source: trunk/src/wp-includes/class-wp-block-bindings-registry.php @ 57641

<?php
/**
 * Block Bindings API: WP_Block_Bindings_Registry class.
 *
 * Supports overriding content in blocks by connecting them to different sources.
 *
 * @package WordPress
 * @subpackage Block Bindings
 * @since 6.5.0
 */

/**
 * Core class used for interacting with block bindings sources.
 *
 *  @since 6.5.0
 */
final class WP_Block_Bindings_Registry {

        /**
         * Holds the registered block bindings sources, keyed by source identifier.
         *
         * @since 6.5.0
         * @var WP_Block_Bindings_Source[]
         */
        private $sources = array();

        /**
         * Container for the main instance of the class.
         *
         * @since 6.5.0
         * @var WP_Block_Bindings_Registry|null
         */
        private static $instance = null;

        /**
         * Supported source properties that can be passed to the registered source.
         *
         * @since 6.5.0
         * @var array
         */
        private $allowed_source_properties = array(
                'label',
                'get_value_callback',
                'uses_context',
        );

        /**
         * Supported blocks that can use the block bindings API.
         *
         * @since 6.5.0
         * @var array
         */
        private $supported_blocks = array(
                'core/paragraph',
                'core/heading',
                'core/image',
                'core/button',
        );

        /**
         * Registers a new block bindings source.
         *
         * This is a low-level method. For most use cases, it is recommended to use
         * the `register_block_bindings_source()` function instead.
         *
         * @see register_block_bindings_source()
         *
         * Sources are used to override block's original attributes with a value
         * coming from the source. Once a source is registered, it can be used by a
         * block by setting its `metadata.bindings` attribute to a value that refers
         * to the source.
         *
         * @since 6.5.0
         *
         * @param string   $source_name       The name of the source. It must be a string containing a namespace prefix, i.e.
         *                                    `my-plugin/my-custom-source`. It must only contain lowercase alphanumeric
         *                                    characters, the forward slash `/` and dashes.
         * @param array    $source_properties {
         *     The array of arguments that are used to register a source.
         *
         *     @type string   $label                   The label of the source.
         *     @type callback $get_value_callback      A callback executed when the source is processed during block rendering.
         *                                             The callback should have the following signature:
         *
         *                                             `function ($source_args, $block_instance,$attribute_name): mixed`
         *                                                 - @param array    $source_args    Array containing source arguments
         *                                                                                   used to look up the override value,
         *                                                                                   i.e. {"key": "foo"}.
         *                                                 - @param WP_Block $block_instance The block instance.
         *                                                 - @param string   $attribute_name The name of the target attribute.
         *                                             The callback has a mixed return type; it may return a string to override
         *                                             the block's original value, null, false to remove an attribute, etc.
         *     @type array    $uses_context (optional) Array of values to add to block `uses_context` needed by the source.
         * }
         * @return WP_Block_Bindings_Source|false Source when the registration was successful, or `false` on failure.
         */
        public function register( string $source_name, array $source_properties ) {
                if ( ! is_string( $source_name ) ) {
                        _doing_it_wrong(
                                __METHOD__,
                                __( 'Block bindings source name must be a string.' ),
                                '6.5.0'
                        );
                        return false;
                }

                if ( preg_match( '/[A-Z]+/', $source_name ) ) {
                        _doing_it_wrong(
                                __METHOD__,
                                __( 'Block bindings source names must not contain uppercase characters.' ),
                                '6.5.0'
                        );
                        return false;
                }

                $name_matcher = '/^[a-z0-9-]+\/[a-z0-9-]+$/';
                if ( ! preg_match( $name_matcher, $source_name ) ) {
                        _doing_it_wrong(
                                __METHOD__,
                                __( 'Block bindings source names must contain a namespace prefix. Example: my-plugin/my-custom-source' ),
                                '6.5.0'
                        );
                        return false;
                }

                if ( $this->is_registered( $source_name ) ) {
                        _doing_it_wrong(
                                __METHOD__,
                                /* translators: %s: Block bindings source name. */
                                sprintf( __( 'Block bindings source "%s" already registered.' ), $source_name ),
                                '6.5.0'
                        );
                        return false;
                }

                // Validates that the source properties contain the label.
                if ( ! isset( $source_properties['label'] ) ) {
                        _doing_it_wrong(
                                __METHOD__,
                                __( 'The $source_properties must contain a "label".' ),
                                '6.5.0'
                        );
                        return false;
                }

                // Validates that the source properties contain the get_value_callback.
                if ( ! isset( $source_properties['get_value_callback'] ) ) {
                        _doing_it_wrong(
                                __METHOD__,
                                __( 'The $source_properties must contain a "get_value_callback".' ),
                                '6.5.0'
                        );
                        return false;
                }

                // Validates that the get_value_callback is a valid callback.
                if ( ! is_callable( $source_properties['get_value_callback'] ) ) {
                        _doing_it_wrong(
                                __METHOD__,
                                __( 'The "get_value_callback" parameter must be a valid callback.' ),
                                '6.5.0'
                        );
                        return false;
                }

                // Validates that the uses_context parameter is an array.
                if ( isset( $source_properties['uses_context'] ) && ! is_array( $source_properties['uses_context'] ) ) {
                        _doing_it_wrong(
                                __METHOD__,
                                __( 'The "uses_context" parameter must be an array.' ),
                                '6.5.0'
                        );
                        return false;
                }

                if ( ! empty( array_diff( array_keys( $source_properties ), $this->allowed_source_properties ) ) ) {
                        _doing_it_wrong(
                                __METHOD__,
                                __( 'The $source_properties array contains invalid properties.' ),
                                '6.5.0'
                        );
                        return false;
                }

                $source = new WP_Block_Bindings_Source(
                        $source_name,
                        $source_properties
                );

                $this->sources[ $source_name ] = $source;

                // Adds `uses_context` defined by block bindings sources.
                add_filter(
                        'get_block_type_uses_context',
                        function ( $uses_context, $block_type ) use ( $source ) {
                                if ( ! in_array( $block_type->name, $this->supported_blocks, true ) || empty( $source->uses_context ) ) {
                                        return $uses_context;
                                }
                                // Use array_values to reset the array keys.
                                return array_values( array_unique( array_merge( $uses_context, $source->uses_context ) ) );
                        },
                        10,
                        2
                );

                return $source;
        }

        /**
         * Unregisters a block bindings source.
         *
         * @since 6.5.0
         *
         * @param string $source_name Block bindings source name including namespace.
         * @return WP_Block_Bindings_Source|false The unregistered block bindings source on success and `false` otherwise.
         */
        public function unregister( string $source_name ) {
                if ( ! $this->is_registered( $source_name ) ) {
                        _doing_it_wrong(
                                __METHOD__,
                                /* translators: %s: Block bindings source name. */
                                sprintf( __( 'Block binding "%s" not found.' ), $source_name ),
                                '6.5.0'
                        );
                        return false;
                }

                $unregistered_source = $this->sources[ $source_name ];
                unset( $this->sources[ $source_name ] );

                return $unregistered_source;
        }

        /**
         * Retrieves the list of all registered block bindings sources.
         *
         * @since 6.5.0
         *
         * @return WP_Block_Bindings_Source[] The array of registered sources.
         */
        public function get_all_registered() {
                return $this->sources;
        }

        /**
         * Retrieves a registered block bindings source.
         *
         * @since 6.5.0
         *
         * @param string $source_name The name of the source.
         * @return WP_Block_Bindings_Source|null The registered block bindings source, or `null` if it is not registered.
         */
        public function get_registered( string $source_name ) {
                if ( ! $this->is_registered( $source_name ) ) {
                        return null;
                }

                return $this->sources[ $source_name ];
        }

        /**
         * Checks if a block bindings source is registered.
         *
         * @since 6.5.0
         *
         * @param string $source_name The name of the source.
         * @return bool `true` if the block bindings source is registered, `false` otherwise.
         */
        public function is_registered( $source_name ) {
                return isset( $this->sources[ $source_name ] );
        }

        /**
         * Wakeup magic method.
         *
         * @since 6.5.0
         */
        public function __wakeup() {
                if ( ! $this->sources ) {
                        return;
                }
                if ( ! is_array( $this->sources ) ) {
                        throw new UnexpectedValueException();
                }
                foreach ( $this->sources as $value ) {
                        if ( ! $value instanceof WP_Block_Bindings_Source ) {
                                throw new UnexpectedValueException();
                        }
                }
        }

        /**
         * Utility method to retrieve the main instance of the class.
         *
         * The instance will be created if it does not exist yet.
         *
         * @since 6.5.0
         *
         * @return WP_Block_Bindings_Registry The main instance.
         */
        public static function get_instance() {
                if ( null === self::$instance ) {
                        self::$instance = new self();
                }

                return self::$instance;
        }
}