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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 nsMemory_h__
#define nsMemory_h__
#include "nsError.h"
/**
*
* A client that wishes to be notified of low memory situations (for
* example, because the client maintains a large memory cache that
* could be released when memory is tight) should register with the
* observer service (see nsIObserverService) using the topic
* "memory-pressure". There are specific types of notifications
* that can occur. These types will be passed as the |aData|
* parameter of the of the "memory-pressure" notification:
*
* "low-memory"
* This will be passed as the extra data when the pressure
* observer is being asked to flush for low-memory conditions.
*
* "low-memory-ongoing"
* This will be passed when we continue to be in a low-memory
* condition and we want to flush caches and do other cheap
* forms of memory minimization, but heavy handed approaches like
* a GC are unlikely to succeed.
*
* "heap-minimize"
* This will be passed as the extra data when the pressure
* observer is being asked to flush because of a heap minimize
* call.
*/
// This is implemented in nsMemoryImpl.cpp.
namespace nsMemory {
/**
* Attempts to shrink the heap.
* @param immediate - if true, heap minimization will occur
* immediately if the call was made on the main thread. If
* false, the flush will be scheduled to happen when the app is
* idle.
* @throws NS_ERROR_FAILURE if 'immediate' is set and the call
* was not on the application's main thread.
*/
nsresult HeapMinimize(bool aImmediate);
/**
* This predicate can be used to determine if the platform is a "low-memory"
* platform. Callers may use this to dynamically tune their behaviour
* to favour reduced memory usage at the expense of performance. The value
* returned by this function will not change over the lifetime of the process.
*/
bool IsLowMemoryPlatform();
} // namespace nsMemory
#endif // nsMemory_h__
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