gecko-dev/xpcom/base/AvailableMemoryWatcher.h

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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 mozilla_AvailableMemoryWatcher_h
#define mozilla_AvailableMemoryWatcher_h
#include "mozilla/ipc/CrashReporterHost.h"
#include "mozilla/UniquePtr.h"
#include "MemoryPressureLevelMac.h"
#include "nsCOMPtr.h"
#include "nsIAvailableMemoryWatcherBase.h"
#include "nsIObserver.h"
#include "nsIObserverService.h"
namespace mozilla {
// This class implements a platform-independent part to watch the system's
// memory situation and invoke the registered callbacks when we detect
// a low-memory situation or a high-memory situation.
// The actual logic to monitor the memory status is implemented in a subclass
// of nsAvailableMemoryWatcherBase per platform.
class nsAvailableMemoryWatcherBase : public nsIAvailableMemoryWatcherBase,
public nsIObserver {
static StaticRefPtr<nsAvailableMemoryWatcherBase> sSingleton;
static const char* const kObserverTopics[];
TimeStamp mLowMemoryStart;
protected:
// On Windows the publicly available methods (::Observe() and ::Notify()) are
// called on the main thread while the ::LowMemoryCallback() method is called
// by an external thread. All functions called from those must acquire a lock
// on this mutex before accessing the object's fields to prevent races.
//
// On Linux we might tell polling to start/stop from our polling thread
// or from the main thread during ::Observe().
Mutex mMutex;
uint32_t mNumOfTabUnloading MOZ_GUARDED_BY(mMutex);
uint32_t mNumOfMemoryPressure MOZ_GUARDED_BY(mMutex);
nsCOMPtr<nsITabUnloader> mTabUnloader;
nsCOMPtr<nsIObserverService> mObserverSvc;
// Do not change this value off the main thread.
bool mInteracting;
virtual ~nsAvailableMemoryWatcherBase() = default;
virtual nsresult Init();
void Shutdown();
void UpdateLowMemoryTimeStamp();
void RecordTelemetryEventOnHighMemory(const MutexAutoLock&)
MOZ_REQUIRES(mMutex);
public:
static already_AddRefed<nsAvailableMemoryWatcherBase> GetSingleton();
nsAvailableMemoryWatcherBase();
#if defined(XP_DARWIN)
virtual void OnMemoryPressureChanged(MacMemoryPressureLevel aNewLevel) {};
virtual void AddChildAnnotations(
const UniquePtr<ipc::CrashReporterHost>& aCrashReporter) {};
#endif
NS_DECL_THREADSAFE_ISUPPORTS
NS_DECL_NSIAVAILABLEMEMORYWATCHERBASE
NS_DECL_NSIOBSERVER
};
// Method to create a platform-specific object
already_AddRefed<nsAvailableMemoryWatcherBase> CreateAvailableMemoryWatcher();
} // namespace mozilla
#endif // ifndef mozilla_AvailableMemoryWatcher_h