gecko-dev/editor/libeditor/JoinNodeTransaction.h

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/* -*- 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
{
protected:
JoinNodeTransaction(EditorBase& aEditorBase,
nsINode& aLeftNode, nsINode& aRightNode);
public:
/**
* Creates a join node transaction. This returns nullptr if cannot join the
* nodes.
*
* @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.
*/
static already_AddRefed<JoinNodeTransaction>
MaybeCreate(EditorBase& aEditorBase, nsINode& aLeftNode, nsINode& aRightNode);
/**
* CanDoIt() returns true if there are enough members and can join or
* restore the nodes. Otherwise, false.
*/
bool CanDoIt() const;
NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(JoinNodeTransaction,
EditTransactionBase)
NS_IMETHOD QueryInterface(REFNSIID aIID, void** aInstancePtr) override;
NS_DECL_EDITTRANSACTIONBASE
protected:
RefPtr<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