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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 mozilla_a11y_TextUpdater_h__
#define mozilla_a11y_TextUpdater_h__
#include "AccEvent.h"
#include "HyperTextAccessible.h"
namespace mozilla {
namespace a11y {
/**
* Used to find a difference between old and new text and fire text change
* events.
*/
class TextUpdater
{
public:
/**
* Start text of the text leaf update.
*/
static void Run(DocAccessible* aDocument, TextLeafAccessible* aTextLeaf,
const nsAString& aNewText);
private:
TextUpdater(DocAccessible* aDocument, TextLeafAccessible* aTextLeaf) :
mDocument(aDocument), mTextLeaf(aTextLeaf), mHyperText(nullptr),
mTextOffset(-1) { }
~TextUpdater()
{ mDocument = nullptr; mTextLeaf = nullptr; mHyperText = nullptr; }
/**
* Update text of the text leaf accessible, fire text change and value change
* (if applicable) events for its container hypertext accessible.
*/
void DoUpdate(const nsAString& aNewText, const nsAString& aOldText,
uint32_t aSkipStart);
private:
TextUpdater();
TextUpdater(const TextUpdater&);
TextUpdater& operator=(const TextUpdater&);
/**
* Fire text change events based on difference between strings.
*/
void ComputeTextChangeEvents(const nsAString& aStr1,
const nsAString& aStr2,
uint32_t* aEntries,
nsTArray<RefPtr<AccEvent> >& aEvents);
/**
* Helper to create text change events for inserted text.
*/
inline void FireInsertEvent(const nsAString& aText, uint32_t aAddlOffset,
nsTArray<RefPtr<AccEvent> >& aEvents)
{
RefPtr<AccEvent> event =
new AccTextChangeEvent(mHyperText, mTextOffset + aAddlOffset,
aText, true);
aEvents.AppendElement(event);
}
/**
* Helper to create text change events for removed text.
*/
inline void FireDeleteEvent(const nsAString& aText, uint32_t aAddlOffset,
nsTArray<RefPtr<AccEvent> >& aEvents)
{
RefPtr<AccEvent> event =
new AccTextChangeEvent(mHyperText, mTextOffset + aAddlOffset,
aText, false);
aEvents.AppendElement(event);
}
/**
* The constant used to skip string difference calculation in case of long
* strings.
*/
const static uint32_t kMaxStrLen = 1 << 6;
private:
DocAccessible* mDocument;
TextLeafAccessible* mTextLeaf;
HyperTextAccessible* mHyperText;
int32_t mTextOffset;
};
} // namespace a11y
} // namespace mozilla
#endif
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