Added helper file with permission related functions.

application/helpers/permission_helper.php

@@ -0,0 +1,77 @@
+<?php defined('BASEPATH') or exit('No direct script access allowed');
+
+/* ----------------------------------------------------------------------------
+ * Easy!Appointments - Open Source Web Scheduler
+ *
+ * @package     EasyAppointments
+ * @author      A.Tselegidis <alextselegidis@gmail.com>
+ * @copyright   Copyright (c) 2013 - 2020, Alex Tselegidis
+ * @license     http://opensource.org/licenses/GPL-3.0 - GPLv3
+ * @link        http://easyappointments.org
+ * @since       v1.5.0
+ * ---------------------------------------------------------------------------- */
+
+if ( ! function_exists('can'))
+{
+    /**
+     * Check if the currently logged-in user can perform an action
+     *
+     * Example:
+     *
+     * if (can('edit', 'appointments') === FALSE) abort(403);
+     *
+     * @param string $action
+     * @param string $resource
+     * @param int|null $user_id
+     *
+     * @return bool
+     */
+    function can(string $action, string $resource, int $user_id = NULL): bool
+    {
+        /** @var EA_Controller $CI */
+        $CI = &get_instance();
+
+        $CI->load->model('roles_model');
+        $CI->load->model('user_model');
+
+        if (empty($user_id))
+        {
+            $role_slug = session('role_slug');
+        }
+        else
+        {
+            $user = $CI->user_model->get_user($user_id);
+            $role_slug = $CI->roles_model->value('slug', $user['id_roles']);
+        }
+
+        if (empty($role_slug))
+        {
+            return FALSE;
+        }
+
+        $permissions = $CI->roles_model->get_privileges($role_slug);
+
+        return $permissions[$resource][$action];
+    }
+}
+
+if ( ! function_exists('cannot'))
+{
+    /**
+     * Check if the currently logged-in user can perform an action
+     *
+     * Example:
+     *
+     * if (cannot('edit', 'appointments')) abort(403);
+     *
+     * @param string $action
+     * @param string $resource
+     * @param int|null $user_id
+     *
+     * @return bool
+     */
+    function cannot(string $action, string $resource, int $user_id = NULL): bool
+    {
+        return ! can($action, $resource, $user_id);
+    }
+}