text: /*
   * Copyright (C) 2010 Apple Inc. All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
   * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
   * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
   * THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  #include "config.h"
  #include "BackForwardController.h"
  
  #include "BackForwardClient.h"
  #include "HistoryItem.h"
  #include "Page.h"
  #include "ShouldTreatAsContinuingLoad.h"
  
  namespace WebCore {
  
  BackForwardController::BackForwardController(Page& page, Ref<BackForwardClient>&& client)
      : m_page(page)
      , m_client(WTFMove(client))
  {
  }
  
  BackForwardController::~BackForwardController() = default;
  
  RefPtr<HistoryItem> BackForwardController::backItem()
  {
      return itemAtIndex(-1);
  }
  
  RefPtr<HistoryItem> BackForwardController::currentItem()
  {
      return itemAtIndex(0);
  }
  
  RefPtr<HistoryItem> BackForwardController::forwardItem()
  {
      return itemAtIndex(1);
  }
  
  bool BackForwardController::canGoBackOrForward(int distance) const
  {
      if (!distance)
          return true;
      if (distance > 0 && static_cast<unsigned>(distance) <= forwardCount())
          return true;
      if (distance < 0 && static_cast<unsigned>(-distance) <= backCount())
          return true;
      return false;
  }
  
  void BackForwardController::goBackOrForward(int distance)
  {
      if (!distance)
          return;
  
      auto historyItem = itemAtIndex(distance);
      if (!historyItem) {
          if (distance > 0) {
              if (int forwardCount = this->forwardCount())
                  historyItem = itemAtIndex(forwardCount);
          } else {
              if (int backCount = this->backCount())
                  historyItem = itemAtIndex(-backCount);
          }
      }
  
      if (!historyItem)
          return;
  
      m_page.goToItem(*historyItem, FrameLoadType::IndexedBackForward, ShouldTreatAsContinuingLoad::No);
  }
  
  bool BackForwardController::goBack()
  {
      auto historyItem = backItem();
      if (!historyItem)
          return false;
  
      m_page.goToItem(*historyItem, FrameLoadType::Back, ShouldTreatAsContinuingLoad::No);
      return true;
  }
  
  bool BackForwardController::goForward()
  {
      auto historyItem = forwardItem();
      if (!historyItem)
          return false;
  
      m_page.goToItem(*historyItem, FrameLoadType::Forward, ShouldTreatAsContinuingLoad::No);
      return true;
  }
  
  void BackForwardController::addItem(Ref<HistoryItem>&& item)
  {
      m_client->addItem(WTFMove(item));
  }
  
  void BackForwardController::setCurrentItem(HistoryItem& item)
  {
      m_client->goToItem(item);
  }
  
  unsigned BackForwardController::count() const
  {
      return m_client->backListCount() + 1 + m_client->forwardListCount();
  }
  
  unsigned BackForwardController::backCount() const
  {
      return m_client->backListCount();
  }
  
  unsigned BackForwardController::forwardCount() const
  {
      return m_client->forwardListCount();
  }
  
  RefPtr<HistoryItem> BackForwardController::itemAtIndex(int i)
  {
      return m_client->itemAtIndex(i);
  }
  
  void BackForwardController::close()
  {
      m_client->close();
  }
  
  } // namespace WebCore
  