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/* vim:set ts=2 sw=2 sts=2 et cindent: */
/* 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
#include "BackgroundVideoDecodingPermissionObserver.h"
#include "mozilla/AsyncEventDispatcher.h"
#include "mozilla/dom/BrowsingContext.h"
#include "mozilla/StaticPrefs_media.h"
#include "MediaDecoder.h"
#include "nsContentUtils.h"
#include "mozilla/dom/Document.h"
#include "mozilla/Services.h"
#include "nsIObserverService.h"
namespace mozilla {
BackgroundVideoDecodingPermissionObserver::
BackgroundVideoDecodingPermissionObserver(MediaDecoder* aDecoder)
: mDecoder(aDecoder), mIsRegisteredForEvent(false) {
MOZ_ASSERT(mDecoder);
}
NS_IMETHODIMP
BackgroundVideoDecodingPermissionObserver::Observe(nsISupports* aSubject,
const char* aTopic,
const char16_t* aData) {
if (!StaticPrefs::media_resume_background_video_on_tabhover()) {
return NS_OK;
}
if (!IsValidEventSender(aSubject)) {
return NS_OK;
}
if (strcmp(aTopic, "unselected-tab-hover") == 0) {
bool allowed = !NS_strcmp(aData, u"true");
mDecoder->SetIsBackgroundVideoDecodingAllowed(allowed);
}
return NS_OK;
}
void BackgroundVideoDecodingPermissionObserver::RegisterEvent() {
MOZ_ASSERT(!mIsRegisteredForEvent);
nsCOMPtr<nsIObserverService> observerService = services::GetObserverService();
if (observerService) {
observerService->AddObserver(this, "unselected-tab-hover", false);
mIsRegisteredForEvent = true;
if (nsContentUtils::IsInStableOrMetaStableState()) {
// Events shall not be fired synchronously to prevent anything visible
// from the scripts while we are in stable state.
if (nsCOMPtr<dom::Document> doc = GetOwnerDoc()) {
doc->Dispatch(NewRunnableMethod(
"BackgroundVideoDecodingPermissionObserver::EnableEvent", this,
&BackgroundVideoDecodingPermissionObserver::EnableEvent));
}
} else {
EnableEvent();
}
}
}
void BackgroundVideoDecodingPermissionObserver::UnregisterEvent() {
MOZ_ASSERT(mIsRegisteredForEvent);
nsCOMPtr<nsIObserverService> observerService = services::GetObserverService();
if (observerService) {
observerService->RemoveObserver(this, "unselected-tab-hover");
mIsRegisteredForEvent = false;
mDecoder->SetIsBackgroundVideoDecodingAllowed(false);
if (nsContentUtils::IsInStableOrMetaStableState()) {
// Events shall not be fired synchronously to prevent anything visible
// from the scripts while we are in stable state.
if (nsCOMPtr<dom::Document> doc = GetOwnerDoc()) {
doc->Dispatch(NewRunnableMethod(
"BackgroundVideoDecodingPermissionObserver::DisableEvent", this,
&BackgroundVideoDecodingPermissionObserver::DisableEvent));
}
} else {
DisableEvent();
}
}
}
BackgroundVideoDecodingPermissionObserver::
~BackgroundVideoDecodingPermissionObserver() {
MOZ_ASSERT(!mIsRegisteredForEvent);
}
void BackgroundVideoDecodingPermissionObserver::EnableEvent() const {
// If we can't get document or outer window, then you can't reach the chrome
// <browser> either, so we don't need want to dispatch the event.
dom::Document* doc = GetOwnerDoc();
if (!doc || !doc->GetWindow()) {
return;
}
RefPtr<AsyncEventDispatcher> asyncDispatcher =
new AsyncEventDispatcher(doc, u"UnselectedTabHover:Enable"_ns,
CanBubble::eYes, ChromeOnlyDispatch::eYes);
asyncDispatcher->PostDOMEvent();
}
void BackgroundVideoDecodingPermissionObserver::DisableEvent() const {
// If we can't get document or outer window, then you can't reach the chrome
// <browser> either, so we don't need want to dispatch the event.
dom::Document* doc = GetOwnerDoc();
if (!doc || !doc->GetWindow()) {
return;
}
RefPtr<AsyncEventDispatcher> asyncDispatcher =
new AsyncEventDispatcher(doc, u"UnselectedTabHover:Disable"_ns,
CanBubble::eYes, ChromeOnlyDispatch::eYes);
asyncDispatcher->PostDOMEvent();
}
dom::BrowsingContext* BackgroundVideoDecodingPermissionObserver::GetOwnerBC()
const {
dom::Document* doc = GetOwnerDoc();
return doc ? doc->GetBrowsingContext() : nullptr;
}
dom::Document* BackgroundVideoDecodingPermissionObserver::GetOwnerDoc() const {
if (!mDecoder->GetOwner()) {
return nullptr;
}
return mDecoder->GetOwner()->GetDocument();
}
bool BackgroundVideoDecodingPermissionObserver::IsValidEventSender(
nsISupports* aSubject) const {
nsCOMPtr<nsPIDOMWindowInner> senderInner(do_QueryInterface(aSubject));
if (!senderInner) {
return false;
}
RefPtr<dom::BrowsingContext> senderBC = senderInner->GetBrowsingContext();
if (!senderBC) {
return false;
}
// Valid sender should be in the same browsing context tree as where owner is.
return GetOwnerBC() ? GetOwnerBC()->Top() == senderBC->Top() : false;
}
NS_IMPL_ISUPPORTS(BackgroundVideoDecodingPermissionObserver, nsIObserver)
} // namespace mozilla