PdfWorker: generatePreviews: take const ref to container with search results

gui/pdfworker.cpp

@@ -67,11 +67,11 @@ struct Renderer
 	}
 };
 
-QFuture<PdfPreview> PdfWorker::generatePreviews(QVector<SearchResult> paths, double scalefactor)
+QFuture<PdfPreview> PdfWorker::generatePreviews(const QVector<SearchResult> paths, double scalefactor)
 {
 	QVector<PdfPreview> previews;
 
-	for(SearchResult &sr : paths)
+	for(const SearchResult &sr : paths)
 	{
 		for(int page : sr.pages)
 		{

gui/pdfworker.h

@@ -16,7 +16,7 @@ class PdfWorker : public QObject
 {
 	Q_OBJECT
   public:
-	QFuture<PdfPreview> generatePreviews(QVector<SearchResult> paths, double scalefactor);
+	QFuture<PdfPreview> generatePreviews(const QVector<SearchResult> paths, double scalefactor);
 };
 
 #endif // PDFWORKER_H