add nova

nova/src/AuthorizedToSee.php

@@ -0,0 +1,40 @@
+<?php
+
+namespace Laravel\Nova;
+
+use Closure;
+use Illuminate\Http\Request;
+
+trait AuthorizedToSee
+{
+    /**
+     * The callback used to authorize viewing the filter or action.
+     *
+     * @var (\Closure(\Illuminate\Http\Request):(bool))|null
+     */
+    public $seeCallback;
+
+    /**
+     * Determine if the filter or action should be available for the given request.
+     *
+     * @param  \Illuminate\Http\Request  $request
+     * @return bool
+     */
+    public function authorizedToSee(Request $request)
+    {
+        return $this->seeCallback ? call_user_func($this->seeCallback, $request) : true;
+    }
+
+    /**
+     * Set the callback to be run to authorize viewing the filter or action.
+     *
+     * @param  \Closure(\Illuminate\Http\Request):bool  $callback
+     * @return $this
+     */
+    public function canSee(Closure $callback)
+    {
+        $this->seeCallback = $callback;
+
+        return $this;
+    }
+}