Bug 1596445 - Add some supporting code to nsINode to deal with NAC and shadow DOM separately. r=bzbarsky

We'll use these to remove GetBindingParent.

Differential Revision: https://phabricator.services.mozilla.com/D53029

--HG--
extra : moz-landing-system : lando

dom/base/FragmentOrElement.cpp

@@ -1056,13 +1056,6 @@ bool FragmentOrElement::IsLink(nsIURI** aURI) const {
   return false;
 }
 
-nsIContent* nsIContent::GetContainingShadowHost() const {
-  if (mozilla::dom::ShadowRoot* shadow = GetContainingShadow()) {
-    return shadow->GetHost();
-  }
-  return nullptr;
-}
-
 void nsIContent::SetAssignedSlot(HTMLSlotElement* aSlot) {
   MOZ_ASSERT(aSlot || GetExistingExtendedContentSlots());
   ExtendedContentSlots()->mAssignedSlot = aSlot;

dom/base/nsIContent.h

@@ -395,8 +395,6 @@ class nsIContent : public nsINode {
 
   /**
    * Gets the root of the node tree for this content if it is in a shadow tree.
-   * This method is called |GetContainingShadow| instead of |GetRootShadowRoot|
-   * to avoid confusion with |GetShadowRoot|.
    *
    * @return The ShadowRoot that is the root of the node tree.
    */
@@ -405,14 +403,6 @@ class nsIContent : public nsINode {
     return slots ? slots->mContainingShadow.get() : nullptr;
   }
 
-  /**
-   * Gets the shadow host if this content is in a shadow tree. That is, the host
-   * of |GetContainingShadow|, if its not null.
-   *
-   * @return The shadow host, if this is in shadow tree, or null.
-   */
-  nsIContent* GetContainingShadowHost() const;
-
   /**
    * Gets the assigned slot associated with this content.
    *

dom/base/nsINode.cpp

@@ -580,9 +580,23 @@ std::ostream& operator<<(std::ostream& aStream, const nsINode& aNode) {
   return aStream << str.get();
 }
 
+ShadowRoot* nsINode::GetContainingShadow() const {
+  if (!IsInShadowTree()) {
+    return nullptr;
+  }
+  return AsContent()->GetContainingShadow();
+}
+
+nsIContent* nsINode::GetContainingShadowHost() const {
+  if (ShadowRoot* shadow = GetContainingShadow()) {
+    return shadow->GetHost();
+  }
+  return nullptr;
+}
+
 SVGUseElement* nsINode::DoGetContainingSVGUseShadowHost() const {
   MOZ_ASSERT(IsInShadowTree());
-  return SVGUseElement::FromNodeOrNull(AsContent()->GetContainingShadowHost());
+  return SVGUseElement::FromNodeOrNull(GetContainingShadowHost());
 }
 
 void nsINode::GetNodeValueInternal(nsAString& aNodeValue) {

dom/base/nsINode.h

@@ -91,6 +91,7 @@ class Optional;
 class OwningNodeOrString;
 template <typename>
 class Sequence;
+class ShadowRoot;
 class SVGUseElement;
 class Text;
 class TextOrElementOrDocument;
@@ -1260,10 +1261,58 @@ class nsINode : public mozilla::dom::EventTarget {
    * TODO(emilio):: Remove this function, and use just
    * IsInNativeAnonymousSubtree, or something?
    */
-  bool IsInAnonymousSubtree() const {
-    return IsInNativeAnonymousSubtree();
+  bool IsInAnonymousSubtree() const { return IsInNativeAnonymousSubtree(); }
+
+  /**
+   * If |this| or any ancestor is native anonymous, return the root of the
+   * native anonymous subtree. Note that in case of nested native anonymous
+   * content, this returns the innermost root, not the outermost.
+   */
+  nsIContent* GetClosestNativeAnonymousSubtreeRoot() const {
+    if (!IsInNativeAnonymousSubtree()) {
+      return nullptr;
+    }
+    MOZ_ASSERT(IsContent(), "How did non-content end up in NAC?");
+    for (const nsINode* node = this; node; node = node->GetParentNode()) {
+      if (node->IsRootOfNativeAnonymousSubtree()) {
+        return const_cast<nsINode*>(node)->AsContent();
+      }
+    }
+    // FIXME(emilio): This should not happen, usually, but editor removes nodes
+    // in native anonymous subtrees, and we don't clean nodes from the current
+    // event content stack from ContentRemoved, so it can actually happen, see
+    // bug 1510208.
+    NS_WARNING("GetClosestNativeAnonymousSubtreeRoot on disconnected NAC!");
+    return nullptr;
   }
 
+  /**
+   * If |this| or any ancestor is native anonymous, return the parent of the
+   * native anonymous subtree. Note that in case of nested native anonymous
+   * content, this returns the parent of the innermost root, not the outermost.
+   */
+  nsIContent* GetClosestNativeAnonymousSubtreeRootParent() const {
+    const nsIContent* root = GetClosestNativeAnonymousSubtreeRoot();
+    if (!root) {
+      return nullptr;
+    }
+    // We could put this in nsIContentInlines.h or such to avoid this
+    // reinterpret_cast, but it doesn't seem worth it.
+    return reinterpret_cast<const nsINode*>(root)->GetParent();
+  }
+
+  /**
+   * Gets the root of the node tree for this content if it is in a shadow tree.
+   */
+  mozilla::dom::ShadowRoot* GetContainingShadow() const;
+  /**
+   * Gets the shadow host if this content is in a shadow tree. That is, the host
+   * of |GetContainingShadow|, if its not null.
+   *
+   * @return The shadow host, if this is in shadow tree, or null.
+   */
+  nsIContent* GetContainingShadowHost() const;
+
   bool IsInSVGUseShadowTree() const {
     return !!GetContainingSVGUseShadowHost();
   }

layout/base/PresShell.cpp

@@ -2007,18 +2007,10 @@ void PresShell::FireResizeEvent() {
 }
 
 static nsIContent* GetNativeAnonymousSubtreeRoot(nsIContent* aContent) {
-  if (!aContent || !aContent->IsInNativeAnonymousSubtree()) {
+  if (!aContent) {
     return nullptr;
   }
-  auto* current = aContent;
-  // FIXME(emilio): This should not need to worry about current being null, but
-  // editor removes nodes in native anonymous subtrees, and we don't clean nodes
-  // from the current event content stack from ContentRemoved, so it can
-  // actually happen, see bug 1510208.
-  while (current && !current->IsRootOfNativeAnonymousSubtree()) {
-    current = current->GetFlattenedTreeParent();
-  }
-  return current;
+  return aContent->GetClosestNativeAnonymousSubtreeRoot();
 }
 
 void PresShell::NativeAnonymousContentRemoved(nsIContent* aAnonContent) {

toolkit/components/find/nsFind.cpp

@@ -73,13 +73,7 @@ nsFind::~nsFind() = default;
 
 static nsIContent& AnonymousSubtreeRootParent(const nsINode& aNode) {
   MOZ_ASSERT(aNode.IsInNativeAnonymousSubtree());
-
-  nsIContent* current = aNode.GetParent();
-  while (current->IsInNativeAnonymousSubtree()) {
-    current = current->GetParent();
-    MOZ_ASSERT(current, "huh?");
-  }
-  return *current;
+  return *aNode.GetClosestNativeAnonymousSubtreeRootParent();
 }
 
 static void DumpNode(const nsINode* aNode) {