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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef DOM_QUOTA_ARTIFICIALFAILURE_H_
#define DOM_QUOTA_ARTIFICIALFAILURE_H_
#include <cstdint>
#include "nsIQuotaArtificialFailure.h"
enum class nsresult : uint32_t;
namespace mozilla {
struct Ok;
template <typename V, typename E>
class Result;
} // namespace mozilla
namespace mozilla::dom::quota {
/**
* Checks if an artificial failure should be triggered based on the specified
* category and the configured probability.
*
* This method evaluates if the provided failure category matches the
* categories set in the preferences. If a match is found, it then checks
* the probability of triggering an artificial failure. A random value is
* generated to determine if the failure should occur based on this
* probability. If both the category matches and the random value falls within
* the defined probability, the method returns an error code indicating the
* artificial failure. Otherwise, it returns a successful result.
*
* @param aCategory - The failure category to check against the configured
* categories for triggering an artificial failure. It must have only one bit
* set.
* @returns Result<Ok, nsresult> - An Ok result if no failure occurs; an Err
* result containing an error code if an artificial failure is triggered.
*
* Note:
* Consider replacing the preferences with a dedicated class with static
* methods for entering and leaving artificial failure mode, something like
* `ChaosMode`. The class would also implement an interface, for example
* `nsIQuotaArtificialFailure` allowing access from scripts.
*
* Example usage:
* This example demonstrates the usage of `ArtificialFailure` in conjunction
* with the `QM_TRY` macro to handle potential artificial failures gracefully.
* The `QM_TRY` macro will return early if an artificial failure occurs, with
* the corresponding error code from `ArtificialFailure`.
*
* ```cpp
* QM_TRY(ArtificialFailure(
* nsIQuotaArtificialFailure::CATEGORY_INITIALIZE_ORIGIN));
* ```
*/
Result<Ok, nsresult> ArtificialFailure(
nsIQuotaArtificialFailure::Category aCategory);
} // namespace mozilla::dom::quota
#endif // DOM_QUOTA_ARTIFICIALFAILURE_H_
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