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// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef BASE_MEMORY_MEMORY_PRESSURE_MONITOR_H_
#define BASE_MEMORY_MEMORY_PRESSURE_MONITOR_H_
#include "base/base_export.h"
#include "base/callback.h"
#include "base/macros.h"
#include "base/memory/memory_pressure_listener.h"
namespace base {
// TODO(chrisha): Make this a concrete class with per-OS implementations rather
// than an abstract base class.
// Declares the interface for a MemoryPressureMonitor. There are multiple
// OS specific implementations of this class. An instance of the memory
// pressure observer is created at the process level, tracks memory usage, and
// pushes memory state change notifications to the static function
// base::MemoryPressureListener::NotifyMemoryPressure. This is turn notifies
// all MemoryPressureListener instances via a callback.
class BASE_EXPORT MemoryPressureMonitor {
public:
using MemoryPressureLevel = base::MemoryPressureListener::MemoryPressureLevel;
using DispatchCallback = base::Callback<void(MemoryPressureLevel level)>;
virtual ~MemoryPressureMonitor();
// Return the singleton MemoryPressureMonitor.
static MemoryPressureMonitor* Get();
// Record memory pressure UMA statistic. A tick is 5 seconds.
static void RecordMemoryPressure(MemoryPressureLevel level, int ticks);
// Returns the currently observed memory pressure.
virtual MemoryPressureLevel GetCurrentPressureLevel() = 0;
// Sets a notification callback. The default callback invokes
// base::MemoryPressureListener::NotifyMemoryPressure.
virtual void SetDispatchCallback(const DispatchCallback& callback) = 0;
protected:
MemoryPressureMonitor();
private:
DISALLOW_COPY_AND_ASSIGN(MemoryPressureMonitor);
};
} // namespace base
#endif // BASE_MEMORY_MEMORY_PRESSURE_MONITOR_H_
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