woothemes/woocommerce

<?php
/**
 * Wraps an array (meta data for now) and tells if there was any changes.
 *
 * The main idea behind this class is to avoid doing unneeded
 * SQL updates if nothing changed.
 *
 * @version 3.2.0
 * @package WooCommerce
 */

defined( 'ABSPATH' ) || exit;

/**
 * Meta data class.
 */
class WC_Meta_Data implements JsonSerializable {

    /**
     * Current data for metadata
     *
     * @since 3.2.0
     * @var array
     */
    protected $current_data;

    /**
     * Metadata data
     *
     * @since 3.2.0
     * @var array
     */
    protected $data;

    /**
     * Constructor.
     *
     * @param array $meta Data to wrap behind this function.
     */
    public function __construct( $meta = array() ) {
        $this->current_data = $meta;
        $this->apply_changes();
    }

    /**
     * When converted to JSON.
     *
     * @return object|array
     */
    public function jsonSerialize() {
        return $this->get_data();
    }

    /**
     * Merge changes with data and clear.
     */
    public function apply_changes() {
        $this->data = $this->current_data;
    }

    /**
     * Creates or updates a property in the metadata object.
     *
     * @param string $key Key to set.
     * @param mixed  $value Value to set.
     */
    public function __set( $key, $value ) {
        $this->current_data[ $key ] = $value;
    }

    /**
     * Checks if a given key exists in our data. This is called internally
     * by `empty` and `isset`.
     *
     * @param string $key Key to check if set.
     *
     * @return bool
     */
    public function __isset( $key ) {
        return array_key_exists( $key, $this->current_data );
    }

    /**
     * Returns the value of any property.
     *
     * @param string $key Key to get.
     * @return mixed Property value or NULL if it does not exists
     */
    public function __get( $key ) {
        if ( array_key_exists( $key, $this->current_data ) ) {
            return $this->current_data[ $key ];
        }
        return null;
    }

    /**
     * Return data changes only.
     *
     * @return array
     */
    public function get_changes() {
        $changes = array();
        foreach ( $this->current_data as $id => $value ) {
            if ( ! array_key_exists( $id, $this->data ) || $value !== $this->data[ $id ] ) {
                $changes[ $id ] = $value;
            }
        }
        return $changes;
    }

    /**
     * Return all data as an array.
     *
     * @return array
     */
    public function get_data() {
        return $this->data;
    }
}