database: add a transaction for tables creation

Creation of tables in the database can fail. If it occurs, we must not
let the database in a weird state. So, table creation is in a
transaction and if it fails, rollback this transaction and throw a
runtime_error.

Change-Id: I7ac4a891545eb18964f47884d57d43e47bf1fa02
Reviewed-by: Guillaume Roguez <guillaume.roguez@savoirfairelinux.com>

src/database.cpp

@@ -70,7 +70,14 @@ Database::Database()
 
     // if db is empty we create them.
     if (db_.tables().empty()) {
+        try {
+            QSqlDatabase::database().transaction();
             createTables();
+            QSqlDatabase::database().commit();
+        } catch (QueryError& e) {
+            QSqlDatabase::database().rollback();
+            throw std::runtime_error("Could not correctly create the database");
+        }
         // NOTE: the migration can take some time.
         migrateOldFiles();
     }