1/*
2 * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
3 * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
4 *           (C) 1999 Antti Koivisto (koivisto@kde.org)
5 *           (C) 2001 Dirk Mueller (mueller@kde.org)
6 * Copyright (C) 2004, 2005, 2006, 2007, 2009, 2010, 2011 Apple Inc. All rights reserved.
7 *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
8 * Copyright (C) 2010 Google Inc. All rights reserved.
9 * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
10 *
11 * This library is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU Library General Public
13 * License as published by the Free Software Foundation; either
14 * version 2 of the License, or (at your option) any later version.
15 *
16 * This library is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
19 * Library General Public License for more details.
20 *
21 * You should have received a copy of the GNU Library General Public License
22 * along with this library; see the file COPYING.LIB.  If not, write to
23 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
24 * Boston, MA 02110-1301, USA.
25 *
26 */
27
28#include "config.h"
29#include "TypeAhead.h"
30
31#include "KeyboardEvent.h"
32#include <wtf/unicode/CharacterNames.h>
33#include <wtf/unicode/Unicode.h>
34
35using namespace WTF::Unicode;
36
37namespace WebCore {
38
39TypeAhead::TypeAhead(TypeAheadDataSource* dataSource)
40    : m_dataSource(dataSource)
41    , m_lastTypeTime(0)
42    , m_repeatingChar(0)
43{
44}
45
46static const DOMTimeStamp typeAheadTimeout = 1000;
47
48static String stripLeadingWhiteSpace(const String& string)
49{
50    unsigned length = string.length();
51
52    unsigned i;
53    for (i = 0; i < length; ++i) {
54        if (string[i] != noBreakSpace && (string[i] <= 0x7F ? !isASCIISpace(string[i]) : (direction(string[i]) != WhiteSpaceNeutral)))
55            break;
56    }
57
58    return string.substring(i, length - i);
59}
60
61int TypeAhead::handleEvent(KeyboardEvent* event, MatchModeFlags matchMode)
62{
63    if (event->timeStamp() < m_lastTypeTime)
64        return -1;
65
66    int optionCount = m_dataSource->optionCount();
67    DOMTimeStamp delta = event->timeStamp() - m_lastTypeTime;
68    m_lastTypeTime = event->timeStamp();
69
70    UChar c = event->charCode();
71
72    if (delta > typeAheadTimeout)
73        m_buffer.clear();
74    m_buffer.append(c);
75
76    if (optionCount < 1)
77        return -1;
78
79    int searchStartOffset = 1;
80    String prefix;
81    if (matchMode & CycleFirstChar && c == m_repeatingChar) {
82        // The user is likely trying to cycle through all the items starting
83        // with this character, so just search on the character.
84        prefix = String(&c, 1);
85        m_repeatingChar = c;
86    } else if (matchMode & MatchPrefix) {
87        prefix = m_buffer.toString();
88        if (m_buffer.length() > 1) {
89            m_repeatingChar = 0;
90            searchStartOffset = 0;
91        } else
92            m_repeatingChar = c;
93    }
94
95    if (!prefix.isEmpty()) {
96        int selected = m_dataSource->indexOfSelectedOption();
97        int index = (selected < 0 ? 0 : selected) + searchStartOffset;
98        index %= optionCount;
99
100        // Compute a case-folded copy of the prefix string before beginning the search for
101        // a matching element. This code uses foldCase to work around the fact that
102        // String::startWith does not fold non-ASCII characters. This code can be changed
103        // to use startWith once that is fixed.
104        String prefixWithCaseFolded(prefix.foldCase());
105        for (int i = 0; i < optionCount; ++i, index = (index + 1) % optionCount) {
106            // Fold the option string and check if its prefix is equal to the folded prefix.
107            String text = m_dataSource->optionAtIndex(index);
108            if (stripLeadingWhiteSpace(text).foldCase().startsWith(prefixWithCaseFolded))
109                return index;
110        }
111    }
112
113    if (matchMode & MatchIndex) {
114        bool ok = false;
115        int index = m_buffer.toString().toInt(&ok);
116        if (index > 0 && index <= optionCount)
117            return index - 1;
118    }
119    return -1;
120}
121
122} // namespace WebCore
123