LegacyVersionUtility.php

<?php

declare (strict_types=1);
namespace Drupal\package_manager;

use Drupal\Core\Extension\ExtensionVersion;

/**
 * A utility class for dealing with legacy version numbers.
 *
 * @internal
 *   This is an internal utility class that could be changed or removed in any
 *   release and should not be used by external code.
 */
final class LegacyVersionUtility {
    
    /**
     * Converts a version number to a semantic version if needed.
     *
     * @param string $version
     *   The version number.
     *
     * @return string
     *   The version number, converted if needed.
     */
    public static function convertToSemanticVersion(string $version) : string {
        if (self::isLegacyVersion($version)) {
            $version = substr($version, 4);
            $version_parts = explode('-', $version);
            $version = $version_parts[0] . '.0';
            if (count($version_parts) === 2) {
                $version .= '-' . $version_parts[1];
            }
        }
        return $version;
    }
    
    /**
     * Converts a version number to a legacy version if needed and possible.
     *
     * @param string $version_string
     *   The version number.
     *
     * @return string|null
     *   The version number, converted if needed, or NULL if not possible. Only
     *   semantic version numbers that have patch level of 0 can be converted into
     *   legacy version numbers.
     */
    public static function convertToLegacyVersion($version_string) : ?string {
        if (self::isLegacyVersion($version_string)) {
            return $version_string;
        }
        $version = ExtensionVersion::createFromVersionString($version_string);
        if ($extra = $version->getVersionExtra()) {
            $version_string_without_extra = str_replace("-{$extra}", '', $version_string);
        }
        else {
            $version_string_without_extra = $version_string;
        }
        [
            ,
            ,
            $patch,
        ] = explode('.', $version_string_without_extra);
        // A semantic version can only be converted to legacy if it's patch level is
        // '0'.
        if ($patch !== '0') {
            return NULL;
        }
        return '8.x-' . $version->getMajorVersion() . '.' . $version->getMinorVersion() . ($extra ? "-{$extra}" : '');
    }
    
    /**
     * Determines if a version is legacy.
     *
     * @param string $version
     *   The version number.
     *
     * @return bool
     *   TRUE if the version is a legacy version number, otherwise FALSE.
     */
    private static function isLegacyVersion(string $version) : bool {
        return stripos($version, '8.x-') === 0;
    }

}