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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_THREADUTILS_H_
#define DOM_QUOTA_THREADUTILS_H_
#include <cstdint>
#include <functional>
#include "mozilla/StaticPrefsBase.h"
enum class nsresult : uint32_t;
namespace mozilla::dom::quota {
/**
* Add a temporary thread observer and listen for the "AfterProcessNextEvent"
* notification. Once the notification is received, remove the temporary thread
* observer and call aCallback.
* In practice, this calls aCallback immediately after the current thread is
* done with running and releasing recently popped event from thread's event
* queue.
* If called multiple times, all the callbacks will be executed, in the
* order in which RunAfterProcessingCurrentEvent() was called.
* Use this method if you need to dispatch the same or some other runnable to
* another thread in a way which prevents any race conditions (for example
* unpredictable releases of objects).
* This method should be used only in existing code which can't be easily
* converted to use MozPromise which doesn't have the problem with
* unpredictable releases of objects, see:
* https://searchfox.org/mozilla-central/rev/4582d908c17fbf7924f5699609fe4a12c28ddc4a/xpcom/threads/MozPromise.h#866
*
* Note: Calling this method from a thread pool is not supported since thread
* pools don't fire the "AfterProcessNextEvent" notification. The method has
* a diagnostic assertion for that so any calls like that will be caught
* in builds with enabled diagnostic assertions. The callback will never
* get executed in other builds, such as release builds. The limitation can
* be removed completely when thread pool implementation gets support for firing
* the "AfterProcessNextEvent".
*/
nsresult RunAfterProcessingCurrentEvent(std::function<void()>&& aCallback);
/**
* Causes the current thread to yield for a specified amount of milliseconds if
* a mirrored preference value is not zero.
*
* @param aMirroredPrefValue
* A mirrored preference value. If this value is greater than zero, the
* function will cause the current thread to sleep for that number of
* milliseconds.
*/
void SleepIfEnabled(StripAtomic<RelaxedAtomicUint32> aMirroredPrefValue);
} // namespace mozilla::dom::quota
#endif // DOM_QUOTA_THREADUTILS_H_
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