Make custom elements work in HTML imports

third_party/WebKit/Source/core/dom/custom/CustomElementUpgradeSorter.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/CustomElementUpgradeSorter.h"
 
 #include "core/dom/Element.h"
 #include "core/dom/ElementTraversal.h"
 #include "core/dom/Node.h"
 #include "core/dom/shadow/ShadowRoot.h"
+#include "core/html/HTMLLinkElement.h"
+#include "core/html/imports/HTMLImportChild.h"
+#include "core/html/imports/HTMLImportLoader.h"
 
 namespace blink {
 
 CustomElementUpgradeSorter::CustomElementUpgradeSorter()
     : m_elements(new HeapHashSet<Member<Element>>())
     , m_parentChildMap(new ParentChildMap())
 {
 }
 
+static HTMLLinkElement* getLinkElement(const Document& document)

[tkent, 2016/08/24 12:07:20]

* Chromium coding style prefers anonymous namespace to static function.
* The name isn't descriptive enough.  getLinkElementImporting(const Document&) ?

[kochi, 2016/08/24 15:36:52]

The static function follows the convention used in this directory.

For the function name, renamed getLinkElementForImport(), and renamed its
argument
from document to import.

+{
+    HTMLImportLoader* loader = document.importLoader();

[tkent, 2016/08/24 12:07:20]

I prefer shorter code like:
    if (HTMLImportLoader* loader = document.importLoader())
        return loader->firstImport()->link();
    return nullptr;

[kochi, 2016/08/24 15:36:52]

Neat.  Done.

+    if (!loader)
+        return nullptr;
+
+    return loader->firstImport()->link();
+}
+
+CustomElementUpgradeSorter::AddResult CustomElementUpgradeSorter::addToParentChildMap(
+    Node* parent,
+    Node* child)
+{
+    ParentChildMap::iterator it = m_parentChildMap->find(parent);
+    if (it != m_parentChildMap->end()) {
+        it->value.add(child);
+        // The entry for the parent exists; so must its parents.
+        return kParentAlreadyExistsInMap;
+    }
+    ParentChildMap::AddResult result =

[tkent, 2016/08/24 12:07:20]

This function contains two hash lookups and avoidable copy of
HeapHashSet<Member<Node>>.  It's an issue of the original code, and you don't
need to fix it in this CL.

[kochi, 2016/08/24 15:36:51]

Will do in a separate CL.

+        m_parentChildMap->add(parent, HeapHashSet<Member<Node>>());
+    result.storedValue->value.add(child);
+    return kParentAddedToMap;
+}
+
 void CustomElementUpgradeSorter::add(Element* element)
 {
     m_elements->add(element);
 
     for (Node* n = element, *parent = n->parentOrShadowHostNode();
         parent;
         n = parent, parent = parent->parentOrShadowHostNode()) {
+        if (addToParentChildMap(parent, n) == kParentAlreadyExistsInMap)
+            break;
 
-        ParentChildMap::iterator it = m_parentChildMap->find(parent);
-        if (it == m_parentChildMap->end()) {
-            ParentChildMap::AddResult result =
-                m_parentChildMap->add(parent, HeapHashSet<Member<Node>>());
-            result.storedValue->value.add(n);
-        } else {
-            it->value.add(n);
-            // The entry for the parent exists; so must its parents.
-            break;
+        // Create parent-child link between <link rel="import"> and its imported
+        // document so that the content of the imported document be visited as if
+        // the imported document were inserted in the link element.
+        if (parent->isDocumentNode()) {
+            Element* link = getLinkElement(*toDocument(parent));
+            if (!link || addToParentChildMap(link, parent) == kParentAlreadyExistsInMap)
+                break;
+            parent = link;
         }
     }
 }
 
 void CustomElementUpgradeSorter::visit(
     HeapVector<Member<Element>>* result,
     ChildSet& children,
     const ChildSet::iterator& it)
 {
     if (it == children.end())
@@ skipping 34 matching lines @@
         visit(result, children, children.find(e));
     }
 
     if (children.size() == 1)
         visit(result, children, children.begin());
 
     DCHECK(children.isEmpty());
 }
 
 } // namespace blink