re-resolve tracks when a resolver is added or removed.

The pipeline emits a signal to queries when a resolver is added/removed. The queries
take action based on their solved() status and if not solved() inform the pipeline to
re-resolve them.

src/libtomahawk/pipeline.cpp

@@ -82,8 +82,9 @@ void
 Pipeline::removeResolver( Resolver* r )
 {
     QMutexLocker lock( &m_mut );
-
+    
     m_resolvers.removeAll( r );
+    emit resolverRemoved( r );
 }
 
 
@@ -100,6 +101,7 @@ Pipeline::addResolver( Resolver* r, bool sort )
                Pipeline::resolverSorter );
     }
     qDebug() << "Adding resolver" << r->name();
+    emit resolverAdded( r );
 
 /*    qDebug() << "Current pipeline:";
     foreach( Resolver * r, m_resolvers )

src/libtomahawk/pipeline.h

@@ -79,6 +79,9 @@ public slots:
 signals:
     void idle();
     void resolving( const Tomahawk::query_ptr& query );
+    
+    void resolverAdded( Resolver* );
+    void resolverRemoved( Resolver* );
 
 private slots:
     void timeoutShunt( const query_ptr& q );

src/libtomahawk/query.cpp

@@ -67,6 +67,11 @@ Query::Query( const QString& artist, const QString& track, const QString& album,
     {
         connect( Database::instance(), SIGNAL( indexReady() ), SLOT( refreshResults() ), Qt::QueuedConnection );
     }
+    
+    connect( Pipeline::instance(), SIGNAL( resolverAdded( Resolver* ) ), 
+            SLOT( onResolverAdded() ), Qt::QueuedConnection );  
+    connect( Pipeline::instance(), SIGNAL( resolverRemoved( Resolver* ) ),
+            SLOT( onResolverRemoved() ), Qt::QueuedConnection );  
 }
 
 
@@ -148,6 +153,26 @@ Query::onResolvingFinished()
 }
 
 
+void
+Query::onResolverAdded( )
+{
+    if ( !solved() ) 
+    {
+        refreshResults();
+    }
+}
+
+void
+Query::onResolverRemoved( )
+{
+    if ( !solved() )
+    {
+        refreshResults();
+    }
+
+}
+
+
 QList< result_ptr >
 Query::results() const
 {

src/libtomahawk/query.h

@@ -105,6 +105,10 @@ public slots:
 
     void onResolvingFinished();
 
+    // resolve if not solved()
+    void onResolverAdded( );
+    void onResolverRemoved( );
+
 private slots:
     void onResultStatusChanged();
     void refreshResults();