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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=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,
#include "MediaUtils.h"
#include "mozilla/AppShutdown.h"
#include "mozilla/Services.h"
namespace mozilla::media {
nsCOMPtr<nsIAsyncShutdownClient> GetShutdownBarrier() {
nsCOMPtr<nsIAsyncShutdownService> svc = services::GetAsyncShutdownService();
if (!svc) {
// We can fail to get the shutdown service if we're already shutting down.
return nullptr;
}
nsCOMPtr<nsIAsyncShutdownClient> barrier;
nsresult rv = svc->GetProfileBeforeChange(getter_AddRefs(barrier));
if (!barrier) {
// We are probably in a content process. We need to do cleanup at
// XPCOM shutdown in leakchecking builds.
rv = svc->GetXpcomWillShutdown(getter_AddRefs(barrier));
}
MOZ_RELEASE_ASSERT(NS_SUCCEEDED(rv));
MOZ_RELEASE_ASSERT(barrier);
return barrier;
}
nsCOMPtr<nsIAsyncShutdownClient> MustGetShutdownBarrier() {
nsCOMPtr<nsIAsyncShutdownClient> barrier = GetShutdownBarrier();
MOZ_RELEASE_ASSERT(barrier);
return barrier;
}
NS_IMPL_ISUPPORTS(ShutdownBlocker, nsIAsyncShutdownBlocker)
namespace {
class TicketBlocker : public ShutdownBlocker {
using ShutdownMozPromise = ShutdownBlockingTicket::ShutdownMozPromise;
public:
explicit TicketBlocker(const nsAString& aName)
: ShutdownBlocker(aName), mPromise(mHolder.Ensure(__func__)) {}
NS_IMETHOD
BlockShutdown(nsIAsyncShutdownClient* aProfileBeforeChange) override {
mHolder.Resolve(true, __func__);
return NS_OK;
}
void RejectIfExists() { mHolder.RejectIfExists(false, __func__); }
ShutdownMozPromise* ShutdownPromise() { return mPromise; }
private:
~TicketBlocker() = default;
MozPromiseHolder<ShutdownMozPromise> mHolder;
const RefPtr<ShutdownMozPromise> mPromise;
};
class ShutdownBlockingTicketImpl : public ShutdownBlockingTicket {
private:
RefPtr<TicketBlocker> mBlocker;
public:
explicit ShutdownBlockingTicketImpl(RefPtr<TicketBlocker> aBlocker)
: mBlocker(std::move(aBlocker)) {}
static UniquePtr<ShutdownBlockingTicket> Create(const nsAString& aName,
const nsAString& aFileName,
int32_t aLineNr) {
auto blocker = MakeRefPtr<TicketBlocker>(aName);
NS_DispatchToMainThread(NS_NewRunnableFunction(
"ShutdownBlockingTicketImpl::AddBlocker",
[blocker, file = nsString(aFileName), aLineNr] {
MustGetShutdownBarrier()->AddBlocker(blocker, file, aLineNr, u""_ns);
}));
if (AppShutdown::IsInOrBeyond(ShutdownPhase::AppShutdown)) {
// Adding a blocker is not guaranteed to succeed. Remove the blocker in
// case it succeeded anyway, and bail.
NS_DispatchToMainThread(NS_NewRunnableFunction(
"ShutdownBlockingTicketImpl::RemoveBlocker", [blocker] {
MustGetShutdownBarrier()->RemoveBlocker(blocker);
blocker->RejectIfExists();
}));
return nullptr;
}
// Adding a blocker is now guaranteed to succeed:
// - If AppShutdown::IsInOrBeyond(AppShutdown) returned false,
// - then the AddBlocker main thread task was queued before AppShutdown's
// sCurrentShutdownPhase is set to ShutdownPhase::AppShutdown,
// - which is before AppShutdown will drain the (main thread) event queue to
// run the AddBlocker task, if not already run,
// - which is before profile-before-change (the earliest barrier we'd add a
// blocker to, see GetShutdownBarrier()) is notified,
// - which is when AsyncShutdown prevents further conditions (blockers)
// being added to the profile-before-change barrier.
return MakeUnique<ShutdownBlockingTicketImpl>(std::move(blocker));
}
~ShutdownBlockingTicketImpl() {
MOZ_ALWAYS_SUCCEEDS(NS_DispatchToMainThread(
NS_NewRunnableFunction(__func__, [blocker = std::move(mBlocker)] {
GetShutdownBarrier()->RemoveBlocker(blocker);
blocker->RejectIfExists();
})));
}
ShutdownMozPromise* ShutdownPromise() override {
return mBlocker->ShutdownPromise();
}
};
} // namespace
UniquePtr<ShutdownBlockingTicket> ShutdownBlockingTicket::Create(
const nsAString& aName, const nsAString& aFileName, int32_t aLineNr) {
return ShutdownBlockingTicketImpl::Create(aName, aFileName, aLineNr);
}
} // namespace mozilla::media