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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 "FeedbackURISelector.h"
#include <cassert>
#include <algorithm>
#include "ServerStatMan.h"
#include "ServerStat.h"
#include "A2STR.h"
#include "FileEntry.h"
#include "Logger.h"
#include "LogFactory.h"
#include "a2algo.h"
#include "uri.h"
#include "fmt.h"
namespace aria2 {
FeedbackURISelector::FeedbackURISelector
(const std::shared_ptr<ServerStatMan>& serverStatMan)
: serverStatMan_(serverStatMan)
{}
FeedbackURISelector::~FeedbackURISelector() {}
std::string FeedbackURISelector::select
(FileEntry* fileEntry,
const std::vector<std::pair<size_t, std::string> >& usedHosts)
{
if(A2_LOG_DEBUG_ENABLED) {
for (const auto& h: usedHosts) {
A2_LOG_DEBUG(fmt("UsedHost=%lu, %s",
static_cast<unsigned long>(h.first),
h.second.c_str()));
}
}
if(fileEntry->getRemainingUris().empty()) {
return A2STR::NIL;
}
// Select URI with usedHosts first. If no URI is selected, then do
// it again without usedHosts.
std::string uri = selectFaster(fileEntry->getRemainingUris(), usedHosts);
if(uri.empty()) {
A2_LOG_DEBUG("No URI returned from selectFaster()");
uri = selectRarer(fileEntry->getRemainingUris(), usedHosts);
}
if(!uri.empty()) {
std::deque<std::string>& uris = fileEntry->getRemainingUris();
uris.erase(std::find(uris.begin(), uris.end(), uri));
}
A2_LOG_DEBUG(fmt("FeedbackURISelector selected %s", uri.c_str()));
return uri;
}
std::string FeedbackURISelector::selectRarer
(const std::deque<std::string>& uris,
const std::vector<std::pair<size_t, std::string> >& usedHosts)
{
// pair of host and URI
std::vector<std::pair<std::string, std::string> > cands;
for (const auto& u: uris) {
uri_split_result us;
if(uri_split(&us, u.c_str()) == -1) {
continue;
}
auto host = uri::getFieldString(us, USR_HOST, u.c_str());
auto protocol = uri::getFieldString(us, USR_SCHEME, u.c_str());
auto ss = serverStatMan_->find(host, protocol);
if(ss && ss->isError()) {
A2_LOG_DEBUG(fmt("Error not considered: %s", u.c_str()));
continue;
}
cands.push_back(std::make_pair(host, u));
}
for (const auto& h: usedHosts) {
for (const auto& c: cands) {
if(h.second == c.first) {
return c.second;
}
}
}
assert(!uris.empty());
return uris.front();
}
std::string FeedbackURISelector::selectFaster
(const std::deque<std::string>& uris,
const std::vector<std::pair<size_t, std::string> >& usedHosts)
{
// Use first 10 good URIs to introduce some randomness.
const size_t NUM_URI = 10;
// Ignore low speed server
const int SPEED_THRESHOLD = 20*1024;
std::vector<std::pair<std::shared_ptr<ServerStat>, std::string> > fastCands;
std::vector<std::string> normCands;
for (const auto& u: uris) {
if (fastCands.size() >= NUM_URI) {
break;
}
uri_split_result us;
if(uri_split(&us, u.c_str()) == -1) {
continue;
}
auto host = uri::getFieldString(us, USR_HOST, u.c_str());
if(findSecond(usedHosts.begin(), usedHosts.end(), host) !=
usedHosts.end()) {
A2_LOG_DEBUG(fmt("%s is in usedHosts, not considered", u.c_str()));
continue;
}
auto protocol = uri::getFieldString(us, USR_SCHEME, u.c_str());
auto ss = serverStatMan_->find(host, protocol);
if(!ss) {
normCands.push_back(u);
} else if(ss->isOK()) {
if(ss->getDownloadSpeed() > SPEED_THRESHOLD) {
fastCands.push_back(std::make_pair(ss, u));
} else {
normCands.push_back(u);
}
}
}
if(fastCands.empty()) {
if(normCands.empty()) {
return A2STR::NIL;
} else {
A2_LOG_DEBUG("Selected from normCands");
return normCands.front();
}
} else {
A2_LOG_DEBUG("Selected from fastCands");
std::sort(fastCands.begin(), fastCands.end(), ServerStatFaster());
return fastCands.front().second;
}
}
} // namespace aria2
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