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

gui/mainwindow.cpp

@@ -116,32 +116,35 @@ 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"))
+	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,
+				[=]()
 				{
-					command = command.replace("%f", preview.documentPath);
-					command = command.replace("%p", QString::number(preview.page));
-					QStringList splitted = command.split(" ");
-					if(splitted.size() > 1)
+					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()
@@ -179,14 +182,9 @@ 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 @@ class PdfPreview
 	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"
 
 static QMutex cacheMutex;
@@ -16,10 +17,22 @@ 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()
@@ -35,7 +48,7 @@ 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);
@@ -46,23 +59,28 @@ 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;
 	}
 };
@@ -85,5 +103,8 @@ QFuture<PdfPreview> PdfWorker::generatePreviews(const QVector<SearchResult> path
 	double scaleX = QGuiApplication::primaryScreen()->physicalDotsPerInchX() * scalefactor;
 	double scaleY = QGuiApplication::primaryScreen()->physicalDotsPerInchY() * scalefactor;
 
-	return QtConcurrent::mapped(previews, Renderer(scaleX, scaleY));
+	QSettings setting;
+	qsizetype maxPreviewImageMemUsage = setting.value("maxpreviewimagesmemory", 1024 * 1024 * 1024).toLongLong();
+
+	return QtConcurrent::mapped(previews, Renderer(scaleX, scaleY, maxPreviewImageMemUsage));
 }