messagecore/asyncnepomukresourceretriever.cpp

   1 /*
   2   Copyright (c) 2011 Volker Krause <vkrause@kde.org>
   3
   4   This library is free software; you can redistribute it and/or modify it
   5   under the terms of the GNU Library General Public License as published by
   6   the Free Software Foundation; either version 2 of the License, or (at your
   7   option) any later version.
   8
   9   This library is distributed in the hope that it will be useful, but WITHOUT
  10   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11   FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
  12   License for more details.
  13
  14   You should have received a copy of the GNU Library General Public License
  15   along with this library; see the file COPYING.LIB.  If not, write to the
  16   Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  17   02110-1301, USA.
  18 */
  19
  20 #include "asyncnepomukresourceretriever.h"
  21
  22 #include <QtCore/QMutex>
  23 #include <QtCore/QRunnable>
  24 #include <QtCore/QThreadPool>
  25
  26 #include <KDebug>
  27 #include <Nepomuk/Resource>
  28 #include <Nepomuk/Variant>
  29
  30 using namespace MessageCore;
  31
  32 namespace MessageCore {
  33
  34 class NepomukResourceRetrieverRunnable : public QRunnable
  35 {
  36   public:
  37     NepomukResourceRetrieverRunnable( const QUrl& url, const QVector<QUrl> &props, QObject *retriever ) :
  38       m_url( url ),
  39       m_props( props ),
  40       m_retriever( retriever )
  41     {}
  42
  43     void run()
  44     {
  45       Nepomuk::Resource resource( m_url );
  46       foreach ( const QUrl &prop, m_props )
  47         resource.property( prop ); // loads and caches this property
  48       QMetaObject::invokeMethod( m_retriever, "resourceRetrievalDone", Qt::QueuedConnection,
  49                                  Q_ARG(QUrl, m_url), Q_ARG(Nepomuk::Resource, resource) );
  50     }
  51
  52   private:
  53     QUrl m_url;
  54     QVector<QUrl> m_props;
  55     QObject* m_retriever;
  56 };
  57
  58 class AsyncNepomukResourceRetrieverPrivate
  59 {
  60   public:
  61     AsyncNepomukResourceRetrieverPrivate( AsyncNepomukResourceRetriever *parent ) : m_parent( parent ), m_running( false )
  62     {
  63       m_nepomukPool.setMaxThreadCount( 1 );
  64       qRegisterMetaType<Nepomuk::Resource>();
  65     }
  66
  67     void createRunnable()
  68     {
  69       Q_ASSERT( !m_pendingRequests.isEmpty() );
  70       Q_ASSERT( !m_running );
  71       m_running = true;
  72       const QUrl url = m_pendingRequests.last();
  73       m_nepomukPool.start( new NepomukResourceRetrieverRunnable( url, m_requestedProperties.value( url ), m_parent ) );
  74     }
  75
  76     void removeRequest( const QUrl &url )
  77     {
  78       const int index = m_pendingRequests.lastIndexOf( url );
  79       if ( index >= 0 )
  80         m_pendingRequests.remove( index );
  81       m_requestedProperties.remove( url );
  82     }
  83
  84     void resourceRetrievalDone( const QUrl &url, const Nepomuk::Resource &res )
  85     {
  86       QMutexLocker locker( &m_mutex );
  87       m_running = false;
  88       removeRequest( url );
  89       if ( !m_pendingRequests.isEmpty() )
  90         createRunnable();
  91       locker.unlock();
  92       m_parent->resourceAvailable( url, res );
  93     }
  94
  95     AsyncNepomukResourceRetriever *m_parent;
  96     QThreadPool m_nepomukPool;
  97     QVector<QUrl> m_pendingRequests;
  98     QHash<QUrl, QVector<QUrl> > m_requestedProperties;
  99     QMutex m_mutex;
 100     bool m_running;
 101 };
 102
 103 }
 104
 105 AsyncNepomukResourceRetriever::AsyncNepomukResourceRetriever(QObject* parent) :
 106   QObject( parent ),
 107   d( new AsyncNepomukResourceRetrieverPrivate( this ) )
 108 {
 109 }
 110
 111 void AsyncNepomukResourceRetriever::requestResource(const QUrl& url, const QVector<QUrl> &properties)
 112 {
 113   QMutexLocker locker( &d->m_mutex );
 114   if ( d->m_pendingRequests.contains( url ) )
 115     return;
 116   d->m_pendingRequests.push_back( url );
 117   d->m_requestedProperties.insert( url, properties );
 118   if ( !d->m_running )
 119     d->createRunnable();
 120 }
 121
 122 void AsyncNepomukResourceRetriever::cancelRequest(const QUrl & url)
 123 {
 124   QMutexLocker locker( &d->m_mutex );
 125   d->removeRequest( url );
 126 }
 127
 128 void AsyncNepomukResourceRetriever::resourceAvailable(const QUrl& url, const Nepomuk::Resource& resource)
 129 {
 130   emit resourceReceived( url, resource );
 131 }
 132
 133
 134 #include "asyncnepomukresourceretriever.moc"