editor/libeditor/ChangeAttributeTransaction.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 ChangeAttributeTransaction_h
#define ChangeAttributeTransaction_h

#include "mozilla/Attributes.h"           // override
#include "mozilla/EditTransactionBase.h"  // base class
#include "nsCOMPtr.h"                     // nsCOMPtr members
#include "nsCycleCollectionParticipant.h"  // NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED
#include "nsISupportsImpl.h"               // NS_DECL_ISUPPORTS_INHERITED
#include "nsString.h"                      // nsString members

class nsAtom;

namespace mozilla {

namespace dom {
class Element;
}  // namespace dom

/**
 * A transaction that changes an attribute of a content node.  This transaction
 * covers add, remove, and change attribute.
 */
class ChangeAttributeTransaction final : public EditTransactionBase {
 protected:
  ChangeAttributeTransaction(dom::Element& aElement, nsAtom& aAttribute,
                             const nsAString* aValue);

 public:
  /**
   * Creates a change attribute transaction to set an attribute to something.
   * This method never returns nullptr.
   *
   * @param aElement    The element whose attribute will be changed.
   * @param aAttribute  The name of the attribute to change.
   * @param aValue      The new value for aAttribute.
   */
  static already_AddRefed<ChangeAttributeTransaction> Create(
      dom::Element& aElement, nsAtom& aAttribute, const nsAString& aValue);

  /**
   * Creates a change attribute transaction to remove an attribute.  This
   * method never returns nullptr.
   *
   * @param aElement    The element whose attribute will be changed.
   * @param aAttribute  The name of the attribute to remove.
   */
  static already_AddRefed<ChangeAttributeTransaction> CreateToRemove(
      dom::Element& aElement, nsAtom& aAttribute);

  NS_DECL_ISUPPORTS_INHERITED
  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(ChangeAttributeTransaction,
                                           EditTransactionBase)

  NS_DECL_EDITTRANSACTIONBASE
  NS_DECL_EDITTRANSACTIONBASE_GETASMETHODS_OVERRIDE(ChangeAttributeTransaction)

  MOZ_CAN_RUN_SCRIPT NS_IMETHOD RedoTransaction() override;

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

 private:
  virtual ~ChangeAttributeTransaction() = default;

  // The element to operate upon
  nsCOMPtr<dom::Element> mElement;

  // The attribute to change
  RefPtr<nsAtom> mAttribute;

  // The value to set the attribute to (ignored if mRemoveAttribute==true)
  nsString mValue;

  // The value to set the attribute to for undo
  nsString mUndoValue;

  // True if the operation is to remove mAttribute from mElement
  bool mRemoveAttribute;

  // True if the mAttribute was set on mElement at the time of execution
  bool mAttributeWasSet;
};

}  // namespace mozilla

#endif  // #ifndef ChangeAttributeTransaction_h