text: /* <!-- copyright */
  /*
   * aria2 - The high speed download utility
   *
   * Copyright (C) 2006 Tatsuhiro Tsujikawa
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   * This program 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 General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
   *
   * In addition, as a special exception, the copyright holders give
   * permission to link the code of portions of this program with the
   * OpenSSL library under certain conditions as described in each
   * individual source file, and distribute linked combinations
   * including the two.
   * You must obey the GNU General Public License in all respects
   * for all of the code used other than OpenSSL.  If you modify
   * file(s) with this exception, you may extend this exception to your
   * version of the file(s), but you are not obligated to do so.  If you
   * do not wish to do so, delete this exception statement from your
   * version.  If you delete this exception statement from all source
   * files in the program, then also delete it here.
   */
  /* copyright --> */
  #include "BtDependency.h"
  #include "RequestGroup.h"
  #include "Option.h"
  #include "LogFactory.h"
  #include "Logger.h"
  #include "DownloadContext.h"
  #include "RecoverableException.h"
  #include "message.h"
  #include "prefs.h"
  #include "util.h"
  #include "PieceStorage.h"
  #include "DiskAdaptor.h"
  #include "File.h"
  #include "bittorrent_helper.h"
  #include "DlAbortEx.h"
  #include "fmt.h"
  #include "FileEntry.h"
  #include "SimpleRandomizer.h"
  
  namespace aria2 {
  
  BtDependency::BtDependency(RequestGroup* dependant,
                             const std::shared_ptr<RequestGroup>& dependee)
      : dependant_(dependant), dependee_(dependee)
  {
  }
  
  BtDependency::~BtDependency() {}
  
  namespace {
  void copyValues(const std::shared_ptr<FileEntry>& d,
                  const std::shared_ptr<FileEntry>& s)
  {
    d->setRequested(true);
    d->setPath(s->getPath());
    d->addUris(std::begin(s->getRemainingUris()),
               std::end(s->getRemainingUris()));
    d->setMaxConnectionPerServer(s->getMaxConnectionPerServer());
    d->setUniqueProtocol(s->isUniqueProtocol());
  }
  } // namespace
  
  namespace {
  struct EntryCmp {
    bool operator()(const std::shared_ptr<FileEntry>& lhs,
                    const std::shared_ptr<FileEntry>& rhs) const
    {
      return lhs->getOriginalName() < rhs->getOriginalName();
    }
  };
  } // namespace
  
  bool BtDependency::resolve()
  {
    if (!dependee_) {
      return true;
    }
    if (dependee_->getNumCommand() == 0 && dependee_->downloadFinished()) {
      std::shared_ptr<RequestGroup> dependee = dependee_;
      // cut reference here
      dependee_.reset();
      auto context = std::make_shared<DownloadContext>();
      try {
        std::shared_ptr<DiskAdaptor> diskAdaptor =
            dependee->getPieceStorage()->getDiskAdaptor();
        diskAdaptor->openExistingFile();
        std::string content = util::toString(diskAdaptor);
        if (dependee->getDownloadContext()->hasAttribute(CTX_ATTR_BT)) {
          auto attrs =
              bittorrent::getTorrentAttrs(dependee->getDownloadContext());
          bittorrent::loadFromMemory(bittorrent::metadata2Torrent(content, attrs),
                                     context, dependant_->getOption(), "default");
          // We don't call bittorrent::adjustAnnounceUri() because it
          // has already been called with attrs.
        }
        else {
          bittorrent::loadFromMemory(
              content, context, dependant_->getOption(),
              File(dependee->getFirstFilePath()).getBasename());
          bittorrent::adjustAnnounceUri(bittorrent::getTorrentAttrs(context),
                                        dependant_->getOption());
        }
        const std::vector<std::shared_ptr<FileEntry>>& fileEntries =
            context->getFileEntries();
        for (auto& fe : fileEntries) {
          auto& uri = fe->getRemainingUris();
          std::shuffle(std::begin(uri), std::end(uri),
                       *SimpleRandomizer::getInstance());
        }
        const std::vector<std::shared_ptr<FileEntry>>& dependantFileEntries =
            dependant_->getDownloadContext()->getFileEntries();
        // If dependant's FileEntry::getOriginalName() is empty, we
        // assume that torrent is single file. In Metalink3, this is
        // always assumed.
        if (fileEntries.size() == 1 && dependantFileEntries.size() == 1 &&
            dependantFileEntries[0]->getOriginalName().empty()) {
          // TODO this may be dead code
          copyValues(fileEntries[0], dependantFileEntries[0]);
        }
        else {
          std::vector<std::shared_ptr<FileEntry>> destFiles;
          destFiles.reserve(fileEntries.size());
          for (auto& e : fileEntries) {
            e->setRequested(false);
            destFiles.push_back(e);
          }
          std::sort(std::begin(destFiles), std::end(destFiles), EntryCmp());
          // Copy file path in dependant_'s FileEntries to newly created
          // context's FileEntries to endorse the path structure of
          // dependant_.  URIs and singleHostMultiConnection are also copied.
          for (const auto& e : dependantFileEntries) {
            const auto d = std::lower_bound(std::begin(destFiles),
                                            std::end(destFiles), e, EntryCmp());
            if (d == std::end(destFiles) ||
                (*d)->getOriginalName() != e->getOriginalName()) {
              throw DL_ABORT_EX(fmt("No entry %s in torrent file",
                                    e->getOriginalName().c_str()));
            }
            else {
              copyValues(*d, e);
            }
          }
        }
      }
      catch (RecoverableException& e) {
        A2_LOG_ERROR_EX(EX_EXCEPTION_CAUGHT, e);
        A2_LOG_INFO(fmt("BtDependency for GID#%s failed. Go without Bt.",
                        GroupId::toHex(dependant_->getGID()).c_str()));
        return true;
      }
      A2_LOG_INFO(fmt("Dependency resolved for GID#%s",
                      GroupId::toHex(dependant_->getGID()).c_str()));
      dependant_->setDownloadContext(context);
      return true;
    }
    else if (dependee_->getNumCommand() == 0) {
      // dependee_'s download failed.
      // cut reference here
      dependee_.reset();
      A2_LOG_INFO(fmt("BtDependency for GID#%s failed. Go without Bt.",
                      GroupId::toHex(dependant_->getGID()).c_str()));
      return true;
    }
    else {
      return false;
    }
  }
  
  } // namespace aria2
  