Small optimization

app/src/main/java/eu/faircode/email/DaoAttachment.java

@@ -103,4 +103,8 @@ public interface DaoAttachment {
     @Query("DELETE FROM attachment" +
             " WHERE id = :id")
     int deleteAttachment(long id);
+
+    @Query("DELETE FROM attachment" +
+            " WHERE message = :message")
+    int deleteAttachments(long message);
 }

app/src/main/java/eu/faircode/email/FragmentMessages.java

@@ -4039,9 +4039,8 @@ public class FragmentMessages extends FragmentBase implements SharedPreferences.
                                     String html = parts.getHtml(context);
                                     Helper.writeText(message.getFile(context), html);
 
-                                    // Remove attachments
-                                    for (EntityAttachment local : attachments)
-                                        db.attachment().deleteAttachment(local.id);
+                                    // Remove existing attachments
+                                    db.attachment().deleteAttachments(id);
 
                                     // Add decrypted attachments
                                     List<EntityAttachment> remotes = parts.getAttachments();