Changeset 143076 in webkit

Timestamp:

Feb 15, 2013 5:39:19 PM (11 years ago)

Author:

akling@apple.com

Message:

Calling DOM Element.attributes shouldn't force creation of ElementData.
<​http://webkit.org/b/109976>

Reviewed by Darin Adler.

Don't create ElementData for an Element unnecessarily just because someone calls .attributes on it.
Previously, JS like this would create empty ElementData when 'element' has no attributes:

for (i = 0; i < element.attributes.length; ++i)

doStuff(element.attributes[i]);

Make NamedNodeMap::length() short-circuit and return 0 if !Element::hasAttributes().

• dom/Element.cpp:

(WebCore::Element::attributes):

• dom/NamedNodeMap.cpp:

(WebCore::NamedNodeMap::length):

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• dom/Element.cpp (modified) (1 diff)
• dom/NamedNodeMap.cpp (modified) (1 diff)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2013-02-15  Andreas Kling  <akling@apple.com>
+
+        Calling DOM Element.attributes shouldn't force creation of ElementData.
+        <http://webkit.org/b/109976>
+
+        Reviewed by Darin Adler.
+
+        Don't create ElementData for an Element unnecessarily just because someone calls .attributes on it.
+        Previously, JS like this would create empty ElementData when 'element' has no attributes:
+
+            for (i = 0; i < element.attributes.length; ++i)
+                doStuff(element.attributes[i]);
+
+        Make NamedNodeMap::length() short-circuit and return 0 if !Element::hasAttributes().
+
+        * dom/Element.cpp:
+        (WebCore::Element::attributes):
+        * dom/NamedNodeMap.cpp:
+        (WebCore::NamedNodeMap::length):
+
 2013-02-15  Kentaro Hara  <haraken@chromium.org>
 

trunk/Source/WebCore/dom/Element.cpp

@@ -314 +314 @@
 NamedNodeMap* Element::attributes() const
 {
-    ensureElementDataWithSynchronizedAttributes();
     ElementRareData* rareData = const_cast<Element*>(this)->ensureElementRareData();
     if (NamedNodeMap* attributeMap = rareData->attributeMap())

trunk/Source/WebCore/dom/NamedNodeMap.cpp

@@ -111 +111 @@
 size_t NamedNodeMap::length() const
 {
+    if (!m_element->hasAttributes())
+        return 0;
     return m_element->attributeCount();
 }