Proyectos de Subversion Moodle

<?php

// This file is part of Moodle - http://moodle.org/

//

// Moodle is free software: you can redistribute it and/or modify

// it under the terms of the GNU General Public License as published by

// the Free Software Foundation, either version 3 of the License, or

// (at your option) any later version.

//

// Moodle is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

// GNU General Public License for more details.

//

// You should have received a copy of the GNU General Public License

// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

namespace core;

use ReflectionAttribute;

/**

 * Helper for loading attributes.

 *

 * @package    core

 * @copyright  2024 Andrew Lyons <andrew@nicols.co.uk>

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

class attribute_helper {

    /**

     * Get an instance of an attribute from a reference.

     *

     * The reference can be:

     * - a string, in which case it will be checked for a function, class, method, property, constant, or enum.

     * - an array

     * - an instantiated object, in which case the object will be checked for a class, method, property, or constant.

     *

     * @param array|string|object $reference A reference of where to find the attribute

     * @param null|string $attributename The name of the attribute to find

     * @param int $attributeflags The flags to use when finding the attribute

     * @return ?object

     */

    public static function instance(

        array|string|object $reference,

        ?string $attributename = null,

        int $attributeflags = ReflectionAttribute::IS_INSTANCEOF,

    ): ?object {

        return self::one_from($reference, $attributename, $attributeflags)?->newInstance();

    }

    /**

     * Get all instance of an attribute from a reference.

     *

     * The reference can be:

     * - a string, in which case it will be checked for a function, class, method, property, constant, or enum.

     * - an array

     * - an instantiated object, in which case the object will be checked for a class, method, property, or constant.

     *

     * @param array|string|object $reference A reference of where to find the attribute

     * @param null|string $attributename The name of the attribute to find

     * @param int $attributeflags The flags to use when finding the attribute

     * @return ?object[]

     */

    public static function instances(

        array|string|object $reference,

        ?string $attributename = null,

        int $attributeflags = ReflectionAttribute::IS_INSTANCEOF,

    ): ?array {

        if ($attributes = self::from($reference, $attributename, $attributeflags)) {

            return array_map(fn ($attribute) => $attribute->newInstance(), $attributes);

        }

        return null;

    }

    /**

     * Get one attribute from a reference.

     *

     * The reference can be:

     * - a string, in which case it will be checked for a function, class, method, property, constant, or enum.

     * - an array

     * - an instantiated object, in which case the object will be checked for a class, method, property, or constant.

     *

     * @param array|string|object $reference A reference of where to find the attribute

     * @param null|string $attributename The name of the attribute to find

     * @param int $attributeflags The flags to use when finding the attribute

     * @return \ReflectionAttribute|null

     */

    public static function one_from(

        array|string|object $reference,

        ?string $attributename = null,

        int $attributeflags = ReflectionAttribute::IS_INSTANCEOF,

    ): ?\ReflectionAttribute {

        $attributes = self::from($reference, $attributename, $attributeflags);

        if ($attributes && count($attributes) > 1) {

            throw new \coding_exception('More than one attribute found');

        }

        return $attributes ? $attributes[0] : null;

    }

    /**

     * Get the attribute from a reference.

     *

     * The reference can be:

     * - a string, in which case it will be checked for a function, class, method, property, constant, or enum.

     * - an array

     * - an instantiated object, in which case the object will be checked for a class, method, property, or constant.

     *

     * @param array|string|object $reference A reference of where to find the attribute

     * @param null|string $attributename The name of the attribute to find

     * @param int $attributeflags The flags to use when finding the attribute

     * @return \ReflectionAttribute[]|null

     */

    public static function from(

        array|string|object $reference,

        ?string $attributename = null,

        int $attributeflags = ReflectionAttribute::IS_INSTANCEOF,

    ): ?array {

        if (is_string($reference)) {

            if (str_contains($reference, '::')) {

                // The reference is a string but it looks to be in the format `object::item`.

                return self::from(explode('::', $reference), $attributename, $attributeflags);;

            }

            if (class_exists($reference)) {

                // The reference looks to be a class name.

                return self::from([$reference], $attributename, $attributeflags);

            }

            if (function_exists($reference)) {

                // The reference looks to be a global function.

                $ref = new \ReflectionFunction($reference);

                return $ref->getAttributes(

                    name: $attributename,

                    flags: $attributeflags,

                );

            }

            return null;

        }

        if (is_object($reference)) {

            // The reference is an object. Normalise and check again.

            return self::from([$reference], $attributename, $attributeflags);

        }

        if (is_array($reference) && count($reference)) {

            if (is_object($reference[0])) {

                // The first array key is an instance of a class, enum, etc.

                $rc = new \ReflectionObject($reference[0]);

                if ($rc->isEnum() && $reference[0]->name) {

                    // Enums can be passed via ::from([enum::NAME]).

                    // In this case they will have a 'name', which must exist.

                    return self::from_reflected_object(

                        rc: $rc,

                        referenceproperty: $reference[0]->name,

                        attributename: $attributename,

                        flags: $attributeflags,

                    );

                }

                // The object is an instance of a class, or similar.

                // That means that, if provided, the second array key is the name of the property, constant, method, etc.

                return self::from_reflected_object(

                    rc: $rc,

                    referenceproperty: $reference[1] ?? null,

                    attributename: $attributename,

                    flags: $attributeflags,

                );

            }

            if (is_string($reference[0]) && class_exists($reference[0])) {

                // The first array key is a class name.

                // That means that, if provided, the second array key is the name of the property, constant, method, etc.

                $rc = new \ReflectionClass($reference[0]);

                return self::from_reflected_object(

                    rc: $rc,

                    referenceproperty: $reference[1] ?? null,

                    attributename: $attributename,

                    flags: $attributeflags,

                );

            }

            // The reference is an array, but it's not an object or a class that currently exists.

            return null;

        }

    }

    /**

     * Fetch an attribute from a reflected object.

     *

     * @param \ReflectionClass $rc The reflected object

     * @param null|string $referenceproperty The name of the thing to find attributes on

     * @param null|string $attributename The name of the attribute to find

     * @param int $attributeflags The flags to use when finding the attribute

     * @return \ReflectionAttribute[]|null

     */

    protected static function from_reflected_object(

        \ReflectionClass $rc,

        ?string $referenceproperty,

        ?string $attributename = null,

        int $flags = 0,

    ): ?array {

        if ($referenceproperty === null) {

            // No name specified - may be the whole class..

            return $rc->getAttributes(

                name: $attributename,

                flags: $flags,

            );

        }

        if ($rc->hasConstant($referenceproperty)) {

            // This class has a constant with the specified name.

            // Note: This also applies to enums.

            $ref = $rc->getReflectionConstant($referenceproperty);

            return $ref->getAttributes(

                name: $attributename,

                flags: $flags,

            );

        }

        if ($rc->hasMethod($referenceproperty)) {

            // This class has a method with the specified name.

            $ref = $rc->getMethod($referenceproperty);

            return $ref->getAttributes(

                name: $attributename,

                flags: $flags,

            );

        }

        if ($rc->hasProperty($referenceproperty)) {

            // This class has a property with the specified name.

            $ref = $rc->getProperty($referenceproperty);

            return $ref->getAttributes(

                name: $attributename,

                flags: $flags,

            );

        }

        return null;

    }

}