Changeset 127375 in webkit

Timestamp:

Sep 1, 2012 10:47:39 AM (12 years ago)

Author:

kling@webkit.org

Message:

Share inline style between cloned Nodes (copy on write.)
<​http://webkit.org/b/95451>

Reviewed by Antti Koivisto.

When cloning a Node, use an immutable StylePropertySet for the new Node's inline style.
If the old Node already had an immutable inline style, we now reuse that, avoiding a copy.
Copying is deferred until mutation (either via CSSOM or setting of the style attribute.)

• dom/ElementAttributeData.cpp:

(WebCore::ElementAttributeData::cloneDataFrom):

• css/StylePropertySet.h:
• css/StylePropertySet.cpp:

(WebCore::StylePropertySet::immutableCopyIfNeeded):

Added. Simply returns 'this' if the object is already immutable, otherwise creates a new one.

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• css/StylePropertySet.cpp (modified) (1 diff)
• css/StylePropertySet.h (modified) (1 diff)
• dom/ElementAttributeData.cpp (modified) (1 diff)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2012-09-01  Andreas Kling  <kling@webkit.org>
+
+        Share inline style between cloned Nodes (copy on write.)
+        <http://webkit.org/b/95451>
+
+        Reviewed by Antti Koivisto.
+
+        When cloning a Node, use an immutable StylePropertySet for the new Node's inline style.
+        If the old Node already had an immutable inline style, we now reuse that, avoiding a copy.
+        Copying is deferred until mutation (either via CSSOM or setting of the style attribute.)
+
+        * dom/ElementAttributeData.cpp:
+        (WebCore::ElementAttributeData::cloneDataFrom):
+        * css/StylePropertySet.h:
+        * css/StylePropertySet.cpp:
+        (WebCore::StylePropertySet::immutableCopyIfNeeded):
+
+            Added. Simply returns 'this' if the object is already immutable, otherwise creates a new one.
+
 2012-09-01  Dirk Schulze  <krit@webkit.org>
 

trunk/Source/WebCore/css/StylePropertySet.cpp

@@ -60 +60 @@
     void* slot = WTF::fastMalloc(immutableStylePropertySetSize(count));
     return adoptRef(new (slot) StylePropertySet(properties, count, cssParserMode, /* makeMutable */ false));
+}
+
+PassRefPtr<StylePropertySet> StylePropertySet::immutableCopyIfNeeded() const
+{
+    if (!isMutable())
+        return const_cast<StylePropertySet*>(this);
+    return createImmutable(m_mutablePropertyVector->data(), m_mutablePropertyVector->size(), cssParserMode());
 }
 

trunk/Source/WebCore/css/StylePropertySet.h

@@ -92 +92 @@
 
     PassRefPtr<StylePropertySet> copy() const;
+    PassRefPtr<StylePropertySet> immutableCopyIfNeeded() const;
 
     void removeEquivalentProperties(const StylePropertySet*);

trunk/Source/WebCore/dom/ElementAttributeData.cpp

@@ -364 +364 @@
 
     if (targetElement.isStyledElement() && sourceData.m_inlineStyleDecl) {
-        m_inlineStyleDecl = sourceData.m_inlineStyleDecl->copy();
+        m_inlineStyleDecl = sourceData.m_inlineStyleDecl->immutableCopyIfNeeded();
         targetElement.setIsStyleAttributeValid(sourceElement.isStyleAttributeValid());
     }