chore(core): improve failed decryption error handling

src/core/toxencrypt.cpp

@@ -325,6 +325,10 @@ QString getDecryptionError(TOX_ERR_DECRYPTION error)
             "The input data was shorter than TOX_PASS_ENCRYPTION_EXTRA_LENGTH bytes.");
     case TOX_ERR_DECRYPTION_BAD_FORMAT:
         return QStringLiteral("The input data is missing the magic number or is corrupted.");
+    case TOX_ERR_DECRYPTION_KEY_DERIVATION_FAILED:
+        return QStringLiteral("The crypto lib was unable to derive a key from the given passphrase.");
+    case TOX_ERR_DECRYPTION_FAILED:
+        return QStringLiteral("Decryption failed. Either the data was corrupted or the password/key was incorrect.");
     default:
         return QStringLiteral("Unknown decryption error.");
     }

src/core/toxencrypt.h

@@ -17,12 +17,12 @@
     along with qTox.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#include <QByteArray>
-#include <QString>
-
 #ifndef TOXENCRYPT_H
 #define TOXENCRYPT_H
 
+#include <QByteArray>
+#include <QString>
+
 #include <memory>
 
 struct Tox_Pass_Key;

src/persistence/profile.cpp

@@ -436,11 +436,11 @@ QPixmap Profile::loadAvatar(const ToxPk& owner)
     QPixmap pic;
     if (Settings::getInstance().getShowIdenticons()) {
 
-        const QByteArray avataData = loadAvatarData(owner);
-        if (avataData.isEmpty()) {
+        const QByteArray avatarData = loadAvatarData(owner);
+        if (avatarData.isEmpty()) {
             pic = QPixmap::fromImage(Identicon(owner.getKey()).toImage(16));
         } else {
-            pic.loadFromData(avataData);
+            pic.loadFromData(avatarData);
         }
 
     } else {
@@ -473,6 +473,9 @@ QByteArray Profile::loadAvatarData(const ToxPk& owner)
     QByteArray pic = file.readAll();
     if (avatarEncrypted && !pic.isEmpty()) {
         pic = passkey->decrypt(pic);
+        if (pic.isEmpty()) {
+            qWarning() << "Failed to decrypt avatar at" << path;
+        }
     }
 
     return pic;