/* -*- 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 "mozilla/EditorUtils.h"

#include "mozilla/Maybe.h"

#include "nsIAbsorbingTransaction.h"

#include "nsCOMPtr.h"

#include "nsWeakPtr.h"

namespace mozilla {

class CompositionTransaction;

/**

 * 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 nsIAbsorbingTransaction

{

protected:

  PlaceholderTransaction(EditorBase& aEditorBase,

                         nsAtom* 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,

         nsAtom* 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)

// ------------ EditAggregateTransaction -----------------------

  NS_DECL_EDITTRANSACTIONBASE

  NS_IMETHOD RedoTransaction() override;

  NS_IMETHOD Merge(nsITransaction* aTransaction, bool* aDidMerge) override;

// ------------ nsIAbsorbingTransaction -----------------------

  NS_IMETHOD GetTxnName(nsAtom** aName) override;

  NS_IMETHOD StartSelectionEquals(SelectionState* aSelState,

                                  bool* aResult) override;

  NS_IMETHOD EndPlaceHolderBatch() override;

  NS_IMETHOD ForwardEndBatchTo(

               nsIAbsorbingTransaction* aForwardingAddress) override;

  NS_IMETHOD Commit() override;

  NS_IMETHOD_(PlaceholderTransaction*) AsPlaceholderTransaction() override

  {

    return this;

  }

  nsresult RememberEndingSelection();

protected:

  virtual ~PlaceholderTransaction();

  // The editor for this transaction.

  RefPtr<EditorBase> mEditorBase;

  nsWeakPtr mForwarding;

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

  mozilla::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