper class for implementing exponential backoff.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_EXPONENTIALBACKOFF_H
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#define LLVM_EXPONENTIALBACKOFF_H
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/Support/Error.h"
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#include <chrono>
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#include <random>
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namespace llvm {
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/// A class to help implement exponential backoff.
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///
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/// Example usage:
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/// \code
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/// ExponentialBackoff Backoff(10s);
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/// do {
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/// if (tryToDoSomething())
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/// return ItWorked;
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/// } while (Backoff.waitForNextAttempt());
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/// return Timeout;
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/// \endcode
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class ExponentialBackoff {
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public:
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using duration = std::chrono::steady_clock::duration;
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using time_point = std::chrono::steady_clock::time_point;
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/// \param Timeout the maximum wall time this should run for starting when
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/// this object is constructed.
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/// \param MinWait the minimum amount of time `waitForNextAttempt` will sleep
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/// for.
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/// \param MaxWait the maximum amount of time `waitForNextAttempt` will sleep
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/// for.
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ExponentialBackoff(duration Timeout,
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duration MinWait = std::chrono::milliseconds(10),
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duration MaxWait = std::chrono::milliseconds(500))
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: MinWait(MinWait), MaxWait(MaxWait),
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EndTime(std::chrono::steady_clock::now() + Timeout) {}
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/// Blocks while waiting for the next attempt.
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/// \returns true if you should try again, false if the timeout has been
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/// reached.
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bool waitForNextAttempt();
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private:
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duration MinWait;
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duration MaxWait;
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time_point EndTime;
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std::random_device RandDev;
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int64_t CurrentMultiplier = 1;
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};
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} // end namespace llvm
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#endif // LLVM_EXPONENTIALBACKOFF_H
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