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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 00:47:55 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 00:47:55 +0000 |
commit | 26a029d407be480d791972afb5975cf62c9360a6 (patch) | |
tree | f435a8308119effd964b339f76abb83a57c29483 /gfx/layers/MemoryPressureObserver.h | |
parent | Initial commit. (diff) | |
download | firefox-26a029d407be480d791972afb5975cf62c9360a6.tar.xz firefox-26a029d407be480d791972afb5975cf62c9360a6.zip |
Adding upstream version 124.0.1.upstream/124.0.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'gfx/layers/MemoryPressureObserver.h')
-rw-r--r-- | gfx/layers/MemoryPressureObserver.h | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/gfx/layers/MemoryPressureObserver.h b/gfx/layers/MemoryPressureObserver.h new file mode 100644 index 0000000000..27048c99ed --- /dev/null +++ b/gfx/layers/MemoryPressureObserver.h @@ -0,0 +1,59 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- + * vim: sw=2 ts=8 et : + */ +/* 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_LAYERS_MEMORYPRESSUREOBSERVER_H +#define MOZILLA_LAYERS_MEMORYPRESSUREOBSERVER_H + +#include "nsIObserver.h" + +namespace mozilla { +namespace layers { + +// A simple memory pressure observer implementation born out of the realization +// that almost all of our memory pressure observers do exactly the same thing. +// +// The intended way to use it is to have the class that nees to react on memory +// pressure inherit the MemoryPressureListener interface and own a strong +// reference to a MemoryPressureListener object. +// Call Unregister on the listener in the destructor of your class or whenever +// you do not which to receive the notification anymore, otherwise the listener +// will be held alive by the observer service (leak) and keep a dangling pointer +// to your class. + +/// See nsIMemory.idl +enum class MemoryPressureReason { + LOW_MEMORY, + LOW_MEMORY_ONGOING, + HEAP_MINIMIZE, +}; + +class MemoryPressureListener { + public: + virtual void OnMemoryPressure(MemoryPressureReason aWhy) = 0; +}; + +class MemoryPressureObserver final : public nsIObserver { + public: + NS_DECL_ISUPPORTS + NS_DECL_NSIOBSERVER + + // Returns null if anything goes wrong. + static already_AddRefed<MemoryPressureObserver> Create( + MemoryPressureListener* aListener); + + void Unregister(); + + private: + explicit MemoryPressureObserver(MemoryPressureListener* aListener); + virtual ~MemoryPressureObserver(); + MemoryPressureListener* mListener; +}; + +} // namespace layers +} // namespace mozilla + +#endif |