Make custom element name checks faster and fewer

third_party/WebKit/Source/core/dom/custom/CustomElement.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CustomElement_h
 #define CustomElement_h
 
 #include "core/CoreExport.h"
 #include "core/HTMLNames.h"
 #include "core/dom/Element.h"
+#include "platform/RuntimeEnabledFeatures.h"
+#include "platform/text/Character.h"
 #include "wtf/Allocator.h"
 #include "wtf/text/AtomicString.h"
 
 namespace blink {
 
 class Document;
 class Element;
 class HTMLElement;
 class QualifiedName;
 class CustomElementDefinition;
 class CustomElementReaction;
 class CustomElementRegistry;
 
 class CORE_EXPORT CustomElement {
     STATIC_ONLY(CustomElement);
 public:
     // Retrieves the CustomElementRegistry for Element, if any. This
     // may be a different object for a given element over its lifetime
     // as it moves between documents.
     static CustomElementRegistry* registry(const Element&);
     static CustomElementRegistry* registry(const Document&);
 
     static CustomElementDefinition* definitionForElement(const Element*);
 
-    static bool isValidName(const AtomicString& name);
+    static bool isValidName(const AtomicString& name)
+    {
+        if (!name.length() || name[0] < 'a' || name[0] > 'z')

[kouhei (in TOK), 2016/08/29 06:59:55]

Can we refactor the name[0] check as a platform/text/Character method?

+            return false;
 
-    static bool shouldCreateCustomElement(const AtomicString& localName);
+        bool hasHyphens = false;
+        if (name.is8Bit()) {
+            for (size_t i = 1; i < name.length(); ) {
+                UChar ch = name[i++];
+                if (ch == '-')
+                    hasHyphens = true;
+                else if (!Character::isPotentialCustomElementNameChar(ch))
+                    return false;
+            }
+        } else {
+            for (size_t i = 1; i < name.length(); ) {
+                UChar32 ch;
+                U16_NEXT(name.characters16(), i, name.length(), ch);
+                if (ch == '-')
+                    hasHyphens = true;
+                else if (!Character::isPotentialCustomElementNameChar(ch))
+                    return false;
+            }
+        }
+        return hasHyphens && !isHyphenContainingElementName(name);
+    }
+
+    static bool shouldCreateCustomElement(const AtomicString& localName)
+    {
+        return RuntimeEnabledFeatures::customElementsV1Enabled()
+            && isValidName(localName);
+    }
+
     static bool shouldCreateCustomElement(const QualifiedName&);
 
-    static HTMLElement* createCustomElementSync(Document&, const AtomicString& localName, ExceptionState&);
-    static HTMLElement* createCustomElementSync(Document&, const QualifiedName&, ExceptionState&);
-    static HTMLElement* createCustomElementSync(Document&, const QualifiedName&);
+    static HTMLElement* createCustomElementSync(Document&, const AtomicString& localName, ExceptionState*);

[esprehn, 2016/08/30 21:32:32]

We normally do ExceptionState& and then default argument = ASSERT_NO_EXCEPTION

+    static HTMLElement* createCustomElementSync(Document&, const QualifiedName&, ExceptionState*);
     static HTMLElement* createCustomElementAsync(Document&, const QualifiedName&);
 
     static HTMLElement* createFailedElement(Document&, const QualifiedName&);
 
     static void enqueue(Element*, CustomElementReaction*);
     static void enqueueConnectedCallback(Element*);
     static void enqueueDisconnectedCallback(Element*);
     static void enqueueAdoptedCallback(Element*);
     static void enqueueAttributeChangedCallback(Element*, const QualifiedName&,
         const AtomicString& oldValue, const AtomicString& newValue);
 
     static void tryToUpgrade(Element*);
 
 private:
     static HTMLElement* createUndefinedElement(Document&, const QualifiedName&);
+
+    // A hyphen-containing element name is an element name from a
+    // specification which contains a hyphen, for example, font-face
+    // from SVG. These are not allowed as custom element names.
+    static bool isHyphenContainingElementName(const AtomicString&);
 };
 
 } // namespace blink
 
 #endif // CustomElement_h