Fix hook situation for Skin::doEditSectionLink

[mediawiki.git] / includes / libs / GenericArrayObject.php

<?php

/**
 * Extends ArrayObject and does two things:
 *
 * Allows for deriving classes to easily intercept additions
 * and deletions for purposes such as additional indexing.
 *
 * Enforces the objects to be of a certain type, so this
 * can be replied upon, much like if this had true support
 * for generics, which sadly enough is not possible in PHP.
 *
 * This program 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 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @since 1.20
 *
 * @file
 *
 * @license GNU GPL v2+
 * @author Jeroen De Dauw < jeroendedauw@gmail.com >
 */
abstract class GenericArrayObject extends ArrayObject {
        /**
         * Returns the name of an interface/class that the element should implement/extend.
         *
         * @since 1.20
         *
         * @return string
         */
        abstract public function getObjectType();

        /**
         * @see SiteList::getNewOffset()
         * @since 1.20
         * @var integer
         */
        protected $indexOffset = 0;

        /**
         * Finds a new offset for when appending an element.
         * The base class does this, so it would be better to integrate,
         * but there does not appear to be any way to do this...
         *
         * @since 1.20
         *
         * @return integer
         */
        protected function getNewOffset() {
                while ( $this->offsetExists( $this->indexOffset ) ) {
                        $this->indexOffset++;
                }

                return $this->indexOffset;
        }

        /**
         * Constructor.
         * @see ArrayObject::__construct
         *
         * @since 1.20
         *
         * @param null|array $input
         * @param int $flags
         * @param string $iterator_class
         */
        public function __construct( $input = null, $flags = 0, $iterator_class = 'ArrayIterator' ) {
                parent::__construct( array(), $flags, $iterator_class );

                if ( !is_null( $input ) ) {
                        foreach ( $input as $offset => $value ) {
                                $this->offsetSet( $offset, $value );
                        }
                }
        }

        /**
         * @see ArrayObject::append
         *
         * @since 1.20
         *
         * @param mixed $value
         */
        public function append( $value ) {
                $this->setElement( null, $value );
        }

        /**
         * @see ArrayObject::offsetSet()
         *
         * @since 1.20
         *
         * @param mixed $index
         * @param mixed $value
         */
        public function offsetSet( $index, $value ) {
                $this->setElement( $index, $value );
        }

        /**
         * Returns if the provided value has the same type as the elements
         * that can be added to this ArrayObject.
         *
         * @since 1.20
         *
         * @param mixed $value
         *
         * @return bool
         */
        protected function hasValidType( $value ) {
                $class = $this->getObjectType();
                return $value instanceof $class;
        }

        /**
         * Method that actually sets the element and holds
         * all common code needed for set operations, including
         * type checking and offset resolving.
         *
         * If you want to do additional indexing or have code that
         * otherwise needs to be executed whenever an element is added,
         * you can overload @see preSetElement.
         *
         * @since 1.20
         *
         * @param mixed $index
         * @param mixed $value
         *
         * @throws InvalidArgumentException
         */
        protected function setElement( $index, $value ) {
                if ( !$this->hasValidType( $value ) ) {
                        throw new InvalidArgumentException(
                                'Can only add ' . $this->getObjectType() . ' implementing objects to '
                                . get_called_class() . '.'
                        );
                }

                if ( is_null( $index ) ) {
                        $index = $this->getNewOffset();
                }

                if ( $this->preSetElement( $index, $value ) ) {
                        parent::offsetSet( $index, $value );
                }
        }

        /**
         * Gets called before a new element is added to the ArrayObject.
         *
         * At this point the index is always set (ie not null) and the
         * value is always of the type returned by @see getObjectType.
         *
         * Should return a boolean. When false is returned the element
         * does not get added to the ArrayObject.
         *
         * @since 1.20
         *
         * @param integer|string $index
         * @param mixed $value
         *
         * @return bool
         */
        protected function preSetElement( $index, $value ) {
                return true;
        }

        /**
         * @see Serializable::serialize
         *
         * @since 1.20
         *
         * @return string
         */
        public function serialize() {
                return serialize( $this->getSerializationData() );
        }

        /**
         * Returns an array holding all the data that should go into serialization calls.
         * This is intended to allow overloading without having to reimplement the
         * behavior of this base class.
         *
         * @since 1.20
         *
         * @return array
         */
        protected function getSerializationData() {
                return array(
                        'data' => $this->getArrayCopy(),
                        'index' => $this->indexOffset,
                );
        }

        /**
         * @see Serializable::unserialize
         *
         * @since 1.20
         *
         * @param string $serialization
         *
         * @return array
         */
        public function unserialize( $serialization ) {
                $serializationData = unserialize( $serialization );

                foreach ( $serializationData['data'] as $offset => $value ) {
                        // Just set the element, bypassing checks and offset resolving,
                        // as these elements have already gone through this.
                        parent::offsetSet( $offset, $value );
                }

                $this->indexOffset = $serializationData['index'];

                return $serializationData;
        }

        /**
         * Returns if the ArrayObject has no elements.
         *
         * @since 1.20
         *
         * @return bool
         */
        public function isEmpty() {
                return $this->count() === 0;
        }
}