gui: stop generating preview images after a memory limit has been reached.

gui/mainwindow.cpp

@@ -113,6 +113,8 @@ void MainWindow::tabChanged()
 }
 
 void MainWindow::pdfPreviewReceived(PdfPreview preview)
+{
+    if(preview.hasPreviewImage())
     {
         ClickLabel *label = new ClickLabel();
         label->setPixmap(QPixmap::fromImage(preview.previewImage));
@@ -139,6 +141,7 @@ void MainWindow::pdfPreviewReceived(PdfPreview preview)
             }
         });
     }
+}
 
 void MainWindow::lineEditReturnPressed()
 {
@@ -174,16 +177,11 @@ void MainWindow::handleSearchResults(const QVector<SearchResult> &results)
        item->setText(0, fileName);
        item->setText(1, result.fileData.absPath);
        item->setText(2, dt.toString(Qt::ISODate));
-
-       //TODO: this must be user defined or done more intelligently
-       if(this->pdfSearchResults.size() < 300)
-       {
        if(result.fileData.absPath.endsWith(".pdf"))
        {
            this->pdfSearchResults.append(result);
        }
    }
-   }
    ui->treeResultsList->resizeColumnToContents(0);
    ui->treeResultsList->resizeColumnToContents(1);
    pdfDirty = ! this->pdfSearchResults.empty();

gui/pdfpreview.h

@@ -9,6 +9,11 @@ public:
     QImage previewImage;
     QString documentPath;
     unsigned int page;
+
+    bool hasPreviewImage()
+    {
+        return ! previewImage.isNull();
+    }
 };
 
 #endif // PDFPREVIEW_H

gui/pdfworker.cpp

@@ -6,6 +6,7 @@
 #include <QMutexLocker>
 #include <QtConcurrent/QtConcurrent>
 #include <QtConcurrent/QtConcurrentMap>
+#include <atomic>
 #include "pdfworker.h"
 
 
@@ -17,13 +18,25 @@ struct Renderer
     double scaleX;
     double scaleY;
     QHash<QString, Poppler::Document *> documentcache;
-    Renderer(double scaleX, double scaleY)
+    qsizetype maxTotalPreviewImageMemUsage;
+    std::atomic<qsizetype> currentTotalPreviewImageMemUsage { 0 };
+
+    Renderer(double scaleX, double scaleY, qsizetype maxPreviewImageMemUsage)
     {
         this->scaleX = scaleX;
         this->scaleY = scaleY;
+        this->maxTotalPreviewImageMemUsage = maxPreviewImageMemUsage;
 
     }
 
+    /*we need this one because std::atomic has none, but this is only a functor for
+    concurrentmap, thus, it's ok for it to be half-broken*/
+    Renderer(const Renderer &o)
+    {
+        this->scaleX = o.scaleX;
+        this->scaleY = o.scaleY;
+    }
+
     ~Renderer()
     {
         qDeleteAll(documentcache);
@@ -38,7 +51,7 @@ struct Renderer
         Poppler::Document *result = Poppler::Document::load(path);
         if(result == nullptr)
         {
-            //TODO: some kind of user feedback would be nicec
+            //TODO: some kind of user feedback would be nice
             return nullptr;
         }
         result->setRenderHint(Poppler::Document::TextAntialiasing);
@@ -50,6 +63,9 @@ struct Renderer
 
 
     PdfPreview operator()(const PdfPreview &preview)
+    {
+        PdfPreview result = preview;
+        if(currentTotalPreviewImageMemUsage.load() < maxTotalPreviewImageMemUsage)
         {
             Poppler::Document *doc = document(preview.documentPath);
             if(doc == nullptr)
@@ -66,8 +82,10 @@ struct Renderer
                 p = 0;
             }
             Poppler::Page *pdfPage = doc->page(p);
-        PdfPreview result = preview;
-        result.previewImage  = pdfPage->renderToImage(scaleX, scaleY);
+            QImage img = pdfPage->renderToImage(scaleX, scaleY);
+            result.previewImage = img;
+            currentTotalPreviewImageMemUsage += img.sizeInBytes();
+        }
         return result;
     }
 };
@@ -94,7 +112,9 @@ QFuture<PdfPreview> PdfWorker::generatePreviews(const QVector<SearchResult> path
     double scaleX = QGuiApplication::primaryScreen()->physicalDotsPerInchX() * scalefactor;
     double scaleY = QGuiApplication::primaryScreen()->physicalDotsPerInchY() * scalefactor;
 
+    QSettings setting;
+    qsizetype maxPreviewImageMemUsage = setting.value("maxpreviewimagesmemory", 1024 * 1024 * 1024).toLongLong();
 
-    return QtConcurrent::mapped(previews, Renderer(scaleX, scaleY));
+    return QtConcurrent::mapped(previews, Renderer(scaleX, scaleY, maxPreviewImageMemUsage));
 }