1 : /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2 : /* ***** BEGIN LICENSE BLOCK *****
3 : * Version: MPL 1.1/GPL 2.0/LGPL 2.1
4 : *
5 : * The contents of this file are subject to the Mozilla Public License Version
6 : * 1.1 (the "License"); you may not use this file except in compliance with
7 : * the License. You may obtain a copy of the License at
8 : * http://www.mozilla.org/MPL/
9 : *
10 : * Software distributed under the License is distributed on an "AS IS" basis,
11 : * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
12 : * for the specific language governing rights and limitations under the
13 : * License.
14 : *
15 : * The Original Code is mozilla.org code.
16 : *
17 : * The Initial Developer of the Original Code is
18 : * Mozilla Foundation.
19 : * Portions created by the Initial Developer are Copyright (C) 2011
20 : * the Initial Developer. All Rights Reserved.
21 : *
22 : * Contributor(s):
23 : * Alexander Surkov <surkov.alexander@gmail.com> (original author)
24 : *
25 : * Alternatively, the contents of this file may be used under the terms of
26 : * either of the GNU General Public License Version 2 or later (the "GPL"),
27 : * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
28 : * in which case the provisions of the GPL or the LGPL are applicable instead
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32 : * decision by deleting the provisions above and replace them with the notice
33 : * and other provisions required by the GPL or the LGPL. If you do not delete
34 : * the provisions above, a recipient may use your version of this file under
35 : * the terms of any one of the MPL, the GPL or the LGPL.
36 : *
37 : * ***** END LICENSE BLOCK ***** */
38 :
39 : #ifndef TextUpdater_h_
40 : #define TextUpdater_h_
41 :
42 : #include "AccEvent.h"
43 : #include "nsHyperTextAccessible.h"
44 :
45 : /**
46 : * Used to find a difference between old and new text and fire text change
47 : * events.
48 : */
49 : class TextUpdater
50 : {
51 : public:
52 : /**
53 : * Start text of the text leaf update.
54 : */
55 : static void Run(nsDocAccessible* aDocument, nsTextAccessible* aTextLeaf,
56 : const nsAString& aNewText);
57 :
58 : private:
59 0 : TextUpdater(nsDocAccessible* aDocument, nsTextAccessible* aTextLeaf) :
60 : mDocument(aDocument), mTextLeaf(aTextLeaf), mHyperText(nsnull),
61 0 : mTextOffset(-1) { }
62 :
63 0 : ~TextUpdater()
64 0 : { mDocument = nsnull; mTextLeaf = nsnull; mHyperText = nsnull; }
65 :
66 : /**
67 : * Update text of the text leaf accessible, fire text change and value change
68 : * (if applicable) events for its container hypertext accessible.
69 : */
70 : void DoUpdate(const nsAString& aNewText, const nsAString& aOldText,
71 : PRUint32 aSkipStart);
72 :
73 : private:
74 : TextUpdater();
75 : TextUpdater(const TextUpdater&);
76 : TextUpdater& operator=(const TextUpdater&);
77 :
78 : /**
79 : * Fire text change events based on difference between strings.
80 : */
81 : void ComputeTextChangeEvents(const nsAString& aStr1,
82 : const nsAString& aStr2,
83 : PRUint32* aEntries,
84 : nsTArray<nsRefPtr<AccEvent> >& aEvents);
85 :
86 : /**
87 : * Helper to create text change events for inserted text.
88 : */
89 0 : inline void FireInsertEvent(const nsAString& aText, PRUint32 aAddlOffset,
90 : nsTArray<nsRefPtr<AccEvent> >& aEvents)
91 : {
92 : nsRefPtr<AccEvent> event =
93 : new AccTextChangeEvent(mHyperText, mTextOffset + aAddlOffset,
94 0 : aText, true);
95 0 : aEvents.AppendElement(event);
96 0 : }
97 :
98 : /**
99 : * Helper to create text change events for removed text.
100 : */
101 0 : inline void FireDeleteEvent(const nsAString& aText, PRUint32 aAddlOffset,
102 : nsTArray<nsRefPtr<AccEvent> >& aEvents)
103 : {
104 : nsRefPtr<AccEvent> event =
105 : new AccTextChangeEvent(mHyperText, mTextOffset + aAddlOffset,
106 0 : aText, false);
107 0 : aEvents.AppendElement(event);
108 0 : }
109 :
110 : /**
111 : * The constant used to skip string difference calculation in case of long
112 : * strings.
113 : */
114 : const static PRUint32 kMaxStrLen = 1 << 6;
115 :
116 : private:
117 : nsDocAccessible* mDocument;
118 : nsTextAccessible* mTextLeaf;
119 : nsHyperTextAccessible* mHyperText;
120 : PRInt32 mTextOffset;
121 : };
122 :
123 : #endif
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