Bug 1797247 - part 1: Add delete transaction classes to use build time type checks r=m_kato

First, `EditorBase::CreateTransactionForDeleteSelection` returns an instance of
`EditAggregateTransaction`. It's a base class of `PlaceholderTransaction` and
`DeleteRangeTransaction` but it's also a concrete class.  However, it's too
generic.  Therefore, this patch creates `DeleteMultipleRangesTransaction` which
is a simple sub-class of it, and makes `EditAggregateTransaction` be an abstract
class.  Then, add `AddChild` methods to each concrete class to restrict the
type of child transactions.

Next, `DeleteRangeTransaction` contains only `DeleteNodeTransaction` and
`DeleteTextTransaction`.  Therefore, once they have a common base class,
we can check the type easier.  Therefore, this patch also adds
`DeleteContentTransactionBase` and
`EditorBase::CreateTransactionForCollapsedRange` becomes clearer what it
returns.

With these changes, `DeleteRangeTransaction` obviously contains only
`DeleteContentTransactionBase`, `DeleteMultipleRangesTransaction` contains only
`DeleteRangeTransaction`, `DeleteNodeTransaction` and `DeleteTextTransaction`.
And they are guaranteed at build time (at least from outside the classes).
***
fix

Differential Revision: https://phabricator.services.mozilla.com/D169038

editor/libeditor/DeleteContentTransactionBase.cpp

@@ -0,0 +1,24 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "DeleteContentTransactionBase.h"
+
+#include "EditorBase.h"
+
+namespace mozilla {
+
+DeleteContentTransactionBase::DeleteContentTransactionBase(
+    EditorBase& aEditorBase)
+    : mEditorBase(&aEditorBase) {}
+
+NS_IMPL_CYCLE_COLLECTION_INHERITED(DeleteContentTransactionBase,
+                                   EditTransactionBase, mEditorBase)
+
+NS_IMPL_ADDREF_INHERITED(DeleteContentTransactionBase, EditTransactionBase)
+NS_IMPL_RELEASE_INHERITED(DeleteContentTransactionBase, EditTransactionBase)
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(DeleteContentTransactionBase)
+NS_INTERFACE_MAP_END_INHERITING(EditTransactionBase)
+
+}  // namespace mozilla

editor/libeditor/DeleteContentTransactionBase.h

@@ -0,0 +1,46 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef DeleteContentTransactionBase_h
+#define DeleteContentTransactionBase_h
+
+#include "EditTransactionBase.h"
+
+#include "EditorForwards.h"
+
+#include "mozilla/RefPtr.h"
+
+#include "nsCycleCollectionParticipant.h"
+#include "nsISupportsImpl.h"
+
+namespace mozilla {
+
+/**
+ * An abstract transaction that removes text or node.
+ */
+class DeleteContentTransactionBase : public EditTransactionBase {
+ public:
+  /**
+   * Return a point to put caret if the transaction instance has an idea.
+   */
+  virtual EditorDOMPoint SuggestPointToPutCaret() const = 0;
+
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(DeleteContentTransactionBase,
+                                           EditTransactionBase)
+
+  NS_DECL_EDITTRANSACTIONBASE_GETASMETHODS_OVERRIDE(
+      DeleteContentTransactionBase)
+
+ protected:
+  explicit DeleteContentTransactionBase(EditorBase& aEditorBase);
+  ~DeleteContentTransactionBase() = default;
+
+  RefPtr<EditorBase> mEditorBase;
+};
+
+}  // namespace mozilla
+
+#endif  // #ifndef DeleteContentTransactionBase_h

editor/libeditor/DeleteMultipleRangesTransaction.cpp

@@ -0,0 +1,90 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "DeleteMultipleRangesTransaction.h"
+
+#include "DeleteContentTransactionBase.h"
+#include "DeleteRangeTransaction.h"
+#include "EditorBase.h"
+
+namespace mozilla {
+
+NS_IMPL_CYCLE_COLLECTION_INHERITED(DeleteMultipleRangesTransaction,
+                                   EditAggregateTransaction)
+
+NS_IMPL_ADDREF_INHERITED(DeleteMultipleRangesTransaction,
+                         EditAggregateTransaction)
+NS_IMPL_RELEASE_INHERITED(DeleteMultipleRangesTransaction,
+                          EditAggregateTransaction)
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(DeleteMultipleRangesTransaction)
+NS_INTERFACE_MAP_END_INHERITING(EditAggregateTransaction)
+
+NS_IMETHODIMP DeleteMultipleRangesTransaction::DoTransaction() {
+  MOZ_LOG(GetLogModule(), LogLevel::Info,
+          ("%p DeleteMultipleRangesTransaction::%s this={ mName=%s } "
+           "Start==============================",
+           this, __FUNCTION__,
+           nsAtomCString(mName ? mName.get() : nsGkAtoms::_empty).get()));
+  nsresult rv = EditAggregateTransaction::DoTransaction();
+  NS_WARNING_ASSERTION(NS_SUCCEEDED(rv),
+                       "EditAggregateTransaction::DoTransaction() failed");
+
+  MOZ_LOG(GetLogModule(), LogLevel::Info,
+          ("%p DeleteMultipleRangesTransaction::%s this={ mName=%s } "
+           "End==============================",
+           this, __FUNCTION__,
+           nsAtomCString(mName ? mName.get() : nsGkAtoms::_empty).get()));
+  return rv;
+}
+
+NS_IMETHODIMP DeleteMultipleRangesTransaction::UndoTransaction() {
+  MOZ_LOG(GetLogModule(), LogLevel::Info,
+          ("%p DeleteMultipleRangesTransaction::%s this={ mName=%s } "
+           "Start==============================",
+           this, __FUNCTION__,
+           nsAtomCString(mName ? mName.get() : nsGkAtoms::_empty).get()));
+
+  nsresult rv = EditAggregateTransaction::UndoTransaction();
+  NS_WARNING_ASSERTION(NS_SUCCEEDED(rv),
+                       "EditAggregateTransaction::UndoTransaction() failed");
+
+  MOZ_LOG(GetLogModule(), LogLevel::Info,
+          ("%p DeleteMultipleRangesTransaction::%s this={ mName=%s } "
+           "End==============================",
+           this, __FUNCTION__,
+           nsAtomCString(mName ? mName.get() : nsGkAtoms::_empty).get()));
+  return rv;
+}
+
+NS_IMETHODIMP DeleteMultipleRangesTransaction::RedoTransaction() {
+  MOZ_LOG(GetLogModule(), LogLevel::Info,
+          ("%p DeleteMultipleRangesTransaction::%s this={ mName=%s } "
+           "Start==============================",
+           this, __FUNCTION__,
+           nsAtomCString(mName ? mName.get() : nsGkAtoms::_empty).get()));
+
+  nsresult rv = EditAggregateTransaction::RedoTransaction();
+  NS_WARNING_ASSERTION(NS_SUCCEEDED(rv),
+                       "EditAggregateTransaction::RedoTransaction() failed");
+
+  MOZ_LOG(GetLogModule(), LogLevel::Info,
+          ("%p DeleteMultipleRangesTransaction::%s this={ mName=%s } "
+           "End==============================",
+           this, __FUNCTION__,
+           nsAtomCString(mName ? mName.get() : nsGkAtoms::_empty).get()));
+  return rv;
+}
+
+void DeleteMultipleRangesTransaction::AppendChild(
+    DeleteContentTransactionBase& aTransaction) {
+  mChildren.AppendElement(aTransaction);
+}
+
+void DeleteMultipleRangesTransaction::AppendChild(
+    DeleteRangeTransaction& aTransaction) {
+  mChildren.AppendElement(aTransaction);
+}
+
+}  // namespace mozilla

editor/libeditor/DeleteMultipleRangesTransaction.h

@@ -0,0 +1,49 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef DeleteMultipleRangesTransactionBase_h
+#define DeleteMultipleRangesTransactionBase_h
+
+#include "DeleteContentTransactionBase.h"
+#include "EditAggregateTransaction.h"
+
+#include "EditorForwards.h"
+
+#include "nsCycleCollectionParticipant.h"
+#include "nsISupportsImpl.h"
+
+namespace mozilla {
+
+/**
+ * An abstract transaction that removes text or node.
+ */
+class DeleteMultipleRangesTransaction final : public EditAggregateTransaction {
+ public:
+  static already_AddRefed<DeleteMultipleRangesTransaction> Create() {
+    RefPtr<DeleteMultipleRangesTransaction> transaction =
+        new DeleteMultipleRangesTransaction();
+    return transaction.forget();
+  }
+
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(DeleteMultipleRangesTransaction,
+                                           EditAggregateTransaction)
+
+  NS_DECL_EDITTRANSACTIONBASE
+  NS_DECL_EDITTRANSACTIONBASE_GETASMETHODS_OVERRIDE(
+      DeleteMultipleRangesTransaction)
+
+  MOZ_CAN_RUN_SCRIPT NS_IMETHOD RedoTransaction() final;
+
+  void AppendChild(DeleteContentTransactionBase& aTransaction);
+  void AppendChild(DeleteRangeTransaction& aTransaction);
+
+ protected:
+  ~DeleteMultipleRangesTransaction() = default;
+};
+
+}  // namespace mozilla
+
+#endif  // #ifndef DeleteMultipleRangesTransaction_h

editor/libeditor/DeleteNodeTransaction.cpp

@@ -5,12 +5,15 @@
 
 #include "DeleteNodeTransaction.h"
 
+#include "EditorBase.h"
+#include "EditorDOMPoint.h"
 #include "HTMLEditUtils.h"
-#include "mozilla/EditorBase.h"
+#include "SelectionState.h"  // RangeUpdater
+#include "TextEditor.h"
+
 #include "mozilla/Logging.h"
-#include "mozilla/SelectionState.h"  // RangeUpdater
-#include "mozilla/TextEditor.h"
 #include "mozilla/ToString.h"
+
 #include "nsDebug.h"
 #include "nsError.h"
 #include "nsAString.h"
@@ -30,7 +33,7 @@ already_AddRefed<DeleteNodeTransaction> DeleteNodeTransaction::MaybeCreate(
 
 DeleteNodeTransaction::DeleteNodeTransaction(EditorBase& aEditorBase,
                                              nsIContent& aContentToDelete)
-    : mEditorBase(&aEditorBase),
+    : DeleteContentTransactionBase(aEditorBase),
       mContentToDelete(&aContentToDelete),
       mParentNode(aContentToDelete.GetParentNode()) {
   MOZ_DIAGNOSTIC_ASSERT_IF(
@@ -64,14 +67,14 @@ std::ostream& operator<<(std::ostream& aStream,
   return aStream;
 }
 
-NS_IMPL_CYCLE_COLLECTION_INHERITED(DeleteNodeTransaction, EditTransactionBase,
-                                   mEditorBase, mContentToDelete, mParentNode,
-                                   mRefContent)
+NS_IMPL_CYCLE_COLLECTION_INHERITED(DeleteNodeTransaction,
+                                   DeleteContentTransactionBase,
+                                   mContentToDelete, mParentNode, mRefContent)
 
-NS_IMPL_ADDREF_INHERITED(DeleteNodeTransaction, EditTransactionBase)
-NS_IMPL_RELEASE_INHERITED(DeleteNodeTransaction, EditTransactionBase)
+NS_IMPL_ADDREF_INHERITED(DeleteNodeTransaction, DeleteContentTransactionBase)
+NS_IMPL_RELEASE_INHERITED(DeleteNodeTransaction, DeleteContentTransactionBase)
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(DeleteNodeTransaction)
-NS_INTERFACE_MAP_END_INHERITING(EditTransactionBase)
+NS_INTERFACE_MAP_END_INHERITING(DeleteContentTransactionBase)
 
 bool DeleteNodeTransaction::CanDoIt() const {
   if (NS_WARN_IF(!mContentToDelete) || NS_WARN_IF(!mEditorBase) ||
@@ -110,6 +113,10 @@ NS_IMETHODIMP DeleteNodeTransaction::DoTransaction() {
   return error.StealNSResult();
 }
 
+EditorDOMPoint DeleteNodeTransaction::SuggestPointToPutCaret() const {
+  return EditorDOMPoint();
+}
+
 NS_IMETHODIMP DeleteNodeTransaction::UndoTransaction() {
   MOZ_LOG(GetLogModule(), LogLevel::Info,
           ("%p DeleteNodeTransaction::%s this=%s", this, __FUNCTION__,

editor/libeditor/DeleteNodeTransaction.h

@@ -6,7 +6,7 @@
 #ifndef DeleteNodeTransaction_h
 #define DeleteNodeTransaction_h
 
-#include "EditTransactionBase.h"
+#include "DeleteContentTransactionBase.h"
 
 #include "EditorForwards.h"
 
@@ -22,7 +22,7 @@ namespace mozilla {
 /**
  * A transaction that deletes a single element
  */
-class DeleteNodeTransaction final : public EditTransactionBase {
+class DeleteNodeTransaction final : public DeleteContentTransactionBase {
  protected:
   DeleteNodeTransaction(EditorBase& aEditorBase, nsIContent& aContentToDelete);
 
@@ -45,12 +45,14 @@ class DeleteNodeTransaction final : public EditTransactionBase {
 
   NS_DECL_ISUPPORTS_INHERITED
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(DeleteNodeTransaction,
-                                           EditTransactionBase)
+                                           DeleteContentTransactionBase)
 
   NS_DECL_EDITTRANSACTIONBASE
   NS_DECL_EDITTRANSACTIONBASE_GETASMETHODS_OVERRIDE(DeleteNodeTransaction)
 
-  MOZ_CAN_RUN_SCRIPT NS_IMETHOD RedoTransaction() override;
+  MOZ_CAN_RUN_SCRIPT NS_IMETHOD RedoTransaction() final;
+
+  EditorDOMPoint SuggestPointToPutCaret() const final;
 
   nsIContent* GetContent() const { return mContentToDelete; }
 
@@ -60,9 +62,6 @@ class DeleteNodeTransaction final : public EditTransactionBase {
  protected:
   virtual ~DeleteNodeTransaction() = default;
 
-  // The editor for this transaction.
-  RefPtr<EditorBase> mEditorBase;
-
   // The element to delete.
   nsCOMPtr<nsIContent> mContentToDelete;
 

editor/libeditor/DeleteRangeTransaction.cpp

@@ -5,6 +5,7 @@
 
 #include "DeleteRangeTransaction.h"
 
+#include "DeleteContentTransactionBase.h"
 #include "DeleteNodeTransaction.h"
 #include "DeleteTextTransaction.h"
 #include "EditorBase.h"
@@ -46,6 +47,11 @@ NS_IMPL_CYCLE_COLLECTION_INHERITED(DeleteRangeTransaction,
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(DeleteRangeTransaction)
 NS_INTERFACE_MAP_END_INHERITING(EditAggregateTransaction)
 
+void DeleteRangeTransaction::AppendChild(
+    DeleteContentTransactionBase& aTransaction) {
+  mChildren.AppendElement(aTransaction);
+}
+
 nsresult
 DeleteRangeTransaction::MaybeExtendDeletingRangeWithSurroundingWhitespace(
     nsRange& aRange) const {
@@ -280,10 +286,7 @@ nsresult DeleteRangeTransaction::AppendTransactionsToDeleteIn(
       NS_WARNING("DeleteTextTransaction::MaybeCreate() failed");
       return NS_ERROR_FAILURE;
     }
-    DebugOnly<nsresult> rvIgnored = AppendChild(deleteTextTransaction);
-    NS_WARNING_ASSERTION(
-        NS_SUCCEEDED(rvIgnored),
-        "DeleteRangeTransaction::AppendChild() failed, but ignored");
+    AppendChild(*deleteTextTransaction);
     return NS_OK;
   }
 
@@ -302,10 +305,7 @@ nsresult DeleteRangeTransaction::AppendTransactionsToDeleteIn(
     RefPtr<DeleteNodeTransaction> deleteNodeTransaction =
         DeleteNodeTransaction::MaybeCreate(*mEditorBase, *child);
     if (deleteNodeTransaction) {
-      DebugOnly<nsresult> rvIgnored = AppendChild(deleteNodeTransaction);
-      NS_WARNING_ASSERTION(
-          NS_SUCCEEDED(rvIgnored),
-          "DeleteRangeTransaction::AppendChild() failed, but ignored");
+      AppendChild(*deleteNodeTransaction);
     }
   }
 
@@ -350,10 +350,7 @@ nsresult DeleteRangeTransaction::AppendTransactionToDeleteText(
     NS_WARNING("DeleteTextTransaction::MaybeCreate() failed");
     return NS_ERROR_FAILURE;
   }
-  DebugOnly<nsresult> rvIgnored = AppendChild(deleteTextTransaction);
-  NS_WARNING_ASSERTION(
-      NS_SUCCEEDED(rvIgnored),
-      "DeleteRangeTransaction::AppendChild() failed, but ignored");
+  AppendChild(*deleteTextTransaction);
   return NS_OK;
 }
 
@@ -384,10 +381,7 @@ DeleteRangeTransaction::AppendTransactionsToDeleteNodesWhoseEndBoundaryIn(
     RefPtr<DeleteNodeTransaction> deleteNodeTransaction =
         DeleteNodeTransaction::MaybeCreate(*mEditorBase, *node->AsContent());
     if (deleteNodeTransaction) {
-      DebugOnly<nsresult> rvIgnored = AppendChild(deleteNodeTransaction);
-      NS_WARNING_ASSERTION(
-          NS_SUCCEEDED(rvIgnored),
-          "DeleteRangeTransaction::AppendChild() failed, but ignored");
+      AppendChild(*deleteNodeTransaction);
     }
   }
   return NS_OK;

editor/libeditor/DeleteRangeTransaction.h

@@ -6,6 +6,7 @@
 #ifndef DeleteRangeTransaction_h
 #define DeleteRangeTransaction_h
 
+#include "DeleteContentTransactionBase.h"
 #include "EditAggregateTransaction.h"
 
 #include "EditorBase.h"
@@ -53,6 +54,8 @@ class DeleteRangeTransaction final : public EditAggregateTransaction {
   NS_DECL_EDITTRANSACTIONBASE
   NS_DECL_EDITTRANSACTIONBASE_GETASMETHODS_OVERRIDE(DeleteRangeTransaction)
 
+  void AppendChild(DeleteContentTransactionBase& aTransaction);
+
   MOZ_CAN_RUN_SCRIPT NS_IMETHOD RedoTransaction() override;
 
  protected:

editor/libeditor/DeleteTextTransaction.cpp

@@ -5,12 +5,14 @@
 
 #include "DeleteTextTransaction.h"
 
+#include "EditorBase.h"
+#include "EditorDOMPoint.h"
 #include "HTMLEditUtils.h"
+#include "SelectionState.h"
+
 #include "mozilla/Assertions.h"
-#include "mozilla/EditorBase.h"
-#include "mozilla/EditorDOMPoint.h"
-#include "mozilla/SelectionState.h"
 #include "mozilla/dom/Selection.h"
+
 #include "nsDebug.h"
 #include "nsError.h"
 #include "nsISupportsImpl.h"
@@ -77,7 +79,7 @@ DeleteTextTransaction::MaybeCreateForNextCharacter(EditorBase& aEditorBase,
 DeleteTextTransaction::DeleteTextTransaction(EditorBase& aEditorBase,
                                              Text& aTextNode, uint32_t aOffset,
                                              uint32_t aLengthToDelete)
-    : mEditorBase(&aEditorBase),
+    : DeleteContentTransactionBase(aEditorBase),
       mTextNode(&aTextNode),
       mOffset(aOffset),
       mLengthToDelete(aLengthToDelete) {
@@ -99,11 +101,11 @@ std::ostream& operator<<(std::ostream& aStream,
   return aStream;
 }
 
-NS_IMPL_CYCLE_COLLECTION_INHERITED(DeleteTextTransaction, EditTransactionBase,
-                                   mEditorBase, mTextNode)
+NS_IMPL_CYCLE_COLLECTION_INHERITED(DeleteTextTransaction,
+                                   DeleteContentTransactionBase, mTextNode)
 
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(DeleteTextTransaction)
-NS_INTERFACE_MAP_END_INHERITING(EditTransactionBase)
+NS_INTERFACE_MAP_END_INHERITING(DeleteContentTransactionBase)
 
 bool DeleteTextTransaction::CanDoIt() const {
   if (NS_WARN_IF(!mTextNode) || NS_WARN_IF(!mEditorBase)) {
@@ -145,12 +147,19 @@ NS_IMETHODIMP DeleteTextTransaction::DoTransaction() {
     return NS_OK;
   }
 
-  editorBase->CollapseSelectionTo(EditorRawDOMPoint(textNode, mOffset), error);
+  editorBase->CollapseSelectionTo(SuggestPointToPutCaret(), error);
   NS_WARNING_ASSERTION(!error.Failed(),
                        "EditorBase::CollapseSelectionTo() failed");
   return error.StealNSResult();
 }
 
+EditorDOMPoint DeleteTextTransaction::SuggestPointToPutCaret() const {
+  if (NS_WARN_IF(!mTextNode) || NS_WARN_IF(!mTextNode->IsInComposedDoc())) {
+    return EditorDOMPoint();
+  }
+  return EditorDOMPoint(mTextNode, mOffset);
+}
+
 // XXX: We may want to store the selection state and restore it properly.  Was
 //     it an insertion point or an extended selection?
 NS_IMETHODIMP DeleteTextTransaction::UndoTransaction() {

editor/libeditor/DeleteTextTransaction.h

@@ -6,11 +6,12 @@
 #ifndef DeleteTextTransaction_h
 #define DeleteTextTransaction_h
 
-#include "EditTransactionBase.h"
+#include "DeleteContentTransactionBase.h"
 
 #include "EditorForwards.h"
 
 #include "mozilla/dom/Text.h"
+
 #include "nsCOMPtr.h"
 #include "nsCycleCollectionParticipant.h"
 #include "nsID.h"
@@ -22,7 +23,7 @@ namespace mozilla {
 /**
  * A transaction that removes text from a content node.
  */
-class DeleteTextTransaction final : public EditTransactionBase {
+class DeleteTextTransaction final : public DeleteContentTransactionBase {
  protected:
   DeleteTextTransaction(EditorBase& aEditorBase, dom::Text& aTextNode,
                         uint32_t aOffset, uint32_t aLengthToDelete);
@@ -62,13 +63,15 @@ class DeleteTextTransaction final : public EditTransactionBase {
   bool CanDoIt() const;
 
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(DeleteTextTransaction,
-                                           EditTransactionBase)
+                                           DeleteContentTransactionBase)
   NS_IMETHOD QueryInterface(REFNSIID aIID, void** aInstancePtr) override;
 
   NS_DECL_EDITTRANSACTIONBASE
   NS_DECL_EDITTRANSACTIONBASE_GETASMETHODS_OVERRIDE(DeleteTextTransaction)
 
-  MOZ_CAN_RUN_SCRIPT NS_IMETHOD RedoTransaction() override;
+  MOZ_CAN_RUN_SCRIPT NS_IMETHOD RedoTransaction() final;
+
+  EditorDOMPoint SuggestPointToPutCaret() const final;
 
   dom::Text* GetText() const { return mTextNode; }
   uint32_t Offset() const { return mOffset; }
@@ -78,9 +81,6 @@ class DeleteTextTransaction final : public EditTransactionBase {
                                   const DeleteTextTransaction& aTransaction);
 
  protected:
-  // The provider of basic editing operations.
-  RefPtr<EditorBase> mEditorBase;
-
   // The CharacterData node to operate upon.
   RefPtr<dom::Text> mTextNode;
 

editor/libeditor/EditAggregateTransaction.cpp

@@ -119,25 +119,6 @@ NS_IMETHODIMP EditAggregateTransaction::Merge(nsITransaction* aOtherTransaction,
   return mChildren[0]->Merge(aOtherTransaction, aDidMerge);
 }
 
-NS_IMETHODIMP EditAggregateTransaction::AppendChild(
-    EditTransactionBase* aTransaction) {
-  if (NS_WARN_IF(!aTransaction)) {
-    return NS_ERROR_INVALID_ARG;
-  }
-
-  mChildren.AppendElement(*aTransaction);
-  return NS_OK;
-}
-
-NS_IMETHODIMP EditAggregateTransaction::GetName(nsAtom** aName) {
-  if (NS_WARN_IF(!aName)) {
-    return NS_ERROR_INVALID_ARG;
-  }
-  if (NS_WARN_IF(!mName)) {
-    return NS_ERROR_FAILURE;
-  }
-  *aName = do_AddRef(mName).take();
-  return NS_OK;
-}
+nsAtom* EditAggregateTransaction::GetName() const { return mName; }
 
 }  // namespace mozilla

editor/libeditor/EditAggregateTransaction.h

@@ -9,12 +9,13 @@
 #include "EditTransactionBase.h"
 
 #include "mozilla/OwningNonNull.h"
+#include "mozilla/RefPtr.h"
+
+#include "nsAtom.h"
 #include "nsCOMPtr.h"
 #include "nsCycleCollectionParticipant.h"
-#include "nsAtom.h"
-#include "nsISupportsImpl.h"
 #include "nsTArray.h"
-#include "nscore.h"
+#include "nsISupportsImpl.h"
 
 namespace mozilla {
 
@@ -23,19 +24,7 @@ namespace mozilla {
  * provides a list of child transactions.
  */
 class EditAggregateTransaction : public EditTransactionBase {
- protected:
-  EditAggregateTransaction() = default;
-
  public:
-  /**
-   * Creates an edit aggregate transaction.  This never returns nullptr.
-   */
-  static already_AddRefed<EditAggregateTransaction> Create() {
-    RefPtr<EditAggregateTransaction> transaction =
-        new EditAggregateTransaction();
-    return transaction.forget();
-  }
-
   NS_DECL_ISUPPORTS_INHERITED
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(EditAggregateTransaction,
                                            EditTransactionBase)
@@ -45,15 +34,10 @@ class EditAggregateTransaction : public EditTransactionBase {
   MOZ_CAN_RUN_SCRIPT NS_IMETHOD RedoTransaction() override;
   NS_IMETHOD Merge(nsITransaction* aOtherTransaction, bool* aDidMerge) override;
 
-  /**
-   * Append a transaction to this aggregate.
-   */
-  NS_IMETHOD AppendChild(EditTransactionBase* aTransaction);
-
   /**
    * Get the name assigned to this transaction.
    */
-  NS_IMETHOD GetName(nsAtom** aName);
+  nsAtom* GetName() const;
 
   const nsTArray<OwningNonNull<EditTransactionBase>>& ChildTransactions()
       const {
@@ -61,6 +45,7 @@ class EditAggregateTransaction : public EditTransactionBase {
   }
 
  protected:
+  EditAggregateTransaction() = default;
   virtual ~EditAggregateTransaction() = default;
 
   nsTArray<OwningNonNull<EditTransactionBase>> mChildren;

editor/libeditor/EditTransactionBase.cpp

@@ -3,13 +3,15 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-#include "mozilla/EditTransactionBase.h"
+#include "EditTransactionBase.h"
 
 #include "mozilla/Logging.h"
 
 #include "ChangeAttributeTransaction.h"
 #include "ChangeStyleTransaction.h"
 #include "CompositionTransaction.h"
+#include "DeleteContentTransactionBase.h"
+#include "DeleteMultipleRangesTransaction.h"
 #include "DeleteNodeTransaction.h"
 #include "DeleteRangeTransaction.h"
 #include "DeleteTextTransaction.h"
@@ -76,6 +78,8 @@ LogModule* EditTransactionBase::GetLogModule() {
 NS_IMPL_EDITTRANSACTIONBASE_GETASMETHODS(ChangeAttributeTransaction)
 NS_IMPL_EDITTRANSACTIONBASE_GETASMETHODS(ChangeStyleTransaction)
 NS_IMPL_EDITTRANSACTIONBASE_GETASMETHODS(CompositionTransaction)
+NS_IMPL_EDITTRANSACTIONBASE_GETASMETHODS(DeleteContentTransactionBase)
+NS_IMPL_EDITTRANSACTIONBASE_GETASMETHODS(DeleteMultipleRangesTransaction)
 NS_IMPL_EDITTRANSACTIONBASE_GETASMETHODS(DeleteNodeTransaction)
 NS_IMPL_EDITTRANSACTIONBASE_GETASMETHODS(DeleteRangeTransaction)
 NS_IMPL_EDITTRANSACTIONBASE_GETASMETHODS(DeleteTextTransaction)

editor/libeditor/EditTransactionBase.h

@@ -51,6 +51,8 @@ class EditTransactionBase : public nsITransaction {
   NS_DECL_GETASTRANSACTION_BASE(ChangeAttributeTransaction)
   NS_DECL_GETASTRANSACTION_BASE(ChangeStyleTransaction)
   NS_DECL_GETASTRANSACTION_BASE(CompositionTransaction)
+  NS_DECL_GETASTRANSACTION_BASE(DeleteContentTransactionBase)
+  NS_DECL_GETASTRANSACTION_BASE(DeleteMultipleRangesTransaction)
   NS_DECL_GETASTRANSACTION_BASE(DeleteNodeTransaction)
   NS_DECL_GETASTRANSACTION_BASE(DeleteRangeTransaction)
   NS_DECL_GETASTRANSACTION_BASE(DeleteTextTransaction)

editor/libeditor/EditorBase.cpp

@@ -8,20 +8,20 @@
 #include <stdio.h>   // for nullptr, stdout
 #include <string.h>  // for strcmp
 
-#include "AutoRangeArray.h"              // for AutoRangeArray
-#include "ChangeAttributeTransaction.h"  // for ChangeAttributeTransaction
-#include "CompositionTransaction.h"      // for CompositionTransaction
-#include "DeleteNodeTransaction.h"       // for DeleteNodeTransaction
-#include "DeleteRangeTransaction.h"      // for DeleteRangeTransaction
-#include "DeleteTextTransaction.h"       // for DeleteTextTransaction
-#include "EditAction.h"                  // for EditSubAction
-#include "EditAggregateTransaction.h"    // for EditAggregateTransaction
-#include "EditorDOMPoint.h"              // for EditorDOMPoint
-#include "EditorUtils.h"                 // for various helper classes.
-#include "EditTransactionBase.h"         // for EditTransactionBase
-#include "EditTransactionBase.h"         // for EditTransactionBase
-#include "EditorEventListener.h"         // for EditorEventListener
-#include "HTMLEditor.h"                  // for HTMLEditor
+#include "AutoRangeArray.h"  // for AutoRangeArray
+#include "ChangeAttributeTransaction.h"
+#include "CompositionTransaction.h"
+#include "DeleteContentTransactionBase.h"
+#include "DeleteMultipleRangesTransaction.h"
+#include "DeleteNodeTransaction.h"
+#include "DeleteRangeTransaction.h"
+#include "DeleteTextTransaction.h"
+#include "EditAction.h"           // for EditSubAction
+#include "EditorDOMPoint.h"       // for EditorDOMPoint
+#include "EditorUtils.h"          // for various helper classes.
+#include "EditTransactionBase.h"  // for EditTransactionBase
+#include "EditorEventListener.h"  // for EditorEventListener
+#include "HTMLEditor.h"           // for HTMLEditor
 #include "HTMLEditorInlines.h"
 #include "HTMLEditUtils.h"           // for HTMLEditUtils
 #include "InsertNodeTransaction.h"   // for InsertNodeTransaction
@@ -3733,7 +3733,7 @@ void EditorBase::DoAfterRedoTransaction() {
   MOZ_ALWAYS_SUCCEEDS(IncrementModificationCount(1));
 }
 
-already_AddRefed<EditAggregateTransaction>
+already_AddRefed<DeleteMultipleRangesTransaction>
 EditorBase::CreateTransactionForDeleteSelection(
     HowToHandleCollapsedRange aHowToHandleCollapsedRange,
     const AutoRangeArray& aRangesToDelete) {
@@ -3748,8 +3748,8 @@ EditorBase::CreateTransactionForDeleteSelection(
   }
 
   // allocate the out-param transaction
-  RefPtr<EditAggregateTransaction> aggregateTransaction =
-      EditAggregateTransaction::Create();
+  RefPtr<DeleteMultipleRangesTransaction> transaction =
+      DeleteMultipleRangesTransaction::Create();
   for (const OwningNonNull<nsRange>& range : aRangesToDelete.Ranges()) {
     // Same with range as with selection; if it is collapsed and action
     // is eNone, do nothing.
@@ -3757,11 +3757,7 @@ EditorBase::CreateTransactionForDeleteSelection(
       RefPtr<DeleteRangeTransaction> deleteRangeTransaction =
           DeleteRangeTransaction::Create(*this, range);
       // XXX Oh, not checking if deleteRangeTransaction can modify the range...
-      DebugOnly<nsresult> rvIgnored =
-          aggregateTransaction->AppendChild(deleteRangeTransaction);
-      NS_WARNING_ASSERTION(
-          NS_SUCCEEDED(rvIgnored),
-          "EditAggregationTransaction::AppendChild() failed, but ignored");
+      transaction->AppendChild(*deleteRangeTransaction);
       continue;
     }
 
@@ -3770,7 +3766,7 @@ EditorBase::CreateTransactionForDeleteSelection(
     }
 
     // Let's extend the collapsed range to delete content around it.
-    RefPtr<EditTransactionBase> deleteNodeOrTextTransaction =
+    RefPtr<DeleteContentTransactionBase> deleteNodeOrTextTransaction =
         CreateTransactionForCollapsedRange(range, aHowToHandleCollapsedRange);
     // XXX When there are two or more ranges and at least one of them is
     //     not editable, deleteNodeOrTextTransaction may be nullptr.
@@ -3779,19 +3775,15 @@ EditorBase::CreateTransactionForDeleteSelection(
       NS_WARNING("EditorBase::CreateTransactionForCollapsedRange() failed");
       return nullptr;
     }
-    DebugOnly<nsresult> rvIgnored =
-        aggregateTransaction->AppendChild(deleteNodeOrTextTransaction);
-    NS_WARNING_ASSERTION(
-        NS_SUCCEEDED(rvIgnored),
-        "EditAggregationTransaction::AppendChild() failed, but ignored");
+    transaction->AppendChild(*deleteNodeOrTextTransaction);
   }
 
-  return aggregateTransaction.forget();
+  return transaction.forget();
 }
 
 // XXX: currently, this doesn't handle edge conditions because GetNext/GetPrior
 // are not implemented
-already_AddRefed<EditTransactionBase>
+already_AddRefed<DeleteContentTransactionBase>
 EditorBase::CreateTransactionForCollapsedRange(
     const nsRange& aCollapsedRange,
     HowToHandleCollapsedRange aHowToHandleCollapsedRange) {
@@ -4651,7 +4643,7 @@ nsresult EditorBase::DeleteRangesWithTransaction(
     return NS_ERROR_FAILURE;
   }
 
-  RefPtr<EditAggregateTransaction> deleteSelectionTransaction =
+  RefPtr<DeleteMultipleRangesTransaction> deleteSelectionTransaction =
       CreateTransactionForDeleteSelection(howToHandleCollapsedRange,
                                           aRangesToDelete);
   if (!deleteSelectionTransaction) {

editor/libeditor/EditorBase.h

@@ -2553,26 +2553,23 @@ class EditorBase : public nsIEditor,
                               const AutoRangeArray& aRangesToDelete);
 
   /**
-   * Create an aggregate transaction for delete the content in aRangesToDelete.
-   * The result may include DeleteNodeTransactions and/or DeleteTextTransactions
-   * as its children.
+   * Create a transaction for delete the content in aRangesToDelete.
+   * The result may include DeleteRangeTransaction (for deleting non-collapsed
+   * range), DeleteNodeTransactions and DeleteTextTransactions (for deleting
+   * collapsed range) as its children.
    *
    * @param aHowToHandleCollapsedRange
    *                            How to handle collapsed ranges.
    * @param aRangesToDelete     The ranges to delete content.
-   * @return                    If it can remove the content in ranges, returns
-   *                            an aggregate transaction which has some
-   *                            DeleteNodeTransactions and/or
-   *                            DeleteTextTransactions as its children.
    */
-  already_AddRefed<EditAggregateTransaction>
+  already_AddRefed<DeleteMultipleRangesTransaction>
   CreateTransactionForDeleteSelection(
       HowToHandleCollapsedRange aHowToHandleCollapsedRange,
       const AutoRangeArray& aRangesToDelete);
 
   /**
-   * Create a transaction for removing the nodes and/or text around
-   * aRangeToDelete.
+   * Create a DeleteNodeTransaction or DeleteTextTransaction for removing a
+   * nodes or some text around aRangeToDelete.
    *
    * @param aCollapsedRange     The range to be removed.  This must be
    *                            collapsed.
@@ -2580,11 +2577,9 @@ class EditorBase : public nsIEditor,
    *                            How to handle aCollapsedRange.  Must
    *                            be HowToHandleCollapsedRange::ExtendBackward or
    *                            HowToHandleCollapsedRange::ExtendForward.
-   * @return                    The transaction to remove content around the
-   *                            range.  Its type is DeleteNodeTransaction or
-   *                            DeleteTextTransaction.
    */
-  already_AddRefed<EditTransactionBase> CreateTransactionForCollapsedRange(
+  already_AddRefed<DeleteContentTransactionBase>
+  CreateTransactionForCollapsedRange(
       const nsRange& aCollapsedRange,
       HowToHandleCollapsedRange aHowToHandleCollapsedRange);
 

editor/libeditor/EditorForwards.h

@@ -91,32 +91,34 @@ class RangeUpdater;                // mozilla/SelectionState.h
 class SelectionState;              // mozilla/SelectionState.h
 class TextEditor;                  // mozilla/TextEditor.h
 
-class AutoRangeArray;               // AutoRangeArray.h
-class ChangeAttributeTransaction;   // ChangeAttributeTransaction.h
-class CompositionTransaction;       // CompositionTransaction.h
-class DeleteNodeTransaction;        // DeleteNodeTransaction.h
-class DeleteRangeTransaction;       // DeleteRangeTransaction.h
-class DeleteTextTransaction;        // DeleteTextTransaction.h
-class EditAggregateTransaction;     // EditAggregateTransaction.h
-class EditorEventListener;          // EditorEventListener.h
-class EditResult;                   // HTMLEditHelpers.h
-class HTMLEditorEventListener;      // HTMLEditorEventListener.h
-class InsertNodeTransaction;        // InsertNodeTransaction.h
-class InsertTextTransaction;        // InsertTextTransaction.h
-class InterCiter;                   // InterCiter.h
-class JoinNodesResult;              // HTMLEditHelpers.h
-class JoinNodesTransaction;         // JoinNodesTransaction.h
-class MoveNodeResult;               // HTMLEditHelpers.h
-class MoveNodeTransaction;          // MoveNodeTransaction.h
-class PlaceholderTransaction;       // PlaceholderTransaction.h
-class ReplaceTextTransaction;       // ReplaceTextTransaction.h
-class SplitNodeResult;              // HTMLEditHelpers.h
-class SplitNodeTransaction;         // SplitNodeTransaction.h
-class SplitRangeOffFromNodeResult;  // HTMLEditHelpers.h
-class SplitRangeOffResult;          // HTMLEditHelpers.h
-class WhiteSpaceVisibilityKeeper;   // WSRunObject.h
-class WSRunScanner;                 // WSRunObject.h
-class WSScanResult;                 // WSRunObject.h
+class AutoRangeArray;                   // AutoRangeArray.h
+class ChangeAttributeTransaction;       // ChangeAttributeTransaction.h
+class CompositionTransaction;           // CompositionTransaction.h
+class DeleteContentTransactionBase;     // DeleteContentTransactionBase.h
+class DeleteMultipleRangesTransaction;  // DeleteMultipleRangesTransaction.h
+class DeleteNodeTransaction;            // DeleteNodeTransaction.h
+class DeleteRangeTransaction;           // DeleteRangeTransaction.h
+class DeleteTextTransaction;            // DeleteTextTransaction.h
+class EditAggregateTransaction;         // EditAggregateTransaction.h
+class EditorEventListener;              // EditorEventListener.h
+class EditResult;                       // HTMLEditHelpers.h
+class HTMLEditorEventListener;          // HTMLEditorEventListener.h
+class InsertNodeTransaction;            // InsertNodeTransaction.h
+class InsertTextTransaction;            // InsertTextTransaction.h
+class InterCiter;                       // InterCiter.h
+class JoinNodesResult;                  // HTMLEditHelpers.h
+class JoinNodesTransaction;             // JoinNodesTransaction.h
+class MoveNodeResult;                   // HTMLEditHelpers.h
+class MoveNodeTransaction;              // MoveNodeTransaction.h
+class PlaceholderTransaction;           // PlaceholderTransaction.h
+class ReplaceTextTransaction;           // ReplaceTextTransaction.h
+class SplitNodeResult;                  // HTMLEditHelpers.h
+class SplitNodeTransaction;             // SplitNodeTransaction.h
+class SplitRangeOffFromNodeResult;      // HTMLEditHelpers.h
+class SplitRangeOffResult;              // HTMLEditHelpers.h
+class WhiteSpaceVisibilityKeeper;       // WSRunObject.h
+class WSRunScanner;                     // WSRunObject.h
+class WSScanResult;                     // WSRunObject.h
 
 /******************************************************************************
  * structs

editor/libeditor/PlaceholderTransaction.cpp

@@ -52,6 +52,10 @@ NS_INTERFACE_MAP_END_INHERITING(EditAggregateTransaction)
 NS_IMPL_ADDREF_INHERITED(PlaceholderTransaction, EditAggregateTransaction)
 NS_IMPL_RELEASE_INHERITED(PlaceholderTransaction, EditAggregateTransaction)
 
+void PlaceholderTransaction::AppendChild(EditTransactionBase& aTransaction) {
+  mChildren.AppendElement(aTransaction);
+}
+
 NS_IMETHODIMP PlaceholderTransaction::DoTransaction() {
   MOZ_LOG(
       GetLogModule(), LogLevel::Info,
@@ -165,11 +169,7 @@ NS_IMETHODIMP PlaceholderTransaction::Merge(nsITransaction* aOtherTransaction,
       if (!mCompositionTransaction) {
         // this is the first IME txn in the placeholder
         mCompositionTransaction = otherCompositionTransaction;
-        DebugOnly<nsresult> rvIgnored =
-            AppendChild(otherCompositionTransaction);
-        NS_WARNING_ASSERTION(
-            NS_SUCCEEDED(rvIgnored),
-            "EditAggregateTransaction::AppendChild() failed, but ignored");
+        AppendChild(*otherCompositionTransaction);
       } else {
         bool didMerge;
         mCompositionTransaction->Merge(otherCompositionTransaction, &didMerge);
@@ -178,11 +178,7 @@ NS_IMETHODIMP PlaceholderTransaction::Merge(nsITransaction* aOtherTransaction,
           // not absorb further IME txns.  So just stack this one after it
           // and remember it as a candidate for further merges.
           mCompositionTransaction = otherCompositionTransaction;
-          DebugOnly<nsresult> rvIgnored =
-              AppendChild(otherCompositionTransaction);
-          NS_WARNING_ASSERTION(
-              NS_SUCCEEDED(rvIgnored),
-              "EditAggregateTransaction::AppendChild() failed, but ignored");
+          AppendChild(*otherCompositionTransaction);
         }
       }
     } else {
@@ -191,10 +187,7 @@ NS_IMETHODIMP PlaceholderTransaction::Merge(nsITransaction* aOtherTransaction,
       if (!otherPlaceholderTransaction) {
         // See bug 171243: just drop incoming placeholders on the floor.
         // Their children will be swallowed by this preexisting one.
-        DebugOnly<nsresult> rvIgnored = AppendChild(otherTransactionBase);
-        NS_WARNING_ASSERTION(
-            NS_SUCCEEDED(rvIgnored),
-            "EditAggregateTransaction::AppendChild() failed, but ignored");
+        AppendChild(*otherTransactionBase);
       }
     }
     *aDidMerge = true;
@@ -228,11 +221,7 @@ NS_IMETHODIMP PlaceholderTransaction::Merge(nsITransaction* aOtherTransaction,
     return NS_OK;
   }
 
-  RefPtr<nsAtom> otherTransactionName;
-  DebugOnly<nsresult> rvIgnored = otherPlaceholderTransaction->GetName(
-      getter_AddRefs(otherTransactionName));
-  NS_WARNING_ASSERTION(NS_SUCCEEDED(rvIgnored),
-                       "PlaceholderTransaction::GetName() failed, but ignored");
+  RefPtr<nsAtom> otherTransactionName = otherPlaceholderTransaction->GetName();
   if (!otherTransactionName || otherTransactionName == nsGkAtoms::_empty ||
       otherTransactionName != mName) {
     MOZ_LOG(GetLogModule(), LogLevel::Debug,
@@ -312,7 +301,7 @@ NS_IMETHODIMP PlaceholderTransaction::Merge(nsITransaction* aOtherTransaction,
   // pre-existing placeholder and drop the new one on the floor.  The
   // EndPlaceHolderBatch() call on the new placeholder will be
   // forwarded to this older one.
-  rvIgnored = RememberEndingSelection();
+  DebugOnly<nsresult> rvIgnored = RememberEndingSelection();
   NS_WARNING_ASSERTION(
       NS_SUCCEEDED(rvIgnored),
       "PlaceholderTransaction::RememberEndingSelection() failed, but "

editor/libeditor/PlaceholderTransaction.h

@@ -51,7 +51,6 @@ class PlaceholderTransaction final : public EditAggregateTransaction,
 
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(PlaceholderTransaction,
                                            EditAggregateTransaction)
-  // ------------ EditAggregateTransaction -----------------------
 
   NS_DECL_EDITTRANSACTIONBASE
   NS_DECL_EDITTRANSACTIONBASE_GETASMETHODS_OVERRIDE(PlaceholderTransaction)
@@ -59,6 +58,8 @@ class PlaceholderTransaction final : public EditAggregateTransaction,
   MOZ_CAN_RUN_SCRIPT NS_IMETHOD RedoTransaction() override;
   NS_IMETHOD Merge(nsITransaction* aTransaction, bool* aDidMerge) override;
 
+  void AppendChild(EditTransactionBase& aTransaction);
+
   nsresult EndPlaceHolderBatch();
 
   void ForwardEndBatchTo(PlaceholderTransaction& aForwardingTransaction) {

editor/libeditor/moz.build

@@ -35,6 +35,8 @@ UNIFIED_SOURCES += [
     "ChangeStyleTransaction.cpp",
     "CompositionTransaction.cpp",
     "CSSEditUtils.cpp",
+    "DeleteContentTransactionBase.cpp",
+    "DeleteMultipleRangesTransaction.cpp",
     "DeleteNodeTransaction.cpp",
     "DeleteRangeTransaction.cpp",
     "DeleteTextTransaction.cpp",

editor/nsIEditActionListener.idl

@@ -14,9 +14,6 @@ webidl Range;
 #include "mozilla/EditorDOMPoint.h"
 class nsINode;
 class nsIContent;
-namespace mozilla {
-template class EditorDOMPointBase<nsINode*, nsIContent*>;
-} // namespace mozilla
 %}
 
 [ref] native EditorRawDOMPointRef(mozilla::EditorDOMPointBase<nsINode*, nsIContent*>);