Make custom element name checks faster and fewer

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

 // 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.
 
 #include "core/dom/custom/CustomElement.h"
 
 #include "core/dom/Document.h"
 #include "core/dom/QualifiedName.h"
 #include "core/dom/custom/CEReactionsScope.h"
 #include "core/dom/custom/CustomElementDefinition.h"
 #include "core/dom/custom/CustomElementReactionStack.h"
 #include "core/dom/custom/CustomElementRegistry.h"
 #include "core/dom/custom/V0CustomElement.h"
 #include "core/dom/custom/V0CustomElementRegistrationContext.h"
 #include "core/frame/LocalDOMWindow.h"
 #include "core/html/HTMLElement.h"
 #include "core/html/HTMLUnknownElement.h"
-#include "platform/text/Character.h"
 #include "wtf/text/AtomicStringHash.h"
 
 namespace blink {
 
 CustomElementRegistry* CustomElement::registry(const Element& element)
 {
     return registry(element.document());
 }
 
 CustomElementRegistry* CustomElement::registry(const Document& document)
 {
     if (LocalDOMWindow* window = document.executingWindow())
         return window->customElements();
     return nullptr;
 }
 
 static CustomElementDefinition* definitionForElementWithoutCheck(const Element& element)
 {
     DCHECK_EQ(element.getCustomElementState(), CustomElementState::Custom);
     return element.customElementDefinition();
 }
 
 CustomElementDefinition* CustomElement::definitionForElement(const Element* element)
 {
     if (!element || element->getCustomElementState() != CustomElementState::Custom)
         return nullptr;
     return definitionForElementWithoutCheck(*element);
 }
 
-bool CustomElement::isValidName(const AtomicString& name)
+bool CustomElement::isHyphenatedSpecElementName(const AtomicString& name)
 {
-    if (!name.length() || name[0] < 'a' || name[0] > 'z')
-        return false;
-
-    bool hasHyphens = false;
-    for (size_t i = 1; i < name.length(); ) {
-        UChar32 ch;
-        if (name.is8Bit())
-            ch = name[i++];
-        else
-            U16_NEXT(name.characters16(), i, name.length(), ch);
-        if (ch == '-')
-            hasHyphens = true;
-        else if (!Character::isPotentialCustomElementNameChar(ch))
-            return false;
-    }
-    if (!hasHyphens)
-        return false;
-
-    // https://html.spec.whatwg.org/multipage/scripting.html#valid-custom-element-name
-    DEFINE_STATIC_LOCAL(HashSet<AtomicString>, hyphenContainingElementNames, ({
+    // Even if Blink does not implement one of the related specs, (for
+    // example annotation-xml is from MathML, which Blink does not
+    // implement) we must prohibit using the name because that is
+    // required by the HTML spec which we *do* implement. Don't remove
+    // names from this list without removing them from the HTML spec
+    // first.
+    DEFINE_STATIC_LOCAL(HashSet<AtomicString>, hyphenatedSpecElementNames, ({
         "annotation-xml",
         "color-profile",
         "font-face",
         "font-face-src",
         "font-face-uri",
         "font-face-format",
         "font-face-name",
         "missing-glyph",
     }));
-    return !hyphenContainingElementNames.contains(name);
+    return hyphenatedSpecElementNames.contains(name);
 }
 
 bool CustomElement::shouldCreateCustomElement(const AtomicString& localName)
 {
     return RuntimeEnabledFeatures::customElementsV1Enabled()
         && isValidName(localName);
 }
 
 bool CustomElement::shouldCreateCustomElement(const QualifiedName& tagName)
 {
@@ skipping 10 matching lines @@
 
 HTMLElement* CustomElement::createCustomElementSync(Document& document, const AtomicString& localName, ExceptionState& exceptionState)
 {
     return createCustomElementSync(document,
         QualifiedName(nullAtom, localName, HTMLNames::xhtmlNamespaceURI),
         exceptionState);
 }
 
 HTMLElement* CustomElement::createCustomElementSync(Document& document, const QualifiedName& tagName, ExceptionState& exceptionState)
 {
-    CHECK(shouldCreateCustomElement(tagName));
+    DCHECK(shouldCreateCustomElement(tagName));
 
     // To create an element:
     // https://dom.spec.whatwg.org/#concept-create-element
     // 6. If definition is non-null, then:
     // 6.1. If the synchronous custom elements flag is set:
     if (CustomElementDefinition* definition = definitionForName(document, tagName))
         return definition->createElementSync(document, tagName, exceptionState);
 
     return createUndefinedElement(document, tagName);
 }
 
 HTMLElement* CustomElement::createCustomElementSync(Document& document, const QualifiedName& tagName)
 {
-    CHECK(shouldCreateCustomElement(tagName));
+    DCHECK(shouldCreateCustomElement(tagName));
 
     // When invoked from "create an element for a token":
     // https://html.spec.whatwg.org/multipage/syntax.html#create-an-element-for-the-token
     // 7. If this step throws an exception, then report the exception,
     // and let element be instead a new element that implements
     // HTMLUnknownElement.
     if (CustomElementDefinition* definition = definitionForName(document, tagName))
         return definition->createElementSync(document, tagName);
 
     return createUndefinedElement(document, tagName);
 }
 
 HTMLElement* CustomElement::createCustomElementAsync(Document& document, const QualifiedName& tagName)
 {
-    CHECK(shouldCreateCustomElement(tagName));
+    DCHECK(shouldCreateCustomElement(tagName));
 
     // To create an element:
     // https://dom.spec.whatwg.org/#concept-create-element
     // 6. If definition is non-null, then:
     // 6.2. If the synchronous custom elements flag is not set:
     if (CustomElementDefinition* definition = definitionForName(document, tagName))
         return definition->createElementAsync(document, tagName);
 
     return createUndefinedElement(document, tagName);
 }
@@ skipping 91 matching lines @@
     CustomElementRegistry* registry = CustomElement::registry(*element);
     if (!registry)
         return;
     if (CustomElementDefinition* definition = registry->definitionForName(element->localName()))
         definition->enqueueUpgradeReaction(element);
     else
         registry->addCandidate(element);
 }
 
 } // namespace blink