<?php

namespace Illuminate\Database\Concerns;

use Closure;
use Illuminate\Database\DeadlockException;
use RuntimeException;
use Throwable;

trait ManagesTransactions
{
    /**
     * Execute a Closure within a transaction.
     *
     * @param  \Closure  $callback
     * @param  int  $attempts
     * @return mixed
     *
     * @throws \Throwable
     */
    public function transaction(Closure $callback, $attempts = 1)
    {
        for ($currentAttempt = 1; $currentAttempt <= $attempts; $currentAttempt++) {
            $this->beginTransaction();

            // We'll simply execute the given callback within a try / catch block and if we
            // catch any exception we can rollback this transaction so that none of this
            // gets actually persisted to a database or stored in a permanent fashion.
            try {
                $callbackResult = $callback($this);
            }

            // If we catch an exception we'll rollback this transaction and try again if we
            // are not out of attempts. If we are out of attempts we will just throw the
            // exception back out, and let the developer handle an uncaught exception.
            catch (Throwable $e) {
                $this->handleTransactionException(
                    $e, $currentAttempt, $attempts
                );

                continue;
            }

            $levelBeingCommitted = $this->transactions;

            try {
                if ($this->transactions == 1) {
                    $this->fireConnectionEvent('committing');
                    $this->getPdo()->commit();
                }

                $this->transactions = max(0, $this->transactions - 1);
            } catch (Throwable $e) {
                $this->handleCommitTransactionException(
                    $e, $currentAttempt, $attempts
                );

                continue;
            }

            $this->transactionsManager?->commit(
                $this->getName(),
                $levelBeingCommitted,
                $this->transactions
            );

            $this->fireConnectionEvent('committed');

            return $callbackResult;
        }
    }

    /**
     * Handle an exception encountered when running a transacted statement.
     *
     * @param  \Throwable  $e
     * @param  int  $currentAttempt
     * @param  int  $maxAttempts
     * @return void
     *
     * @throws \Throwable
     */
    protected function handleTransactionException(Throwable $e, $currentAttempt, $maxAttempts)
    {
        // On a deadlock, MySQL rolls back the entire transaction so we can't just
        // retry the query. We have to throw this exception all the way out and
        // let the developer handle it in another way. We will decrement too.
        if ($this->causedByConcurrencyError($e) &&
            $this->transactions > 1) {
            $this->transactions--;

            $this->transactionsManager?->rollback(
                $this->getName(), $this->transactions
            );

            throw new DeadlockException($e->getMessage(), is_int($e->getCode()) ? $e->getCode() : 0, $e);
        }

        // If there was an exception we will rollback this transaction and then we
        // can check if we have exceeded the maximum attempt count for this and
        // if we haven't we will return and try this query again in our loop.
        $this->rollBack();

        if ($this->causedByConcurrencyError($e) &&
            $currentAttempt < $maxAttempts) {
            return;
        }

        throw $e;
    }

    /**
     * Start a new database transaction.
     *
     * @return void
     *
     * @throws \Throwable
     */
    public function beginTransaction()
    {
        foreach ($this->beforeStartingTransaction as $callback) {
            $callback($this);
        }

        $this->createTransaction();

        $this->transactions++;

        $this->transactionsManager?->begin(
            $this->getName(), $this->transactions
        );

        $this->fireConnectionEvent('beganTransaction');
    }

    /**
     * Create a transaction within the database.
     *
     * @return void
     *
     * @throws \Throwable
     */
    protected function createTransaction()
    {
        if ($this->transactions == 0) {
            $this->reconnectIfMissingConnection();

            try {
                $this->getPdo()->beginTransaction();
            } catch (Throwable $e) {
                $this->handleBeginTransactionException($e);
            }
        } elseif ($this->transactions >= 1 && $this->queryGrammar->supportsSavepoints()) {
            $this->createSavepoint();
        }
    }

    /**
     * Create a save point within the database.
     *
     * @return void
     *
     * @throws \Throwable
     */
    protected function createSavepoint()
    {
        $this->getPdo()->exec(
            $this->queryGrammar->compileSavepoint('trans'.($this->transactions + 1))
        );
    }

    /**
     * Handle an exception from a transaction beginning.
     *
     * @param  \Throwable  $e
     * @return void
     *
     * @throws \Throwable
     */
    protected function handleBeginTransactionException(Throwable $e)
    {
        if ($this->causedByLostConnection($e)) {
            $this->reconnect();

            $this->getPdo()->beginTransaction();
        } else {
            throw $e;
        }
    }

    /**
     * Commit the active database transaction.
     *
     * @return void
     *
     * @throws \Throwable
     */
    public function commit()
    {
        if ($this->transactionLevel() == 1) {
            $this->fireConnectionEvent('committing');
            $this->getPdo()->commit();
        }

        [$levelBeingCommitted, $this->transactions] = [
            $this->transactions,
            max(0, $this->transactions - 1),
        ];

        $this->transactionsManager?->commit(
            $this->getName(), $levelBeingCommitted, $this->transactions
        );

        $this->fireConnectionEvent('committed');
    }

    /**
     * Handle an exception encountered when committing a transaction.
     *
     * @param  \Throwable  $e
     * @param  int  $currentAttempt
     * @param  int  $maxAttempts
     * @return void
     *
     * @throws \Throwable
     */
    protected function handleCommitTransactionException(Throwable $e, $currentAttempt, $maxAttempts)
    {
        $this->transactions = max(0, $this->transactions - 1);

        if ($this->causedByConcurrencyError($e) && $currentAttempt < $maxAttempts) {
            return;
        }

        if ($this->causedByLostConnection($e)) {
            $this->transactions = 0;
        }

        throw $e;
    }

    /**
     * Rollback the active database transaction.
     *
     * @param  int|null  $toLevel
     * @return void
     *
     * @throws \Throwable
     */
    public function rollBack($toLevel = null)
    {
        // We allow developers to rollback to a certain transaction level. We will verify
        // that this given transaction level is valid before attempting to rollback to
        // that level. If it's not we will just return out and not attempt anything.
        $toLevel = is_null($toLevel)
                    ? $this->transactions - 1
                    : $toLevel;

        if ($toLevel < 0 || $toLevel >= $this->transactions) {
            return;
        }

        // Next, we will actually perform this rollback within this database and fire the
        // rollback event. We will also set the current transaction level to the given
        // level that was passed into this method so it will be right from here out.
        try {
            $this->performRollBack($toLevel);
        } catch (Throwable $e) {
            $this->handleRollBackException($e);
        }

        $this->transactions = $toLevel;

        $this->transactionsManager?->rollback(
            $this->getName(), $this->transactions
        );

        $this->fireConnectionEvent('rollingBack');
    }

    /**
     * Perform a rollback within the database.
     *
     * @param  int  $toLevel
     * @return void
     *
     * @throws \Throwable
     */
    protected function performRollBack($toLevel)
    {
        if ($toLevel == 0) {
            $pdo = $this->getPdo();

            if ($pdo->inTransaction()) {
                $pdo->rollBack();
            }
        } elseif ($this->queryGrammar->supportsSavepoints()) {
            $this->getPdo()->exec(
                $this->queryGrammar->compileSavepointRollBack('trans'.($toLevel + 1))
            );
        }
    }

    /**
     * Handle an exception from a rollback.
     *
     * @param  \Throwable  $e
     * @return void
     *
     * @throws \Throwable
     */
    protected function handleRollBackException(Throwable $e)
    {
        if ($this->causedByLostConnection($e)) {
            $this->transactions = 0;

            $this->transactionsManager?->rollback(
                $this->getName(), $this->transactions
            );
        }

        throw $e;
    }

    /**
     * Get the number of active transactions.
     *
     * @return int
     */
    public function transactionLevel()
    {
        return $this->transactions;
    }

    /**
     * Execute the callback after a transaction commits.
     *
     * @param  callable  $callback
     * @return void
     *
     * @throws \RuntimeException
     */
    public function afterCommit($callback)
    {
        if ($this->transactionsManager) {
            return $this->transactionsManager->addCallback($callback);
        }

        throw new RuntimeException('Transactions Manager has not been set.');
    }
}

.NET Framework

Project Request

ProjectC

Vehicle Maintenance

Movie Navigator

Customers Exchange

ATM

.NET Core

Mail Daemon

Custom

Buns of code

PHP

Mediabox

Loan Castle

Content Management

Laravel

Phone Check

Frontend

Forex Wall

Business projects

Certification Center

Amerikas Auto

Pet projects

Geolocation Assistant

Web Dynamics

Blackball

Good old times

DOS Clock

BrainOut

Airport Administrator

Atomizer

Mediabox