Perform fastresume data saving in separate thread

Closes #4315

src/base/base.pri

@@ -36,6 +36,7 @@ HEADERS += \
     $$PWD/bittorrent/private/bandwidthscheduler.h \
     $$PWD/bittorrent/private/filterparserthread.h \
     $$PWD/bittorrent/private/statistics.h \
+    $$PWD/bittorrent/private/resumedatasavingmanager.h \
     $$PWD/rss/rssmanager.h \
     $$PWD/rss/rssfeed.h \
     $$PWD/rss/rssfolder.h \
@@ -87,6 +88,7 @@ SOURCES += \
     $$PWD/bittorrent/private/bandwidthscheduler.cpp \
     $$PWD/bittorrent/private/filterparserthread.cpp \
     $$PWD/bittorrent/private/statistics.cpp \
+    $$PWD/bittorrent/private/resumedatasavingmanager.cpp \
     $$PWD/rss/rssmanager.cpp \
     $$PWD/rss/rssfeed.cpp \
     $$PWD/rss/rssfolder.cpp \

src/base/bittorrent/private/resumedatasavingmanager.cpp

@@ -0,0 +1,54 @@
+/*
+ * Bittorrent Client using Qt and libtorrent.
+ * Copyright (C) 2015  Vladimir Golovnev <glassez@yandex.ru>
+ *
+ * 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 this program with the OpenSSL project's "OpenSSL" library (or with
+ * modified versions of it that use the same license as the "OpenSSL" library),
+ * and distribute the linked executables. 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), 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.
+ */
+
+#include <QDebug>
+#include <QFile>
+
+#include "base/utils/fs.h"
+#include "resumedatasavingmanager.h"
+
+ResumeDataSavingManager::ResumeDataSavingManager(const QString &resumeFolderPath)
+    : m_resumeDataDir(resumeFolderPath)
+{
+}
+
+void ResumeDataSavingManager::saveResumeData(QString infoHash, QByteArray data, int priority) const
+{
+    QStringList filters(QString("%1.fastresume.*").arg(infoHash));
+    const QStringList files = m_resumeDataDir.entryList(filters, QDir::Files, QDir::Unsorted);
+    foreach (const QString &file, files)
+        Utils::Fs::forceRemove(m_resumeDataDir.absoluteFilePath(file));
+
+    QString filename = QString("%1.fastresume.%2").arg(infoHash).arg(priority);
+    QString filepath = m_resumeDataDir.absoluteFilePath(filename);
+
+    qDebug() << "Saving resume data in" << filepath;
+    QFile resumeFile(filepath);
+    if (resumeFile.open(QIODevice::WriteOnly))
+        resumeFile.write(data);
+}

src/base/bittorrent/private/resumedatasavingmanager.h

@@ -0,0 +1,50 @@
+/*
+ * Bittorrent Client using Qt and libtorrent.
+ * Copyright (C) 2015  Vladimir Golovnev <glassez@yandex.ru>
+ *
+ * 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 this program with the OpenSSL project's "OpenSSL" library (or with
+ * modified versions of it that use the same license as the "OpenSSL" library),
+ * and distribute the linked executables. 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), 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.
+ */
+
+#ifndef RESUMEDATASAVINGMANAGER_H
+#define RESUMEDATASAVINGMANAGER_H
+
+#include <QObject>
+#include <QByteArray>
+#include <QDir>
+
+class ResumeDataSavingManager: public QObject
+{
+    Q_OBJECT
+
+public:
+    explicit ResumeDataSavingManager(const QString &resumeFolderPath);
+
+public slots:
+    void saveResumeData(QString infoHash, QByteArray data, int priority) const;
+
+private:
+    QDir m_resumeDataDir;
+};
+
+#endif // RESUMEDATASAVINGMANAGER_H

src/base/bittorrent/session.cpp

@@ -43,6 +43,7 @@ using namespace BitTorrent;
 #include <QTimer>
 #include <QProcess>
 #include <QCoreApplication>
+#include <QThread>
 
 #include <queue>
 #include <vector>
@@ -80,6 +81,7 @@ using namespace BitTorrent;
 #include "private/filterparserthread.h"
 #include "private/statistics.h"
 #include "private/bandwidthscheduler.h"
+#include "private/resumedatasavingmanager.h"
 #include "trackerentry.h"
 #include "tracker.h"
 #include "magneturi.h"
@@ -205,6 +207,11 @@ Session::Session(QObject *parent)
     connect(&m_networkManager, SIGNAL(configurationRemoved(const QNetworkConfiguration&)), SLOT(networkConfigurationChange(const QNetworkConfiguration&)));
     connect(&m_networkManager, SIGNAL(configurationChanged(const QNetworkConfiguration&)), SLOT(networkConfigurationChange(const QNetworkConfiguration&)));
 
+    m_ioThread = new QThread(this);
+    m_resumeDataSavingManager = new ResumeDataSavingManager(m_resumeFolderPath);
+    m_resumeDataSavingManager->moveToThread(m_ioThread);
+    connect(m_ioThread, SIGNAL(finished()), m_resumeDataSavingManager, SLOT(deleteLater()));
+    m_ioThread->start();
     m_resumeDataTimer->start();
 
     // initialize PortForwarder instance
@@ -282,6 +289,9 @@ Session::~Session()
     qDebug("Deleting the session");
     delete m_nativeSession;
 
+    m_ioThread->quit();
+    m_ioThread->wait();
+
     m_resumeFolderLock.close();
     m_resumeFolderLock.remove();
 }
@@ -1710,7 +1720,17 @@ void Session::handleTorrentFinished(TorrentHandle *const torrent)
 void Session::handleTorrentResumeDataReady(TorrentHandle *const torrent, const libtorrent::entry &data)
 {
     --m_numResumeData;
-    writeResumeDataFile(torrent, data);
+
+    // Separated thread is used for the blocking IO which results in slow processing of many torrents.
+    // Encoding data in parallel while doing IO saves time. Copying libtorrent::entry objects around
+    // isn't cheap too.
+
+    QByteArray out;
+    libt::bencode(std::back_inserter(out), data);
+
+    QMetaObject::invokeMethod(m_resumeDataSavingManager, "saveResumeData",
+                              Q_ARG(QString, torrent->hash()), Q_ARG(QByteArray, out),
+                              Q_ARG(int, torrent->queuePosition()));
 }
 
 void Session::handleTorrentResumeDataFailed(TorrentHandle *const torrent)
@@ -2356,28 +2376,6 @@ bool loadTorrentResumeData(const QByteArray &data, AddTorrentData &out, MagnetUr
     return true;
 }
 
-bool Session::writeResumeDataFile(TorrentHandle *const torrent, const libt::entry &data)
-{
-    const QDir resumeDataDir(m_resumeFolderPath);
-
-    QStringList filters(QString("%1.fastresume.*").arg(torrent->hash()));
-    const QStringList files = resumeDataDir.entryList(filters, QDir::Files, QDir::Unsorted);
-    foreach (const QString &file, files)
-        Utils::Fs::forceRemove(resumeDataDir.absoluteFilePath(file));
-
-    QString filename = QString("%1.fastresume.%2").arg(torrent->hash()).arg(torrent->queuePosition());
-    QString filepath = resumeDataDir.absoluteFilePath(filename);
-
-    qDebug("Saving resume data in %s", qPrintable(filepath));
-    QFile resumeFile(filepath);
-    QVector<char> out;
-    libt::bencode(std::back_inserter(out), data);
-    if (resumeFile.open(QIODevice::WriteOnly))
-        return (resumeFile.write(&out[0], out.size()) == out.size());
-
-    return false;
-}
-
 void torrentQueuePositionUp(const libt::torrent_handle &handle)
 {
     try {

src/base/bittorrent/session.h

@@ -86,6 +86,7 @@ namespace libtorrent
     struct external_ip_alert;
 }
 
+class QThread;
 class QTimer;
 class QStringList;
 class QString;
@@ -95,6 +96,7 @@ template<typename T> class QList;
 class FilterParserThread;
 class BandwidthScheduler;
 class Statistics;
+class ResumeDataSavingManager;
 
 typedef QPair<QString, QString> QStringPair;
 
@@ -314,7 +316,6 @@ namespace BitTorrent
         void handleExternalIPAlert(libtorrent::external_ip_alert *p);
 
         void saveResumeData();
-        bool writeResumeDataFile(TorrentHandle *const torrent, const libtorrent::entry &data);
 
         void dispatchAlerts(std::auto_ptr<libtorrent::alert> alertPtr);
         void getPendingAlerts(QVector<libtorrent::alert *> &out, ulong time = 0);
@@ -355,6 +356,9 @@ namespace BitTorrent
         QPointer<BandwidthScheduler> m_bwScheduler;
         // Tracker
         QPointer<Tracker> m_tracker;
+        // fastresume data writing thread
+        QThread *m_ioThread;
+        ResumeDataSavingManager *m_resumeDataSavingManager;
 
         QHash<InfoHash, TorrentInfo> m_loadedMetadata;
         QHash<InfoHash, TorrentHandle *> m_torrents;