gecko-dev/dom/serviceworkers/ServiceWorkerShutdownBlocker.h

93 строки
2.6 KiB
C++

/* -*- 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 mozilla_dom_serviceworkershutdownblocker_h__
#define mozilla_dom_serviceworkershutdownblocker_h__
#include "nsCOMPtr.h"
#include "nsIAsyncShutdown.h"
#include "nsISupportsImpl.h"
#include "mozilla/MozPromise.h"
namespace mozilla {
namespace dom {
/**
* Main thread only.
*/
class ServiceWorkerShutdownBlocker final : public nsIAsyncShutdownBlocker {
public:
NS_DECL_ISUPPORTS
NS_DECL_NSIASYNCSHUTDOWNBLOCKER
/**
* Returns the registered shutdown blocker if registration succeeded and
* nullptr otherwise.
*/
static already_AddRefed<ServiceWorkerShutdownBlocker> CreateAndRegisterOn(
nsIAsyncShutdownClient* aShutdownBarrier);
/**
* Blocks shutdown until `aPromise` settles.
*
* Can be called multiple times, and shutdown will be blocked until all the
* calls' promises settle, but all of these calls must happen before
* `StopAcceptingPromises()` is called (assertions will enforce this).
*/
void WaitOnPromise(GenericNonExclusivePromise* aPromise);
/**
* Once this is called, shutdown will be blocked until all promises
* passed to `WaitOnPromise()` settle, and there must be no more calls to
* `WaitOnPromise()` (assertions will enforce this).
*/
void StopAcceptingPromises();
private:
ServiceWorkerShutdownBlocker();
~ServiceWorkerShutdownBlocker();
/**
* No-op if any of the following are true:
* 1) `BlockShutdown()` hasn't been called yet, or
* 2) `StopAcceptingPromises()` hasn't been called yet, or
* 3) `StopAcceptingPromises()` HAS been called, but there are still pending
* promises.
*/
void MaybeUnblockShutdown();
/**
* Returns the remaining pending promise count (i.e. excluding the promise
* that just settled).
*/
uint32_t PromiseSettled();
bool IsAcceptingPromises() const;
uint32_t GetPendingPromises() const;
struct AcceptingPromises {
uint32_t mPendingPromises = 0;
};
struct NotAcceptingPromises {
explicit NotAcceptingPromises(AcceptingPromises aPreviousState);
uint32_t mPendingPromises = 0;
};
Variant<AcceptingPromises, NotAcceptingPromises> mState;
nsCOMPtr<nsIAsyncShutdownClient> mShutdownClient;
};
} // namespace dom
} // namespace mozilla
#endif // mozilla_dom_serviceworkershutdownblocker_h__