缓存操作 - TP5源代码阅读

public static function init(array $options = [])
    {
 if (is_null(self::$handler)) {
     // 自动初始化缓存
     if (!empty($options)) {
  self::connect($options);
     } elseif ('complex' == Config::get('cache.type')) {
  self::connect(Config::get('cache.default'));
     } else {
  self::connect(Config::get('cache'));
     }
 }
    }



## 1-2 缓存存储连接

### Cache::connect()
>>创建配置中指定类型的缓存存储。

public static function connect(array $options = [], $name = false)
    {
 $type = !empty($options['type']) ? $options['type'] : 'File';
 if (false === $name) {
     $name = md5(serialize($options));
 }

 if (true === $name || !isset(self::$instance[$name])) {
     $class = false !== strpos($type, '\') ? $type : '\think\cache\driver\' . ucwords($type);

     // 记录初始化信息
     App::$debug && Log::record('[ CACHE ] INIT ' . $type, 'info');
     if (true === $name) {
  return new $class($options);
     } else {
  self::$instance[$name] = new $class($options);
     }
 }
 self::$handler = self::$instance[$name];
 return self::$handler;
    }

>>由上可知缓存机制默认使用File存储，其多种存储驱动实现在(cachedriver)目录下

## 1-3切换缓存存储类型
>>可以用来切换缓存的存储类型

### Cache::store()

public static function store($name)
    {
 if ('complex' == Config::get('cache.type')) {
     self::connect(Config::get('cache.' . $name), strtolower($name));
 }
 return self::$handler;
    }


# 2 缓存操作
>>缓存的操作包括，存储数据到缓存存储器中，读取缓存存储器中的数据

### Cache::get()
>>读取缓存中数据

public static function get($name, $default = false)
    {
 self::init();
 self::$readTimes++;
 return self::$handler->get($name, $default);
    }


### Cache::set()
>>存储数据到缓存

public static function set($name, $value, $expire = null)
    {
 self::init();
 self::$writeTimes++;
 return self::$handler->set($name, $value, $expire);
    }


### Cache::has()
>>检查缓存数据

 public static function has($name)
    {
 self::init();
 self::$readTimes++;
 return self::$handler->has($name);
    }


### Cache::inc()
>>缓存自增

 public static function inc($name, $step = 1)
    {
 self::init();
 self::$writeTimes++;
 return self::$handler->inc($name, $step);
    }

### Cache::dec()
>>缓存自减

public static function dec($name, $step = 1)
    {
 self::init();
 self::$writeTimes++;
 return self::$handler->dec($name, $step);
    }


### Cache::rm()
>>删除缓存

public static function rm($name)
    {
 self::init();
 self::$writeTimes++;
 return self::$handler->rm($name);
    }


### Cache::clear()
>>清空缓存

public static function clear($tag = null)
    {
 self::init();
 self::$writeTimes++;
 return self::$handler->clear($tag);
    }


### Cache::tag()
>>带标签缓存

 public static function tag($name, $keys = null, $overlay = false)
    {
 self::init();
 return self::$handler->tag($name, $keys, $overlay);
    }


# 3 内置缓存驱动

>>tp5内置了多种缓存驱动实现不同形式的存储方式。如File,Redis,Memacahce.

>这里简单分析File类缓存驱动
>其他类型缓存接口相似

## 3-1 缓存驱动抽象类(Driver)

### $driver->getCacheKey()
>> 获取缓存标识

protected function getCacheKey($name)
    {
 return $this->options['prefix'] . $name;
    }


### $driver->pull()
>>读取缓存并删除

public function pull($name)
    {
 $result = $this->get($name, false);
 if ($result) {
     $this->rm($name);
     return $result;
 } else {
     return null;
 }
    }


### $driver->tag()
>>带标签缓存

public function tag($name, $keys = null, $overlay = false)
    {
 if (is_null($keys)) {
     $this->tag = $name;
 } else {
     $key = 'tag_' . md5($name);
     if (is_string($keys)) {
  $keys = explode(',', $keys);
     }
     $keys = array_map([$this, 'getCacheKey'], $keys);
     if ($overlay) {
  $value = $keys;
     } else {
  $value = array_unique(array_merge($this->getTagItem($name), $keys));
     }
     $this->set($key, implode(',', $value));
 }
 return $this;
    }


### $driver->setTagItem()
>>设置缓存标签

protected function setTagItem($name)
    {
 if ($this->tag) {
     $key= 'tag_' . md5($this->tag);
     $this->tag = null;
     if ($this->has($key)) {
  $value = $this->get($key);
  $value .= ',' . $name;
     } else {
  $value = $name;
     }
     $this->set($key, $value);
 }
    }


### $driver->getTagItem()
>>获取缓存标签

protected function getTagItem($tag)
    {
 $key   = 'tag_' . md5($tag);
 $value = $this->get($key);
 if ($value) {
     return explode(',', $value);
 } else {
     return [];
 }
    }


## 3-2 缓存驱动实现类(File)
### $file->__construct()
>>文件存储缓存构造函数

### $file->init()
>>文件缓存初始化

### $file->getCacheKey()
>>获取变量的存储文件名

### $file->has()
>>判断缓存是否存在

### $file->get()
>> 读取缓存

### $file->set()
>> 写入缓存

### $file->inc()
>>自增缓存

### $file->dec()
>>自减缓存

### $file->rm()
>>删除缓存

### $file->clear()
>>清空缓存

### $file->unlink()
>>文件删除。