networkdiskcachegc.cpp

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/**********************************************************************
 * LeechCraft - modular cross-platform feature rich internet client.
 * Copyright (C) 2006-2014  Georg Rudoy
 *
 * Distributed under the Boost Software License, Version 1.0.
 * (See accompanying file LICENSE or copy at https://www.boost.org/LICENSE_1_0.txt)
 **********************************************************************/
 
#include "networkdiskcachegc.h"
#include <QTimer>
#include <QDir>
#include <QDirIterator>
#include <QtConcurrentRun>
#include <QDateTime>
#include <QtDebug>
#include <util/sll/qtutil.h>
#include <util/sll/prelude.h>
#include <util/sll/util.h>
#include <util/threads/futures.h>
 
namespace LC::Util
{
    NetworkDiskCacheGC::NetworkDiskCacheGC ()
    {
        const auto timer = new QTimer { this };
        connect (timer,
                &QTimer::timeout,
                this,
                &NetworkDiskCacheGC::HandleCollect);
        timer->start (60 * 60 * 1000);
    }
 
    NetworkDiskCacheGC& NetworkDiskCacheGC::Instance ()
    {
        static NetworkDiskCacheGC gc;
        return gc;
    }
 
    namespace
    {
        struct SizeCollectInfo
        {
            QMultiMap<QDateTime, QString> Items_;
            qint64 TotalSize_ = 0;
        };
 
        SizeCollectInfo CollectSizes (const QString& cacheDirectory)
        {
            SizeCollectInfo result;
 
            const QDir::Filters filters = QDir::AllDirs | QDir:: Files | QDir::NoDotAndDotDot;
            QDirIterator it { cacheDirectory, filters, QDirIterator::Subdirectories };
 
            while (it.hasNext ())
            {
                const auto& path = it.next ();
                const auto& info = it.fileInfo ();
                result.Items_.insert (info.birthTime (), path);
                result.TotalSize_ += info.size ();
            }
 
            return result;
        }
    }
 
    QFuture<qint64> NetworkDiskCacheGC::GetCurrentSize (const QString& path) const
    {
        return QtConcurrent::run ([path] { return CollectSizes (path).TotalSize_; });
    }
 
    Util::DefaultScopeGuard NetworkDiskCacheGC::RegisterDirectory (const QString& path,
            const std::function<int ()>& sizeGetter)
    {
        auto& list = Directories_ [path];
        list.push_front (sizeGetter);
        const auto thisItem = list.begin ();
 
        return Util::MakeScopeGuard ([this, path, thisItem] { UnregisterDirectory (path, thisItem); }).EraseType ();
    }
 
    void NetworkDiskCacheGC::UnregisterDirectory (const QString& path, CacheSizeGetters_t::iterator pos)
    {
        if (!Directories_.contains (path))
        {
            qWarning () << Q_FUNC_INFO
                    << "unknown directory"
                    << path;
            return;
        }
 
        auto& list = Directories_ [path];
        list.erase (pos);
 
        if (!list.empty ())
            return;
 
        Directories_.remove (path);
        LastSizes_.remove (path);
    }
 
    namespace
    {
        qint64 Collector (const QString& cacheDirectory, qint64 goal)
        {
            if (cacheDirectory.isEmpty ())
                return 0;
 
            qDebug () << Q_FUNC_INFO << "running..." << cacheDirectory << goal;
 
            auto sizeInfoResult = CollectSizes (cacheDirectory);
 
            for (auto i = sizeInfoResult.Items_.constBegin ();
                    i != sizeInfoResult.Items_.constEnd () && sizeInfoResult.TotalSize_ > goal;
                    ++i)
            {
                QFile file { *i };
                sizeInfoResult.TotalSize_ -= file.size ();
                file.remove ();
            }
 
            qDebug () << "collector finished" << sizeInfoResult.TotalSize_;
 
            return sizeInfoResult.TotalSize_;
        }
    };
 
    void NetworkDiskCacheGC::HandleCollect ()
    {
        if (IsCollecting_)
        {
            qWarning () << Q_FUNC_INFO
                    << "already collecting";
            return;
        }
 
        QList<QPair<QString, int>> dirs;
        for (const auto& pair : Util::Stlize (Directories_))
        {
            const auto& getters = pair.second;
            const auto minSize = (*std::min_element (getters.begin (), getters.end (),
                        Util::ComparingBy (Apply))) ();
            dirs.append ({ pair.first, minSize });
        }
 
        if (dirs.isEmpty ())
            return;
 
        IsCollecting_ = true;
 
        Util::Sequence (this,
                QtConcurrent::run ([dirs]
                        {
                            QMap<QString, qint64> sizes;
                            for (const auto& pair : dirs)
                                sizes [pair.first] = Collector (pair.first, pair.second);
                            return sizes;
                        })) >>
                [this] (const QMap<QString, qint64>& sizes)
                {
                    IsCollecting_ = false;
                    for (const auto& pair : Util::Stlize (sizes))
                        LastSizes_ [pair.first] = pair.second;
                };
    }
}