/* <!-- 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 "RequestGroupMan.h"

#include <unistd.h>
#include <cstring>
#include <iomanip>
#include <sstream>
#include <ostream>
#include <fstream>
#include <numeric>
#include <algorithm>

#include "BtProgressInfoFile.h"
#include "RecoverableException.h"
#include "RequestGroup.h"
#include "LogFactory.h"
#include "Logger.h"
#include "DownloadEngine.h"
#include "message.h"
#include "a2functional.h"
#include "DownloadResult.h"
#include "DownloadContext.h"
#include "ServerStatMan.h"
#include "ServerStat.h"
#include "PeerStat.h"
#include "SegmentMan.h"
#include "FeedbackURISelector.h"
#include "InOrderURISelector.h"
#include "AdaptiveURISelector.h"
#include "Option.h"
#include "prefs.h"
#include "File.h"
#include "Util.h"
#include "Command.h"
#include "FileEntry.h"

namespace aria2 {

RequestGroupMan::RequestGroupMan(const RequestGroups& requestGroups,
				 unsigned int maxSimultaneousDownloads,
				 const Option* option):
  _requestGroups(requestGroups),
  _logger(LogFactory::getInstance()),
  _maxSimultaneousDownloads(maxSimultaneousDownloads),
  _gidCounter(0),
  _option(option),
  _serverStatMan(new ServerStatMan()),
  _maxOverallDownloadSpeedLimit
  (option->getAsInt(PREF_MAX_OVERALL_DOWNLOAD_LIMIT)),
  _maxOverallUploadSpeedLimit(option->getAsInt(PREF_MAX_OVERALL_UPLOAD_LIMIT))
{}

bool RequestGroupMan::downloadFinished()
{
#ifdef ENABLE_XML_RPC
  if(_option->getAsBool(PREF_ENABLE_XML_RPC)) {
    return false;
  }
#endif // ENABLE_XML_RPC
  if(!_reservedGroups.empty()) {
    return false;
  }
  for(RequestGroups::iterator itr = _requestGroups.begin();
      itr != _requestGroups.end(); ++itr) {
    if((*itr)->getNumCommand() > 0 || !(*itr)->downloadFinished()) {
      return false;
    }
  }
  return true;
}

void RequestGroupMan::addRequestGroup(const RequestGroupHandle& group)
{
  _requestGroups.push_back(group);
}

void RequestGroupMan::addReservedGroup(const RequestGroups& groups)
{
  _reservedGroups.insert(_reservedGroups.end(), groups.begin(), groups.end());
}

void RequestGroupMan::addReservedGroup(const RequestGroupHandle& group)
{
  _reservedGroups.push_back(group);
}

size_t RequestGroupMan::countRequestGroup() const
{
  return _requestGroups.size();
}

RequestGroupHandle RequestGroupMan::getRequestGroup(size_t index) const
{
  if(index < _requestGroups.size()) {
    return _requestGroups[index];
  } else {
    return SharedHandle<RequestGroup>();
  }
}

template<typename Iterator>
static Iterator findByGID(Iterator first, Iterator last, int32_t gid)
{
  for(; first != last; ++first) {
    if((*first)->getGID() == gid) {
      return first;
    }
  }
  return first;
}

SharedHandle<RequestGroup>
RequestGroupMan::findRequestGroup(int32_t gid) const
{
  std::deque<SharedHandle<RequestGroup> >::const_iterator i =
    findByGID(_requestGroups.begin(), _requestGroups.end(), gid);
  if(i == _requestGroups.end()) {
    return SharedHandle<RequestGroup>();
  } else {
    return *i;
  }
}

SharedHandle<RequestGroup>
RequestGroupMan::findReservedGroup(int32_t gid) const
{
  std::deque<SharedHandle<RequestGroup> >::const_iterator i =
    findByGID(_reservedGroups.begin(), _reservedGroups.end(), gid);
  if(i == _reservedGroups.end()) {
    return SharedHandle<RequestGroup>();
  } else {
    return *i;
  }
}

bool RequestGroupMan::removeReservedGroup(int32_t gid)
{
  std::deque<SharedHandle<RequestGroup> >::iterator i =
    findByGID(_reservedGroups.begin(), _reservedGroups.end(), gid);
  if(i == _reservedGroups.end()) {
    return false;
  } else {
    _reservedGroups.erase(i);
    return true;
  }
}

static void executeHook(const std::string& command, int gid)
{
  LogFactory::getInstance()->info("Executing user command: %s %d",
				  command.c_str(), gid);
  pid_t cpid = fork();
  if(cpid == -1) {
    LogFactory::getInstance()->error("fork() failed."
				     " Cannot execute user command.");
  } else if(cpid == 0) {
    execl(command.c_str(), command.c_str(), Util::itos(gid).c_str(), (char*)0);
    perror(("Could not execute user command: "+command).c_str());
    _exit(1);
  }
}

static void executeStartHook
(const SharedHandle<RequestGroup>& group, const Option* option)
{
  if(!option->blank(PREF_ON_DOWNLOAD_START)) {
    executeHook(option->get(PREF_ON_DOWNLOAD_START), group->getGID());
  }
}

static void executeStopHook
(const SharedHandle<DownloadResult>& result, const Option* option)
{
  if(result->result == DownloadResult::FINISHED &&
     !option->blank(PREF_ON_DOWNLOAD_COMPLETE)) {
    executeHook(option->get(PREF_ON_DOWNLOAD_COMPLETE), result->gid);
  } else if(result->result != DownloadResult::IN_PROGRESS &&
	    !option->blank(PREF_ON_DOWNLOAD_ERROR)) {
    executeHook(option->get(PREF_ON_DOWNLOAD_ERROR), result->gid);
  } else if(!option->blank(PREF_ON_DOWNLOAD_STOP)) {
    executeHook(option->get(PREF_ON_DOWNLOAD_STOP), result->gid);
  }
}

class ProcessStoppedRequestGroup {
private:
  DownloadEngine* _e;
  std::deque<SharedHandle<RequestGroup> >& _reservedGroups;
  std::deque<SharedHandle<DownloadResult> >& _downloadResults;
  Logger* _logger;

  void saveSignature(const SharedHandle<RequestGroup>& group)
  {
    SharedHandle<Signature> sig =
      group->getDownloadContext()->getSignature();
    if(!sig.isNull() && !sig->getBody().empty()) {
      // filename of signature file is the path to download file followed by
      // ".sig".
      std::string signatureFile = group->getFilePath()+".sig";
      if(sig->save(signatureFile)) {
	_logger->notice(MSG_SIGNATURE_SAVED, signatureFile.c_str());
      } else {
	_logger->notice(MSG_SIGNATURE_NOT_SAVED, signatureFile.c_str());
      }
    }
  }
public:
  ProcessStoppedRequestGroup
  (DownloadEngine* e,
   std::deque<SharedHandle<RequestGroup> >& reservedGroups,
   std::deque<SharedHandle<DownloadResult> >& downloadResults):
    _e(e),
    _reservedGroups(reservedGroups),
    _downloadResults(downloadResults),
    _logger(LogFactory::getInstance()) {}

  void operator()(const SharedHandle<RequestGroup>& group)
  {
    if(group->getNumCommand() == 0) {
      try {
	group->closeFile();
	if(group->downloadFinished()) {
	  group->applyLastModifiedTimeToLocalFiles();
	  group->reportDownloadFinished();
	  if(group->allDownloadFinished()) {
	    group->getProgressInfoFile()->removeFile();
	    saveSignature(group);
	  } else {
	    group->getProgressInfoFile()->save();
	  }
	  RequestGroups nextGroups;
	  group->postDownloadProcessing(nextGroups);
	  if(!nextGroups.empty()) {
	    _logger->debug
	      ("Adding %lu RequestGroups as a result of PostDownloadHandler.",
	       static_cast<unsigned long>(nextGroups.size()));
	    _reservedGroups.insert(_reservedGroups.begin(),
				   nextGroups.begin(), nextGroups.end());
	  }
	} else {
	  group->getProgressInfoFile()->save();
	}
      } catch(RecoverableException& ex) {
	_logger->error(EX_EXCEPTION_CAUGHT, ex);
      }
      group->releaseRuntimeResource(_e);
      _downloadResults.push_back(group->createDownloadResult());

      executeStopHook(_downloadResults.back(), _e->option);
    }
  }
};

class CollectServerStat {
private:
  RequestGroupMan* _requestGroupMan;
public:
  CollectServerStat(RequestGroupMan* requestGroupMan):
    _requestGroupMan(requestGroupMan) {}

  void operator()(const SharedHandle<RequestGroup>& group)
  {
    if(group->getNumCommand() == 0) {
      // Collect statistics during download in PeerStats and update/register
      // ServerStatMan
      if(!group->getSegmentMan().isNull()) {
	const std::deque<SharedHandle<PeerStat> >& peerStats =
	  group->getSegmentMan()->getPeerStats();

	for(std::deque<SharedHandle<PeerStat> >::const_iterator i =
	      peerStats.begin(); i != peerStats.end(); ++i) {
	  if((*i)->getHostname().empty() || (*i)->getProtocol().empty()) {
	    continue;
	  }
	  int speed = (*i)->getAvgDownloadSpeed();
	  if (speed == 0) continue;

	  SharedHandle<ServerStat> ss =
	    _requestGroupMan->getOrCreateServerStat((*i)->getHostname(),
						    (*i)->getProtocol());
          ss->increaseCounter();
	  ss->updateDownloadSpeed(speed);
          if(peerStats.size() == 1) {
            ss->updateSingleConnectionAvgSpeed(speed);
          }
          else {
            ss->updateMultiConnectionAvgSpeed(speed);
          }
	}
      }
    }    
  }
};

class FindStoppedRequestGroup {
public:
  bool operator()(const SharedHandle<RequestGroup>& group) {
    return group->getNumCommand() == 0;
  }
};

void RequestGroupMan::updateServerStat()
{
  std::for_each(_requestGroups.begin(), _requestGroups.end(),
		CollectServerStat(this));
}

void RequestGroupMan::removeStoppedGroup(DownloadEngine* e)
{
  size_t numPrev = _requestGroups.size();

  updateServerStat();

  std::for_each(_requestGroups.begin(), _requestGroups.end(),
		ProcessStoppedRequestGroup(e, _reservedGroups,
					   _downloadResults));

  _requestGroups.erase(std::remove_if(_requestGroups.begin(),
				      _requestGroups.end(),
				      FindStoppedRequestGroup()),
		       _requestGroups.end());

  size_t numRemoved = numPrev-_requestGroups.size();
  if(numRemoved > 0) {
    _logger->debug("%lu RequestGroup(s) deleted.",
		   static_cast<unsigned long>(numRemoved));
  }
}

void RequestGroupMan::configureRequestGroup
(const SharedHandle<RequestGroup>& requestGroup) const
{
  const std::string& uriSelectorValue = _option->get(PREF_URI_SELECTOR);
  if(uriSelectorValue == V_FEEDBACK) {
    requestGroup->setURISelector
      (SharedHandle<URISelector>(new FeedbackURISelector(_serverStatMan)));
  } else if(uriSelectorValue == V_INORDER) {
    requestGroup->setURISelector
      (SharedHandle<URISelector>(new InOrderURISelector()));
  } else if(uriSelectorValue == V_ADAPTIVE) {
    requestGroup->setURISelector
      (SharedHandle<URISelector>(new AdaptiveURISelector(_serverStatMan,
							 requestGroup.get())));
  }
}

static void createInitialCommand(const SharedHandle<RequestGroup>& requestGroup,
				 std::deque<Command*>& commands,
				 DownloadEngine* e,
				 bool useHead)
{
  requestGroup->createInitialCommand(commands, e,
				     useHead ?
				     Request::METHOD_HEAD :
				     Request::METHOD_GET);
}

void RequestGroupMan::fillRequestGroupFromReserver(DownloadEngine* e)
{
  RequestGroups temp;
  removeStoppedGroup(e);
  unsigned int count = 0;
  for(int num = _maxSimultaneousDownloads-_requestGroups.size();
      num > 0 && !_reservedGroups.empty(); --num) {
    RequestGroupHandle groupToAdd = _reservedGroups.front();
    _reservedGroups.pop_front();
    try {
      if(!groupToAdd->isDependencyResolved()) {
	temp.push_back(groupToAdd);
	continue;
      }
      configureRequestGroup(groupToAdd);
      Commands commands;
      createInitialCommand(groupToAdd, commands, e,
			   _option->getAsBool(PREF_USE_HEAD)||
			   _option->getAsBool(PREF_DRY_RUN));
      _requestGroups.push_back(groupToAdd);
      ++count;
      e->addCommand(commands);
      executeStartHook(groupToAdd, e->option);
    } catch(RecoverableException& ex) {
      _logger->error(EX_EXCEPTION_CAUGHT, ex);
      groupToAdd->releaseRuntimeResource(e);
      _downloadResults.push_back(groupToAdd->createDownloadResult());
    }
  }
  _reservedGroups.insert(_reservedGroups.begin(), temp.begin(), temp.end());
  if(count > 0) {
    e->setNoWait(true);
    _logger->debug("%d RequestGroup(s) added.", count);
  }
}

void RequestGroupMan::getInitialCommands(std::deque<Command*>& commands,
					 DownloadEngine* e)
{
  for(RequestGroups::iterator itr = _requestGroups.begin();
	itr != _requestGroups.end();) {
    try {
      if((*itr)->isDependencyResolved()) {
	configureRequestGroup(*itr);
	createInitialCommand(*itr, commands, e,
			     _option->getAsBool(PREF_USE_HEAD));
	executeStartHook(*itr, e->option);
	++itr;
      } else {
	_reservedGroups.push_front((*itr));
	itr = _requestGroups.erase(itr);
      }
    } catch(RecoverableException& e) {
      _logger->error(EX_EXCEPTION_CAUGHT, e);
      _downloadResults.push_back((*itr)->createDownloadResult());
      itr = _requestGroups.erase(itr);
    }  
  }
}

void RequestGroupMan::save()
{
  for(RequestGroups::iterator itr = _requestGroups.begin();
      itr != _requestGroups.end(); ++itr) {
    if((*itr)->allDownloadFinished()) {
      (*itr)->getProgressInfoFile()->removeFile();
    } else {
      try {
	(*itr)->getProgressInfoFile()->save();
      } catch(RecoverableException& e) {
	_logger->error(EX_EXCEPTION_CAUGHT, e);
      }
    }
  }
}

void RequestGroupMan::closeFile()
{
  for(RequestGroups::iterator itr = _requestGroups.begin();
      itr != _requestGroups.end(); ++itr) {
    (*itr)->closeFile();
  }
}

RequestGroupMan::DownloadStat RequestGroupMan::getDownloadStat() const
{
  size_t finished = 0;
  size_t error = 0;
  size_t inprogress = 0;
  DownloadResult::RESULT lastError = DownloadResult::FINISHED;
  for(std::deque<SharedHandle<DownloadResult> >::const_iterator itr = _downloadResults.begin();
      itr != _downloadResults.end(); ++itr) {
    if((*itr)->result == DownloadResult::FINISHED) {
      ++finished;
    } else {
      ++error;
      lastError = (*itr)->result;
    }
  }
  for(RequestGroups::const_iterator itr = _requestGroups.begin();
      itr != _requestGroups.end(); ++itr) {
    DownloadResultHandle result = (*itr)->createDownloadResult();
    if(result->result == DownloadResult::FINISHED) {
      ++finished;
    } else {
      ++inprogress;
    }
  }
  return DownloadStat(finished, error, inprogress, _reservedGroups.size(),
		      lastError);
}

void RequestGroupMan::showDownloadResults(std::ostream& o) const
{
  static const std::string MARK_OK("OK");
  static const std::string MARK_ERR("ERR");
  static const std::string MARK_INPR("INPR");

  // Download Results:
  // idx|stat|path/length
  // ===+====+=======================================================================
  o << "\n"
    <<_("Download Results:") << "\n"
    << "gid|stat|avg speed  |path/URI" << "\n"
    << "===+====+===========+==========================================================" << "\n";

  int ok = 0;
  int err = 0;
  int inpr = 0;

  for(std::deque<SharedHandle<DownloadResult> >::const_iterator itr = _downloadResults.begin();
      itr != _downloadResults.end(); ++itr) {
    std::string status;
    if((*itr)->result == DownloadResult::FINISHED) {
      status = MARK_OK;
      ++ok;
    } else if((*itr)->result == DownloadResult::IN_PROGRESS) {
      status = MARK_INPR;
      ++inpr;
    } else {
      status = MARK_ERR;
      ++err;
    }
    o << formatDownloadResult(status, *itr) << "\n";
  }
  for(RequestGroups::const_iterator itr = _requestGroups.begin();
      itr != _requestGroups.end(); ++itr) {
    DownloadResultHandle result = (*itr)->createDownloadResult();
    std::string status;
    if(result->result == DownloadResult::FINISHED) {
      status = MARK_OK;
      ++ok;
    } else {
      // Since this RequestGroup is not processed by ProcessStoppedRequestGroup,
      // its download stop time is not reseted.
      // Reset download stop time and assign sessionTime here.
      (*itr)->getDownloadContext()->resetDownloadStopTime();
      result->sessionTime =
	(*itr)->getDownloadContext()->calculateSessionTime();
      status = MARK_INPR;
      ++inpr;
    }
    o << formatDownloadResult(status, result) << "\n";
  }
  if(ok > 0 || err > 0 || inpr > 0) {
    o << "\n"
      << _("Status Legend:") << "\n";

    if(ok > 0) {
      o << " (OK):download completed.";
    }
    if(err > 0) {
      o << "(ERR):error occurred.";
    }
    if(inpr > 0) {
      o << "(INPR):download in-progress.";
    }
    o << "\n";
  }
}

template<typename InputIterator>
static SharedHandle<FileEntry> getFirstRequestedFileEntry
(InputIterator first, InputIterator last)
{
  for(; first != last; ++first) {
    if((*first)->isRequested()) {
      return *first;
    }
  }
  return SharedHandle<FileEntry>();
}

template<typename InputIterator>
static size_t countRequestedFileEntry(InputIterator first, InputIterator last)
{
  size_t count = 0;
  for(; first != last; ++first) {
    if((*first)->isRequested()) {
      ++count;
    }
  }
  return count;
}

template<typename InputIterator>
static void writeFilePath
(InputIterator first, InputIterator last, std::ostream& o, bool memory)
{
  SharedHandle<FileEntry> e = getFirstRequestedFileEntry(first, last);
  if(e.isNull()) {
    o << "n/a";
  } else {
    if(e->getPath().empty()) {
      o << "n/a";
    } else {
      if(memory) {
	o << "[MEMORY]" << File(e->getPath()).getBasename();
      } else {
	o << e->getPath();
      }
    }
    size_t count = countRequestedFileEntry(first, last);
    if(count > 1) {
      o << " (" << count-1 << "more)";
    }
  }
}

std::string RequestGroupMan::formatDownloadResult(const std::string& status, const DownloadResultHandle& downloadResult) const
{
  std::stringstream o;
  o << std::setw(3) << downloadResult->gid << "|"
    << std::setw(4) << status << "|"
    << std::setw(11);
  if(downloadResult->sessionTime > 0) {
    o << Util::abbrevSize
      (downloadResult->sessionDownloadLength*1000/downloadResult->sessionTime)+
      "B/s";
  } else {
    o << "n/a";
  }
  o << "|";
  const std::deque<SharedHandle<FileEntry> >& fileEntries =
    downloadResult->fileEntries;
  if(downloadResult->result == DownloadResult::FINISHED ||
     downloadResult->numUri == 0) {
    writeFilePath(fileEntries.begin(), fileEntries.end(), o,
		  downloadResult->inMemoryDownload);
  } else {
    o << downloadResult->uri;
    if(downloadResult->numUri > 1) {
      o << " (" << downloadResult->numUri-1 << "more)";
    }
  }
  return o.str();
}

template<typename StringInputIterator, typename FileEntryInputIterator>
static bool sameFilePathExists(StringInputIterator sfirst,
			       StringInputIterator slast,
			       FileEntryInputIterator ffirst,
			       FileEntryInputIterator flast)
{
  for(; ffirst != flast; ++ffirst) {
    if(std::binary_search(sfirst, slast, (*ffirst)->getPath())) {
      return true;
    }
  }
  return false;
}

bool RequestGroupMan::isSameFileBeingDownloaded(RequestGroup* requestGroup) const
{
  // TODO it may be good to use dedicated method rather than use
  // isPreLocalFileCheckEnabled
  if(!requestGroup->isPreLocalFileCheckEnabled()) {
    return false;
  }
  std::deque<std::string> files;
  for(RequestGroups::const_iterator itr = _requestGroups.begin();
      itr != _requestGroups.end(); ++itr) {
    if((*itr).get() != requestGroup) {
      std::deque<SharedHandle<FileEntry> > entries =
	(*itr)->getDownloadContext()->getFileEntries();
      std::transform(entries.begin(), entries.end(),
		     std::back_inserter(files),
		     mem_fun_sh(&FileEntry::getPath));
    }
  }
  std::sort(files.begin(), files.end());
  std::deque<SharedHandle<FileEntry> > entries =
    requestGroup->getDownloadContext()->getFileEntries();
  return sameFilePathExists(files.begin(), files.end(),
			    entries.begin(), entries.end());
}

void RequestGroupMan::halt()
{
  for(RequestGroups::const_iterator itr = _requestGroups.begin();
      itr != _requestGroups.end(); ++itr) {
    (*itr)->setHaltRequested(true);
  }
}

void RequestGroupMan::forceHalt()
{
  for(RequestGroups::const_iterator itr = _requestGroups.begin();
      itr != _requestGroups.end(); ++itr) {
    (*itr)->setForceHaltRequested(true);
  }
}

TransferStat RequestGroupMan::calculateStat()
{
  TransferStat s;
  for(std::deque<SharedHandle<RequestGroup> >::const_iterator i =
	_requestGroups.begin(); i != _requestGroups.end(); ++i) {
    s += (*i)->calculateStat();
  }
  return s;
}

SharedHandle<DownloadResult>
RequestGroupMan::findDownloadResult(int32_t gid) const
{
  for(std::deque<SharedHandle<DownloadResult> >::const_iterator i =
	_downloadResults.begin(); i != _downloadResults.end(); ++i) {
    if((*i)->gid == gid) {
      return *i;
    }
  }
  return SharedHandle<DownloadResult>();
}

void RequestGroupMan::purgeDownloadResult()
{
  _downloadResults.clear();
}

SharedHandle<ServerStat>
RequestGroupMan::findServerStat(const std::string& hostname,
				const std::string& protocol) const
{
  return _serverStatMan->find(hostname, protocol);
}

SharedHandle<ServerStat>
RequestGroupMan::getOrCreateServerStat(const std::string& hostname,
				       const std::string& protocol)
{
  SharedHandle<ServerStat> ss = findServerStat(hostname, protocol);
  if(ss.isNull()) {
    ss.reset(new ServerStat(hostname, protocol));
    addServerStat(ss);
  }
  return ss;
}

bool RequestGroupMan::addServerStat(const SharedHandle<ServerStat>& serverStat)
{
  return _serverStatMan->add(serverStat);
}

bool RequestGroupMan::loadServerStat(const std::string& filename)
{
  std::ifstream in(filename.c_str(), std::ios::binary);
  if(!in) {
    _logger->error(MSG_OPENING_READABLE_SERVER_STAT_FILE_FAILED, filename.c_str());
    return false;
  }
  if(_serverStatMan->load(in)) {
    _logger->notice(MSG_SERVER_STAT_LOADED, filename.c_str());
    return true;
  } else {
    _logger->error(MSG_READING_SERVER_STAT_FILE_FAILED, filename.c_str());
    return false;
  }
}

bool RequestGroupMan::saveServerStat(const std::string& filename) const
{
  std::string tempfile = filename+"__temp";
  std::ofstream out(tempfile.c_str(), std::ios::binary);
  if(!out) {
    _logger->error(MSG_OPENING_WRITABLE_SERVER_STAT_FILE_FAILED,
		   tempfile.c_str());
    return false;
  }
  if (_serverStatMan->save(out)) {
    out.close();
    if (File(tempfile).renameTo(filename)) {
      _logger->notice(MSG_SERVER_STAT_SAVED, filename.c_str());
      return true;
    }
  }
  _logger->error(MSG_WRITING_SERVER_STAT_FILE_FAILED, filename.c_str());
  return false;
}

void RequestGroupMan::removeStaleServerStat(time_t timeout)
{
  _serverStatMan->removeStaleServerStat(timeout);
}

bool RequestGroupMan::doesOverallDownloadSpeedExceed()
{
  return _maxOverallDownloadSpeedLimit > 0 &&
    _maxOverallDownloadSpeedLimit < calculateStat().getDownloadSpeed();
}

bool RequestGroupMan::doesOverallUploadSpeedExceed()
{
  return _maxOverallUploadSpeedLimit > 0 &&
    _maxOverallUploadSpeedLimit < calculateStat().getUploadSpeed();
}

} // namespace aria2