text: /*
   * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
   * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
   *           (C) 1999 Antti Koivisto (koivisto@kde.org)
   *           (C) 2001 Dirk Mueller (mueller@kde.org)
   * Copyright (C) 2004, 2005, 2006, 2007, 2009, 2010, 2011 Apple Inc. All rights reserved.
   *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
   * Copyright (C) 2010 Google Inc. All rights reserved.
   * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
   *
   * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Library General Public
   * License as published by the Free Software Foundation; either
   * version 2 of the License, or (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Library General Public License for more details.
   *
   * You should have received a copy of the GNU Library General Public License
   * along with this library; see the file COPYING.LIB.  If not, write to
   * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
   * Boston, MA 02110-1301, USA.
   *
   */
  
  #include "config.h"
  #include "TypeAhead.h"
  
  #include "KeyboardEvent.h"
  #include <wtf/unicode/CharacterNames.h>
  
  using namespace WTF::Unicode;
  
  namespace WebCore {
  
  TypeAhead::TypeAhead(TypeAheadDataSource* dataSource)
      : m_dataSource(dataSource)
      , m_lastTypeTime(0)
      , m_repeatingChar(0)
  {
  }
  
  static const DOMTimeStamp typeAheadTimeout = 1000;
  
  static String stripLeadingWhiteSpace(const String& string)
  {
      unsigned length = string.length();
  
      unsigned i;
      for (i = 0; i < length; ++i) {
          if (string[i] != noBreakSpace && (string[i] <= 0x7F ? !isASCIISpace(string[i]) : (u_charDirection(string[i]) != U_WHITE_SPACE_NEUTRAL)))
              break;
      }
  
      return string.substring(i, length - i);
  }
  
  int TypeAhead::handleEvent(KeyboardEvent* event, MatchModeFlags matchMode)
  {
      if (event->timeStamp() < m_lastTypeTime)
          return -1;
  
      int optionCount = m_dataSource->optionCount();
      DOMTimeStamp delta = event->timeStamp() - m_lastTypeTime;
      m_lastTypeTime = event->timeStamp();
  
      UChar c = event->charCode();
  
      if (delta > typeAheadTimeout)
          m_buffer.clear();
      m_buffer.append(c);
  
      if (optionCount < 1)
          return -1;
  
      int searchStartOffset = 1;
      String prefix;
      if (matchMode & CycleFirstChar && c == m_repeatingChar) {
          // The user is likely trying to cycle through all the items starting
          // with this character, so just search on the character.
          prefix = String(&c, 1);
          m_repeatingChar = c;
      } else if (matchMode & MatchPrefix) {
          prefix = m_buffer.toString();
          if (m_buffer.length() > 1) {
              m_repeatingChar = 0;
              searchStartOffset = 0;
          } else
              m_repeatingChar = c;
      }
  
      if (!prefix.isEmpty()) {
          int selected = m_dataSource->indexOfSelectedOption();
          int index = (selected < 0 ? 0 : selected) + searchStartOffset;
          index %= optionCount;
  
          // Compute a case-folded copy of the prefix string before beginning the search for
          // a matching element. This code uses foldCase to work around the fact that
          // String::startWith does not fold non-ASCII characters. This code can be changed
          // to use startWith once that is fixed.
          String prefixWithCaseFolded(prefix.foldCase());
          for (int i = 0; i < optionCount; ++i, index = (index + 1) % optionCount) {
              // Fold the option string and check if its prefix is equal to the folded prefix.
              String text = m_dataSource->optionAtIndex(index);
              if (stripLeadingWhiteSpace(text).foldCase().startsWith(prefixWithCaseFolded))
                  return index;
          }
      }
  
      if (matchMode & MatchIndex) {
          bool ok = false;
          int index = m_buffer.toString().toInt(&ok);
          if (index > 0 && index <= optionCount)
              return index - 1;
      }
      return -1;
  }
  
  } // namespace WebCore
  