1 files changed, 68 insertions, 0 deletions
diff --git a/editor/libeditor/JoinNodeTransaction.h b/editor/libeditor/JoinNodeTransaction.h
new file mode 100644
index 0000000000..84208cb45d
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+++ b/editor/libeditor/JoinNodeTransaction.h
@@ -0,0 +1,68 @@
+/* -*- 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 JoinNodeTransaction_h
+#define JoinNodeTransaction_h
+
+#include "mozilla/EditTransactionBase.h" // for EditTransactionBase, etc.
+#include "nsCOMPtr.h"                   // for nsCOMPtr
+#include "nsCycleCollectionParticipant.h"
+#include "nsID.h"                       // for REFNSIID
+#include "nscore.h"                     // for NS_IMETHOD
+
+class nsINode;
+
+namespace mozilla {
+
+class EditorBase;
+
+/**
+ * A transaction that joins two nodes E1 (left node) and E2 (right node) into a
+ * single node E.  The children of E are the children of E1 followed by the
+ * children of E2.  After DoTransaction() and RedoTransaction(), E1 is removed
+ * from the content tree and E2 remains.
+ */
+class JoinNodeTransaction final : public EditTransactionBase
+{
+public:
+  /**
+   * @param aEditorBase     The provider of core editing operations.
+   * @param aLeftNode       The first of two nodes to join.
+   * @param aRightNode      The second of two nodes to join.
+   */
+  JoinNodeTransaction(EditorBase& aEditorBase,
+                      nsINode& aLeftNode, nsINode& aRightNode);
+
+  /**
+   * Call this after constructing to ensure the inputs are correct.
+   */
+  nsresult CheckValidity();
+
+  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(JoinNodeTransaction,
+                                           EditTransactionBase)
+  NS_IMETHOD QueryInterface(REFNSIID aIID, void** aInstancePtr) override;
+
+  NS_DECL_EDITTRANSACTIONBASE
+
+protected:
+  EditorBase& mEditorBase;
+
+  // The nodes to operate upon.  After the merge, mRightNode remains and
+  // mLeftNode is removed from the content tree.
+  nsCOMPtr<nsINode> mLeftNode;
+  nsCOMPtr<nsINode> mRightNode;
+
+  // The offset into mNode where the children of mElement are split (for
+  // undo). mOffset is the index of the first child in the right node.  -1
+  // means the left node had no children.
+  uint32_t  mOffset;
+
+  // The parent node containing mLeftNode and mRightNode.
+  nsCOMPtr<nsINode> mParent;
+};
+
+} // namespace mozilla
+
+#endif // #ifndef JoinNodeTransaction_h