Bug 394442, Optimize ID, class and style getters, r=bz+sicking, sr=sicking, a=jst

content/base/public/nsINode.h

@@ -92,8 +92,14 @@ enum {
 
   NODE_IS_EDITABLE =             0x00000100U,
 
+  // Optimizations to quickly check whether element may have ID, class or style
+  // attributes. Not all element implementations may use these!
+  NODE_MAY_HAVE_ID =             0x00000200U,
+  NODE_MAY_HAVE_CLASS =          0x00000400U,
+  NODE_MAY_HAVE_STYLE =          0x00000800U,
+
   // Four bits for the script-type ID
-  NODE_SCRIPT_TYPE_OFFSET =                9,
+  NODE_SCRIPT_TYPE_OFFSET =               12,
 
   NODE_SCRIPT_TYPE_SIZE =                  4,
 

content/base/src/nsGenericElement.cpp

@@ -2268,6 +2268,10 @@ nsGenericElement::DispatchDOMEvent(nsEvent* aEvent,
 nsIAtom*
 nsGenericElement::GetID() const
 {
+  if (!HasFlag(NODE_MAY_HAVE_ID)) {
+    return nsnull;
+  }
+
   nsIAtom* IDName = GetIDAttributeName();
   if (IDName) {
     const nsAttrValue* attrVal = mAttrsAndChildren.GetAttr(IDName);
@@ -3683,6 +3687,7 @@ nsGenericElement::ParseAttribute(PRInt32 aNamespaceID,
 {
   if (aNamespaceID == kNameSpaceID_None &&
       aAttribute == GetIDAttributeName() && !aValue.IsEmpty()) {
+    SetFlags(NODE_MAY_HAVE_ID);
     // Store id as an atom.  id="" means that the element has no id,
     // not that it has an emptystring as the id.
     aResult.ParseAtom(aValue);

content/base/src/nsStyledElement.cpp

@@ -73,6 +73,9 @@ nsStyledElement::GetIDAttributeName() const
 const nsAttrValue*
 nsStyledElement::GetClasses() const
 {
+  if (!HasFlag(NODE_MAY_HAVE_CLASS)) {
+    return nsnull;
+  }
   return mAttrsAndChildren.GetAttr(nsGkAtoms::_class);
 }
 
@@ -82,10 +85,12 @@ nsStyledElement::ParseAttribute(PRInt32 aNamespaceID, nsIAtom* aAttribute,
 {
   if (aNamespaceID == kNameSpaceID_None) {
     if (aAttribute == nsGkAtoms::style) {
+      SetFlags(NODE_MAY_HAVE_STYLE);
       ParseStyleAttribute(this, aValue, aResult);
       return PR_TRUE;
     }
     if (aAttribute == nsGkAtoms::_class) {
+      SetFlags(NODE_MAY_HAVE_CLASS);
 #ifdef MOZ_SVG
       NS_ASSERTION(!nsCOMPtr<nsIDOMSVGStylable>(do_QueryInterface(this)),
                    "SVG code should have handled this 'class' attribute!");
@@ -102,6 +107,7 @@ nsStyledElement::ParseAttribute(PRInt32 aNamespaceID, nsIAtom* aAttribute,
 NS_IMETHODIMP
 nsStyledElement::SetInlineStyleRule(nsICSSStyleRule* aStyleRule, PRBool aNotify)
 {
+  SetFlags(NODE_MAY_HAVE_STYLE);
   PRBool modification = PR_FALSE;
   nsAutoString oldValueStr;
 
@@ -135,6 +141,9 @@ nsStyledElement::SetInlineStyleRule(nsICSSStyleRule* aStyleRule, PRBool aNotify)
 nsICSSStyleRule*
 nsStyledElement::GetInlineStyleRule()
 {
+  if (!HasFlag(NODE_MAY_HAVE_STYLE)) {
+    return nsnull;
+  }
   const nsAttrValue* attrVal = mAttrsAndChildren.GetAttr(nsGkAtoms::style);
 
   if (attrVal && attrVal->Type() == nsAttrValue::eCSSStyleRule) {
@@ -186,6 +195,7 @@ nsStyledElement::GetStyle(nsIDOMCSSStyleDeclaration** aStyle)
     rv = gCSSOMFactory->CreateDOMCSSAttributeDeclaration(this,
                                                  getter_AddRefs(slots->mStyle));
     NS_ENSURE_SUCCESS(rv, rv);
+    SetFlags(NODE_MAY_HAVE_STYLE);
   }
 
   // Why bother with QI?
@@ -196,6 +206,9 @@ nsStyledElement::GetStyle(nsIDOMCSSStyleDeclaration** aStyle)
 nsresult
 nsStyledElement::ReparseStyleAttribute()
 {
+  if (!HasFlag(NODE_MAY_HAVE_STYLE)) {
+    return NS_OK;
+  }
   const nsAttrValue* oldVal = mAttrsAndChildren.GetAttr(nsGkAtoms::style);
   
   if (oldVal && oldVal->Type() != nsAttrValue::eCSSStyleRule) {

content/xul/content/src/nsXULElement.cpp

@@ -275,6 +275,15 @@ nsXULElement::Create(nsXULPrototypeElement* aPrototype, nsINodeInfo *aNodeInfo,
         NS_ADDREF(element);
 
         element->mPrototype = aPrototype;
+        if (aPrototype->mHasIdAttribute) {
+            element->SetFlags(NODE_MAY_HAVE_ID);
+        }
+        if (aPrototype->mHasClassAttribute) {
+            element->SetFlags(NODE_MAY_HAVE_CLASS);
+        }
+        if (aPrototype->mHasStyleAttribute) {
+            element->SetFlags(NODE_MAY_HAVE_STYLE);
+        }
 
         NS_ASSERTION(aPrototype->mScriptTypeID != nsIProgrammingLanguage::UNKNOWN,
                     "Need to know the language!");
@@ -1069,11 +1078,13 @@ nsXULElement::ParseAttribute(PRInt32 aNamespaceID,
     // Any changes should be made to both functions.
     if (aNamespaceID == kNameSpaceID_None) {
         if (aAttribute == nsGkAtoms::style) {
+            SetFlags(NODE_MAY_HAVE_STYLE);
             nsStyledElement::ParseStyleAttribute(this, aValue, aResult);
             return PR_TRUE;
         }
 
         if (aAttribute == nsGkAtoms::_class) {
+            SetFlags(NODE_MAY_HAVE_CLASS);
             aResult.ParseAtomArray(aValue);
             return PR_TRUE;
         }
@@ -1632,6 +1643,10 @@ nsXULElement::InsertChildAt(nsIContent* aKid, PRUint32 aIndex, PRBool aNotify)
 nsIAtom*
 nsXULElement::GetID() const
 {
+    if (!HasFlag(NODE_MAY_HAVE_ID)) {
+        return nsnull;
+    }
+
     const nsAttrValue* attrVal = FindLocalOrProtoAttr(kNameSpaceID_None, nsGkAtoms::id);
 
     NS_ASSERTION(!attrVal ||
@@ -1649,6 +1664,9 @@ nsXULElement::GetID() const
 const nsAttrValue*
 nsXULElement::GetClasses() const
 {
+    if (!HasFlag(NODE_MAY_HAVE_CLASS)) {
+        return nsnull;
+    }
     return FindLocalOrProtoAttr(kNameSpaceID_None, nsGkAtoms::_class);
 }
 
@@ -1661,6 +1679,9 @@ nsXULElement::WalkContentStyleRules(nsRuleWalker* aRuleWalker)
 nsICSSStyleRule*
 nsXULElement::GetInlineStyleRule()
 {
+    if (!HasFlag(NODE_MAY_HAVE_STYLE)) {
+        return nsnull;
+    }
     // Fetch the cached style rule from the attributes.
     const nsAttrValue* attrVal = FindLocalOrProtoAttr(kNameSpaceID_None, nsGkAtoms::style);
 
@@ -1674,6 +1695,7 @@ nsXULElement::GetInlineStyleRule()
 NS_IMETHODIMP
 nsXULElement::SetInlineStyleRule(nsICSSStyleRule* aStyleRule, PRBool aNotify)
 {
+  SetFlags(NODE_MAY_HAVE_STYLE);
   PRBool modification = PR_FALSE;
   nsAutoString oldValueStr;
 
@@ -1887,6 +1909,7 @@ nsXULElement::GetStyle(nsIDOMCSSStyleDeclaration** aStyle)
         rv = gCSSOMFactory->CreateDOMCSSAttributeDeclaration(this,
                 getter_AddRefs(slots->mStyle));
         NS_ENSURE_SUCCESS(rv, rv);
+        SetFlags(NODE_MAY_HAVE_STYLE);
     }
 
     NS_IF_ADDREF(*aStyle = slots->mStyle);
@@ -2470,7 +2493,10 @@ nsXULPrototypeElement::Deserialize(nsIObjectInputStream* aStream,
     nsresult rv;
 
     // Read script language
-    rv = aStream->Read32(&mScriptTypeID);
+    PRUint32 scriptId = 0;
+    rv = aStream->Read32(&scriptId);
+    mScriptTypeID = scriptId;
+
     // Read Node Info
     PRUint32 number;
     rv |= aStream->Read32(&number);
@@ -2610,6 +2636,7 @@ nsXULPrototypeElement::SetAttrAt(PRUint32 aPos, const nsAString& aValue,
 
     if (mAttributes[aPos].mName.Equals(nsGkAtoms::id) &&
         !aValue.IsEmpty()) {
+        mHasIdAttribute = PR_TRUE;
         // Store id as atom.
         // id="" means that the element has no id. Not that it has
         // emptystring as id.
@@ -2618,12 +2645,14 @@ nsXULPrototypeElement::SetAttrAt(PRUint32 aPos, const nsAString& aValue,
         return NS_OK;
     }
     else if (mAttributes[aPos].mName.Equals(nsGkAtoms::_class)) {
+        mHasClassAttribute = PR_TRUE;
         // Compute the element's class list
         mAttributes[aPos].mValue.ParseAtomArray(aValue);
         
         return NS_OK;
     }
     else if (mAttributes[aPos].mName.Equals(nsGkAtoms::style)) {
+        mHasStyleAttribute = PR_TRUE;
         // Parse the element's 'style' attribute
         nsCOMPtr<nsICSSStyleRule> rule;
         nsICSSParser* parser = GetCSSParser();

content/xul/content/src/nsXULElement.h

@@ -246,6 +246,9 @@ public:
           mChildren(nsnull),
           mNumAttributes(0),
           mAttributes(nsnull),
+          mHasIdAttribute(PR_FALSE),
+          mHasClassAttribute(PR_FALSE),
+          mHasStyleAttribute(PR_FALSE),
           mScriptTypeID(nsIProgrammingLanguage::UNKNOWN)
     {
         NS_LOG_ADDREF(this, 1, ClassName(), ClassSize());
@@ -298,12 +301,16 @@ public:
 
     PRUint32                 mNumAttributes;
     nsXULPrototypeAttribute* mAttributes;         // [OWNER]
+    
+    PRPackedBool             mHasIdAttribute:1;
+    PRPackedBool             mHasClassAttribute:1;
+    PRPackedBool             mHasStyleAttribute:1;
 
     // The language ID can not be set on a per-node basis, but is tracked
     // so that the language ID from the originating root can be used
     // (eg, when a node from an overlay ends up in our document, that node
     // must use its original script language, not our document's default.
-    PRUint32                 mScriptTypeID;
+    PRUint16                 mScriptTypeID;
     static void ReleaseGlobals()
     {
         NS_IF_RELEASE(sCSSParser);

content/xul/document/src/nsXULContentSink.cpp

@@ -855,7 +855,9 @@ XULContentSinkImpl::SetElementScriptType(nsXULPrototypeElement* element,
             // Ask the top-node for its script type (which has already
             // had this function called for it - so no need to recurse
             // until we find it)
-            rv = mContextStack.GetTopNodeScriptType(&element->mScriptTypeID);
+            PRUint32 scriptId = 0;
+            rv = mContextStack.GetTopNodeScriptType(&scriptId);
+            element->mScriptTypeID = scriptId;
         }
     }
     return rv;