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

gui/mainwindow.cpp

@@ -114,30 +114,33 @@ void MainWindow::tabChanged()
 
 void MainWindow::pdfPreviewReceived(PdfPreview preview)
 {
-    ClickLabel *label = new ClickLabel();
-    label->setPixmap(QPixmap::fromImage(preview.previewImage));
-    label->setToolTip(preview.documentPath);
-    ui->scrollAreaWidgetContents->layout()->addWidget(label);
-    connect(label, &ClickLabel::leftClick, [=]() {
-        QSettings settings;
-        QString command = settings.value("pdfviewer").toString();
-        if(command != "" && command.contains("%p") && command.contains("%f"))
-        {
-            command = command.replace("%f", preview.documentPath);
-            command = command.replace("%p", QString::number(preview.page));
-            QStringList splitted = command.split(" ");
-            if(splitted.size() > 1)
+    if(preview.hasPreviewImage())
+    {
+        ClickLabel *label = new ClickLabel();
+        label->setPixmap(QPixmap::fromImage(preview.previewImage));
+        label->setToolTip(preview.documentPath);
+        ui->scrollAreaWidgetContents->layout()->addWidget(label);
+        connect(label, &ClickLabel::leftClick, [=]() {
+            QSettings settings;
+            QString command = settings.value("pdfviewer").toString();
+            if(command != "" && command.contains("%p") && command.contains("%f"))
             {
-                QString cmd = splitted[0];
-                QStringList args = splitted.mid(1);
-                QProcess::startDetached(cmd, args);
+                command = command.replace("%f", preview.documentPath);
+                command = command.replace("%p", QString::number(preview.page));
+                QStringList splitted = command.split(" ");
+                if(splitted.size() > 1)
+                {
+                    QString cmd = splitted[0];
+                    QStringList args = splitted.mid(1);
+                    QProcess::startDetached(cmd, args);
+                }
             }
-        }
-        else
-        {
-            QDesktopServices::openUrl(QUrl::fromLocalFile(preview.documentPath));
-        }
-    });
+            else
+            {
+                QDesktopServices::openUrl(QUrl::fromLocalFile(preview.documentPath));
+            }
+        });
+    }
 }
 
 void MainWindow::lineEditReturnPressed()
@@ -174,14 +177,9 @@ 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"))
        {
-           if(result.fileData.absPath.endsWith(".pdf"))
-           {
-               this->pdfSearchResults.append(result);
-           }
+           this->pdfSearchResults.append(result);
        }
    }
    ui->treeResultsList->resizeColumnToContents(0);

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);
@@ -51,23 +64,28 @@ struct Renderer
 
     PdfPreview operator()(const PdfPreview &preview)
     {
-        Poppler::Document *doc = document(preview.documentPath);
-        if(doc == nullptr)
-        {
-            return preview;
-        }
-        if(doc->isLocked())
-        {
-            return preview;
-        }
-        int p = (int)preview.page - 1;
-        if(p < 0)
-        {
-            p = 0;
-        }
-        Poppler::Page *pdfPage = doc->page(p);
         PdfPreview result = preview;
-        result.previewImage  = pdfPage->renderToImage(scaleX, scaleY);
+        if(currentTotalPreviewImageMemUsage.load() < maxTotalPreviewImageMemUsage)
+        {
+            Poppler::Document *doc = document(preview.documentPath);
+            if(doc == nullptr)
+            {
+                return preview;
+            }
+            if(doc->isLocked())
+            {
+                return preview;
+            }
+            int p = (int)preview.page - 1;
+            if(p < 0)
+            {
+                p = 0;
+            }
+            Poppler::Page *pdfPage = doc->page(p);
+            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));
 }