Bug 1465478: Introduce Element::FromNode. r=smaug

And use it in a couple places I noticed.

MozReview-Commit-ID: 8baSMrbdEbF

accessible/base/ARIAMap.h

@@ -290,7 +290,7 @@ class AttrIterator
 {
 public:
   explicit AttrIterator(nsIContent* aContent)
-    : mElement(aContent->IsElement() ? aContent->AsElement() : nullptr)
+    : mElement(Element::FromNode(aContent))
     , mAttrIdx(0)
   {
     mAttrCount = mElement ? mElement->GetAttrCount() : 0;

accessible/generic/Accessible.h

@@ -168,8 +168,8 @@ public:
   virtual nsINode* GetNode() const;
 
   nsIContent* GetContent() const { return mContent; }
-  mozilla::dom::Element* Elm() const
-    { return mContent && mContent->IsElement() ? mContent->AsElement() : nullptr; }
+  dom::Element* Elm() const
+    { return dom::Element::FromNodeOrNull(mContent); }
 
   /**
    * Return node type information of DOM node associated with the accessible.

accessible/generic/HyperTextAccessible.cpp

@@ -334,11 +334,10 @@ HyperTextAccessible::TransformOffset(Accessible* aDescendant,
  */
 static nsIContent* GetElementAsContentOf(nsINode* aNode)
 {
-  if (aNode->IsElement()) {
-    return aNode->AsContent();
+  if (Element* element = Element::FromNode(aNode)) {
+    return element;
   }
-  nsIContent* parent = aNode->GetParent();
-  return parent && parent->IsElement() ? parent : nullptr;
+  return aNode->GetParentElement();
 }
 
 bool

dom/base/CharacterData.h

@@ -225,9 +225,7 @@ protected:
 
   virtual Element* GetNameSpaceElement() override
   {
-    nsINode *parent = GetParentNode();
-
-    return parent && parent->IsElement() ? parent->AsElement() : nullptr;
+    return Element::FromNodeOrNull(GetParentNode());
   }
 
   nsresult SetTextInternal(uint32_t aOffset, uint32_t aCount,

dom/base/Element.h

@@ -167,6 +167,8 @@ public:
 
   NS_DECL_ADDSIZEOFEXCLUDINGTHIS
 
+  NS_IMPL_FROMNODE_HELPER(Element, IsElement())
+
   NS_IMETHOD QueryInterface(REFNSIID aIID, void** aInstancePtr) override;
 
   /**
@@ -2048,7 +2050,7 @@ inline const mozilla::dom::Element* nsINode::AsElement() const
 
 inline mozilla::dom::Element* nsINode::GetParentElement() const
 {
-  return mParent && mParent->IsElement() ? mParent->AsElement() : nullptr;
+  return mozilla::dom::Element::FromNodeOrNull(mParent);
 }
 
 /**

dom/base/nsDocument.cpp

@@ -3803,14 +3803,15 @@ AssertNoStaleServoDataIn(const nsINode& aSubtreeRoot)
   for (const nsINode* node = &aSubtreeRoot;
        node;
        node = node->GetNextNode(&aSubtreeRoot)) {
-    if (!node->IsElement()) {
+    Element* element = Element::FromNode(node);
+    if (!element) {
       continue;
     }
-    MOZ_ASSERT(!node->AsElement()->HasServoData());
-    if (auto* shadow = node->AsElement()->GetShadowRoot()) {
+    MOZ_ASSERT(!element->HasServoData());
+    if (auto* shadow = element->GetShadowRoot()) {
       AssertNoStaleServoDataIn(*shadow);
     }
-    if (nsXBLBinding* binding = node->AsElement()->GetXBLBinding()) {
+    if (nsXBLBinding* binding = element->GetXBLBinding()) {
       if (nsXBLBinding* bindingWithContent = binding->GetBindingWithContent()) {
         nsIContent* content = bindingWithContent->GetAnonymousContent();
         MOZ_ASSERT(!content->AsElement()->HasServoData());
@@ -4144,10 +4145,9 @@ nsIDocument::GetRootElementInternal() const
   // are likely to appear before the root element.
   uint32_t i;
   for (i = mChildren.ChildCount(); i > 0; --i) {
-    nsIContent* child = mChildren.ChildAt(i - 1);
-    if (child->IsElement()) {
-      const_cast<nsIDocument*>(this)->mCachedRootElement = child->AsElement();
-      return child->AsElement();
+    if (Element* element = Element::FromNode(mChildren.ChildAt(i - 1))) {
+      const_cast<nsIDocument*>(this)->mCachedRootElement = element;
+      return element;
     }
   }
 
@@ -5553,7 +5553,7 @@ nsIDocument::GetAnonRootIfInAnonymousContentContainer(nsINode* aNode) const
   nsINode* parent = aNode->GetParentNode();
   while (parent && parent->IsInNativeAnonymousSubtree()) {
     if (parent == customContainer) {
-      return child->IsElement() ? child->AsElement() : nullptr;
+      return Element::FromNode(child);
     }
     child = parent;
     parent = child->GetParentNode();
@@ -6124,14 +6124,13 @@ nsIDocument::GetAnonymousElementByAttribute(nsIContent* aElement,
   bool universalMatch = aAttrValue.EqualsLiteral("*");
 
   for (uint32_t i = 0; i < length; ++i) {
-    nsIContent* current = nodeList->Item(i);
-    if (!current->IsElement()) {
+    Element* current = Element::FromNode(nodeList->Item(i));
+    if (!current) {
       continue;
     }
 
     Element* matchedElm =
-      GetElementByAttribute(current->AsElement(), aAttrName, aAttrValue,
-                            universalMatch);
+      GetElementByAttribute(current, aAttrName, aAttrValue, universalMatch);
     if (matchedElm)
       return matchedElm;
   }
@@ -6933,12 +6932,10 @@ nsIDocument::GetCompatMode(nsString& aCompatMode) const
 }
 
 void
-nsDOMAttributeMap::BlastSubtreeToPieces(nsINode *aNode)
+nsDOMAttributeMap::BlastSubtreeToPieces(nsINode* aNode)
 {
-  if (aNode->IsElement()) {
-    Element *element = aNode->AsElement();
-    const nsDOMAttributeMap *map = element->GetAttributeMap();
-    if (map) {
+  if (Element* element = Element::FromNode(aNode)) {
+    if (const nsDOMAttributeMap* map = element->GetAttributeMap()) {
       while (true) {
         nsCOMPtr<nsIAttribute> attr;
         {
@@ -7062,8 +7059,8 @@ nsIDocument::AdoptNode(nsINode& aAdoptedNode, ErrorResult& rv)
         // have a binding applied. Remove the binding from the element now
         // that it's getting adopted into a new document.
         // TODO Fully tear down the binding.
-        if (adoptedNode->IsElement()) {
-          adoptedNode->AsElement()->SetXBLBinding(nullptr);
+        if (Element* element = Element::FromNode(adoptedNode)) {
+          element->SetXBLBinding(nullptr);
         }
       }
 

dom/base/nsDocumentEncoder.cpp

@@ -373,11 +373,8 @@ nsDocumentEncoder::SerializeNodeStart(nsINode* aNode,
         nsLayoutUtils::IsInvisibleBreak(node)) {
       return NS_OK;
     }
-    Element* originalElement =
-      aOriginalNode && aOriginalNode->IsElement() ?
-        aOriginalNode->AsElement() : nullptr;
-    mSerializer->AppendElementStart(node->AsElement(),
-                                    originalElement, aStr);
+    Element* originalElement = Element::FromNodeOrNull(aOriginalNode);
+    mSerializer->AppendElementStart(node->AsElement(), originalElement, aStr);
     return NS_OK;
   }
 

dom/base/nsNodeUtils.cpp

@@ -354,13 +354,9 @@ nsNodeUtils::LastRelease(nsINode* aNode)
     aNode->UnsetFlags(NODE_HAS_LISTENERMANAGER);
   }
 
-  if (aNode->IsElement()) {
-    nsIDocument* ownerDoc = aNode->OwnerDoc();
-    Element* elem = aNode->AsElement();
-    ownerDoc->ClearBoxObjectFor(elem);
-
-    NS_ASSERTION(!elem->GetXBLBinding(),
-                 "Node has binding on destruction");
+  if (Element* element = Element::FromNode(aNode)) {
+    element->OwnerDoc()->ClearBoxObjectFor(element);
+    NS_ASSERTION(!element->GetXBLBinding(), "Node has binding on destruction");
   }
 
   aNode->ReleaseWrapper(aNode);
@@ -429,7 +425,7 @@ nsNodeUtils::CloneAndAdopt(nsINode *aNode, bool aClone, bool aDeep,
     nodeInfo = newNodeInfo;
   }
 
-  Element *elem = aNode->IsElement() ? aNode->AsElement() : nullptr;
+  Element* elem = Element::FromNode(aNode);
 
   nsCOMPtr<nsINode> clone;
   if (aClone) {
@@ -496,10 +492,9 @@ nsNodeUtils::CloneAndAdopt(nsINode *aNode, bool aClone, bool aDeep,
   else if (nodeInfoManager) {
     nsIDocument* oldDoc = aNode->OwnerDoc();
     bool wasRegistered = false;
-    if (aNode->IsElement()) {
-      Element* element = aNode->AsElement();
-      oldDoc->ClearBoxObjectFor(element);
-      wasRegistered = oldDoc->UnregisterActivityObserver(element);
+    if (elem) {
+      oldDoc->ClearBoxObjectFor(elem);
+      wasRegistered = oldDoc->UnregisterActivityObserver(elem);
     }
 
     aNode->mNodeInfo.swap(newNodeInfo);
@@ -509,20 +504,17 @@ nsNodeUtils::CloneAndAdopt(nsINode *aNode, bool aClone, bool aDeep,
 
     nsIDocument* newDoc = aNode->OwnerDoc();
     if (newDoc) {
-      if (CustomElementRegistry::IsCustomElementEnabled(newDoc)) {
+      if (elem && CustomElementRegistry::IsCustomElementEnabled(newDoc)) {
         // Adopted callback must be enqueued whenever a node’s
         // shadow-including inclusive descendants that is custom.
-        Element* element = aNode->IsElement() ? aNode->AsElement() : nullptr;
-        if (element) {
-          CustomElementData* data = element->GetCustomElementData();
-          if (data && data->mState == CustomElementData::State::eCustom) {
-            LifecycleAdoptedCallbackArgs args = {
-              oldDoc,
-              newDoc
-            };
-            nsContentUtils::EnqueueLifecycleCallback(nsIDocument::eAdopted,
-                                                     element, nullptr, &args);
-          }
+        CustomElementData* data = elem->GetCustomElementData();
+        if (data && data->mState == CustomElementData::State::eCustom) {
+          LifecycleAdoptedCallbackArgs args = {
+            oldDoc,
+            newDoc
+          };
+          nsContentUtils::EnqueueLifecycleCallback(nsIDocument::eAdopted,
+                                                   elem, nullptr, &args);
         }
       }
 

dom/html/HTMLLabelElement.cpp

@@ -257,7 +257,7 @@ HTMLLabelElement::GetFirstLabelableDescendant() const
 {
   for (nsIContent* cur = nsINode::GetFirstChild(); cur;
        cur = cur->GetNextNode(this)) {
-    Element* element = cur->IsElement() ? cur->AsElement() : nullptr;
+    Element* element = Element::FromNode(cur);
     if (element && element->IsLabelable()) {
       return static_cast<nsGenericHTMLElement*>(element);
     }

dom/svg/SVGAnimationElement.cpp

@@ -6,6 +6,7 @@
 
 #include "mozilla/dom/SVGAnimationElement.h"
 #include "mozilla/dom/SVGSVGElement.h"
+#include "mozilla/dom/ElementInlines.h"
 #include "nsSMILTimeContainer.h"
 #include "nsSMILAnimationController.h"
 #include "nsSMILAnimationFunction.h"
@@ -71,8 +72,7 @@ SVGAnimationElement::GetTargetElementContent()
              "if we don't have an xlink:href or href attribute");
 
   // No "href" or "xlink:href" attribute --> I should target my parent.
-  nsIContent* parent = GetFlattenedTreeParent();
-  return parent && parent->IsElement() ? parent->AsElement() : nullptr;
+  return GetFlattenedTreeParentElement();
 }
 
 bool

dom/xbl/nsXBLService.cpp

@@ -404,17 +404,18 @@ EnsureSubtreeStyled(Element* aElement)
   for (nsIContent* child = iter.GetNextChild();
        child;
        child = iter.GetNextChild()) {
-    if (!child->IsElement()) {
+    Element* element = Element::FromNode(child);
+    if (!element) {
       continue;
     }
 
-    if (child->AsElement()->HasServoData()) {
+    if (element->HasServoData()) {
       // If any child was styled, all of them should be styled already, so we
       // can bail out.
       return;
     }
 
-    servoSet->StyleNewSubtree(child->AsElement());
+    servoSet->StyleNewSubtree(element);
   }
 }
 
@@ -615,8 +616,7 @@ nsXBLService::AttachGlobalKeyHandler(EventTarget* aTarget)
   if (contentNode && contentNode->GetProperty(nsGkAtoms::listener))
     return NS_OK;
 
-  Element* elt =
-   contentNode && contentNode->IsElement() ? contentNode->AsElement() : nullptr;
+  Element* elt = Element::FromNodeOrNull(contentNode);
 
   // Create the key handler
   RefPtr<nsXBLWindowKeyHandler> handler =

dom/xul/XULDocument.cpp

@@ -1419,12 +1419,11 @@ XULDocument::AddSubtreeToDocument(nsIContent* aContent)
 {
     NS_ASSERTION(aContent->GetUncomposedDoc() == this, "Element not in doc!");
     // From here on we only care about elements.
-    if (!aContent->IsElement()) {
+    Element* aElement = Element::FromNode(aContent);
+    if (!aElement) {
         return NS_OK;
     }
 
-    Element* aElement = aContent->AsElement();
-
     // Do pre-order addition magic
     nsresult rv = AddElementToDocumentPre(aElement);
     if (NS_FAILED(rv)) return rv;
@@ -1447,12 +1446,11 @@ nsresult
 XULDocument::RemoveSubtreeFromDocument(nsIContent* aContent)
 {
     // From here on we only care about elements.
-    if (!aContent->IsElement()) {
+    Element* aElement = Element::FromNode(aContent);
+    if (!aElement) {
         return NS_OK;
     }
 
-    Element* aElement = aContent->AsElement();
-
     // Do a bunch of cleanup to remove an element from the XUL
     // document.
     nsresult rv;
@@ -3709,7 +3707,7 @@ XULDocument::FindBroadcaster(Element* aElement,
             return NS_FINDBROADCASTER_AWAIT_OVERLAYS;
         }
 
-        *aListener = parent->IsElement() ? parent->AsElement() : nullptr;
+        *aListener = Element::FromNode(parent);
         NS_IF_ADDREF(*aListener);
 
         aElement->GetAttr(kNameSpaceID_None, nsGkAtoms::element, aBroadcasterID);
@@ -3841,14 +3839,14 @@ XULDocument::InsertElement(nsINode* aParent, nsIContent* aChild, bool aNotify)
     bool wasInserted = false;
 
     // insert after an element of a given id
-    if (aChild->IsElement()) {
-        aChild->AsElement()->GetAttr(kNameSpaceID_None, nsGkAtoms::insertafter, posStr);
+    if (Element* element = Element::FromNode(aChild)) {
+        element->GetAttr(kNameSpaceID_None, nsGkAtoms::insertafter, posStr);
     }
 
     bool isInsertAfter = true;
     if (posStr.IsEmpty()) {
-        if (aChild->IsElement()) {
-            aChild->AsElement()->GetAttr(kNameSpaceID_None, nsGkAtoms::insertbefore, posStr);
+        if (Element* element = Element::FromNode(aChild)) {
+            element->GetAttr(kNameSpaceID_None, nsGkAtoms::insertbefore, posStr);
         }
         isInsertAfter = false;
     }

dom/xul/XULPopupElement.cpp

@@ -226,16 +226,16 @@ XULPopupElement::GetTriggerNode() const
   return nsMenuPopupFrame::GetTriggerContent(menuPopupFrame);
 }
 
+// FIXME(emilio): should probably be renamed to GetAnchorElement?
 Element*
 XULPopupElement::GetAnchorNode() const
 {
-  nsMenuPopupFrame *menuPopupFrame = do_QueryFrame(GetPrimaryFrame());
+  nsMenuPopupFrame* menuPopupFrame = do_QueryFrame(GetPrimaryFrame());
   if (!menuPopupFrame) {
     return nullptr;
   }
 
-  nsIContent* anchor = menuPopupFrame->GetAnchor();
-  return anchor && anchor->IsElement() ? anchor->AsElement() : nullptr;
+  return Element::FromNodeOrNull(menuPopupFrame->GetAnchor());
 }
 
 already_AddRefed<DOMRect>

editor/libeditor/EditorBase.cpp

@@ -1266,8 +1266,7 @@ EditorBase::MarkNodeDirty(nsINode* aNode)
   if (!OutputsMozDirty()) {
     return NS_OK;
   }
-  if (aNode && aNode->IsElement()) {
-    RefPtr<Element> element = aNode->AsElement();
+  if (RefPtr<Element> element = Element::FromNodeOrNull(aNode)) {
     element->SetAttr(kNameSpaceID_None, nsGkAtoms::mozdirty, EmptyString(),
                      false);
   }
@@ -3920,8 +3919,7 @@ EditorBase::IsPreformatted(nsINode* aNode)
   }
   // Look at the node (and its parent if it's not an element), and grab its
   // ComputedStyle.
-  RefPtr<ComputedStyle> elementStyle;
-  Element* element = aNode->IsElement() ? aNode->AsElement() : nullptr;
+  Element* element = Element::FromNode(aNode);
   if (!element) {
     element = aNode->GetParentElement();
     if (!element) {
@@ -3929,7 +3927,7 @@ EditorBase::IsPreformatted(nsINode* aNode)
     }
   }
 
-  elementStyle =
+  RefPtr<ComputedStyle> elementStyle =
     nsComputedDOMStyle::GetComputedStyleNoFlush(element, nullptr);
   if (!elementStyle) {
     // Consider nodes without a ComputedStyle to be NOT preformatted:

editor/libeditor/EditorDOMPoint.h

@@ -170,7 +170,7 @@ public:
   dom::Element*
   GetContainerAsElement() const
   {
-    return mParent && mParent->IsElement() ? mParent->AsElement() : nullptr;
+    return Element::FromNodeOrNull(mParent);
   }
 
   dom::Text*

editor/libeditor/EditorUtils.h

@@ -377,8 +377,7 @@ public:
   nsIContent* GetLeftContent() const { return mLeftContent; }
   dom::Element* GetLeftContentAsElement() const
   {
-    return mLeftContent && mLeftContent->IsElement() ?
-             mLeftContent->AsElement() : nullptr;
+    return Element::FromNodeOrNull(mLeftContent);
   }
 
   /**
@@ -389,8 +388,7 @@ public:
   nsIContent* GetMiddleContent() const { return mMiddleContent; }
   dom::Element* GetMiddleContentAsElement() const
   {
-    return mMiddleContent && mMiddleContent->IsElement() ?
-             mMiddleContent->AsElement() : nullptr;
+    return Element::FromNodeOrNull(mMiddleContent);
   }
 
   /**
@@ -401,8 +399,7 @@ public:
   nsIContent* GetRightContent() const { return mRightContent; }
   dom::Element* GetRightContentAsElement() const
   {
-    return mRightContent && mRightContent->IsElement() ?
-             mRightContent->AsElement() : nullptr;
+    return Element::FromNodeOrNull(mRightContent);
   }
 
   SplitRangeOffFromNodeResult(nsIContent* aLeftContent, nsIContent* aMiddleContent,

editor/libeditor/HTMLEditor.cpp

@@ -2593,9 +2593,7 @@ HTMLEditor::GetSelectedElement(const nsAString& aTagName,
         // Query interface to cast nsIContent to Element
         //  then get tagType to compare to  aTagName
         // Clone node of each desired type and append it to the aDomFrag
-        nsINode* currentNode = iter->GetCurrentNode();
-        selectedElement = currentNode && currentNode->IsElement() ?
-          currentNode->AsElement() : nullptr;
+        selectedElement = Element::FromNodeOrNull(iter->GetCurrentNode());
         if (selectedElement) {
           // If we already found a node, then we have another element,
           //  thus there's not just one element selected
@@ -2604,7 +2602,7 @@ HTMLEditor::GetSelectedElement(const nsAString& aTagName,
             break;
           }
 
-          domTagName = currentNode->NodeName();
+          domTagName = selectedElement->NodeName();
           ToLowerCase(domTagName);
 
           if (anyTag) {

layout/base/AccessibleCaretManager.cpp

@@ -861,8 +861,7 @@ AccessibleCaretManager::ChangeFocusToOrClearOldFocus(nsIFrame* aFrame) const
   if (aFrame) {
     nsIContent* focusableContent = aFrame->GetContent();
     MOZ_ASSERT(focusableContent, "Focusable frame must have content!");
-    RefPtr<Element> focusableElement =
-      focusableContent->IsElement() ? focusableContent->AsElement() : nullptr;
+    RefPtr<Element> focusableElement = Element::FromNode(focusableContent);
     fm->SetFocus(focusableElement, nsIFocusManager::FLAG_BYMOUSE);
   } else {
     nsPIDOMWindowOuter* win = mPresShell->GetDocument()->GetWindow();

layout/generic/nsFrame.cpp

@@ -9831,9 +9831,7 @@ GetCorrectedParent(const nsIFrame* aFrame)
   // inherit from the NAC generator element instead.
   if (pseudo) {
     MOZ_ASSERT(aFrame->GetContent());
-    Element* element =
-      aFrame->GetContent()->IsElement()
-        ? aFrame->GetContent()->AsElement() : nullptr;
+    Element* element = Element::FromNode(aFrame->GetContent());
     // Make sure to avoid doing the fixup for non-element-backed pseudos like
     // ::first-line and such.
     if (element &&

toolkit/components/find/nsWebBrowserFind.cpp

@@ -398,8 +398,7 @@ nsWebBrowserFind::SetSelectionAndScroll(nsPIDOMWindowOuter* aWindow,
     nsCOMPtr<nsIFocusManager> fm = do_GetService(FOCUSMANAGER_CONTRACTID);
     if (fm) {
       if (tcFrame) {
-        RefPtr<Element> newFocusedElement =
-          content->IsElement() ? content->AsElement() : nullptr;
+        RefPtr<Element> newFocusedElement = Element::FromNode(content);
         fm->SetFocus(newFocusedElement, nsIFocusManager::FLAG_NOSCROLL);
       } else {
         RefPtr<Element> result;