diff options
Diffstat (limited to 'dom/base/ResizeObserverController.cpp')
| -rw-r--r-- | dom/base/ResizeObserverController.cpp | 234 |
1 files changed, 234 insertions, 0 deletions
diff --git a/dom/base/ResizeObserverController.cpp b/dom/base/ResizeObserverController.cpp new file mode 100644 index 000000000..924bba10d --- /dev/null +++ b/dom/base/ResizeObserverController.cpp @@ -0,0 +1,234 @@ +/* -*- 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/. */ + +#include "mozilla/dom/ResizeObserverController.h" +#include "mozilla/dom/Element.h" +#include "mozilla/dom/ErrorEvent.h" +#include "nsIPresShell.h" +#include "nsPresContext.h" + +namespace mozilla { +namespace dom { + +void +ResizeObserverNotificationHelper::WillRefresh(TimeStamp aTime) +{ + MOZ_ASSERT(mOwner, "Why is mOwner already dead when this RefreshObserver is still registered?"); + if (mOwner) { + mOwner->Notify(); + } +} + +nsRefreshDriver* +ResizeObserverNotificationHelper::GetRefreshDriver() const +{ + nsIPresShell* presShell = mOwner->GetShell(); + if (MOZ_UNLIKELY(!presShell)) { + return nullptr; + } + + nsPresContext* presContext = presShell->GetPresContext(); + if (MOZ_UNLIKELY(!presContext)) { + return nullptr; + } + + return presContext->RefreshDriver(); +} + +void +ResizeObserverNotificationHelper::Register() +{ + if (mRegistered) { + return; + } + + nsRefreshDriver* refreshDriver = GetRefreshDriver(); + if (!refreshDriver) { + // We maybe navigating away from this page or currently in an iframe with + // display: none. Just abort the Register(), no need to do notification. + return; + } + + refreshDriver->AddRefreshObserver(this, Flush_Display); + mRegistered = true; +} + +void +ResizeObserverNotificationHelper::Unregister() +{ + if (!mRegistered) { + return; + } + + nsRefreshDriver* refreshDriver = GetRefreshDriver(); + if (!refreshDriver) { + // We can't access RefreshDriver now. Just abort the Unregister(). + return; + } + + refreshDriver->RemoveRefreshObserver(this, Flush_Display); + mRegistered = false; +} + +void +ResizeObserverNotificationHelper::Disconnect() +{ + Unregister(); + // Our owner is dying. Clear our pointer to it, in case we outlive it. + mOwner = nullptr; +} + +ResizeObserverNotificationHelper::~ResizeObserverNotificationHelper() +{ + Unregister(); +} + +void +ResizeObserverController::Traverse(nsCycleCollectionTraversalCallback& aCb) +{ + ImplCycleCollectionTraverse(aCb, mResizeObservers, "mResizeObservers"); +} + +void +ResizeObserverController::Unlink() +{ + mResizeObservers.Clear(); +} + +void +ResizeObserverController::AddResizeObserver(ResizeObserver* aObserver) +{ + MOZ_ASSERT(aObserver, "AddResizeObserver() should never be called with " + "a null parameter"); + mResizeObservers.AppendElement(aObserver); +} + +void +ResizeObserverController::Notify() +{ + if (mResizeObservers.IsEmpty()) { + return; + } + + uint32_t shallowestTargetDepth = 0; + + GatherAllActiveObservations(shallowestTargetDepth); + + while (HasAnyActiveObservations()) { + DebugOnly<uint32_t> oldShallowestTargetDepth = shallowestTargetDepth; + shallowestTargetDepth = BroadcastAllActiveObservations(); + NS_ASSERTION(oldShallowestTargetDepth < shallowestTargetDepth, + "shallowestTargetDepth should be getting strictly deeper"); + + // Flush layout, so that any callback functions' style changes / resizes + // get a chance to take effect. + mDocument->FlushPendingNotifications(Flush_Layout); + + // To avoid infinite resize loop, we only gather all active observations + // that have the depth of observed target element more than current + // shallowestTargetDepth. + GatherAllActiveObservations(shallowestTargetDepth); + } + + mResizeObserverNotificationHelper->Unregister(); + + // Per spec, we deliver an error if the document has any skipped observations. + if (HasAnySkippedObservations()) { + RootedDictionary<ErrorEventInit> init(RootingCx()); + + init.mMessage.AssignLiteral("ResizeObserver loop completed with undelivered" + " notifications."); + init.mCancelable = true; + init.mBubbles = true; + + nsEventStatus status = nsEventStatus_eIgnore; + + nsCOMPtr<nsPIDOMWindowInner> window = + mDocument->GetWindow()->GetCurrentInnerWindow(); + + if (window) { + nsCOMPtr<nsIScriptGlobalObject> sgo = do_QueryInterface(window); + MOZ_ASSERT(sgo); + + if (NS_WARN_IF(NS_FAILED(sgo->HandleScriptError(init, &status)))) { + status = nsEventStatus_eIgnore; + } + } else { + // We don't fire error events at any global for non-window JS on the main + // thread. + } + + // We need to deliver pending notifications in next cycle. + ScheduleNotification(); + } +} + +void +ResizeObserverController::GatherAllActiveObservations(uint32_t aDepth) +{ + for (auto observer : mResizeObservers) { + observer->GatherActiveObservations(aDepth); + } +} + +uint32_t +ResizeObserverController::BroadcastAllActiveObservations() +{ + uint32_t shallowestTargetDepth = UINT32_MAX; + + for (auto observer : mResizeObservers) { + + uint32_t targetDepth = observer->BroadcastActiveObservations(); + + if (targetDepth < shallowestTargetDepth) { + shallowestTargetDepth = targetDepth; + } + } + + return shallowestTargetDepth; +} + +bool +ResizeObserverController::HasAnyActiveObservations() const +{ + for (auto observer : mResizeObservers) { + if (observer->HasActiveObservations()) { + return true; + } + } + return false; +} + +bool +ResizeObserverController::HasAnySkippedObservations() const +{ + for (auto observer : mResizeObservers) { + if (observer->HasSkippedObservations()) { + return true; + } + } + return false; +} + +void +ResizeObserverController::ScheduleNotification() +{ + mResizeObserverNotificationHelper->Register(); +} + +nsIPresShell* +ResizeObserverController::GetShell() const +{ + return mDocument->GetShell(); +} + +ResizeObserverController::~ResizeObserverController() +{ + mResizeObserverNotificationHelper->Disconnect(); +} + +} // namespace dom +} // namespace mozilla |