PlaceholderTransaction.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 PlaceholderTransaction_h

#define PlaceholderTransaction_h

#include "EditAggregateTransaction.h"

#include "EditorForwards.h"

#include "SelectionState.h"

#include "mozilla/Maybe.h"

#include "mozilla/WeakPtr.h"

namespace mozilla {

/**

 * An aggregate transaction that knows how to absorb all subsequent

 * transactions with the same name.  This transaction does not "Do" anything.

 * But it absorbs other transactions via merge, and can undo/redo the

 * transactions it has absorbed.

*/

class PlaceholderTransaction final : public EditAggregateTransaction,

                                     public SupportsWeakPtr {

 protected:

  PlaceholderTransaction(EditorBase& aEditorBase, nsStaticAtom& aName,

                         Maybe<SelectionState>&& aSelState);

 public:

/**

   * Creates a placeholder transaction.  This never returns nullptr.

   * @param aEditorBase     The editor.

   * @param aName           The name of creating transaction.

   * @param aSelState       The selection state of aEditorBase.

*/

  static already_AddRefed<PlaceholderTransaction> Create(

      EditorBase& aEditorBase, nsStaticAtom& aName,

      Maybe<SelectionState>&& aSelState) {

    // Make sure to move aSelState into a local variable to null out the

    // original Maybe<SelectionState> variable.

    Maybe<SelectionState> selState(std::move(aSelState));

    RefPtr<PlaceholderTransaction> transaction =

        new PlaceholderTransaction(aEditorBase, aName, std::move(selState));

    return transaction.forget();

  NS_DECL_ISUPPORTS_INHERITED

  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(PlaceholderTransaction,

                                           EditAggregateTransaction)

  NS_DECL_EDITTRANSACTIONBASE

  NS_DECL_EDITTRANSACTIONBASE_GETASMETHODS_OVERRIDE(PlaceholderTransaction)

  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) {

    mForwardingTransaction = &aForwardingTransaction;

  void Commit() { mCommitted = true; }

  nsresult RememberEndingSelection();

 protected:

  virtual ~PlaceholderTransaction() = default;

  // The editor for this transaction.

  RefPtr<EditorBase> mEditorBase;

  WeakPtr<PlaceholderTransaction> mForwardingTransaction;

  // First IME txn in this placeholder - used for IME merging.

  WeakPtr<CompositionTransaction> mCompositionTransaction;

  // These next two members store the state of the selection in a safe way.

  // Selection at the start of the transaction is stored, as is the selection

  // at the end.  This is so that UndoTransaction() and RedoTransaction() can

  // restore the selection properly.

  SelectionState mStartSel;

  SelectionState mEndSel;

  // Do we auto absorb any and all transaction?

  bool mAbsorb;

  // Do we stop auto absorbing any matching placeholder transactions?

  bool mCommitted;

};

}  // namespace mozilla

#endif  // #ifndef PlaceholderTransaction_h