Support for CSSOM CSSNamespaceRule interface

Source/core/css/StyleSheetContents.cpp

Index: Source/core/css/StyleSheetContents.cpp
diff --git a/Source/core/css/StyleSheetContents.cpp b/Source/core/css/StyleSheetContents.cpp
index 8769973ac24db5e64a08a10153db03957ce0627b..4f240e9e00879ce63d095ec90c5b5929586f6245 100644
--- a/Source/core/css/StyleSheetContents.cpp
+++ b/Source/core/css/StyleSheetContents.cpp
@@ -75,6 +75,7 @@ StyleSheetContents::StyleSheetContents(const StyleSheetContents& o)
     : m_ownerRule(nullptr)
     , m_originalURL(o.m_originalURL)
     , m_importRules(o.m_importRules.size())
+    , m_namespaceRules(o.m_namespaceRules.size())
     , m_childRules(o.m_childRules.size())
     , m_namespaces(o.m_namespaces)
     , m_hasSyntacticallyValidCSSHeader(o.m_hasSyntacticallyValidCSSHeader)
@@ -156,10 +157,12 @@ void StyleSheetContents::parserAppendRule(PassRefPtrWillBeRawPtr<StyleRuleBase>
     }
 
     if (rule->isNamespaceRule()) {
-        // Parser enforces that @namespace rules come before anything else
+        // Parser enforces that @namespace rules come before all rules other than
+        // import/namespace/charset rules

[Timothy Loh, 2015/09/04 01:35:50]

not sure you want to write namespace here

[ramya.v, 2015/09/07 09:06:28]

Done.

         ASSERT(m_childRules.isEmpty());
         StyleRuleNamespace& namespaceRule = toStyleRuleNamespace(*rule);
         parserAddNamespace(namespaceRule.prefix(), namespaceRule.uri());
+        m_namespaceRules.append(&namespaceRule);
         return;
     }
 
@@ -184,12 +187,18 @@ StyleRuleBase* StyleSheetContents::ruleAt(unsigned index) const
         return m_importRules[index].get();
 
     index -= m_importRules.size();
+
+    if (index < m_namespaceRules.size())
+        return m_namespaceRules[index].get();
+
+    index -= m_namespaceRules.size();
+
     return m_childRules[index].get();
 }
 
 unsigned StyleSheetContents::ruleCount() const
 {
-    return m_importRules.size() + m_childRules.size();
+    return m_importRules.size() + m_namespaceRules.size() + m_childRules.size();
 }
 
 void StyleSheetContents::clearRules()
@@ -199,6 +208,7 @@ void StyleSheetContents::clearRules()
         m_importRules[i]->clearParentStyleSheet();
     }
     m_importRules.clear();
+    m_namespaceRules.clear();
     m_childRules.clear();
 }
 
@@ -231,13 +241,32 @@ bool StyleSheetContents::wrapperInsertRule(PassRefPtrWillBeRawPtr<StyleRuleBase>
 
     index -= m_importRules.size();
 
+    if (index < m_namespaceRules.size() || (index == m_namespaceRules.size() && rule->isNamespaceRule())) {
+        // Inserting non-namespace rules other than import rule before @namespace is not allowed.
+        if (!rule->isNamespaceRule())
+            return false;
+        // Inserting @namespace rule when rules other than import/namespace/charset are present is not allowed.
+        if (m_childRules.size() > 0)
+            return false;
+
+        StyleRuleNamespace* namespaceRule = toStyleRuleNamespace(rule.get());
+        m_namespaceRules.insert(index, namespaceRule);
+        parserAddNamespace(namespaceRule->prefix(), namespaceRule->uri());

[Timothy Loh, 2015/09/04 01:35:50]

parserAddNamespace won't do what you want here. If a stylesheet specifies a
namespace prefix multiple times, the url is given by the last valid declaration.
If a namespace rule is inserted in the middle of a bunch of namespace rules, we
might end up using that rule instead of a later one with the same prefix.

[ramya.v, 2015/09/07 05:28:23]

Hi Tim just one doubt.
As per spec it was given
If a namespace prefix or default namespace is declared more than once only the
last declaration shall be used. Declaring a namespace prefix or default
namespace more than once is nonconforming.


As per your comments what I understood is if there are bunch of namespace rules
with same prefix, the rule which comes last in css rule list should be used.

However firefox and IE are using the rule which is declared later in time frame
even if it is added an index previous to existing namespace rules.

Ex: In the below example as per our understanding div3 with mango should have
background color red, however in Firefox and IE div2 with apple is having
background color red.

<html xmlns="http://www.w3.org/1999/xhtml">
    
    <style>
    @namespace abc url(banana);
     </style>


     <div id="div1" xmlns="banana"> div1</div>
	 <div id="div3" xmlns="apple">div3</div>
	 <div id="div2" xmlns="mango">div2</div>
    <script>
	document.styleSheets[0].insertRule('@namespace abc url(mango);',
document.styleSheets[0].cssRules.length);
	document.styleSheets[0].insertRule('@namespace abc url(apple);', 0);
	document.styleSheets[0].insertRule('div { color: red;}',
document.styleSheets[0].cssRules.length);
	document.styleSheets[0].insertRule('abc|div { color: green;}',
document.styleSheets[0].cssRules.length);
	</script>
</html>


Can you please let me know if this compatibility difference is fine?
Do I have to confirm the behavior with spec editors?

+        return true;
+    }
+
+    if (rule->isNamespaceRule())
+        return false;
+
+    index -= m_namespaceRules.size();
+
     if (rule->isFontFaceRule())
         setHasFontFaceRule(true);
     m_childRules.insert(index, rule);
     return true;
 }
 
-void StyleSheetContents::wrapperDeleteRule(unsigned index)
+bool StyleSheetContents::wrapperDeleteRule(unsigned index)
 {
     ASSERT(m_isMutable);
     ASSERT_WITH_SECURITY_IMPLICATION(index < ruleCount());
@@ -247,13 +276,22 @@ void StyleSheetContents::wrapperDeleteRule(unsigned index)
         if (m_importRules[index]->isFontFaceRule())
             notifyRemoveFontFaceRule(toStyleRuleFontFace(m_importRules[index].get()));
         m_importRules.remove(index);
-        return;
+        return true;
     }
     index -= m_importRules.size();
 
+    if (index < m_namespaceRules.size()) {
+        if (m_childRules.size() > 0)

[Timothy Loh, 2015/09/04 01:35:50]

!m_childRules.isEmpty() probably reads better

[ramya.v, 2015/09/07 09:06:28]

Done.

+            return false;
+        m_namespaceRules.remove(index);
+        return true;
+    }
+    index -= m_namespaceRules.size();
+
     if (m_childRules[index]->isFontFaceRule())
         notifyRemoveFontFaceRule(toStyleRuleFontFace(m_childRules[index].get()));
     m_childRules.remove(index);
+    return true;
 }
 
 void StyleSheetContents::parserAddNamespace(const AtomicString& prefix, const AtomicString& uri)
@@ -624,6 +662,7 @@ DEFINE_TRACE(StyleSheetContents)
 #if ENABLE(OILPAN)
     visitor->trace(m_ownerRule);
     visitor->trace(m_importRules);
+    visitor->trace(m_namespaceRules);
     visitor->trace(m_childRules);
     visitor->trace(m_loadingClients);
     visitor->trace(m_completedClients);