Update HTML parser's foster-parenting algorithm to match the current spec

Source/core/html/parser/HTMLConstructionSite.cpp

 /*
  * Copyright (C) 2010 Google, Inc. All Rights Reserved.
  * Copyright (C) 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 16 matching lines @@
 #include "config.h"
 #include "core/html/parser/HTMLConstructionSite.h"
 
 #include "core/HTMLElementFactory.h"
 #include "core/HTMLNames.h"
 #include "core/dom/Comment.h"
 #include "core/dom/DocumentFragment.h"
 #include "core/dom/DocumentType.h"
 #include "core/dom/Element.h"
 #include "core/dom/ScriptLoader.h"
+#include "core/dom/TemplateContentDocumentFragment.h"
 #include "core/dom/Text.h"
 #include "core/frame/LocalFrame.h"
 #include "core/html/HTMLFormElement.h"
 #include "core/html/HTMLHtmlElement.h"
 #include "core/html/HTMLPlugInElement.h"
 #include "core/html/HTMLScriptElement.h"
 #include "core/html/HTMLTemplateElement.h"
 #include "core/html/parser/AtomicHTMLToken.h"
 #include "core/html/parser/HTMLParserIdioms.h"
 #include "core/html/parser/HTMLStackItem.h"
@@ skipping 772 matching lines @@
 {
     while (hasImpliedEndTag(currentStackItem()))
         m_openElements.pop();
 }
 
 bool HTMLConstructionSite::inQuirksMode()
 {
     return m_inQuirksMode;
 }
 
+
+// Adjusts |task| to match the "adjusted insertion location" determined by the foster parenting algorithm,
+// laid out as the substeps of step 2 of https://html.spec.whatwg.org/#appropriate-place-for-inserting-a-node
 void HTMLConstructionSite::findFosterSite(HTMLConstructionSiteTask& task)
 {
-    // When a node is to be foster parented, the last template element with no table element is below it in the stack of open elements is the foster parent element (NOT the template's parent!)
-    HTMLElementStack::ElementRecord* lastTemplateElement = m_openElements.topmost(templateTag.localName());
-    if (lastTemplateElement && !m_openElements.inTableScope(tableTag)) {
-        task.parent = lastTemplateElement->element();
+    // 2.1
+    HTMLElementStack::ElementRecord* lastTemplate = m_openElements.topmost(templateTag.localName());
+
+    // 2.2
+    HTMLElementStack::ElementRecord* lastTable = m_openElements.topmost(tableTag.localName());
+
+    // 2.3
+    if (lastTemplate && (!lastTable || lastTemplate->isAbove(lastTable))) {
+        task.parent = lastTemplate->element();
         return;
     }
 
-    HTMLElementStack::ElementRecord* lastTableElementRecord = m_openElements.topmost(tableTag.localName());
-    if (lastTableElementRecord) {
-        Element* lastTableElement = lastTableElementRecord->element();
-        ContainerNode* parent;
-        if (lastTableElementRecord->next()->stackItem()->hasTagName(templateTag))
-            parent = lastTableElementRecord->next()->element();
-        else
-            parent = lastTableElement->parentNode();
-
-        // When parsing HTML fragments, we skip step 4.2 ("Let root be a new html element with no attributes") for efficiency,
-        // and instead use the DocumentFragment as a root node. So we must treat the root node (DocumentFragment) as if it is a html element here.
-        if (parent && (parent->isElementNode() || (m_isParsingFragment && parent == m_openElements.rootNode()))) {
-            task.parent = parent;
-            task.nextChild = lastTableElement;
-            return;
-        }
-        task.parent = lastTableElementRecord->next()->element();
+    // 2.4
+    if (!lastTable) {
+        // Fragment case
+        task.parent = m_openElements.rootNode(); // DocumentFragment
         return;
     }
-    // Fragment case
-    task.parent = m_openElements.rootNode(); // DocumentFragment
+
+    // 2.5
+    if (ContainerNode* parent = lastTable->element()->parentNode()) {
+        task.parent = parent;
+        task.nextChild = lastTable->element();
+        return;
+    }
+
+    // 2.6, 2.7
+    task.parent = lastTable->next()->element();
 }
 
 bool HTMLConstructionSite::shouldFosterParent() const
 {
     return m_redirectAttachToFosterParent
         && currentStackItem()->isElementNode()
         && currentStackItem()->causesFosterParenting();
 }
 
 void HTMLConstructionSite::fosterParent(PassRefPtrWillBeRawPtr<Node> node)
 {
     HTMLConstructionSiteTask task(HTMLConstructionSiteTask::Insert);
     findFosterSite(task);
     task.child = node;
     ASSERT(task.parent);
     queueTask(task);
 }
 
 void HTMLConstructionSite::PendingText::trace(Visitor* visitor)
 {
     visitor->trace(parent);
     visitor->trace(nextChild);
 }
 
 
 }