refactor(asyncimageresponse): use QMimeDatabase for SVG check

Signed-off-by: Jyrki Gadinger <nilsding@nilsding.org>

Author: nilsding

src/gui/tray/asyncimageresponse.cpp

@@ -6,6 +6,7 @@
 #include "asyncimageresponse.h"
 
 #include <QIcon>
+#include <QMimeDatabase>
 #include <QPainter>
 #include <QSvgRenderer>
 
@@ -116,11 +117,10 @@ void AsyncImageResponse::processNetworkReply(QNetworkReply *reply)
         return;
     }
 
-    // check whether the reply might be an SVG by looking at the content type and the first 512 bytes of the response for `<svg`.
     // Some graphics programs export SVGs that begin with `<?xml version="1.0" [...]` and/or include some comments after that (e.g.
     // `<!-- Generator: ...`), so we can't rely on just the response to start with `<svg`.
-    if (const auto contentTypeHeader = reply->header(QNetworkRequest::ContentTypeHeader);
-        !(contentTypeHeader.toString().startsWith("image/svg"_ba) || imageData.first(qMin(imageData.size(), 512)).contains("<svg"_ba))) {
+    if (const auto mimetype = QMimeDatabase().mimeTypeForData(imageData);
+        !(mimetype.isValid() && mimetype.inherits("image/svg+xml"_L1))) {
         // Not an SVG: let's let QImage deal with the response.
         setImageAndEmitFinished(QImage::fromData(imageData).scaled(_requestedImageSize));
         return;