更新内核

core/library/think/cache/Driver.php

@@ -109,6 +109,27 @@ abstract class Driver
         }
     }
 
+    /**
+     * 如果不存在则写入缓存
+     * @access public
+     * @param string    $name 缓存变量名
+     * @param mixed     $value  存储数据
+     * @param int       $expire  有效时间 0为永久
+     * @return mixed
+     */
+    public function remember($name, $value, $expire = null)
+    {
+        if (!$this->has($name)) {
+            if ($value instanceof \Closure) {
+                $value = call_user_func($value);
+            }
+            $this->set($name, $value, $expire);
+        } else {
+            $value = $this->get($name);
+        }
+        return $value;
+    }
+
     /**
      * 缓存标签
      * @access public