Dive pictures: refactor image downloader

Instead of generating one ImageDownloader object per image to be
downloaded and running every image download in a separate worker
thread, use one global ImageDownloader object owned by the UI thread.

The images are downloaded using event based IO (as probably was the
intention of the QNetworkManager class).

User-visible change: after download from the internet, the thumbnail
is shown without having to change dives.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

1 files changed, 13 insertions, 8 deletions

diff --git a/core/imagedownloader.h b/core/imagedownloader.h
index 92edea0b6..bee262854 100644
--- a/core/imagedownloader.h
+++ b/core/imagedownloader.h
@@ -10,13 +10,17 @@
 class ImageDownloader : public QObject {
 	Q_OBJECT
 public:
-	ImageDownloader(const QString &filename);
-	void load(bool fromHash);
-
+	static ImageDownloader *instance();
+	ImageDownloader();
+public slots:
+	void load(QString filename, bool fromHash);
+signals:
+	void loaded(QString filename);
+	void failed(QString filename);
 private:
-	bool loadFromUrl(const QUrl &);	// return true on success
-	void saveImage(QNetworkReply *reply, bool &success);
-	QString filename;
+	QNetworkAccessManager manager;
+	void loadFromUrl(const QString &filename, const QUrl &);
+	void saveImage(QNetworkReply *reply);
 };
 
 class PictureEntry;
@@ -35,6 +39,9 @@ public:
 	static int maxThumbnailSize();
 	static int defaultThumbnailSize();
 	static int thumbnailSize(double zoomLevel);
+public slots:
+	void imageDownloaded(QString filename);
+	void imageDownloadFailed(QString filename);
 signals:
 	void thumbnailChanged(QString filename, QImage thumbnail);
 private:
@@ -49,6 +56,4 @@ private:
 	QMap<QString,QFuture<void>> workingOn;
 };
 
-QImage getHashedImage(const QString &filename);
-
 #endif // IMAGEDOWNLOADER_H