michael@0: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef mozilla_a11y_TextUpdater_h__
michael@0: #define mozilla_a11y_TextUpdater_h__
michael@0: 
michael@0: #include "AccEvent.h"
michael@0: #include "HyperTextAccessible.h"
michael@0: 
michael@0: namespace mozilla {
michael@0: namespace a11y {
michael@0: 
michael@0: /**
michael@0:  * Used to find a difference between old and new text and fire text change
michael@0:  * events.
michael@0:  */
michael@0: class TextUpdater
michael@0: {
michael@0: public:
michael@0:   /**
michael@0:    * Start text of the text leaf update.
michael@0:    */
michael@0:   static void Run(DocAccessible* aDocument, TextLeafAccessible* aTextLeaf,
michael@0:                   const nsAString& aNewText);
michael@0: 
michael@0: private:
michael@0:   TextUpdater(DocAccessible* aDocument, TextLeafAccessible* aTextLeaf) :
michael@0:     mDocument(aDocument), mTextLeaf(aTextLeaf), mHyperText(nullptr),
michael@0:     mTextOffset(-1) { }
michael@0: 
michael@0:   ~TextUpdater()
michael@0:     { mDocument = nullptr; mTextLeaf = nullptr; mHyperText = nullptr; }
michael@0: 
michael@0:   /**
michael@0:    * Update text of the text leaf accessible, fire text change and value change
michael@0:    * (if applicable) events for its container hypertext accessible.
michael@0:    */
michael@0:   void DoUpdate(const nsAString& aNewText, const nsAString& aOldText,
michael@0:                 uint32_t aSkipStart);
michael@0: 
michael@0: private:
michael@0:   TextUpdater();
michael@0:   TextUpdater(const TextUpdater&);
michael@0:   TextUpdater& operator=(const TextUpdater&);
michael@0: 
michael@0:   /**
michael@0:    * Fire text change events based on difference between strings.
michael@0:    */
michael@0:   void ComputeTextChangeEvents(const nsAString& aStr1,
michael@0:                                const nsAString& aStr2,
michael@0:                                uint32_t* aEntries,
michael@0:                                nsTArray<nsRefPtr<AccEvent> >& aEvents);
michael@0: 
michael@0:   /**
michael@0:    * Helper to create text change events for inserted text.
michael@0:    */
michael@0:   inline void FireInsertEvent(const nsAString& aText, uint32_t aAddlOffset,
michael@0:                               nsTArray<nsRefPtr<AccEvent> >& aEvents)
michael@0:   {
michael@0:     nsRefPtr<AccEvent> event =
michael@0:       new AccTextChangeEvent(mHyperText, mTextOffset + aAddlOffset,
michael@0:                              aText, true);
michael@0:     aEvents.AppendElement(event);
michael@0:   }
michael@0: 
michael@0:   /**
michael@0:    * Helper to create text change events for removed text.
michael@0:    */
michael@0:   inline void FireDeleteEvent(const nsAString& aText, uint32_t aAddlOffset,
michael@0:                               nsTArray<nsRefPtr<AccEvent> >& aEvents)
michael@0:   {
michael@0:     nsRefPtr<AccEvent> event =
michael@0:       new AccTextChangeEvent(mHyperText, mTextOffset + aAddlOffset,
michael@0:                              aText, false);
michael@0:     aEvents.AppendElement(event);
michael@0:   }
michael@0: 
michael@0:   /**
michael@0:    * The constant used to skip string difference calculation in case of long
michael@0:    * strings.
michael@0:    */
michael@0:   const static uint32_t kMaxStrLen = 1 << 6;
michael@0: 
michael@0: private:
michael@0:   DocAccessible* mDocument;
michael@0:   TextLeafAccessible* mTextLeaf;
michael@0:   HyperTextAccessible* mHyperText;
michael@0:   int32_t mTextOffset;
michael@0: };
michael@0: 
michael@0: } // namespace a11y
michael@0: } // namespace mozilla
michael@0: 
michael@0: #endif