Cache类增加has方法 get方法支持默认值

library/think/cache/driver/File.php

@@ -11,8 +11,6 @@
 
 namespace think\cache\driver;
 
-use think\Cache;
-
 /**
  * 文件类型缓存类
  * @author    liu21st <liu21st@gmail.com>
@@ -86,6 +84,18 @@ class File
         return $this->options['path'] . $filename;
     }
 
+    /**
+     * 判断缓存是否存在
+     * @access public
+     * @param string $name 缓存变量名
+     * @return bool
+     */
+    public function has($name)
+    {
+        $filename = $this->filename($name);
+        return is_file($filename);
+    }
+
     /**
      * 读取缓存
      * @access public

library/think/cache/driver/Lite.php

@@ -11,8 +11,6 @@
 
 namespace think\cache\driver;
 
-use think\Cache;
-
 /**
  * 文件类型缓存类
  * @author    liu21st <liu21st@gmail.com>
@@ -53,6 +51,18 @@ class Lite
         return $this->options['path'] . $this->options['prefix'] . md5($name) . '.php';
     }
 
+    /**
+     * 判断缓存是否存在
+     * @access public
+     * @param string $name 缓存变量名
+     * @return mixed
+     */
+    public function has($name)
+    {
+        $filename = $this->filename($name);
+        return is_file($filename);
+    }
+
     /**
      * 读取缓存
      * @access public

library/think/cache/driver/Memcache.php

@@ -11,7 +11,6 @@
 
 namespace think\cache\driver;
 
-use think\Cache;
 use think\Exception;
 
 class Memcache
@@ -56,6 +55,18 @@ class Memcache
         }
     }
 
+    /**
+     * 判断缓存
+     * @access public
+     * @param string $name 缓存变量名
+     * @return bool
+     */
+    public function has($name)
+    {
+        $name = $this->options['prefix'] . $name;
+        return $this->handler->get($name) ? true : false;
+    }
+
     /**
      * 读取缓存
      * @access public

library/think/cache/driver/Memcached.php

@@ -11,8 +11,6 @@
 
 namespace think\cache\driver;
 
-use think\Cache;
-
 class Memcached
 {
     protected $handler;
@@ -62,6 +60,18 @@ class Memcached
         }
     }
 
+    /**
+     * 判断缓存
+     * @access public
+     * @param string $name 缓存变量名
+     * @return bool
+     */
+    public function has($name)
+    {
+        $name = $this->options['prefix'] . $name;
+        return $this->handler->get($name) ? true : false;
+    }
+
     /**
      * 读取缓存
      * @access public

library/think/cache/driver/Redis.php

@@ -11,9 +11,6 @@
 
 namespace think\cache\driver;
 
-use think\Cache;
-use think\Exception;
-
 /**
  * Redis缓存驱动，适合单机部署、有前端代理实现高可用的场景，性能最好
  * 有需要在业务层实现读写分离、或者使用RedisCluster的需求，请使用Redisd驱动
@@ -56,6 +53,17 @@ class Redis
         }
     }
 
+    /**
+     * 判断缓存
+     * @access public
+     * @param string $name 缓存变量名
+     * @return bool
+     */
+    public function has($name)
+    {
+        return $this->handler->get($this->options['prefix'] . $name) ? true : false;
+    }
+
     /**
      * 读取缓存
      * @access public

library/think/cache/driver/Redisd.php

@@ -12,7 +12,6 @@
 namespace think\cache\driver;
 
 use think\App;
-use think\Cache;
 use think\Exception;
 use think\Log;
 
@@ -199,6 +198,17 @@ class Redisd
         return $this;
     }
 
+    /**
+     * 判断缓存
+     * @access public
+     * @param string $name 缓存变量名
+     * @return bool
+     */
+    public function has($name)
+    {
+        return $this->get($name) ? true : false;
+    }
+
     /**
      * 读取缓存
      *

library/think/cache/driver/Sqlite.php

@@ -11,7 +11,6 @@
 
 namespace think\cache\driver;
 
-use think\Cache;
 use think\Exception;
 
 /**
@@ -47,6 +46,20 @@ class Sqlite
         $this->handler = $func($this->options['db']);
     }
 
+    /**
+     * 判断缓存
+     * @access public
+     * @param string $name 缓存变量名
+     * @return bool
+     */
+    public function has($name)
+    {
+        $name   = $this->options['prefix'] . sqlite_escape_string($name);
+        $sql    = 'SELECT value FROM ' . $this->options['table'] . ' WHERE var=\'' . $name . '\' AND (expire=0 OR expire >' . $_SERVER['REQUEST_TIME'] . ') LIMIT 1';
+        $result = sqlite_query($this->handler, $sql);
+        return sqlite_num_rows($result);
+    }
+
     /**
      * 读取缓存
      * @access public

library/think/cache/driver/Wincache.php

@@ -11,7 +11,6 @@
 
 namespace think\cache\driver;
 
-use think\Cache;
 use think\Exception;
 
 /**
@@ -41,6 +40,18 @@ class Wincache
         }
     }
 
+    /**
+     * 判断缓存
+     * @access public
+     * @param string $name 缓存变量名
+     * @return bool
+     */
+    public function has($name)
+    {
+        $name = $this->options['prefix'] . $name;
+        return wincache_ucache_exists($name);
+    }
+
     /**
      * 读取缓存
      * @access public

library/think/cache/driver/Xcache.php

@@ -11,7 +11,6 @@
 
 namespace think\cache\driver;
 
-use think\Cache;
 use think\Exception;
 
 /**
@@ -41,6 +40,18 @@ class Xcache
         }
     }
 
+    /**
+     * 判断缓存
+     * @access public
+     * @param string $name 缓存变量名
+     * @return bool
+     */
+    public function has($name)
+    {
+        $name = $this->options['prefix'] . $name;
+        return xcache_isset($name);
+    }
+
     /**
      * 读取缓存
      * @access public