tor-browser

The Tor Browser
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PlaceholderTransaction.h (3400B)

      1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
      2 /* This Source Code Form is subject to the terms of the Mozilla Public
      3 * License, v. 2.0. If a copy of the MPL was not distributed with this
      4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      5 
      6 #ifndef PlaceholderTransaction_h
      7 #define PlaceholderTransaction_h
      8 
      9 #include "EditAggregateTransaction.h"
     10 #include "EditorForwards.h"
     11 #include "SelectionState.h"
     12 
     13 #include "mozilla/Maybe.h"
     14 #include "mozilla/WeakPtr.h"
     15 
     16 namespace mozilla {
     17 
     18 /**
     19 * An aggregate transaction that knows how to absorb all subsequent
     20 * transactions with the same name.  This transaction does not "Do" anything.
     21 * But it absorbs other transactions via merge, and can undo/redo the
     22 * transactions it has absorbed.
     23 */
     24 
     25 class PlaceholderTransaction final : public EditAggregateTransaction,
     26                                     public SupportsWeakPtr {
     27 protected:
     28  PlaceholderTransaction(EditorBase& aEditorBase, nsStaticAtom& aName,
     29                         Maybe<SelectionState>&& aSelState);
     30 
     31 public:
     32  /**
     33   * Creates a placeholder transaction.  This never returns nullptr.
     34   *
     35   * @param aEditorBase     The editor.
     36   * @param aName           The name of creating transaction.
     37   * @param aSelState       The selection state of aEditorBase.
     38   */
     39  static already_AddRefed<PlaceholderTransaction> Create(
     40      EditorBase& aEditorBase, nsStaticAtom& aName,
     41      Maybe<SelectionState>&& aSelState) {
     42    // Make sure to move aSelState into a local variable to null out the
     43    // original Maybe<SelectionState> variable.
     44    Maybe<SelectionState> selState(std::move(aSelState));
     45    RefPtr<PlaceholderTransaction> transaction =
     46        new PlaceholderTransaction(aEditorBase, aName, std::move(selState));
     47    return transaction.forget();
     48  }
     49 
     50  NS_DECL_ISUPPORTS_INHERITED
     51 
     52  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(PlaceholderTransaction,
     53                                           EditAggregateTransaction)
     54 
     55  NS_DECL_EDITTRANSACTIONBASE
     56  NS_DECL_EDITTRANSACTIONBASE_GETASMETHODS_OVERRIDE(PlaceholderTransaction)
     57 
     58  MOZ_CAN_RUN_SCRIPT NS_IMETHOD RedoTransaction() override;
     59  NS_IMETHOD Merge(nsITransaction* aTransaction, bool* aDidMerge) override;
     60 
     61  void AppendChild(EditTransactionBase& aTransaction);
     62 
     63  nsresult EndPlaceHolderBatch();
     64 
     65  void ForwardEndBatchTo(PlaceholderTransaction& aForwardingTransaction) {
     66    mForwardingTransaction = &aForwardingTransaction;
     67  }
     68 
     69  void Commit() { mCommitted = true; }
     70 
     71  nsresult RememberEndingSelection();
     72 
     73 protected:
     74  virtual ~PlaceholderTransaction() = default;
     75 
     76  // The editor for this transaction.
     77  RefPtr<EditorBase> mEditorBase;
     78 
     79  WeakPtr<PlaceholderTransaction> mForwardingTransaction;
     80 
     81  // First IME txn in this placeholder - used for IME merging.
     82  WeakPtr<CompositionTransaction> mCompositionTransaction;
     83 
     84  // These next two members store the state of the selection in a safe way.
     85  // Selection at the start of the transaction is stored, as is the selection
     86  // at the end.  This is so that UndoTransaction() and RedoTransaction() can
     87  // restore the selection properly.
     88 
     89  SelectionState mStartSel;
     90  SelectionState mEndSel;
     91 
     92  // Do we auto absorb any and all transaction?
     93  bool mAbsorb;
     94  // Do we stop auto absorbing any matching placeholder transactions?
     95  bool mCommitted;
     96 };
     97 
     98 }  // namespace mozilla
     99 
    100 #endif  // #ifndef PlaceholderTransaction_h