Diff
Modified: trunk/LayoutTests/ChangeLog (292946 => 292947)
--- trunk/LayoutTests/ChangeLog 2022-04-17 04:22:20 UTC (rev 292946)
+++ trunk/LayoutTests/ChangeLog 2022-04-17 08:08:00 UTC (rev 292947)
@@ -1,3 +1,23 @@
+2022-04-16 Ryosuke Niwa <[email protected]>
+
+ Make release assertion in Document::updateLayout more precise for FrameSelection::setSelection
+ https://bugs.webkit.org/show_bug.cgi?id=239431
+
+ Reviewed by Alan Bujtas.
+
+ Add a regression test, and fix existing accessibility tests which were mutating DOM inside setSelection
+ via should* functions. In production, this will never happen since accessibility notification will be sent
+ to UI process asynchronously and accesssibility code won't try to mutate DOM synchronously.
+
+ * accessibility/mac/focus-setting-selection-syncronizing-not-clearing-expected.txt: Rebaselined.
+ * accessibility/mac/focus-setting-selection-syncronizing-not-clearing.html: Delay DOM mutations in should*
+ until the notification is over.
+ * accessibility/mac/selection-change-userinfo.html: Ditto.
+ * accessibility/mac/selection-sync.html: Ditto.
+ * accessibility/mac/selection-value-changes-for-aria-textbox.html: Ditto.
+ * fast/forms/textarea-selection-update-during-DOMNodeRemoved-crash-expected.txt: Added.
+ * fast/forms/textarea-selection-update-during-DOMNodeRemoved-crash.html: Added.
+
2022-04-15 Matteo Flores <[email protected]>
REBASLINE: [ Monterey wk2 ] 7 /paymentrequest/* tests are constant text failures
Modified: trunk/LayoutTests/accessibility/mac/focus-setting-selection-syncronizing-not-clearing-expected.txt (292946 => 292947)
--- trunk/LayoutTests/accessibility/mac/focus-setting-selection-syncronizing-not-clearing-expected.txt 2022-04-17 04:22:20 UTC (rev 292946)
+++ trunk/LayoutTests/accessibility/mac/focus-setting-selection-syncronizing-not-clearing-expected.txt 2022-04-17 08:08:00 UTC (rev 292947)
@@ -7,9 +7,9 @@
PASS addedNotification is true
+PASS accessibilityController.focusedElement.isEqual(accessibilityController.accessibleElementById("1")) is true
PASS axTextStateSyncOne is undefined
-PASS accessibilityController.accessibleElementById("1").isFocusable is true
-PASS accessibilityController.focusedElement.isEqual(accessibilityController.accessibleElementById("1")) is true
+PASS accessibleElement1WasFocusable is true
PASS axTextStateSyncTwo is undefined
PASS successfullyParsed is true
Modified: trunk/LayoutTests/accessibility/mac/focus-setting-selection-syncronizing-not-clearing.html (292946 => 292947)
--- trunk/LayoutTests/accessibility/mac/focus-setting-selection-syncronizing-not-clearing.html 2022-04-17 04:22:20 UTC (rev 292946)
+++ trunk/LayoutTests/accessibility/mac/focus-setting-selection-syncronizing-not-clearing.html 2022-04-17 08:08:00 UTC (rev 292947)
@@ -26,6 +26,7 @@
var webArea = 0;
var axTextStateSyncOne = 0;
+ var accessibleElement1WasFocusable = false;
var axTextStateSyncTwo = 0;
var selectCount = 0;
var focusCount = 0;
@@ -39,13 +40,10 @@
selectCount++;
if (selectCount == 1) {
axTextStateSyncOne = userInfo["AXTextStateSync"];
- shouldBe("axTextStateSyncOne", "undefined");
-
- shouldBe("accessibilityController.accessibleElementById(\"1\").isFocusable", "true");
+ accessibleElement1WasFocusable = accessibilityController.accessibleElementById("1").isFocusable;
accessibilityController.accessibleElementById("1").takeFocus();
} else if (selectCount == 2) {
axTextStateSyncTwo = userInfo["AXTextStateSync"];
- shouldBe("axTextStateSyncTwo", "undefined");
}
} else if (notification == "AXFocusChanged") {
focusCount++;
@@ -55,7 +53,12 @@
}
if (selectCount == 2 && focusCount == 3) {
webArea.removeNotificationListener();
- finishJSTest();
+ setTimeout(() => {
+ shouldBe("axTextStateSyncOne", "undefined");
+ shouldBe("accessibleElement1WasFocusable", "true");
+ shouldBe("axTextStateSyncTwo", "undefined");
+ finishJSTest();
+ }, 0);
}
}
Modified: trunk/LayoutTests/accessibility/mac/selection-change-userinfo.html (292946 => 292947)
--- trunk/LayoutTests/accessibility/mac/selection-change-userinfo.html 2022-04-17 04:22:20 UTC (rev 292946)
+++ trunk/LayoutTests/accessibility/mac/selection-change-userinfo.html 2022-04-17 08:08:00 UTC (rev 292947)
@@ -43,7 +43,12 @@
count++;
if (userInfo)
results.push(userInfo);
- if (count == gran.length * 4) {
+ if (count != gran.length * 4)
+ return;
+
+ webArea.removeNotificationListener();
+
+ setTimeout(() => {
resultIndex++;
shouldBe("results[resultIndex][\"AXTextStateChangeType\"]", "AXTextStateChangeTypeSelectionMove");
shouldBe("results[resultIndex][\"AXTextSelectionGranularity\"]", "AXTextSelectionGranularityCharacter");
@@ -179,9 +184,8 @@
shouldBe("results[resultIndex][\"AXTextSelectionGranularity\"]", "AXTextSelectionGranularityDocument");
shouldBe("results[resultIndex][\"AXTextSelectionDirection\"]", "AXTextSelectionDirectionEnd");
- webArea.removeNotificationListener();
finishJSTest();
- }
+ }, 0);
}
}
Modified: trunk/LayoutTests/accessibility/mac/selection-sync.html (292946 => 292947)
--- trunk/LayoutTests/accessibility/mac/selection-sync.html 2022-04-17 04:22:20 UTC (rev 292946)
+++ trunk/LayoutTests/accessibility/mac/selection-sync.html 2022-04-17 08:08:00 UTC (rev 292947)
@@ -31,7 +31,12 @@
count++;
if (userInfo)
results.push(userInfo);
- if (count == 5) {
+ if (count != 5)
+ return;
+
+ webArea.removeNotificationListener();
+
+ setTimeout(() => {
shouldBe("results[resultIndex][\"AXTextStateChangeType\"]", "AXTextStateChangeTypeSelectionMove");
shouldBe("results[resultIndex][\"AXTextSelectionDirection\"]", "AXTextSelectionDirectionDiscontiguous");
shouldBe("results[resultIndex][\"AXTextStateSync\"]", "true");
@@ -56,9 +61,8 @@
shouldBe("results[resultIndex][\"AXTextSelectionDirection\"]", "AXTextSelectionDirectionDiscontiguous");
shouldBe("results[resultIndex][\"AXTextStateSync\"]", "true");
- webArea.removeNotificationListener();
finishJSTest();
- }
+ }, 0);
}
}
Modified: trunk/LayoutTests/accessibility/mac/selection-value-changes-for-aria-textbox.html (292946 => 292947)
--- trunk/LayoutTests/accessibility/mac/selection-value-changes-for-aria-textbox.html 2022-04-17 04:22:20 UTC (rev 292946)
+++ trunk/LayoutTests/accessibility/mac/selection-value-changes-for-aria-textbox.html 2022-04-17 08:08:00 UTC (rev 292947)
@@ -18,14 +18,18 @@
description("This tests that ARIA removing an element from a live region sends the correct notification.");
var axTextbox = 0;
+ var result = '';
function notificationCallback(notification) {
if (notification == "AXValueChanged") {
- document.getElementById("notifications").innerHTML += "Successfully received " + notification + "<br>";
+ result += "Successfully received " + notification + "<br>";
axTextbox.removeNotificationListener();
- finishJSTest();
+ setTimeout(() => {
+ document.getElementById("notifications").innerHTML += result;
+ finishJSTest();
+ }, 0);
}
else if (notification == "AXSelectedTextChanged") {
- document.getElementById("notifications").innerHTML += "Successfully received " + notification + "<br>";
+ result += "Successfully received " + notification + "<br>";
}
}
Added: trunk/LayoutTests/fast/forms/textarea-selection-update-during-DOMNodeRemoved-crash-expected.txt (0 => 292947)
--- trunk/LayoutTests/fast/forms/textarea-selection-update-during-DOMNodeRemoved-crash-expected.txt (rev 0)
+++ trunk/LayoutTests/fast/forms/textarea-selection-update-during-DOMNodeRemoved-crash-expected.txt 2022-04-17 08:08:00 UTC (rev 292947)
@@ -0,0 +1,3 @@
+This tests updating selection within DOMNodeRemoved. WebKit should not hit any release assertions.
+
+PASS
Added: trunk/LayoutTests/fast/forms/textarea-selection-update-during-DOMNodeRemoved-crash.html (0 => 292947)
--- trunk/LayoutTests/fast/forms/textarea-selection-update-during-DOMNodeRemoved-crash.html (rev 0)
+++ trunk/LayoutTests/fast/forms/textarea-selection-update-during-DOMNodeRemoved-crash.html 2022-04-17 08:08:00 UTC (rev 292947)
@@ -0,0 +1,33 @@
+<script>
+if (window.testRunner) {
+ testRunner.dumpAsText();
+ testRunner.waitUntilDone();
+}
+
+setTimeout(() => {
+ textarea1.selectionStart = 1;
+
+ span2.appendChild(textarea1);
+ document.documentElement.appendChild(canvas1);
+
+ textarea1.addEventListener("DOMNodeRemoved", () => {
+ other1.appendChild(span1);
+ textarea1.selectionStart = -1;
+ document.getSelection().collapse(span1);
+ });
+
+ textarea1.innerHTML = '';
+
+ document.body.innerHTML = '<p>This tests updating selection within DOMNodeRemoved. WebKit should not hit any release assertions.</p>PASS';
+
+ if (window.testRunner)
+ testRunner.notifyDone();
+}, 0);
+</script>
+<textarea id="textarea1">hello</textarea>
+<canvas id="canvas1"><other-element id="other1"></other-element></canvas>
+<span id="span1">
+ <audio controls="controls" src=""
+ <span id="span2">G'lzKsb6[Xava</span>
+ </audio>
+</span>
Modified: trunk/Source/WebCore/ChangeLog (292946 => 292947)
--- trunk/Source/WebCore/ChangeLog 2022-04-17 04:22:20 UTC (rev 292946)
+++ trunk/Source/WebCore/ChangeLog 2022-04-17 08:08:00 UTC (rev 292947)
@@ -1,3 +1,39 @@
+2022-04-16 Ryosuke Niwa <[email protected]>
+
+ Make release assertion in Document::updateLayout more precise for FrameSelection::setSelection
+ https://bugs.webkit.org/show_bug.cgi?id=239431
+
+ Reviewed by Alan Bujtas.
+
+ Avoid the assertion failure by allowing no-op layout updates within FrameSelection::setSelection.
+
+ To do this, this patch introduces a new RAII object, UpToDateLayoutScope, which denotes when when the layout
+ is up-to-date and therefore does not require a new layout update. When this scope exists in the stack frame,
+ we allow calls to Document::updateLayout even inside ScriptDisallowedScope. We also assert that nobody attempts
+ to schedule a new style resolution or layout when this object exists.
+
+ Test: fast/forms/textarea-selection-update-during-DOMNodeRemoved-crash.html
+
+ * WebCore.xcodeproj/project.pbxproj:
+ * dom/Document.cpp:
+ (WebCore::Document::scheduleStyleRecalc):
+ (WebCore::Document::updateLayout):
+ * dom/Document.h:
+ (WebCore::Document::upToDateLayoutScopeCount const):
+ (WebCore::Document::incrementUpToDateLayoutScopeCount):
+ (WebCore::Document::decrementUpToDateLayoutScopeCount):
+ * editing/FrameSelection.cpp:
+ (WebCore::FrameSelection::setSelection):
+ * page/FrameViewLayoutContext.cpp:
+ (WebCore::FrameViewLayoutContext::scheduleLayout):
+ * rendering/RenderObject.h:
+ (WebCore::RenderObject::isSetNeedsLayoutForbidden const):
+ * rendering/UpToDateLayoutScope.h: Added.
+ (WebCore::UpToDateLayoutScope::UpToDateLayoutScope):
+ (WebCore::UpToDateLayoutScope::~UpToDateLayoutScope):
+ (WebCore::UpToDateLayoutScope::scopeIfLayoutIsUpToUpdate):
+ (WebCore::UpToDateLayoutScope::needsLayout):
+
2022-04-16 Chris Dumez <[email protected]>
Drop String::truncate() and use String::left() instead
Modified: trunk/Source/WebCore/WebCore.xcodeproj/project.pbxproj (292946 => 292947)
--- trunk/Source/WebCore/WebCore.xcodeproj/project.pbxproj 2022-04-17 04:22:20 UTC (rev 292946)
+++ trunk/Source/WebCore/WebCore.xcodeproj/project.pbxproj 2022-04-17 08:08:00 UTC (rev 292947)
@@ -3281,6 +3281,7 @@
9B27FC60234D9ADB00394A46 /* WindowEventLoop.h in Headers */ = {isa = PBXBuildFile; fileRef = 9B27FC5E234D9ADA00394A46 /* WindowEventLoop.h */; settings = {ATTRIBUTES = (Private, ); }; };
9B2D8A7914997CCF00ECEF3E /* UndoStep.h in Headers */ = {isa = PBXBuildFile; fileRef = 9B2D8A7814997CCF00ECEF3E /* UndoStep.h */; settings = {ATTRIBUTES = (Private, ); }; };
9B32CDA913DF7FA900F34D13 /* RenderedPosition.h in Headers */ = {isa = PBXBuildFile; fileRef = 9B32CDA713DF7FA900F34D13 /* RenderedPosition.h */; };
+ 9B33DF8628090B5600ECFAE7 /* UpToDateLayoutScope.h in Headers */ = {isa = PBXBuildFile; fileRef = 9B33DF8428090B5600ECFAE7 /* UpToDateLayoutScope.h */; };
9B417064125662B3006B28FC /* ApplyBlockElementCommand.h in Headers */ = {isa = PBXBuildFile; fileRef = 9B417062125662B3006B28FC /* ApplyBlockElementCommand.h */; };
9B50B1DE17CD4C0F0087F63C /* FormNamedItem.h in Headers */ = {isa = PBXBuildFile; fileRef = 9B50B1DC17CD4C0F0087F63C /* FormNamedItem.h */; settings = {ATTRIBUTES = (Private, ); }; };
9B532EA41BA928570038A827 /* SlotAssignment.h in Headers */ = {isa = PBXBuildFile; fileRef = 9B532EA21BA928570038A827 /* SlotAssignment.h */; };
@@ -13466,6 +13467,7 @@
9B2D8A7814997CCF00ECEF3E /* UndoStep.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = UndoStep.h; sourceTree = "<group>"; };
9B32CDA713DF7FA900F34D13 /* RenderedPosition.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = RenderedPosition.h; sourceTree = "<group>"; };
9B32CDA813DF7FA900F34D13 /* RenderedPosition.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = RenderedPosition.cpp; sourceTree = "<group>"; };
+ 9B33DF8428090B5600ECFAE7 /* UpToDateLayoutScope.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = UpToDateLayoutScope.h; sourceTree = "<group>"; };
9B417062125662B3006B28FC /* ApplyBlockElementCommand.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ApplyBlockElementCommand.h; sourceTree = "<group>"; };
9B417063125662B3006B28FC /* ApplyBlockElementCommand.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = ApplyBlockElementCommand.cpp; sourceTree = "<group>"; };
9B4376EF2117E872009D03A0 /* ThrowOnDynamicMarkupInsertionCountIncrementer.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = ThrowOnDynamicMarkupInsertionCountIncrementer.h; sourceTree = "<group>"; };
@@ -32421,6 +32423,7 @@
1C18DA57181AF6A500C4EF22 /* TextPainter.h */,
E4C91A0F1802343900A17F6D /* TextPaintStyle.cpp */,
E4C91A0D1802343100A17F6D /* TextPaintStyle.h */,
+ 9B33DF8428090B5600ECFAE7 /* UpToDateLayoutScope.h */,
BCA257141293C010007A263D /* VerticalPositionCache.h */,
);
path = rendering;
@@ -38040,6 +38043,7 @@
C18CC0A42580EFB1003D75FB /* UniversalAccessZoom.h in Headers */,
D086FE9809D53AAB005BC74D /* UnlinkCommand.h in Headers */,
FD1762E0176686D900D836A8 /* UpSampler.h in Headers */,
+ 9B33DF8628090B5600ECFAE7 /* UpToDateLayoutScope.h in Headers */,
93D437A21D57B3FE00AB85EA /* URLDecomposition.h in Headers */,
267726051A5DF6F2003C24DD /* URLFilterParser.h in Headers */,
F55B3DDE1251F12D003EF269 /* URLInputType.h in Headers */,
Modified: trunk/Source/WebCore/dom/Document.cpp (292946 => 292947)
--- trunk/Source/WebCore/dom/Document.cpp 2022-04-17 04:22:20 UTC (rev 292946)
+++ trunk/Source/WebCore/dom/Document.cpp 2022-04-17 08:08:00 UTC (rev 292947)
@@ -252,6 +252,7 @@
#include "TransformSource.h"
#include "TreeWalker.h"
#include "UndoManager.h"
+#include "UpToDateLayoutScope.h"
#include "UserGestureIndicator.h"
#include "ValidationMessageClient.h"
#include "VisibilityChangeClient.h"
@@ -1977,6 +1978,7 @@
if (m_styleRecalcTimer.isActive() || backForwardCacheState() != NotInBackForwardCache)
return;
+ RELEASE_ASSERT(!m_upToDateLayoutScopeCount);
ASSERT(childNeedsStyleRecalc() || m_needsFullStyleRebuild);
m_styleRecalcTimer.startOneShot(0_s);
@@ -2224,8 +2226,10 @@
ASSERT_NOT_REACHED();
return;
}
- RELEASE_ASSERT_WITH_SECURITY_IMPLICATION(isSafeToUpdateStyleOrLayout(*this));
+ bool safeToUpdateStyleOrLayout = isSafeToUpdateStyleOrLayout(*this);
+ RELEASE_ASSERT_WITH_SECURITY_IMPLICATION(safeToUpdateStyleOrLayout || (m_upToDateLayoutScopeCount && !UpToDateLayoutScope::needsLayout(*this)));
+
RenderView::RepaintRegionAccumulator repaintRegionAccumulator(renderView());
if (RefPtr owner = ownerElement())
@@ -2240,6 +2244,9 @@
if (!frameView->layoutContext().isLayoutPending() && !renderView()->needsLayout())
return;
+ // needsLayout may have changed.
+ RELEASE_ASSERT_WITH_SECURITY_IMPLICATION(safeToUpdateStyleOrLayout);
+
frameView->layoutContext().layout();
Style::Scope::QueryContainerUpdateContext queryContainerUpdateContext;
Modified: trunk/Source/WebCore/dom/Document.h (292946 => 292947)
--- trunk/Source/WebCore/dom/Document.h 2022-04-17 04:22:20 UTC (rev 292946)
+++ trunk/Source/WebCore/dom/Document.h 2022-04-17 08:08:00 UTC (rev 292947)
@@ -621,7 +621,11 @@
unsigned lastStyleUpdateSizeForTesting() const { return m_lastStyleUpdateSizeForTesting; }
WEBCORE_EXPORT void updateLayout();
-
+
+ unsigned upToDateLayoutScopeCount() const { return m_upToDateLayoutScopeCount; }
+ void incrementUpToDateLayoutScopeCount() { ++m_upToDateLayoutScopeCount; }
+ void decrementUpToDateLayoutScopeCount() { ASSERT(m_upToDateLayoutScopeCount); --m_upToDateLayoutScopeCount; }
+
// updateLayoutIgnorePendingStylesheets() forces layout even if we are waiting for pending stylesheet loads,
// so calling this may cause a flash of unstyled content (FOUC).
enum class RunPostLayoutTasks { Asynchronously, Synchronously };
@@ -2107,6 +2111,8 @@
unsigned m_writeRecursionDepth { 0 };
+ unsigned m_upToDateLayoutScopeCount { 0 };
+
InheritedBool m_designMode { inherit };
MediaProducerMediaStateFlags m_mediaState;
bool m_userHasInteractedWithMediaElement { false };
Modified: trunk/Source/WebCore/editing/FrameSelection.cpp (292946 => 292947)
--- trunk/Source/WebCore/editing/FrameSelection.cpp 2022-04-17 04:22:20 UTC (rev 292946)
+++ trunk/Source/WebCore/editing/FrameSelection.cpp 2022-04-17 08:08:00 UTC (rev 292947)
@@ -73,6 +73,7 @@
#include "StyleProperties.h"
#include "StyleTreeResolver.h"
#include "TypingCommand.h"
+#include "UpToDateLayoutScope.h"
#include "VisibleUnits.h"
#include <stdio.h>
#include <wtf/text/CString.h>
@@ -447,13 +448,10 @@
m_selectionRevealIntent = intent;
m_pendingSelectionUpdate = true;
- if (protectedDocument->hasPendingStyleRecalc())
+ auto layoutScope = UpToDateLayoutScope::scopeIfLayoutIsUpToUpdate(*protectedDocument);
+ if (!layoutScope)
return;
- auto frameView = protectedDocument->view();
- if (frameView && frameView->layoutContext().isLayoutPending())
- return;
-
updateAndRevealSelection(intent, options.contains(SmoothScroll) ? ScrollBehavior::Smooth : ScrollBehavior::Instant, options.contains(RevealSelectionBounds) ? RevealExtentOption::DoNotRevealExtent : RevealExtentOption::RevealExtent);
if (options & IsUserTriggered) {
Modified: trunk/Source/WebCore/page/FrameViewLayoutContext.cpp (292946 => 292947)
--- trunk/Source/WebCore/page/FrameViewLayoutContext.cpp 2022-04-17 04:22:20 UTC (rev 292946)
+++ trunk/Source/WebCore/page/FrameViewLayoutContext.cpp 2022-04-17 08:08:00 UTC (rev 292947)
@@ -373,6 +373,8 @@
// too many false assertions. See <rdar://problem/7218118>.
ASSERT(frame().view() == &view());
+ RELEASE_ASSERT(!frame().document()->upToDateLayoutScopeCount());
+
if (subtreeLayoutRoot())
convertSubtreeLayoutToFullLayout();
if (!isLayoutSchedulingEnabled())
Modified: trunk/Source/WebCore/rendering/RenderObject.h (292946 => 292947)
--- trunk/Source/WebCore/rendering/RenderObject.h 2022-04-17 04:22:20 UTC (rev 292946)
+++ trunk/Source/WebCore/rendering/RenderObject.h 2022-04-17 08:08:00 UTC (rev 292947)
@@ -1166,7 +1166,7 @@
inline bool RenderObject::isSetNeedsLayoutForbidden() const
{
#if ASSERT_ENABLED
- return m_setNeedsLayoutForbidden;
+ return m_setNeedsLayoutForbidden || document().upToDateLayoutScopeCount();
#else
return false;
#endif
Added: trunk/Source/WebCore/rendering/UpToDateLayoutScope.h (0 => 292947)
--- trunk/Source/WebCore/rendering/UpToDateLayoutScope.h (rev 0)
+++ trunk/Source/WebCore/rendering/UpToDateLayoutScope.h 2022-04-17 08:08:00 UTC (rev 292947)
@@ -0,0 +1,74 @@
+/*
+ * Copyright (C) 2022 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
+ * THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include "Document.h"
+#include "FrameView.h"
+#include "RenderView.h"
+
+namespace WebCore {
+
+class UpToDateLayoutScope {
+ WTF_MAKE_NONCOPYABLE(UpToDateLayoutScope);
+public:
+ UpToDateLayoutScope(Document& document)
+ : m_document { &document }
+ {
+ m_document->incrementUpToDateLayoutScopeCount();
+ RELEASE_ASSERT(!needsLayout(document));
+ }
+
+ UpToDateLayoutScope(UpToDateLayoutScope&& source)
+ : m_document { std::exchange(source.m_document, nullptr) }
+ {
+ }
+
+ ~UpToDateLayoutScope()
+ {
+ if (m_document)
+ m_document->decrementUpToDateLayoutScopeCount();
+ }
+
+ static std::optional<UpToDateLayoutScope> scopeIfLayoutIsUpToUpdate(Document& document)
+ {
+ if (needsLayout(document))
+ return std::nullopt;
+ return UpToDateLayoutScope { document };
+ }
+
+ static bool needsLayout(Document& document)
+ {
+ if (document.needsStyleRecalc())
+ return true;
+ RefPtr frameView = document.view();
+ return frameView && frameView->layoutContext().needsLayout();
+ }
+
+private:
+ RefPtr<Document> m_document;
+};
+
+}
