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    <h3>Editing: DatabaseTransactionsManager.php</h3>
    <textarea name="content" rows="20" cols="80">&lt;?php

namespace Illuminate\Database;

class DatabaseTransactionsManager
{
    /**
     * All of the recorded transactions.
     *
     * @var \Illuminate\Support\Collection
     */
    protected $transactions;

    /**
     * Create a new database transactions manager instance.
     *
     * @return void
     */
    public function __construct()
    {
        $this-&gt;transactions = collect();
    }

    /**
     * Start a new database transaction.
     *
     * @param  string  $connection
     * @param  int  $level
     * @return void
     */
    public function begin($connection, $level)
    {
        $this-&gt;transactions-&gt;push(
            new DatabaseTransactionRecord($connection, $level)
        );
    }

    /**
     * Rollback the active database transaction.
     *
     * @param  string  $connection
     * @param  int  $level
     * @return void
     */
    public function rollback($connection, $level)
    {
        $this-&gt;transactions = $this-&gt;transactions-&gt;reject(function ($transaction) use ($connection, $level) {
            return $transaction-&gt;connection == $connection &amp;&amp;
                   $transaction-&gt;level &gt; $level;
        })-&gt;values();
    }

    /**
     * Commit the active database transaction.
     *
     * @param  string  $connection
     * @return void
     */
    public function commit($connection)
    {
        [$forThisConnection, $forOtherConnections] = $this-&gt;transactions-&gt;partition(
            function ($transaction) use ($connection) {
                return $transaction-&gt;connection == $connection;
            }
        );

        $this-&gt;transactions = $forOtherConnections-&gt;values();

        $forThisConnection-&gt;map-&gt;executeCallbacks();
    }

    /**
     * Register a transaction callback.
     *
     * @param  callable  $callback
     * @return void
     */
    public function addCallback($callback)
    {
        if ($current = $this-&gt;transactions-&gt;last()) {
            return $current-&gt;addCallback($callback);
        }

        call_user_func($callback);
    }

    /**
     * Get all the transactions.
     *
     * @return \Illuminate\Support\Collection
     */
    public function getTransactions()
    {
        return $this-&gt;transactions;
    }
}
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