Merge "Make addIdentifierQuotes part of IDatabase"

diff --combined includes/libs/rdbms/database/Database.php
index 3475b09,174182f..49b2792
--- 1/includes/libs/rdbms/database/Database.php
--- 2/includes/libs/rdbms/database/Database.php
+++ b/includes/libs/rdbms/database/Database.php
@@@ -1019,22 -1019,13 +1019,22 @@@ abstract class Database implements IDat
        }
  
        /**
 -       * Run a query and return a DBMS-dependent wrapper (that has all IResultWrapper methods)
 +       * Run a query and return a DBMS-dependent wrapper or boolean
         *
 -       * This might return things, such as mysqli_result, that do not formally implement
 -       * IResultWrapper, but nonetheless implement all of its methods correctly
 +       * For SELECT queries, this returns either:
 +       *   - a) A driver-specific value/resource, only on success. This can be iterated
 +       *        over by calling fetchObject()/fetchRow() until there are no more rows.
 +       *        Alternatively, the result can be passed to resultObject() to obtain a
 +       *        ResultWrapper instance which can then be iterated over via "foreach".
 +       *   - b) False, on any query failure
         *
 -       * @param string $sql SQL query.
 -       * @return IResultWrapper|bool Iterator to feed to fetchObject/fetchRow; false on failure
 +       * For non-SELECT queries, this returns either:
 +       *   - a) A driver-specific value/resource, only on success
 +       *   - b) True, only on success (e.g. no meaningful result other than "OK")
 +       *   - c) False, on any query failure
 +       *
 +       * @param string $sql SQL query
 +       * @return mixed|bool An object, resource, or true on success; false on failure
         */
        abstract protected function doQuery( $sql );
  
@@@ -1347,19 -1338,12 +1347,19 @@@
        }
  
        /**
 +       * Error out if the DB is not in a valid state for a query via query()
 +       *
         * @param string $sql
         * @param string $fname
         * @throws DBTransactionStateError
         */
        private function assertTransactionStatus( $sql, $fname ) {
 -              if ( $this->getQueryVerb( $sql ) === 'ROLLBACK' ) { // transaction/savepoint
 +              $verb = $this->getQueryVerb( $sql );
 +              if ( $verb === 'USE' ) {
 +                      throw new DBUnexpectedError( $this, "Got USE query; use selectDomain() instead." );
 +              }
 +
 +              if ( $verb === 'ROLLBACK' ) { // transaction/savepoint
                        return;
                }
  
@@@ -2294,9 -2278,7 +2294,9 @@@
        }
  
        public function buildStringCast( $field ) {
 -              return $field;
 +              // In theory this should work for any standards-compliant
 +              // SQL implementation, although it may not be the best way to do it.
 +              return "CAST( $field AS CHARACTER )";
        }
  
        public function buildIntegerCast( $field ) {
@@@ -2682,15 -2664,6 +2682,6 @@@
                }
        }
  
-       /**
-        * Quotes an identifier using `backticks` or "double quotes" depending on the database type.
-        * MySQL uses `backticks` while basically everything else uses double quotes.
-        * Since MySQL is the odd one out here the double quotes are our generic
-        * and we implement backticks in DatabaseMysqlBase.
-        *
-        * @param string $s
-        * @return string
-        */
        public function addIdentifierQuotes( $s ) {
                return '"' . str_replace( '"', '""', $s ) . '"';
        }