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   1  <?php
   2  /**
   3   * Block Bindings API: WP_Block_Bindings_Registry class.
   4   *
   5   * Supports overriding content in blocks by connecting them to different sources.
   6   *
   7   * @package WordPress
   8   * @subpackage Block Bindings
   9   * @since 6.5.0
  10   */
  11  
  12  /**
  13   * Core class used for interacting with block bindings sources.
  14   *
  15   * @since 6.5.0
  16   */
  17  final class WP_Block_Bindings_Registry {
  18  
  19      /**
  20       * Holds the registered block bindings sources, keyed by source identifier.
  21       *
  22       * @since 6.5.0
  23       * @var WP_Block_Bindings_Source[]
  24       */
  25      private $sources = array();
  26  
  27      /**
  28       * Container for the main instance of the class.
  29       *
  30       * @since 6.5.0
  31       * @var WP_Block_Bindings_Registry|null
  32       */
  33      private static $instance = null;
  34  
  35      /**
  36       * Supported source properties that can be passed to the registered source.
  37       *
  38       * @since 6.5.0
  39       * @var string[]
  40       */
  41      private $allowed_source_properties = array(
  42          'label',
  43          'get_value_callback',
  44          'uses_context',
  45      );
  46  
  47      /**
  48       * Registers a new block bindings source.
  49       *
  50       * This is a low-level method. For most use cases, it is recommended to use
  51       * the `register_block_bindings_source()` function instead.
  52       *
  53       * @see register_block_bindings_source()
  54       *
  55       * Sources are used to override block's original attributes with a value
  56       * coming from the source. Once a source is registered, it can be used by a
  57       * block by setting its `metadata.bindings` attribute to a value that refers
  58       * to the source.
  59       *
  60       * @since 6.5.0
  61       *
  62       * @param string $source_name       The name of the source. It must be a string containing a namespace prefix, i.e.
  63       *                                  `my-plugin/my-custom-source`. It must only contain lowercase alphanumeric
  64       *                                  characters, the forward slash `/` and dashes.
  65       * @param array  $source_properties {
  66       *     The array of arguments that are used to register a source.
  67       *
  68       *     @type string   $label              The label of the source.
  69       *     @type callable $get_value_callback A callback executed when the source is processed during block rendering.
  70       *                                        The callback should have the following signature:
  71       *
  72       *                                        `function( $source_args, $block_instance, $attribute_name ): mixed`
  73       *                                            - @param array    $source_args    Array containing source arguments
  74       *                                                                              used to look up the override value,
  75       *                                                                              i.e. {"key": "foo"}.
  76       *                                            - @param WP_Block $block_instance The block instance.
  77       *                                            - @param string   $attribute_name The name of the target attribute.
  78       *                                        The callback has a mixed return type; it may return a string to override
  79       *                                        the block's original value, null, false to remove an attribute, etc.
  80       *     @type string[] $uses_context       Optional. Array of values to add to block `uses_context` needed by the source.
  81       * }
  82       * @return WP_Block_Bindings_Source|false Source when the registration was successful, or `false` on failure.
  83       *
  84       * @phpstan-param lowercase-string&non-falsy-string $source_name
  85       */
  86  	public function register( string $source_name, array $source_properties ) {
  87          if ( ! is_string( $source_name ) ) {
  88              _doing_it_wrong(
  89                  __METHOD__,
  90                  __( 'Block bindings source name must be a string.' ),
  91                  '6.5.0'
  92              );
  93              return false;
  94          }
  95  
  96          if ( preg_match( '/[A-Z]+/', $source_name ) ) {
  97              _doing_it_wrong(
  98                  __METHOD__,
  99                  __( 'Block bindings source names must not contain uppercase characters.' ),
 100                  '6.5.0'
 101              );
 102              return false;
 103          }
 104  
 105          $name_matcher = '/^[a-z0-9-]+\/[a-z0-9-]+$/';
 106          if ( ! preg_match( $name_matcher, $source_name ) ) {
 107              _doing_it_wrong(
 108                  __METHOD__,
 109                  __( 'Block bindings source names must contain a namespace prefix. Example: my-plugin/my-custom-source' ),
 110                  '6.5.0'
 111              );
 112              return false;
 113          }
 114  
 115          if ( $this->is_registered( $source_name ) ) {
 116              _doing_it_wrong(
 117                  __METHOD__,
 118                  /* translators: %s: Block bindings source name. */
 119                  sprintf( __( 'Block bindings source "%s" already registered.' ), $source_name ),
 120                  '6.5.0'
 121              );
 122              return false;
 123          }
 124  
 125          // Validates that the source properties contain the label.
 126          if ( ! isset( $source_properties['label'] ) ) {
 127              _doing_it_wrong(
 128                  __METHOD__,
 129                  __( 'The $source_properties must contain a "label".' ),
 130                  '6.5.0'
 131              );
 132              return false;
 133          }
 134  
 135          // Validates that the source properties contain the get_value_callback.
 136          if ( ! isset( $source_properties['get_value_callback'] ) ) {
 137              _doing_it_wrong(
 138                  __METHOD__,
 139                  __( 'The $source_properties must contain a "get_value_callback".' ),
 140                  '6.5.0'
 141              );
 142              return false;
 143          }
 144  
 145          // Validates that the get_value_callback is a valid callback.
 146          if ( ! is_callable( $source_properties['get_value_callback'] ) ) {
 147              _doing_it_wrong(
 148                  __METHOD__,
 149                  __( 'The "get_value_callback" parameter must be a valid callback.' ),
 150                  '6.5.0'
 151              );
 152              return false;
 153          }
 154  
 155          // Validates that the uses_context parameter is an array.
 156          if ( isset( $source_properties['uses_context'] ) && ! is_array( $source_properties['uses_context'] ) ) {
 157              _doing_it_wrong(
 158                  __METHOD__,
 159                  __( 'The "uses_context" parameter must be an array.' ),
 160                  '6.5.0'
 161              );
 162              return false;
 163          }
 164  
 165          if ( ! empty( array_diff( array_keys( $source_properties ), $this->allowed_source_properties ) ) ) {
 166              _doing_it_wrong(
 167                  __METHOD__,
 168                  __( 'The $source_properties array contains invalid properties.' ),
 169                  '6.5.0'
 170              );
 171              return false;
 172          }
 173  
 174          $source = new WP_Block_Bindings_Source(
 175              $source_name,
 176              $source_properties
 177          );
 178  
 179          $this->sources[ $source_name ] = $source;
 180  
 181          return $source;
 182      }
 183  
 184      /**
 185       * Unregisters a block bindings source.
 186       *
 187       * @since 6.5.0
 188       *
 189       * @param string $source_name Block bindings source name including namespace.
 190       * @return WP_Block_Bindings_Source|false The unregistered block bindings source on success and `false` otherwise.
 191       */
 192  	public function unregister( string $source_name ) {
 193          if ( ! $this->is_registered( $source_name ) ) {
 194              _doing_it_wrong(
 195                  __METHOD__,
 196                  /* translators: %s: Block bindings source name. */
 197                  sprintf( __( 'Block binding "%s" not found.' ), $source_name ),
 198                  '6.5.0'
 199              );
 200              return false;
 201          }
 202  
 203          $unregistered_source = $this->sources[ $source_name ];
 204          unset( $this->sources[ $source_name ] );
 205  
 206          return $unregistered_source;
 207      }
 208  
 209      /**
 210       * Retrieves the list of all registered block bindings sources.
 211       *
 212       * @since 6.5.0
 213       *
 214       * @return WP_Block_Bindings_Source[] The array of registered sources.
 215       */
 216  	public function get_all_registered() {
 217          return $this->sources;
 218      }
 219  
 220      /**
 221       * Retrieves a registered block bindings source.
 222       *
 223       * @since 6.5.0
 224       *
 225       * @param string $source_name The name of the source.
 226       * @return WP_Block_Bindings_Source|null The registered block bindings source, or `null` if it is not registered.
 227       */
 228  	public function get_registered( string $source_name ) {
 229          if ( ! $this->is_registered( $source_name ) ) {
 230              return null;
 231          }
 232  
 233          return $this->sources[ $source_name ];
 234      }
 235  
 236      /**
 237       * Checks if a block bindings source is registered.
 238       *
 239       * @since 6.5.0
 240       *
 241       * @param string|null $source_name The name of the source.
 242       * @return bool `true` if the block bindings source is registered, `false` otherwise.
 243       */
 244  	public function is_registered( $source_name ) {
 245          return isset( $source_name, $this->sources[ $source_name ] );
 246      }
 247  
 248      /**
 249       * Wakeup magic method.
 250       *
 251       * @since 6.5.0
 252       */
 253  	public function __wakeup() {
 254          if ( ! $this->sources ) {
 255              return;
 256          }
 257          if ( ! is_array( $this->sources ) ) {
 258              throw new UnexpectedValueException();
 259          }
 260          foreach ( $this->sources as $value ) {
 261              if ( ! $value instanceof WP_Block_Bindings_Source ) {
 262                  throw new UnexpectedValueException();
 263              }
 264          }
 265      }
 266  
 267      /**
 268       * Utility method to retrieve the main instance of the class.
 269       *
 270       * The instance will be created if it does not exist yet.
 271       *
 272       * @since 6.5.0
 273       *
 274       * @return WP_Block_Bindings_Registry The main instance.
 275       */
 276  	public static function get_instance() {
 277          self::$instance ??= new self();
 278  
 279          return self::$instance;
 280      }
 281  }