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61 lines
1.8 KiB
C++
61 lines
1.8 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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#ifndef DOM_BASE_GLOBALFREEZEOBSERVER_H_
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#define DOM_BASE_GLOBALFREEZEOBSERVER_H_
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#include "mozilla/Attributes.h"
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#include "nsIGlobalObject.h"
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#include "nsISupports.h"
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namespace mozilla {
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class GlobalFreezeObserver : public nsISupports,
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public LinkedListElement<GlobalFreezeObserver> {
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public:
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virtual void FrozenCallback(nsIGlobalObject* aOwner) = 0;
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virtual void ThawedCallback(nsIGlobalObject* aOwner) {};
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bool Observing() { return !!mOwner; }
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/**
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* This method is non-virtual because it's expected that any object
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* subclassing GlobalFreezeObserver that wants to know when it is disconnected
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* from the global will also subclass GlobalTeardownObserver and take any
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* relevant action by overriding GlobalTeardownObserver::DisconnectFromOwner.
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*/
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void DisconnectFreezeObserver() {
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if (mOwner) {
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mOwner->RemoveGlobalFreezeObserver(this);
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mOwner = nullptr;
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}
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}
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protected:
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virtual ~GlobalFreezeObserver() { DisconnectFreezeObserver(); }
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void BindToOwner(nsIGlobalObject* aOwner) {
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MOZ_ASSERT(!mOwner);
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if (aOwner) {
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MOZ_ASSERT(
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NS_IsMainThread(),
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"GlobalFreezeObserver is currently only supported in window object");
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mOwner = aOwner;
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aOwner->AddGlobalFreezeObserver(this);
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}
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}
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private:
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// The parent global object. The global will clear this when
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// it is destroyed by calling DisconnectFreezeObserver().
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nsIGlobalObject* MOZ_NON_OWNING_REF mOwner = nullptr;
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};
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} // namespace mozilla
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#endif
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