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			77 lines
		
	
	
	
		
			2.2 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			77 lines
		
	
	
	
		
			2.2 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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 * License, v. 2.0. If a copy of the MPL was not distributed with this
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 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "MemoryPressureObserver.h"
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#include "mozilla/Services.h"
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#include "nsCOMPtr.h"
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#include "nsDependentString.h"
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#include "nsIObserverService.h"
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#include "nsLiteralString.h"
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namespace mozilla {
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namespace layers {
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MemoryPressureObserver::MemoryPressureObserver(
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    MemoryPressureListener* aListener)
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    : mListener(aListener) {}
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MemoryPressureObserver::~MemoryPressureObserver() {
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  // If this assertion is hit we probably forgot to unregister the observer.
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  MOZ_ASSERT(!mListener);
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}
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already_AddRefed<MemoryPressureObserver> MemoryPressureObserver::Create(
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    MemoryPressureListener* aListener) {
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  nsCOMPtr<nsIObserverService> service = services::GetObserverService();
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  if (!service) {
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    return nullptr;
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  }
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  RefPtr<MemoryPressureObserver> observer =
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      new MemoryPressureObserver(aListener);
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  bool useWeakRef = false;
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  service->AddObserver(observer, "memory-pressure", useWeakRef);
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  return observer.forget();
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}
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void MemoryPressureObserver::Unregister() {
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  if (!mListener) {
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    return;
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  }
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  nsCOMPtr<nsIObserverService> service = services::GetObserverService();
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  if (service) {
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    service->RemoveObserver(this, "memory-pressure");
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  }
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  mListener = nullptr;
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}
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NS_IMETHODIMP
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MemoryPressureObserver::Observe(nsISupports* aSubject, const char* aTopic,
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                                const char16_t* aData) {
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  if (mListener && strcmp(aTopic, "memory-pressure") == 0) {
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    MemoryPressureReason reason = MemoryPressureReason::LOW_MEMORY;
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    auto reason_string = nsDependentString(aData);
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    if (StringBeginsWith(reason_string, u"low-memory-ongoing"_ns)) {
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      reason = MemoryPressureReason::LOW_MEMORY_ONGOING;
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    } else if (StringBeginsWith(reason_string, u"heap-minimize"_ns)) {
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      reason = MemoryPressureReason::HEAP_MINIMIZE;
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    }
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    mListener->OnMemoryPressure(reason);
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  }
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  return NS_OK;
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}
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NS_IMPL_ISUPPORTS(MemoryPressureObserver, nsIObserver)
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}  // namespace layers
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}  // namespace mozilla
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