Bug 1658472 - part 6: Make some utility methods for AutoInclusiveAncestorBlockElementsJoiner r=m_kato

This patch changes the behavior in the following 2 points:
* When both content is in same block element, won't return error
* When `<hr>` element has block children accidentally, this solves its container

The former case must not change actual behavior because
`AutoBlockElementsJoiner` is used with content nodes which are in different
blocks.

Differential Revision: https://phabricator.services.mozilla.com/D86886

editor/libeditor/HTMLEditSubActionHandler.cpp

@@ -4624,16 +4624,14 @@ HTMLEditor::AutoBlockElementsJoiner::JoinNodesDeepWithTransaction(
 
 EditActionResult HTMLEditor::AutoBlockElementsJoiner::
     AutoInclusiveAncestorBlockElementsJoiner::Prepare() {
-  mLeftBlockElement = HTMLEditUtils::GetInclusiveAncestorBlockElement(
-      mInclusiveDescendantOfLeftBlockElement);
-  mRightBlockElement = HTMLEditUtils::GetInclusiveAncestorBlockElement(
-      mInclusiveDescendantOfRightBlockElement);
+  mLeftBlockElement =
+      HTMLEditUtils::GetInclusiveAncestorBlockElementExceptHRElement(
+          mInclusiveDescendantOfLeftBlockElement);
+  mRightBlockElement =
+      HTMLEditUtils::GetInclusiveAncestorBlockElementExceptHRElement(
+          mInclusiveDescendantOfRightBlockElement);
 
-  // Sanity checks
-  if (NS_WARN_IF(!mLeftBlockElement) || NS_WARN_IF(!mRightBlockElement)) {
-    return EditActionIgnored(NS_ERROR_NULL_POINTER);
-  }
-  if (NS_WARN_IF(mLeftBlockElement == mRightBlockElement)) {
+  if (NS_WARN_IF(!IsSet())) {
     return EditActionIgnored(NS_ERROR_UNEXPECTED);
   }
 
@@ -4643,25 +4641,8 @@ EditActionResult HTMLEditor::AutoBlockElementsJoiner::
     return EditActionCanceled();
   }
 
-  // Make sure we don't try to move things into HR's, which look like blocks
-  // but aren't containers
-  if (mLeftBlockElement->IsHTMLElement(nsGkAtoms::hr)) {
-    mLeftBlockElement =
-        HTMLEditUtils::GetAncestorBlockElement(*mLeftBlockElement);
-    if (NS_WARN_IF(!mLeftBlockElement)) {
-      return EditActionIgnored(NS_ERROR_UNEXPECTED);
-    }
-  }
-  if (mRightBlockElement->IsHTMLElement(nsGkAtoms::hr)) {
-    mRightBlockElement =
-        HTMLEditUtils::GetAncestorBlockElement(*mRightBlockElement);
-    if (NS_WARN_IF(!mRightBlockElement)) {
-      return EditActionIgnored(NS_ERROR_UNEXPECTED);
-    }
-  }
-
   // Bail if both blocks the same
-  if (mLeftBlockElement == mRightBlockElement) {
+  if (IsSameBlockElement()) {
     return EditActionIgnored();
   }
 
@@ -4707,7 +4688,7 @@ EditActionResult HTMLEditor::AutoBlockElementsJoiner::
   MOZ_ASSERT(mLeftBlockElement);
   MOZ_ASSERT(mRightBlockElement);
 
-  if (mLeftBlockElement == mRightBlockElement) {
+  if (IsSameBlockElement()) {
     return EditActionIgnored();
   }
 

editor/libeditor/HTMLEditUtils.h

@@ -528,6 +528,24 @@ class HTMLEditUtils final {
     return GetAncestorBlockElement(aContent, aAncestorLimiter);
   }
 
+  /**
+   * GetInclusiveAncestorBlockElementExceptHRElement() returns inclusive
+   * ancestor block element except `<hr>` element.
+   */
+  static Element* GetInclusiveAncestorBlockElementExceptHRElement(
+      const nsIContent& aContent, const nsINode* aAncestorLimiter = nullptr) {
+    Element* blockElement =
+        GetInclusiveAncestorBlockElement(aContent, aAncestorLimiter);
+    if (!blockElement || !blockElement->IsHTMLElement(nsGkAtoms::hr)) {
+      return blockElement;
+    }
+    if (!blockElement->GetParentElement()) {
+      return nullptr;
+    }
+    return GetInclusiveAncestorBlockElementExceptHRElement(
+        *blockElement->GetParentElement(), aAncestorLimiter);
+  }
+
   /**
    * GetInclusiveAncestorEditableBlockElementOrInlineEditingHost() returns
    * inclusive block ancestor element of aContent.  If aContent is in inline

editor/libeditor/HTMLEditor.h

@@ -2947,6 +2947,11 @@ class HTMLEditor final : public TextEditor,
             mInclusiveDescendantOfRightBlockElement(
                 aInclusiveDescendantOfRightBlockElement) {}
 
+      bool IsSet() const { return mLeftBlockElement && mRightBlockElement; }
+      bool IsSameBlockElement() const {
+        return mLeftBlockElement && mLeftBlockElement == mRightBlockElement;
+      }
+
       /**
        * Prepare for joining inclusive ancestor block elements.  When this
        * returns error or "canceled" or "handled" state, don't call Run().