1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/accessible/src/base/TextUpdater.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,96 @@
1.4 +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
1.5 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +#ifndef mozilla_a11y_TextUpdater_h__
1.10 +#define mozilla_a11y_TextUpdater_h__
1.11 +
1.12 +#include "AccEvent.h"
1.13 +#include "HyperTextAccessible.h"
1.14 +
1.15 +namespace mozilla {
1.16 +namespace a11y {
1.17 +
1.18 +/**
1.19 + * Used to find a difference between old and new text and fire text change
1.20 + * events.
1.21 + */
1.22 +class TextUpdater
1.23 +{
1.24 +public:
1.25 + /**
1.26 + * Start text of the text leaf update.
1.27 + */
1.28 + static void Run(DocAccessible* aDocument, TextLeafAccessible* aTextLeaf,
1.29 + const nsAString& aNewText);
1.30 +
1.31 +private:
1.32 + TextUpdater(DocAccessible* aDocument, TextLeafAccessible* aTextLeaf) :
1.33 + mDocument(aDocument), mTextLeaf(aTextLeaf), mHyperText(nullptr),
1.34 + mTextOffset(-1) { }
1.35 +
1.36 + ~TextUpdater()
1.37 + { mDocument = nullptr; mTextLeaf = nullptr; mHyperText = nullptr; }
1.38 +
1.39 + /**
1.40 + * Update text of the text leaf accessible, fire text change and value change
1.41 + * (if applicable) events for its container hypertext accessible.
1.42 + */
1.43 + void DoUpdate(const nsAString& aNewText, const nsAString& aOldText,
1.44 + uint32_t aSkipStart);
1.45 +
1.46 +private:
1.47 + TextUpdater();
1.48 + TextUpdater(const TextUpdater&);
1.49 + TextUpdater& operator=(const TextUpdater&);
1.50 +
1.51 + /**
1.52 + * Fire text change events based on difference between strings.
1.53 + */
1.54 + void ComputeTextChangeEvents(const nsAString& aStr1,
1.55 + const nsAString& aStr2,
1.56 + uint32_t* aEntries,
1.57 + nsTArray<nsRefPtr<AccEvent> >& aEvents);
1.58 +
1.59 + /**
1.60 + * Helper to create text change events for inserted text.
1.61 + */
1.62 + inline void FireInsertEvent(const nsAString& aText, uint32_t aAddlOffset,
1.63 + nsTArray<nsRefPtr<AccEvent> >& aEvents)
1.64 + {
1.65 + nsRefPtr<AccEvent> event =
1.66 + new AccTextChangeEvent(mHyperText, mTextOffset + aAddlOffset,
1.67 + aText, true);
1.68 + aEvents.AppendElement(event);
1.69 + }
1.70 +
1.71 + /**
1.72 + * Helper to create text change events for removed text.
1.73 + */
1.74 + inline void FireDeleteEvent(const nsAString& aText, uint32_t aAddlOffset,
1.75 + nsTArray<nsRefPtr<AccEvent> >& aEvents)
1.76 + {
1.77 + nsRefPtr<AccEvent> event =
1.78 + new AccTextChangeEvent(mHyperText, mTextOffset + aAddlOffset,
1.79 + aText, false);
1.80 + aEvents.AppendElement(event);
1.81 + }
1.82 +
1.83 + /**
1.84 + * The constant used to skip string difference calculation in case of long
1.85 + * strings.
1.86 + */
1.87 + const static uint32_t kMaxStrLen = 1 << 6;
1.88 +
1.89 +private:
1.90 + DocAccessible* mDocument;
1.91 + TextLeafAccessible* mTextLeaf;
1.92 + HyperTextAccessible* mHyperText;
1.93 + int32_t mTextOffset;
1.94 +};
1.95 +
1.96 +} // namespace a11y
1.97 +} // namespace mozilla
1.98 +
1.99 +#endif
