editor/libeditor/DeleteNodeTransaction.h
author Markus Stange <mstange.moz@gmail.com>
Fri, 15 Oct 2021 16:52:33 +0000
changeset 596026 ff6d6594f7b046db57fa377eee3e8760a3ff4751
parent 574318 bc3c88ef4ea51dcb162e1820a7d282ff3a45b509
permissions -rw-r--r--
Bug 1736049 - Stop calling `[[NSCursor currentCursor] set]` on every mouse move. r=emilio This was only necessary when we had binary plug-ins overriding the cursor from under us. We no longer support plug-ins. Calling -[NSCursor set] has a performance cost on macOS Monterey when cursor accessibility coloring is enabled, so we want to avoid calling it unnecessarily. It also leaks memory in the current Monterey Beta (see bug 1735345), so calling it less often will leak less memory. I have checked the testcases of bug 496601 and of bug 1423275, they still work as expected with this fix. Differential Revision: https://phabricator.services.mozilla.com/D128612

/* -*- 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 DeleteNodeTransaction_h
#define DeleteNodeTransaction_h

#include "mozilla/EditTransactionBase.h"
#include "nsCOMPtr.h"
#include "nsCycleCollectionParticipant.h"
#include "nsIContent.h"
#include "nsINode.h"
#include "nsISupportsImpl.h"
#include "nscore.h"

namespace mozilla {

class EditorBase;

/**
 * A transaction that deletes a single element
 */
class DeleteNodeTransaction final : public EditTransactionBase {
 protected:
  DeleteNodeTransaction(EditorBase& aEditorBase, nsIContent& aContentToDelete);

 public:
  /**
   * Creates a delete node transaction instance.  This returns nullptr if
   * it cannot remove the node from its parent.
   *
   * @param aEditorBase         The editor.
   * @param aContentToDelete    The node to be removed from the DOM tree.
   */
  static already_AddRefed<DeleteNodeTransaction> MaybeCreate(
      EditorBase& aEditorBase, nsIContent& aContentToDelete);

  /**
   * CanDoIt() returns true if there are enough members and can modify the
   * parent.  Otherwise, false.
   */
  bool CanDoIt() const;

  NS_DECL_ISUPPORTS_INHERITED
  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(DeleteNodeTransaction,
                                           EditTransactionBase)

  NS_DECL_EDITTRANSACTIONBASE
  NS_DECL_EDITTRANSACTIONBASE_GETASMETHODS_OVERRIDE(DeleteNodeTransaction)

  MOZ_CAN_RUN_SCRIPT NS_IMETHOD RedoTransaction() override;

  nsIContent* GetContent() const { return mContentToDelete; }

  friend std::ostream& operator<<(std::ostream& aStream,
                                  const DeleteNodeTransaction& aTransaction);

 protected:
  virtual ~DeleteNodeTransaction() = default;

  // The editor for this transaction.
  RefPtr<EditorBase> mEditorBase;

  // The element to delete.
  nsCOMPtr<nsIContent> mContentToDelete;

  // Parent of node to delete.
  nsCOMPtr<nsINode> mParentNode;

  // Next sibling to remember for undo/redo purposes.
  nsCOMPtr<nsIContent> mRefContent;
};

}  // namespace mozilla

#endif  // #ifndef DeleteNodeTransaction_h