tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
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TextUpdater.h (2785B)

      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 mozilla_a11y_TextUpdater_h__
      7 #define mozilla_a11y_TextUpdater_h__
      8 
      9 #include "AccEvent.h"
     10 #include "HyperTextAccessible.h"
     11 
     12 namespace mozilla {
     13 namespace a11y {
     14 
     15 /**
     16 * Used to find a difference between old and new text and fire text change
     17 * events.
     18 */
     19 class TextUpdater {
     20 public:
     21  /**
     22   * Start text of the text leaf update.
     23   */
     24  static void Run(DocAccessible* aDocument, TextLeafAccessible* aTextLeaf,
     25                  const nsAString& aNewText);
     26 
     27 private:
     28  TextUpdater(DocAccessible* aDocument, TextLeafAccessible* aTextLeaf)
     29      : mDocument(aDocument),
     30        mTextLeaf(aTextLeaf),
     31        mHyperText(nullptr),
     32        mTextOffset(-1) {}
     33 
     34  ~TextUpdater() {
     35    mDocument = nullptr;
     36    mTextLeaf = nullptr;
     37    mHyperText = nullptr;
     38  }
     39 
     40  /**
     41   * Update text of the text leaf accessible, fire text change and value change
     42   * (if applicable) events for its container hypertext accessible.
     43   */
     44  void DoUpdate(const nsAString& aNewText, const nsAString& aOldText,
     45                uint32_t aSkipStart);
     46 
     47 private:
     48  TextUpdater();
     49  TextUpdater(const TextUpdater&);
     50  TextUpdater& operator=(const TextUpdater&);
     51 
     52  /**
     53   * Fire text change events based on difference between strings.
     54   */
     55  void ComputeTextChangeEvents(const nsAString& aStr1, const nsAString& aStr2,
     56                               uint32_t* aEntries,
     57                               nsTArray<RefPtr<AccEvent> >& aEvents);
     58 
     59  /**
     60   * Helper to create text change events for inserted text.
     61   */
     62  inline void FireInsertEvent(const nsAString& aText, uint32_t aAddlOffset,
     63                              nsTArray<RefPtr<AccEvent> >& aEvents) {
     64    RefPtr<AccEvent> event = new AccTextChangeEvent(
     65        mHyperText, mTextOffset + aAddlOffset, aText, true);
     66    aEvents.AppendElement(event);
     67  }
     68 
     69  /**
     70   * Helper to create text change events for removed text.
     71   */
     72  inline void FireDeleteEvent(const nsAString& aText, uint32_t aAddlOffset,
     73                              nsTArray<RefPtr<AccEvent> >& aEvents) {
     74    RefPtr<AccEvent> event = new AccTextChangeEvent(
     75        mHyperText, mTextOffset + aAddlOffset, aText, false);
     76    aEvents.AppendElement(event);
     77  }
     78 
     79  /**
     80   * The constant used to skip string difference calculation in case of long
     81   * strings.
     82   */
     83  const static uint32_t kMaxStrLen = 1 << 6;
     84 
     85 private:
     86  DocAccessible* mDocument;
     87  TextLeafAccessible* mTextLeaf;
     88  HyperTextAccessible* mHyperText;
     89  int32_t mTextOffset;
     90 };
     91 
     92 }  // namespace a11y
     93 }  // namespace mozilla
     94 
     95 #endif