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<?php

namespace TYPO3\PharStreamWrapper;

/*

 * This file is part of the TYPO3 project.

 *

 * It is free software; you can redistribute it and/or modify it under the terms

 * of the MIT License (MIT). For the full copyright and license information,

 * please read the LICENSE file that was distributed with this source code.

 *

 * The TYPO3 project - inspiring people to share!

 */

/**

 * Helper provides low-level tools on file name resolving. However it does not

 * (and should not) maintain any runtime state information. In order to resolve

 * Phar archive paths according resolvers have to be used.

 *

 * @see \TYPO3\PharStreamWrapper\Resolvable::resolve()

 */

class Helper

{

    /*

     * Resets PHP's OPcache if enabled as work-around for issues in `include()`

     * or `require()` calls and OPcache delivering wrong results.

     *

     * @see https://bugs.php.net/bug.php?id=66569

     */

    public static function resetOpCache()

    {

        if (function_exists('opcache_reset')

            && function_exists('opcache_get_status')

        ) {

            $status = opcache_get_status();

            if (!empty($status['opcache_enabled'])) {

                opcache_reset();

            }

        }

    }

    /**

     * Determines base file that can be accessed using the regular file system.

     * For e.g. "phar:///home/user/bundle.phar/content.txt" that would result

     * into "/home/user/bundle.phar".

     *

     * @param string $path

     * @return string|null

     */

    public static function determineBaseFile($path)

    {

        $parts = explode('/', static::normalizePath($path));

        while (count($parts)) {

            $currentPath = implode('/', $parts);

            if (@is_file($currentPath) && realpath($currentPath) !== false) {

                return $currentPath;

            }

            array_pop($parts);

        }

        return null;

    }

    /**

     * @param string $path

     * @return bool

     */

    public static function hasPharPrefix($path)

    {

        return stripos($path, 'phar://') === 0;

    }

    /**

     * @param string $path

     * @return string

     */

    public static function removePharPrefix($path)

    {

        $path = trim($path);

        if (!static::hasPharPrefix($path)) {

            return $path;

        }

        return substr($path, 7);

    }

    /**

     * Normalizes a path, removes phar:// prefix, fixes Windows directory

     * separators. Result is without trailing slash.

     *

     * @param string $path

     * @return string

     */

    public static function normalizePath($path)

    {

        return rtrim(

            static::normalizeWindowsPath(

                static::removePharPrefix($path)

            ),

            '/'

        );

    }

    /**

     * Fixes a path for windows-backslashes and reduces double-slashes to single slashes

     *

     * @param string $path File path to process

     * @return string

     */

    public static function normalizeWindowsPath($path)

    {

        return str_replace('\\', '/', $path);

    }

    /**

     * Resolves all dots, slashes and removes spaces after or before a path...

     *

     * @param string $path Input string

     * @return string Canonical path, always without trailing slash

     */

    private static function getCanonicalPath($path)

    {

        $path = static::normalizeWindowsPath($path);

        $absolutePathPrefix = '';

        if (static::isAbsolutePath($path)) {

            if (static::isWindows() && strpos($path, ':/') === 1) {

                $absolutePathPrefix = substr($path, 0, 3);

                $path = substr($path, 3);

            } else {

                $path = ltrim($path, '/');

                $absolutePathPrefix = '/';

            }

        }

        $pathParts = explode('/', $path);

        $pathPartsLength = count($pathParts);

        for ($partCount = 0; $partCount < $pathPartsLength; $partCount++) {

            // double-slashes in path: remove element

            if ($pathParts[$partCount] === '') {

                array_splice($pathParts, $partCount, 1);

                $partCount--;

                $pathPartsLength--;

            }

            // "." in path: remove element

            if ((isset($pathParts[$partCount]) ? $pathParts[$partCount] : '') === '.') {

                array_splice($pathParts, $partCount, 1);

                $partCount--;

                $pathPartsLength--;

            }

            // ".." in path:

            if ((isset($pathParts[$partCount]) ? $pathParts[$partCount] : '') === '..') {

                if ($partCount === 0) {

                    array_splice($pathParts, $partCount, 1);

                    $partCount--;

                    $pathPartsLength--;

                } elseif ($partCount >= 1) {

                    // Rremove this and previous element

                    array_splice($pathParts, $partCount - 1, 2);

                    $partCount -= 2;

                    $pathPartsLength -= 2;

                } elseif ($absolutePathPrefix) {

                    // can't go higher than root dir

                    // simply remove this part and continue

                    array_splice($pathParts, $partCount, 1);

                    $partCount--;

                    $pathPartsLength--;

                }

            }

        }

        return $absolutePathPrefix . implode('/', $pathParts);

    }

    /**

     * Checks if the $path is absolute or relative (detecting either '/' or

     * 'x:/' as first part of string) and returns TRUE if so.

     *

     * @param string $path File path to evaluate

     * @return bool

     */

    private static function isAbsolutePath($path)

    {

        // Path starting with a / is always absolute, on every system

        // On Windows also a path starting with a drive letter is absolute: X:/

        return (isset($path[0]) ? $path[0] : null) === '/'

            || static::isWindows() && (

                strpos($path, ':/') === 1

                || strpos($path, ':\\') === 1

            );

    }

    /**

     * @return bool

     */

    private static function isWindows()

    {

        return stripos(PHP_OS, 'WIN') === 0;

    }

}