LibWeb: Support (and validate) prefixes in Document.createElementNS()

1% progression on ACID3. :^)

Userland/Libraries/LibWeb/DOM/Document.cpp

@@ -877,11 +877,22 @@ DOM::ExceptionOr<NonnullRefPtr<Element>> Document::create_element(String const&
     return DOM::create_element(*this, tag_name, Namespace::HTML);
 }
 
+// https://dom.spec.whatwg.org/#dom-document-createelementns
 // https://dom.spec.whatwg.org/#internal-createelementns-steps
 // FIXME: This only implements step 4 of the algorithm and does not take in options.
-DOM::ExceptionOr<NonnullRefPtr<Element>> Document::create_element_ns(const String& namespace_, const String& qualified_name)
+DOM::ExceptionOr<NonnullRefPtr<Element>> Document::create_element_ns(String const& namespace_, String const& qualified_name)
 {
-    return DOM::create_element(*this, qualified_name, namespace_);
+    // 1. Let namespace, prefix, and localName be the result of passing namespace and qualifiedName to validate and extract.
+    auto result = validate_and_extract(namespace_, qualified_name);
+    if (result.is_exception())
+        return result.exception();
+    auto qname = result.release_value();
+
+    // FIXME: 2. Let is be null.
+    // FIXME: 3. If options is a dictionary and options["is"] exists, then set is to it.
+
+    // 4. Return the result of creating an element given document, localName, namespace, prefix, is, and with the synchronous custom elements flag set.
+    return DOM::create_element(*this, qname.local_name(), qname.namespace_(), qname.prefix());
 }
 
 NonnullRefPtr<DocumentFragment> Document::create_document_fragment()

Userland/Libraries/LibWeb/DOM/Element.cpp

@@ -101,13 +101,15 @@ ExceptionOr<void> Element::set_attribute(const FlyString& name, const String& va
 }
 
 // https://dom.spec.whatwg.org/#validate-and-extract
-static ExceptionOr<QualifiedName> validate_and_extract(FlyString namespace_, FlyString qualified_name)
+ExceptionOr<QualifiedName> validate_and_extract(FlyString namespace_, FlyString qualified_name)
 {
     // 1. If namespace is the empty string, then set it to null.
     if (namespace_.is_empty())
         namespace_ = {};
 
-    // FIXME: 2. Validate qualifiedName.
+    // 2. Validate qualifiedName.
+    if (auto result = Document::validate_qualified_name(qualified_name); result.is_exception())
+        return result.exception();
 
     // 3. Let prefix be null.
     FlyString prefix = {};

Userland/Libraries/LibWeb/DOM/Element.h

@@ -160,4 +160,6 @@ private:
 template<>
 inline bool Node::fast_is<Element>() const { return is_element(); }
 
+ExceptionOr<QualifiedName> validate_and_extract(FlyString namespace_, FlyString qualified_name);
+
 }

Userland/Libraries/LibWeb/DOM/ElementFactory.cpp

@@ -89,18 +89,30 @@
 
 namespace Web::DOM {
 
-NonnullRefPtr<Element> create_element(Document& document, FlyString tag_name, FlyString namespace_)
+// https://dom.spec.whatwg.org/#concept-create-element
+NonnullRefPtr<Element> create_element(Document& document, FlyString local_name, FlyString namespace_, FlyString prefix)
 {
-    auto lowercase_tag_name = tag_name.to_lowercase();
+    // 1. If prefix was not given, let prefix be null.
+    // NOTE: This is already taken care of by `prefix` having a default value.
 
-    FlyString prefix;
-    auto parts = tag_name.view().split_view(':');
-    if (parts.size() > 1) {
-        prefix = parts[0];
-        tag_name = tag_name.view().substring_view_starting_from_substring(parts[1]);
-    }
+    // FIXME: 2. If is was not given, let is be null.
+    // FIXME: 3. Let result be null.
+    // FIXME: 4. Let definition be the result of looking up a custom element definition given document, namespace, localName, and is.
+    // FIXME: 5. If definition is non-null, and definition’s name is not equal to its local name (i.e., definition represents a customized built-in element), then: ...
+    // FIXME: 6. Otherwise, if definition is non-null, then: ...
 
-    auto qualified_name = QualifiedName(tag_name, prefix, namespace_);
+    // 7. Otherwise:
+    //    1. Let interface be the element interface for localName and namespace.
+    //    2. Set result to a new element that implements interface, with no attributes, namespace set to namespace, namespace prefix set to prefix,
+    //       local name set to localName, custom element state set to "uncustomized", custom element definition set to null, is value set to is,
+    //       and node document set to document.
+    //    FIXME: 3. If namespace is the HTML namespace, and either localName is a valid custom element name or is is non-null,
+    //           then set result’s custom element state to "undefined".
+    // 8. Return result.
+
+    auto lowercase_tag_name = local_name.to_lowercase();
+
+    auto qualified_name = QualifiedName { local_name, prefix, namespace_ };
     if (lowercase_tag_name == HTML::TagNames::a)
         return adopt_ref(*new HTML::HTMLAnchorElement(document, move(qualified_name)));
     if (lowercase_tag_name == HTML::TagNames::area)

Userland/Libraries/LibWeb/DOM/ElementFactory.h

@@ -10,6 +10,6 @@
 
 namespace Web::DOM {
 
-NonnullRefPtr<Element> create_element(Document&, FlyString tag_name, FlyString namespace_);
+NonnullRefPtr<Element> create_element(Document&, FlyString local_name, FlyString namespace_, FlyString prefix = {});
 
 }