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/* <!-- 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 "ServerStatURISelector.h"
#include "ServerStatMan.h"
#include "ServerStat.h"
#include "Request.h"
#include "A2STR.h"
#include <algorithm>
namespace aria2 {
ServerStatURISelector::ServerStatURISelector
(const SharedHandle<ServerStatMan>& serverStatMan):
_serverStatMan(serverStatMan) {}
ServerStatURISelector::~ServerStatURISelector() {}
class ServerStatFaster {
public:
bool operator()(const std::pair<SharedHandle<ServerStat>, std::string> lhs,
const std::pair<SharedHandle<ServerStat>, std::string> rhs)
const
{
return lhs.first->getDownloadSpeed() > rhs.first->getDownloadSpeed();
}
};
std::string ServerStatURISelector::select(std::deque<std::string>& uris)
{
if(uris.empty()) {
return A2STR::NIL;
}
// Use first 10 URIs to introduce some randomness.
const int NUM_URI = 10;
// Ignore low speed server
const unsigned int SPEED_THRESHOLD = 20*1024;
size_t max = std::min(uris.size(), static_cast<size_t>(NUM_URI));
std::deque<std::string>::iterator urisLast = uris.begin()+max;
std::deque<std::pair<SharedHandle<ServerStat>, std::string> > cands;
for(std::deque<std::string>::iterator i = uris.begin();
i != urisLast; ++i) {
Request r;
r.setUrl(*i);
SharedHandle<ServerStat> ss = _serverStatMan->find(r.getHost(),
r.getProtocol());
if(!ss.isNull() && ss->isOK() && ss->getDownloadSpeed() > SPEED_THRESHOLD) {
cands.push_back(std::pair<SharedHandle<ServerStat>, std::string>(ss, *i));
}
}
if(cands.empty()) {
for(std::deque<std::string>::iterator i = uris.begin();
i != uris.end(); ++i) {
Request r;
r.setUrl(*i);
SharedHandle<ServerStat> ss = _serverStatMan->find(r.getHost(),
r.getProtocol());
// Skip ERROR state URI
if(ss.isNull() || ss->isOK()) {
std::string nextURI = *i;
uris.erase(uris.begin(), i+1);
return nextURI;
}
}
// All URIs are inspected but aria2 cannot find usable one.
// Return first URI anyway in this case.
std::string nextURI = uris.front();
uris.pop_front();
return nextURI;
} else {
std::sort(cands.begin(), cands.end(), ServerStatFaster());
uris.erase(std::find(uris.begin(), uris.end(), cands.front().second));
return cands.front().second;
}
}
} // namespace aria2
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