metadatamover.cpp

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/* This file is part of the KDE Project
   Copyright (c) 2009-2011 Sebastian Trueg <trueg@kde.org>

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public
   License version 2 as published by the Free Software Foundation.

   This library 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public License
   along with this library; see the file COPYING.LIB.  If not, write to
   the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
   Boston, MA 02110-1301, USA.
*/

#include "metadatamover.h"
#include "nepomukfilewatch.h"
#include "datamanagement.h"
#include "resourcemanager.h"

#include <QtCore/QTimer>

#include <Soprano/Model>
#include <Soprano/Node>
#include <Soprano/QueryResultIterator>

#include "nie.h"

#include <KDebug>
#include <KJob>
#include <KLocale>

using namespace Nepomuk2::Vocabulary;

Nepomuk2::MetadataMover::MetadataMover( Soprano::Model* model, QObject* parent )
    : QObject( parent ),
      m_queueMutex(QMutex::Recursive),
      m_model( model )
{
    // setup the main update queue timer
    m_queueTimer = new QTimer(this);
    connect(m_queueTimer, SIGNAL(timeout()),
            this, SLOT(slotWorkUpdateQueue()),
            Qt::DirectConnection);

}


Nepomuk2::MetadataMover::~MetadataMover()
{
}


void Nepomuk2::MetadataMover::moveFileMetadata( const KUrl& from, const KUrl& to )
{
//    kDebug() << from << to;
    Q_ASSERT( !from.path().isEmpty() && from.path() != "/" );
    Q_ASSERT( !to.path().isEmpty() && to.path() != "/" );

    QMutexLocker lock(&m_queueMutex);

    UpdateRequest req( from, to );
    if ( !m_updateQueue.contains( req ) )
        m_updateQueue.enqueue( req );

    QTimer::singleShot(0, this, SLOT(slotStartUpdateTimer()));
}


void Nepomuk2::MetadataMover::removeFileMetadata( const KUrl& file )
{
    Q_ASSERT( !file.path().isEmpty() && file.path() != "/" );
    removeFileMetadata( KUrl::List() << file );
}


void Nepomuk2::MetadataMover::removeFileMetadata( const KUrl::List& files )
{
    kDebug() << files;
    QMutexLocker lock(&m_queueMutex);

    foreach( const KUrl& file, files ) {
        UpdateRequest req( file );
        if ( !m_updateQueue.contains( req ) )
            m_updateQueue.enqueue( req );
    }

    QTimer::singleShot(0, this, SLOT(slotStartUpdateTimer()));
}


void Nepomuk2::MetadataMover::slotWorkUpdateQueue()
{
    // lock for initial iteration
    QMutexLocker lock(&m_queueMutex);

    emit metadataUpdateStarted();

    // work the queue
    if( !m_updateQueue.isEmpty() ) {
        UpdateRequest updateRequest = m_updateQueue.dequeue();

        // unlock after queue utilization
        lock.unlock();

//        kDebug() << "========================= handling" << updateRequest.source() << updateRequest.target();

        // an empty second url means deletion
        if( updateRequest.target().isEmpty() ) {

            emit statusMessage( i18n("Remove metadata from %1",updateRequest.source().prettyUrl()) );
            removeMetadata( updateRequest.source() );
        }
        else {
            const KUrl from = updateRequest.source();
            const KUrl to = updateRequest.target();

            emit statusMessage( i18n("Move metadata from %1 to %2",from.prettyUrl(),to.prettyUrl()) );

            // We do NOT get deleted messages for overwritten files! Thus, we
            // have to remove all metadata for overwritten files first.
            removeMetadata( to );

            // and finally update the old statements
            updateMetadata( from, to );
        }

//        kDebug() << "========================= done with" << updateRequest.source() << updateRequest.target();
    }
    else {
        //kDebug() << "All update requests handled. Stopping timer.";

        emit metadataUpdateStopped();
        m_queueTimer->stop();
    }
}


namespace {
    QUrl fetchUriFromUrl(const QUrl& nieUrl) {
        if( nieUrl.isEmpty() ) {
            return QUrl();
        }

        QString query = QString::fromLatin1("select ?r where { ?r nie:url %1 . } LIMIT 1")
                        .arg( Soprano::Node::resourceToN3(nieUrl) );

        Soprano::Model* model = Nepomuk2::ResourceManager::instance()->mainModel();
        Soprano::QueryResultIterator it = model->executeQuery( query, Soprano::Query::QueryLanguageSparqlNoInference );
        if( it.next() )
            return it[0].uri();

        return QUrl();
    }
}

void Nepomuk2::MetadataMover::removeMetadata( const KUrl& url )
{
    if( url.isEmpty() ) {
        kDebug() << "empty path. Looks like a bug somewhere...";
        return;
    }

    const QUrl uri = fetchUriFromUrl(url);
    if( uri.isEmpty() )
        return;

    // When the url is a folder we do not remove the metadata for all
    // the files in that folder, since inotify gives us a delete event
    // for each of those files
    KJob* job = Nepomuk2::removeResources( QList<QUrl>() << uri );
    job->exec();
    if( job->error() )
        kError() << job->errorString();
}


void Nepomuk2::MetadataMover::updateMetadata( const KUrl& from, const KUrl& to )
{
    kDebug() << from << "->" << to;
    if( from.isEmpty() || to.isEmpty() ) {
        kError() << "Paths Empty - File a bug" << from << to;
        return;
    }

    const QUrl uri = fetchUriFromUrl(from);
    if( !uri.isEmpty() ) {
        KJob* job = Nepomuk2::setProperty(QList<QUrl>() << uri, NIE::url(), QVariantList() << to);
        job->exec();
        if( job->error() )
            kError() << job->errorString();
    }
    else {
        //
        // If we have no metadata yet we need to tell the file indexer (if running) so it can
        // create the metadata in case the target folder is configured to be indexed.
        //
        emit movedWithoutData( to.path() );
    }
}



// start the timer in the update thread
void Nepomuk2::MetadataMover::slotStartUpdateTimer()
{
    if(!m_queueTimer->isActive()) {
        m_queueTimer->start();
    }
}

#include "metadatamover.moc"