Add cache for SVGPathElement "d" attribute parsing

https://bugs.webkit.org/show_bug.cgi?id=263195 rdar://110970184 Reviewed by Ryosuke Niwa. Add cache for SVGPathElement "d" attribute parsing to avoid spending CPU time re-parsing the same "d" attribute values. * Source/WebCore/page/MemoryRelease.cpp: (WebCore::releaseNoncriticalMemory): * Source/WebCore/svg/SVGPathByteStream.h: (WebCore::SVGPathByteStream::setData): * Source/WebCore/svg/SVGPathElement.cpp: (WebCore::pathSegListCache): (WebCore::SVGPathElement::attributeChanged): (WebCore::SVGPathElement::clearCache): * Source/WebCore/svg/SVGPathElement.h: * Source/WebCore/svg/SVGPathSegList.h: Canonical link: https://commits.webkit.org/269372@main
WebKit · Oct 16, 2023 · 75b8829 · 75b8829
1 parent 722fe4f
commit 75b8829
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Showing 5 changed files with 46 additions and 2 deletions.
diff --git a/Source/WebCore/page/MemoryRelease.cpp b/Source/WebCore/page/MemoryRelease.cpp
@@ -50,6 +50,7 @@
 #include "Page.h"
 #include "PerformanceLogging.h"
 #include "RenderTheme.h"
+#include "SVGPathElement.h"
 #include "ScrollingThread.h"
 #include "SelectorQuery.h"
 #include "StyleScope.h"
@@ -89,6 +90,7 @@ static void releaseNoncriticalMemory(MaintainMemoryCache maintainMemoryCache)
     InlineStyleSheetOwner::clearCache();
     HTMLNameCache::clear();
     ImmutableStyleProperties::clearDeduplicationMap();
+    SVGPathElement::clearCache();
 }
 
 static void releaseCriticalMemory(Synchronous synchronous, MaintainBackForwardCache maintainBackForwardCache, MaintainMemoryCache maintainMemoryCache)

diff --git a/Source/WebCore/svg/SVGPathByteStream.h b/Source/WebCore/svg/SVGPathByteStream.h
@@ -89,6 +89,7 @@ class SVGPathByteStream {
     void shrinkToFit() { m_data.shrinkToFit(); }
 
     const Data& data() const { return m_data; }
+    void setData(const Data& data) { m_data = data; }
 
 private:
     Data m_data;

diff --git a/Source/WebCore/svg/SVGPathElement.cpp b/Source/WebCore/svg/SVGPathElement.cpp
@@ -37,6 +37,15 @@ namespace WebCore {
 
 WTF_MAKE_ISO_ALLOCATED_IMPL(SVGPathElement);
 
+static constexpr uint64_t maxPathSegListCacheSize = 150 * 1024; // 150 Kb.
+static uint64_t pathSegListCacheSize = 0;
+
+static HashMap<AtomString, SVGPathByteStream::Data>& pathSegListCache()
+{
+    static MainThreadNeverDestroyed<HashMap<AtomString, SVGPathByteStream::Data>> cache;
+    return cache;
+}
+
 inline SVGPathElement::SVGPathElement(const QualifiedName& tagName, Document& document)
     : SVGGeometryElement(tagName, document, makeUniqueRef<PropertyRegistry>(*this))
 {
@@ -56,13 +65,35 @@ Ref<SVGPathElement> SVGPathElement::create(const QualifiedName& tagName, Documen
 void SVGPathElement::attributeChanged(const QualifiedName& name, const AtomString& oldValue, const AtomString& newValue, AttributeModificationReason attributeModificationReason)
 {
     if (name == SVGNames::dAttr) {
-        if (!m_pathSegList->baseVal()->parse(newValue))
-            document().accessSVGExtensions().reportError("Problem parsing d=\"" + newValue + "\"");
+        auto& cache = pathSegListCache();
+        if (auto it = cache.find(newValue); it != cache.end())
+            m_pathSegList->baseVal()->updateByteStreamData(it->value);
+        else {
+            if (m_pathSegList->baseVal()->parse(newValue)) {
+                size_t newDataSize = m_pathSegList->baseVal()->existingPathByteStream().data().size();
+                if (LIKELY(newDataSize <= (maxPathSegListCacheSize / 2))) {
+                    pathSegListCacheSize += newDataSize;
+                    while (pathSegListCacheSize > maxPathSegListCacheSize) {
+                        auto iteratorToRemove = cache.random();
+                        ASSERT(pathSegListCacheSize >= iteratorToRemove->value.size());
+                        pathSegListCacheSize -= iteratorToRemove->value.size();
+                        cache.remove(iteratorToRemove);
+                    }
+                    cache.add(newValue, m_pathSegList->baseVal()->existingPathByteStream().data());
+                }
+            } else
+                document().accessSVGExtensions().reportError("Problem parsing d=\"" + newValue + "\"");
+        }
     }
 
     SVGGeometryElement::attributeChanged(name, oldValue, newValue, attributeModificationReason);
 }
 
+void SVGPathElement::clearCache()
+{
+    pathSegListCache().clear();
+}
+
 void SVGPathElement::svgAttributeChanged(const QualifiedName& attrName)
 {
     if (PropertyRegistry::isKnownAttribute(attrName)) {

diff --git a/Source/WebCore/svg/SVGPathElement.h b/Source/WebCore/svg/SVGPathElement.h
@@ -100,6 +100,8 @@ class SVGPathElement final : public SVGGeometryElement {
     Path path() const { return m_pathSegList->currentPath(); }
     size_t approximateMemoryCost() const final { return m_pathSegList->approximateMemoryCost(); }
 
+    static void clearCache();
+
 private:
     SVGPathElement(const QualifiedName&, Document&);
 

diff --git a/Source/WebCore/svg/SVGPathSegList.h b/Source/WebCore/svg/SVGPathSegList.h
@@ -123,6 +123,14 @@ class SVGPathSegList final : public SVGPropertyList<SVGPathSeg> {
         return { };
     }
 
+    void updateByteStreamData(const SVGPathByteStream::Data& byteStreamData)
+    {
+        pathByteStreamWillChange();
+        m_pathByteStream.setData(byteStreamData);
+    }
+
+    const SVGPathByteStream& existingPathByteStream() const { return m_pathByteStream; }
+
     const SVGPathByteStream& pathByteStream() const { return const_cast<SVGPathSegList*>(this)->pathByteStream(); }
     SVGPathByteStream& pathByteStream()
     {