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