CSS Custom Highlights optimization add flag for when live ranges are …

…changed

https://bugs.webkit.org/show_bug.cgi?id=259804
rdar://113361192

Reviewed by Ryosuke Niwa.

Does not collect range data for live ranges that were not changed/updated.
Before, would collect range data for all live ranges all the time, and repainting them.

* Source/WebCore/dom/Document.cpp:
(WebCore::Document::collectRangeDataFromRegister):
* Source/WebCore/dom/Range.cpp:
(WebCore::Range::setStart):
(WebCore::Range::setEnd):
(WebCore::Range::nodeChildrenChanged):
(WebCore::Range::nodeChildrenWillBeRemoved):
(WebCore::Range::nodeWillBeRemoved):
(WebCore::Range::textInserted):
(WebCore::Range::textRemoved):
(WebCore::Range::textNodesMerged):
(WebCore::Range::textNodeSplit):
* Source/WebCore/dom/Range.h:

Canonical link: https://commits.webkit.org/266614@main

Source/WebCore/dom/Document.cpp

@@ -2989,15 +2989,26 @@ void Document::collectRangeDataFromRegister(Vector<WeakPtr<HighlightRangeData>>&
 {
     for (auto& highlight : highlightRegister.map()) {
         for (auto& rangeData : highlight.value->rangesData()) {
-            // FIXME: For live ranges, we can optimize by only performing this when the range changed.
             if (rangeData->startPosition().isNotNull() && rangeData->endPosition().isNotNull() && !rangeData->range().isLiveRange())
                 continue;
+
+            if (auto* liveRange = dynamicDowncast<Range>(rangeData->range()); liveRange && !liveRange->didChangeHighlight())
+                continue;
+
             auto simpleRange = makeSimpleRange(rangeData->range());
             if (&simpleRange.startContainer().treeScope() != &simpleRange.endContainer().treeScope())
                 continue;
             rangesData.append(rangeData.get());
         }
     }
+
+    // One range can belong to multiple highlights so resetting a range's flag cannot be done in the loops above.
+    for (auto& highlight : highlightRegister.map()) {
+        for (auto& rangeData : highlight.value->rangesData()) {
+            if (auto* liveRange = dynamicDowncast<Range>(rangeData->range()); liveRange && liveRange->didChangeHighlight())
+                liveRange->resetDidChangeHighlight();
+        }
+    }
 }
 
 void Document::updateHighlightPositions()

Source/WebCore/dom/Range.cpp

@@ -130,6 +130,7 @@ ExceptionOr<void> Range::setStart(Ref<Node>&& container, unsigned offset)
         m_end = m_start;
     updateAssociatedSelection();
     updateDocument();
+    m_didChangeHighlight = true;
     return { };
 }
 
@@ -144,6 +145,7 @@ ExceptionOr<void> Range::setEnd(Ref<Node>&& container, unsigned offset)
         m_start = m_end;
     updateAssociatedSelection();
     updateDocument();
+    m_didChangeHighlight = true;
     return { };
 }
 
@@ -897,6 +899,7 @@ void Range::nodeChildrenChanged(ContainerNode& container)
     ASSERT(&container.document() == m_ownerDocument.ptr());
     boundaryNodeChildrenChanged(m_start, container);
     boundaryNodeChildrenChanged(m_end, container);
+    m_didChangeHighlight = true;
 }
 
 static inline void boundaryNodeChildrenWillBeRemoved(RangeBoundaryPoint& boundary, ContainerNode& containerOfNodesToBeRemoved)
@@ -910,6 +913,7 @@ void Range::nodeChildrenWillBeRemoved(ContainerNode& container)
     ASSERT(&container.document() == m_ownerDocument.ptr());
     boundaryNodeChildrenWillBeRemoved(m_start, container);
     boundaryNodeChildrenWillBeRemoved(m_end, container);
+    m_didChangeHighlight = true;
 }
 
 static inline void boundaryNodeWillBeRemoved(RangeBoundaryPoint& boundary, Node& nodeToBeRemoved)
@@ -927,6 +931,7 @@ void Range::nodeWillBeRemoved(Node& node)
     ASSERT(node.parentNode());
     boundaryNodeWillBeRemoved(m_start, node);
     boundaryNodeWillBeRemoved(m_end, node);
+    m_didChangeHighlight = true;
 }
 
 bool Range::parentlessNodeMovedToNewDocumentAffectsRange(Node& node)
@@ -956,6 +961,7 @@ void Range::textInserted(Node& text, unsigned offset, unsigned length)
     ASSERT(&text.document() == m_ownerDocument.ptr());
     boundaryTextInserted(m_start, text, offset, length);
     boundaryTextInserted(m_end, text, offset, length);
+    m_didChangeHighlight = true;
 }
 
 static inline void boundaryTextRemoved(RangeBoundaryPoint& boundary, Node& text, unsigned offset, unsigned length)
@@ -976,6 +982,7 @@ void Range::textRemoved(Node& text, unsigned offset, unsigned length)
     ASSERT(&text.document() == m_ownerDocument.ptr());
     boundaryTextRemoved(m_start, text, offset, length);
     boundaryTextRemoved(m_end, text, offset, length);
+    m_didChangeHighlight = true;
 }
 
 static inline void boundaryTextNodesMerged(RangeBoundaryPoint& boundary, NodeWithIndex& oldNode, unsigned offset)
@@ -996,6 +1003,7 @@ void Range::textNodesMerged(NodeWithIndex& oldNode, unsigned offset)
     ASSERT(oldNode.node()->previousSibling()->isTextNode());
     boundaryTextNodesMerged(m_start, oldNode, offset);
     boundaryTextNodesMerged(m_end, oldNode, offset);
+    m_didChangeHighlight = true;
 }
 
 static inline void boundaryTextNodesSplit(RangeBoundaryPoint& boundary, Text& oldNode)
@@ -1028,6 +1036,7 @@ void Range::textNodeSplit(Text& oldNode)
     ASSERT(!oldNode.parentNode() || oldNode.nextSibling()->isTextNode());
     boundaryTextNodesSplit(m_start, oldNode);
     boundaryTextNodesSplit(m_end, oldNode);
+    m_didChangeHighlight = true;
 }
 
 ExceptionOr<void> Range::expand(const String& unit)

Source/WebCore/dom/Range.h

@@ -52,6 +52,9 @@ class Range final : public AbstractRange, public CanMakeWeakPtr<Range> {
     bool collapsed() const final { return m_start == m_end; }
     WEBCORE_EXPORT Node* commonAncestorContainer() const;
 
+    void resetDidChangeHighlight() { m_didChangeHighlight = false; }
+    bool didChangeHighlight() const { return m_didChangeHighlight; }
+
     WEBCORE_EXPORT ExceptionOr<void> setStart(Ref<Node>&&, unsigned offset);
     WEBCORE_EXPORT ExceptionOr<void> setEnd(Ref<Node>&&, unsigned offset);
     WEBCORE_EXPORT ExceptionOr<void> setStartBefore(Node&);
@@ -133,6 +136,7 @@ class Range final : public AbstractRange, public CanMakeWeakPtr<Range> {
     RangeBoundaryPoint m_start;
     RangeBoundaryPoint m_end;
     bool m_isAssociatedWithSelection { false };
+    bool m_didChangeHighlight { false };
 };
 
 WEBCORE_EXPORT SimpleRange makeSimpleRange(const Range&);