Preserve installed card databases when Oracle refresh fails (#7739)

* Preserve installed card databases when Oracle refresh fails

* Fix the Oracle refresh verdict and cover the parser write path

A background refresh that already installed cards.xml exited 1 when the
token save afterwards failed, so the client kept its old in-memory
database and reported the update as failed. Return the same verdict
main() already computes: a reject after the database was written is a
successful update.

Cover the writer Oracle actually uses: add a short-write death test for
CockatriceXml4Parser::saveToFile, which reverted to QFile would truncate
an installed database without any test noticing.

Route a failed background token download through reject() instead of a
modal box on a hidden wizard, which left the client waiting with no
timeout and blocked later updates. Test the first non-space byte in
place rather than copying the payload, and report an import refusal with
the importer's own message.

---------

Co-authored-by: Lukas Brübach <Bruebach.Lukas@bdosecurity.de>

oracle/src/pagetemplates.cpp

@@ -1,5 +1,6 @@
 #include "pagetemplates.h"
 
+#include "database_writer.h"
 #include "oraclewizard.h"
 
 #include <QCheckBox>
@@ -184,9 +185,17 @@ void SimpleDownloadFilePage::actDownloadFinished()
     }
     QNetworkReply::NetworkError errorCode = reply->error();
     if (errorCode != QNetworkReply::NoError) {
-        QMessageBox::critical(this, tr("Error"), tr("Network error: %1.").arg(reply->errorString()));
-        wizard()->enableButtons();
+        const QString message = tr("Network error: %1.").arg(reply->errorString());
         reply->deleteLater();
+        // A hidden wizard cannot show a modal box: without an explicit stop it would sit
+        // here forever and the hosting client would wait with no timeout.
+        if (wizard()->backgroundMode) {
+            qWarning() << message;
+            wizard()->reject();
+            return;
+        }
+        QMessageBox::critical(this, tr("Error"), message);
+        wizard()->enableButtons();
         return;
     }
 
@@ -218,6 +227,15 @@ void SimpleDownloadFilePage::actDownloadFinished()
 
 bool SimpleDownloadFilePage::saveToFile()
 {
+    const auto failSave = [this](const QString &message) {
+        qWarning() << message;
+        if (wizard()->backgroundMode) {
+            wizard()->reject();
+        } else {
+            QMessageBox::critical(this, tr("Error"), message);
+        }
+        return false;
+    };
     QString defaultPath = getDefaultSavePath();
     QString windowName = getWindowTitle();
     QString fileType = getFileType();
@@ -236,12 +254,11 @@ bool SimpleDownloadFilePage::saveToFile()
     QFileInfo fi(fileName);
     QDir fileDir(fi.path());
     if (!fileDir.exists() && !fileDir.mkpath(fileDir.absolutePath())) {
-        return false;
+        return failSave(tr("The database directory could not be created: %1").arg(fileDir.absolutePath()));
     }
 
     if (!internalSaveToFile(fileName)) {
-        QMessageBox::critical(this, tr("Error"), tr("The file could not be saved to %1").arg(fileName));
-        return false;
+        return failSave(tr("The file could not be saved to %1").arg(fileName));
     }
 
     // clean saved downloadData
@@ -252,17 +269,10 @@ bool SimpleDownloadFilePage::saveToFile()
 
 bool SimpleDownloadFilePage::internalSaveToFile(const QString &fileName)
 {
-    QFile file(fileName);
-    if (!file.open(QIODevice::WriteOnly)) {
-        qDebug() << "File open (w) failed for" << fileName;
+    QString error;
+    if (!OracleDatabase::saveXml(fileName, downloadData, &error)) {
+        qWarning() << error;
         return false;
     }
-
-    if (file.write(downloadData) == -1) {
-        qDebug() << "File write (w) failed for" << fileName;
-        return false;
-    }
-
-    file.close();
     return true;
 }