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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/. */
#include "MemoryPressureObserver.h"
#include "mozilla/Services.h"
#include "nsCOMPtr.h"
#include "nsDependentString.h"
#include "nsIObserverService.h"
#include "nsLiteralString.h"
namespace mozilla {
namespace layers {
MemoryPressureObserver::MemoryPressureObserver(
MemoryPressureListener* aListener)
: mListener(aListener) {}
MemoryPressureObserver::~MemoryPressureObserver() {
// If this assertion is hit we probably forgot to unregister the observer.
MOZ_ASSERT(!mListener);
}
already_AddRefed<MemoryPressureObserver> MemoryPressureObserver::Create(
MemoryPressureListener* aListener) {
nsCOMPtr<nsIObserverService> service = services::GetObserverService();
if (!service) {
return nullptr;
}
RefPtr<MemoryPressureObserver> observer =
new MemoryPressureObserver(aListener);
bool useWeakRef = false;
service->AddObserver(observer, "memory-pressure", useWeakRef);
return observer.forget();
}
void MemoryPressureObserver::Unregister() {
if (!mListener) {
return;
}
nsCOMPtr<nsIObserverService> service = services::GetObserverService();
if (service) {
service->RemoveObserver(this, "memory-pressure");
}
mListener = nullptr;
}
NS_IMETHODIMP
MemoryPressureObserver::Observe(nsISupports* aSubject, const char* aTopic,
const char16_t* aData) {
if (mListener && strcmp(aTopic, "memory-pressure") == 0) {
MemoryPressureReason reason = MemoryPressureReason::LOW_MEMORY;
auto reason_string = nsDependentString(aData);
if (StringBeginsWith(reason_string, u"low-memory-ongoing"_ns)) {
reason = MemoryPressureReason::LOW_MEMORY_ONGOING;
} else if (StringBeginsWith(reason_string, u"heap-minimize"_ns)) {
reason = MemoryPressureReason::HEAP_MINIMIZE;
}
mListener->OnMemoryPressure(reason);
}
return NS_OK;
}
NS_IMPL_ISUPPORTS(MemoryPressureObserver, nsIObserver)
} // namespace layers
} // namespace mozilla
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