/**
* Wraps a transaction around a closure or string callback.
* If an Exception is thrown inside, the operation is automatically rolled back.
* If no Exception happens, it commits automatically.
* It also supports (simulated) nested transactions (that is useful when
* you have many methods that needs transactions but are unaware of
* each other).
*
* Example:
*
* <code>
* $from = 1;
* $to = 2;
* $amount = 300;
*
* R::transaction(function() use($from, $to, $amount)
* {
* $accountFrom = R::load('account', $from);
* $accountTo = R::load('account', $to);
* $accountFrom->money -= $amount;
* $accountTo->money += $amount;
* R::store($accountFrom);
* R::store($accountTo);
* });
* </code>
*
* @param Adapter $adapter Database Adapter providing transaction mechanisms.
* @param callable $callback Closure (or other callable) with the transaction logic
*
* @return mixed
*/
public static function transaction(Adapter $adapter, $callback)
{
if (!is_callable($callback)) {
throw new RedException('R::transaction needs a valid callback.');
}
static $depth = 0;
$result = null;
try {
if ($depth == 0) {
$adapter->startTransaction();
}
$depth++;
$result = call_user_func($callback);
//maintain 5.2 compatibility
$depth--;
if ($depth == 0) {
$adapter->commit();
}
} catch (\Exception $exception) {
$depth--;
if ($depth == 0) {
$adapter->rollback();
}
throw $exception;
}
return $result;
}
