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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 XPCOM_THREADS_TARGETSHUTDOWNTASKSET_H_
#define XPCOM_THREADS_TARGETSHUTDOWNTASKSET_H_
#include "mozilla/LinkedList.h"
#include "nsITargetShutdownTask.h"
class nsIRunnable;
// TargetShutdownTaskSet manages a set of nsITargetShutdownTask.
// It keeps a strong reference on added tasks until they are either Remove(d)
// or Extract(ed).
class TargetShutdownTaskSet {
public:
using TasksList = mozilla::LinkedList<RefPtr<nsITargetShutdownTask>>;
using TasksArray = AutoTArray<nsCOMPtr<nsITargetShutdownTask>, 8>;
TargetShutdownTaskSet() = default;
TargetShutdownTaskSet(TargetShutdownTaskSet&& aOther) = default;
TargetShutdownTaskSet(TargetShutdownTaskSet& aOther) = delete;
// Add a task to the set and keep it owned. The caller can forget it if
// it is not interested in being ever able to remove it.
// Returns NS_ERROR_UNEXPECTED if the task is already in a
// TargetShutdownTaskSet.
nsresult AddTask(nsITargetShutdownTask* aTask) {
MOZ_ASSERT(aTask);
MOZ_ASSERT(!mShutdownTasksTaken);
if (aTask->isInList()) {
MOZ_ASSERT_UNREACHABLE(
"A shutdown task can only be registered to one target.");
return NS_ERROR_UNEXPECTED;
}
mShutdownTasks.insertBack(aTask);
++mShutdownTaskCount;
return NS_OK;
}
// Remove a task from the set, based on its pointer value.
// Returns NS_ERROR_UNEXPECTED if the task is not found.
// Note that RemoveTask releases the set's owning reference on aTask in case
// it was found.
nsresult RemoveTask(nsITargetShutdownTask* aTask) {
MOZ_ASSERT(aTask);
if (!aTask->isInList()) {
return NS_ERROR_UNEXPECTED;
}
aTask->removeFrom(mShutdownTasks);
--mShutdownTaskCount;
return NS_OK;
}
// Returns an array with owning pointers of all tasks. This must be called
// only once. It's the caller's duty to decide how to run them.
inline TasksArray Extract() {
MOZ_ASSERT(!mShutdownTasksTaken);
TasksArray ret;
ret.SetCapacity(mShutdownTaskCount);
while (!mShutdownTasks.isEmpty()) {
auto task = mShutdownTasks.popFirst();
ret.AppendElement(std::move(task));
}
mShutdownTaskCount = 0;
#ifdef DEBUG
mShutdownTasksTaken = true;
#endif
return ret;
}
bool IsEmpty() { return mShutdownTasks.isEmpty(); }
~TargetShutdownTaskSet() { MOZ_ASSERT(mShutdownTasks.isEmpty()); }
private:
TasksList mShutdownTasks;
uint32_t mShutdownTaskCount{0};
#ifdef DEBUG
bool mShutdownTasksTaken{false};
#endif
};
#endif
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