WC_Deprecated_Hooks abstract

includes/abstracts/abstract-wc-deprecated-hooks.php

@@ -0,0 +1,93 @@
+<?php
+if ( ! defined( 'ABSPATH' ) ) {
+	exit;
+}
+
+/**
+ * WC_Deprecated_Hooks class maps old actions and filters to new ones. This is the base class for handling those deprecated hooks.
+ *
+ * Based on the WCS_Hook_Deprecator class by Prospress.
+ *
+ * @since 2.7.0
+ */
+abstract class WC_Deprecated_Hooks {
+
+	/**
+	 * Array of deprecated hooks we need to handle.
+	 *
+	 * @var array
+	 */
+	protected $deprecated_hooks = array();
+
+	/**
+	 * Constructor.
+	 */
+	public function __construct() {
+		array_walk( array_keys( $this->deprecated_hooks ), array( $this, 'hook_in' ) );
+	}
+
+	/**
+	 * Hook into the new hook so we can handle deprecated hooks once fired.
+	 *
+	 * @param  string $hook_name
+	 */
+	abstract function hook_in( $hook_name );
+
+	/**
+	 * Get old hooks to map to new hook.
+	 *
+	 * @param  string $new_hook
+	 * @return array
+	 */
+	public function get_old_hooks( $new_hook ) {
+		$old_hooks = isset( $this->deprecated_hooks[ $new_hook ] ) ? $this->deprecated_hooks[ $new_hook ] : array();
+		$old_hooks = is_array( $old_hooks ) ? $old_hooks : array( $old_hooks );
+
+		return $old_hooks;
+	}
+
+	/**
+	 * If the hook is Deprecated, call the old hooks here.
+	 */
+	public function maybe_handle_deprecated_hook() {
+		$new_hook          = current_filter();
+		$old_hooks         = $this->get_old_hooks( $new_hook );
+		$new_callback_args = func_get_args();
+		$return_value      = $new_callback_args[0];
+
+		foreach ( $old_hooks as $old_hook ) {
+			$return_value = $this->handle_deprecated_hook( $new_hook, $old_hook, $new_callback_args, $return_value );
+		}
+
+		return $return_value;
+	}
+
+	/**
+	 * If the old hook is in-use, trigger it.
+	 *
+	 * @param string $new_hook
+	 * @param string $old_hook
+	 * @param array $new_callback_args
+	 * @param mixed $return_value
+	 * @return mixed
+	 */
+	abstract function handle_deprecated_hook( $new_hook, $old_hook, $new_callback_args, $return_value );
+
+	/**
+	 * Display a deprecated notice for old hooks.
+	 *
+	 * @since 2.0
+	 */
+	protected static function display_notice( $old_hook, $new_hook ) {
+		_deprecated_function( sprintf( 'The "%s" hook uses out of date data structures so', esc_html( $old_hook ) ), false, esc_html( $new_hook ) );
+	}
+
+	/**
+	 * Fire off a legacy hook with it's args.
+	 *
+	 * @param  string $old_hook
+	 * @param  array $new_callback_args
+	 * @return mixed
+	 */
+	abstract function trigger_hook( $old_hook, $new_callback_args );
+}