moodle/lib/classes/attribute_helper.php
Andrew Nicols 2b7754ccc2
MDL-81011 core: Add attribute alternative to hooks interfaces
This change replaces the requirement for:
- \core\hook\deprecated_callback_replacement
- \core\hook\described_hook

These are replaced by appropriate Attributes.
2024-03-07 18:56:05 +08:00

246 lines
9.5 KiB
PHP

<?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;
}
}