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authorMoonchild <moonchild@palemoon.org>2020-09-16 18:21:14 +0000
committerMoonchild <moonchild@palemoon.org>2020-09-16 18:26:30 +0000
commita53a2a3a38d03721b19768480dbdb0bccb4616d9 (patch)
tree36717e8e30e8ecbabbec41355dfeabc633a6bdd3
parent1b73824161e6cd2f5d2f63bc323b4e8a607207d0 (diff)
downloaduxp-a53a2a3a38d03721b19768480dbdb0bccb4616d9.tar.gz
Issue #1643 - Part 3: Implement ResizeObserverController
-rw-r--r--dom/base/ResizeObserverController.cpp234
-rw-r--r--dom/base/ResizeObserverController.h129
-rwxr-xr-xdom/base/moz.build2
3 files changed, 365 insertions, 0 deletions
diff --git a/dom/base/ResizeObserverController.cpp b/dom/base/ResizeObserverController.cpp
new file mode 100644
index 0000000000..924bba10d1
--- /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
diff --git a/dom/base/ResizeObserverController.h b/dom/base/ResizeObserverController.h
new file mode 100644
index 0000000000..a775115874
--- /dev/null
+++ b/dom/base/ResizeObserverController.h
@@ -0,0 +1,129 @@
+/* -*- 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/. */
+
+#ifndef mozilla_dom_ResizeObserverController_h
+#define mozilla_dom_ResizeObserverController_h
+
+#include "mozilla/dom/ResizeObserver.h"
+#include "mozilla/TimeStamp.h"
+#include "nsRefreshDriver.h"
+
+namespace mozilla {
+namespace dom {
+
+class ResizeObserverController;
+
+/*
+ * ResizeObserverNotificationHelper will trigger ResizeObserver notifications
+ * by registering with the Refresh Driver.
+*/
+class ResizeObserverNotificationHelper final : public nsARefreshObserver
+{
+public:
+ NS_INLINE_DECL_REFCOUNTING(ResizeObserverNotificationHelper, override)
+
+ explicit ResizeObserverNotificationHelper(ResizeObserverController* aOwner)
+ : mOwner(aOwner)
+ , mRegistered(false)
+ {
+ MOZ_ASSERT(mOwner, "Need a non-null owner");
+ }
+
+ void WillRefresh(TimeStamp aTime) override;
+
+ nsRefreshDriver* GetRefreshDriver() const;
+
+ void Register();
+
+ void Unregister();
+
+ void Disconnect();
+
+protected:
+ virtual ~ResizeObserverNotificationHelper();
+
+ ResizeObserverController* mOwner;
+ bool mRegistered;
+};
+
+/*
+ * ResizeObserverController contains the list of ResizeObservers and controls
+ * the flow of notification.
+*/
+class ResizeObserverController final
+{
+public:
+ explicit ResizeObserverController(nsIDocument* aDocument)
+ : mDocument(aDocument)
+ , mIsNotificationActive(false)
+ {
+ MOZ_ASSERT(mDocument, "Need a non-null document");
+ mResizeObserverNotificationHelper =
+ new ResizeObserverNotificationHelper(this);
+ }
+
+ // Methods for supporting cycle-collection
+ void Traverse(nsCycleCollectionTraversalCallback& aCb);
+ void Unlink();
+
+ void AddResizeObserver(ResizeObserver* aObserver);
+
+ /*
+ * Schedule the notification via ResizeObserverNotificationHelper refresh
+ * observer.
+ */
+ void ScheduleNotification();
+
+ /*
+ * Notify all ResizeObservers by gathering and broadcasting all active
+ * observations.
+ */
+ void Notify();
+
+ nsIPresShell* GetShell() const;
+
+ ~ResizeObserverController();
+
+private:
+ /*
+ * Calls GatherActiveObservations(aDepth) for all ResizeObservers in this
+ * controller. All observations in each ResizeObserver with element's depth
+ * more than aDepth will be gathered.
+ */
+ void GatherAllActiveObservations(uint32_t aDepth);
+
+ /*
+ * Calls BroadcastActiveObservations() for all ResizeObservers in this
+ * controller. It also returns the shallowest depth of observed target
+ * elements from all ResizeObserver or UINT32_MAX if there is no any
+ * active obsevations at all.
+ */
+ uint32_t BroadcastAllActiveObservations();
+
+ /*
+ * Returns whether there is any ResizeObserver that has active observations.
+ */
+ bool HasAnyActiveObservations() const;
+
+ /*
+ * Returns whether there is any ResizeObserver that has skipped observations.
+ */
+ bool HasAnySkippedObservations() const;
+
+protected:
+ // Raw pointer is OK because mDocument strongly owns us & hence must outlive
+ // us.
+ nsIDocument* const mDocument;
+
+ RefPtr<ResizeObserverNotificationHelper> mResizeObserverNotificationHelper;
+ nsTArray<RefPtr<ResizeObserver>> mResizeObservers;
+ bool mIsNotificationActive;
+};
+
+} // namespace dom
+} // namespace mozilla
+
+#endif // mozilla_dom_ResizeObserverController_h
diff --git a/dom/base/moz.build b/dom/base/moz.build
index 27322475ed..aff13bee0c 100755
--- a/dom/base/moz.build
+++ b/dom/base/moz.build
@@ -205,6 +205,7 @@ EXPORTS.mozilla.dom += [
'Pose.h',
'ProcessGlobal.h',
'ResizeObserver.h',
+ 'ResizeObserverController.h',
'ResponsiveImageSelector.h',
'SameProcessMessageQueue.h',
'ScreenOrientation.h',
@@ -352,6 +353,7 @@ SOURCES += [
'PostMessageEvent.cpp',
'ProcessGlobal.cpp',
'ResizeObserver.cpp',
+ 'ResizeObserverController.cpp',
'ResponsiveImageSelector.cpp',
'SameProcessMessageQueue.cpp',
'ScreenOrientation.cpp',