diff --git a/src/core/fileopener.cpp b/src/core/fileopener.cpp
index d448f56..a8f91a0 100644
--- a/src/core/fileopener.cpp
+++ b/src/core/fileopener.cpp
@@ -1,131 +1,131 @@
 // SPDX-FileCopyrightText: 2023 g10 Code GmbH
 // SPDX-FileContributor: Carl Schwan <carl.schwan@gnupg.com>
 // SPDX-License-Identifier: LGPL-2.0-or-later
 
 #include "fileopener.h"
 #include "mimetreeparser_core_debug.h"
 
 #include <KMbox/MBox>
 #include <QFile>
 #include <QMimeDatabase>
 #include <QMimeType>
 
 using namespace MimeTreeParser::Core;
 
 namespace
 {
 KMime::Message::Ptr openSmimeEncrypted(const QByteArray &content)
 {
     KMime::Message::Ptr message(new KMime::Message);
 
     auto contentType = message->contentType();
     contentType->setMimeType("application/pkcs7-mime");
     contentType->setParameter(QStringLiteral("smime-type"), QStringLiteral("enveloped-data"));
 
     auto contentDisposition = new KMime::Headers::ContentDisposition;
     contentDisposition->setDisposition(KMime::Headers::CDattachment);
     contentDisposition->setFilename(QStringLiteral("smime.p7m"));
     message->appendHeader(contentDisposition);
 
     auto cte = message->contentTransferEncoding();
     cte->setEncoding(KMime::Headers::CE7Bit);
     cte->setDecoded(true);
 
     message->setBody(content);
     message->assemble();
 
     return message;
 }
 
 KMime::Message::Ptr openPgpEncrypted(const QByteArray &content)
 {
     KMime::Message::Ptr message(new KMime::Message);
 
     auto contentType = message->contentType();
     contentType->setMimeType("multipart/encrypted");
     contentType->setBoundary(KMime::multiPartBoundary());
     contentType->setParameter(QStringLiteral("protocol"), QStringLiteral("application/pgp-encrypted"));
 
     auto cte = message->contentTransferEncoding();
     cte->setEncoding(KMime::Headers::CE7Bit);
     cte->setDecoded(true);
 
     auto pgpEncrypted = new KMime::Content;
     pgpEncrypted->contentType()->setMimeType("application/pgp-encrypted");
     auto contentDisposition = new KMime::Headers::ContentDisposition;
     contentDisposition->setDisposition(KMime::Headers::CDattachment);
     pgpEncrypted->appendHeader(contentDisposition);
     pgpEncrypted->setBody("Version: 1");
     message->appendContent(pgpEncrypted);
 
     auto encryptedContent = new KMime::Content;
     encryptedContent->contentType()->setMimeType("application/octet-stream");
     contentDisposition = new KMime::Headers::ContentDisposition;
     contentDisposition->setDisposition(KMime::Headers::CDinline);
     contentDisposition->setFilename(QStringLiteral("msg.asc"));
     encryptedContent->appendHeader(contentDisposition);
     encryptedContent->setBody(content);
     message->appendContent(encryptedContent);
 
     message->assemble();
 
     return message;
 }
 
 QList<KMime::Message::Ptr> openMbox(const QString &fileName)
 {
     KMBox::MBox mbox;
     const bool ok = mbox.load(fileName);
     if (!ok) {
         qCWarning(MIMETREEPARSER_CORE_LOG) << "Unable to open" << fileName;
         return {};
     }
 
     QList<KMime::Message::Ptr> messages;
     const auto entries = mbox.entries();
     for (const auto &entry : entries) {
         messages << KMime::Message::Ptr(mbox.readMessage(entry));
     }
     return messages;
 }
 }
 
 QList<KMime::Message::Ptr> FileOpener::openFile(const QString &fileName)
 {
     QMimeDatabase db;
     QMimeType mime = db.mimeTypeForFile(fileName);
 
     QFile file(fileName);
     file.open(QIODevice::ReadOnly);
     if (!file.isOpen()) {
         qCWarning(MIMETREEPARSER_CORE_LOG) << "Could not open file";
         return {};
     }
 
     const auto content = file.readAll();
 
-    if (content.length() == 0) {
+    if (content.isEmpty()) {
         qCWarning(MIMETREEPARSER_CORE_LOG) << "File is empty";
         return {};
     }
 
     if (mime.inherits(QStringLiteral("application/pkcs7-mime")) || fileName.endsWith(QStringLiteral("smime.p7m"))) {
         return {openSmimeEncrypted(content)};
     } else if (mime.inherits(QStringLiteral("application/pgp-encrypted")) || fileName.endsWith(QStringLiteral(".asc"))) {
         return {openPgpEncrypted(content)};
     } else if (content.startsWith("From ")) {
         return openMbox(fileName);
     } else {
         auto msg = new KMime::Message;
         msg->setContent(KMime::CRLFtoLF(content));
         msg->parse();
         if (!msg->hasContent()) {
             delete msg;
             msg = nullptr;
             return {};
         }
         return {KMime::Message::Ptr(msg)};
     }
 
     return {};
 }