Icons: Add APIs for collection and icon registration

src/wp-includes/class-wp-icon-collections-registry.php

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+<?php
+/**
+ * Icons API: WP_Icon_Collections_Registry class
+ *
+ * @package WordPress
+ * @since 7.1.0
+ */
+
+/**
+ * Core class used for interacting with registered icon collections.
+ *
+ * Icons are always associated with a single collection. Collections act as
+ * a namespace for icons and allow grouping icons coming from different
+ * sources (e.g. core, Font Awesome, Google Material Icons).
+ *
+ * @since 7.1.0
+ */
+class WP_Icon_Collections_Registry {
+
+	/**
+	 * Registered icon collections array.
+	 *
+	 * @since 7.1.0
+	 * @var array[]
+	 */
+	protected $registered_collections = array();
+
+	/**
+	 * Container for the main instance of the class.
+	 *
+	 * @since 7.1.0
+	 * @var WP_Icon_Collections_Registry|null
+	 */
+	protected static $instance = null;
+
+	/**
+	 * Registers an icon collection.
+	 *
+	 * @since 7.1.0
+	 *
+	 * @param string $collection_slug       Icon collection slug.
+	 * @param array  $collection_properties {
+	 *     List of properties for the icon collection.
+	 *
+	 *     @type string $label       Required. A human-readable label for the icon collection.
+	 *     @type string $description Optional. A human-readable description for the icon collection.
+	 * }
+	 * @return bool True if the collection was registered successfully, false otherwise.
+	 */
+	public function register( $collection_slug, $collection_properties ) {
+		if ( ! isset( $collection_slug ) || ! is_string( $collection_slug ) ) {
+			_doing_it_wrong(
+				__METHOD__,
+				__( 'Icon collection slug must be a string.' ),
+				'7.1.0'
+			);
+			return false;
+		}
+
+		if ( ! preg_match( '/^[a-z0-9-]+$/', $collection_slug ) ) {
+			_doing_it_wrong(
+				__METHOD__,
+				__( 'Icon collection slug must only contain lowercase alphanumeric characters and hyphens.' ),
+				'7.1.0'
+			);
+			return false;
+		}
+
+		if ( $this->is_registered( $collection_slug ) ) {
+			_doing_it_wrong(
+				__METHOD__,
+				__( 'Icon collection is already registered.' ),
+				'7.1.0'
+			);
+			return false;
+		}
+
+		if ( ! is_array( $collection_properties ) ) {
+			_doing_it_wrong(
+				__METHOD__,
+				__( 'Icon collection properties must be an array.' ),
+				'7.1.0'
+			);
+			return false;
+		}
+
+		$allowed_keys = array_fill_keys( array( 'label', 'description' ), 1 );
+		foreach ( array_keys( $collection_properties ) as $key ) {
+			if ( ! array_key_exists( $key, $allowed_keys ) ) {
+				_doing_it_wrong(
+					__METHOD__,
+					sprintf(
+						/* translators: %s: The name of a user-provided key. */
+						__( 'Invalid icon collection property: "%s".' ),
+						$key
+					),
+					'7.1.0'
+				);
+				return false;
+			}
+		}
+
+		if ( ! isset( $collection_properties['label'] ) || ! is_string( $collection_properties['label'] ) ) {
+			_doing_it_wrong(
+				__METHOD__,
+				__( 'Icon collection label must be a string.' ),
+				'7.1.0'
+			);
+			return false;
+		}
+
+		$defaults = array(
+			'description' => '',
+		);
+
+		$collection = array_merge(
+			$defaults,
+			$collection_properties,
+			array( 'slug' => $collection_slug )
+		);
+
+		$this->registered_collections[ $collection_slug ] = $collection;
+
+		return true;
+	}
+
+	/**
+	 * Unregisters an icon collection.
+	 *
+	 * Any icons registered under the given collection are also unregistered.
+	 *
+	 * @since 7.1.0
+	 *
+	 * @param string $collection_slug Icon collection slug.
+	 * @return bool True if the collection was unregistered successfully, false otherwise.
+	 */
+	public function unregister( $collection_slug ) {
+		if ( ! $this->is_registered( $collection_slug ) ) {
+			_doing_it_wrong(
+				__METHOD__,
+				sprintf(
+					/* translators: %s: Icon collection slug. */
+					__( 'Icon collection "%s" not found.' ),
+					$collection_slug
+				),
+				'7.1.0'
+			);
+			return false;
+		}
+
+		$icons_registry = WP_Icons_Registry::get_instance();
+		foreach ( $icons_registry->get_registered_icons() as $icon ) {
+			if ( isset( $icon['collection'] ) && $icon['collection'] === $collection_slug ) {
+				$icons_registry->unregister( $icon['name'] );
+			}
+		}
+
+		unset( $this->registered_collections[ $collection_slug ] );
+
+		return true;
+	}
+
+	/**
+	 * Retrieves an array containing the properties of a registered icon collection.
+	 *
+	 * @since 7.1.0
+	 *
+	 * @param string $collection_slug Icon collection slug.
+	 * @return array|null Registered collection properties, or `null` if the collection is not registered.
+	 */
+	public function get_registered( $collection_slug ) {
+		if ( ! $this->is_registered( $collection_slug ) ) {
+			return null;
+		}
+
+		return $this->registered_collections[ $collection_slug ];
+	}
+
+	/**
+	 * Retrieves all registered icon collections.
+	 *
+	 * @since 7.1.0
+	 *
+	 * @return array[] Array of arrays containing the registered icon collections properties.
+	 */
+	public function get_all_registered() {
+		return array_values( $this->registered_collections );
+	}
+
+	/**
+	 * Checks if an icon collection is registered.
+	 *
+	 * @since 7.1.0
+	 *
+	 * @param string|null $collection_slug Icon collection slug.
+	 * @return bool True if the icon collection is registered, false otherwise.
+	 */
+	public function is_registered( $collection_slug ) {
+		return isset( $collection_slug, $this->registered_collections[ $collection_slug ] );
+	}
+
+	/**
+	 * Utility method to retrieve the main instance of the class.
+	 *
+	 * The instance will be created if it does not exist yet.
+	 *
+	 * @since 7.1.0
+	 *
+	 * @return WP_Icon_Collections_Registry The main instance.
+	 */
+	public static function get_instance() {
+		if ( null === self::$instance ) {
+			self::$instance = new self();
+		}
+
+		return self::$instance;
+	}
+}