---
### 1. 樂觀鎖
>
class BaseModel extends Model
{
/**
* 樂觀鎖更新 compare and update
* @return bool|int
* @throws Throwable
*/
public function cas()
{
throw_if(!$this->exists, \Exception::class,['model not exists when cas']);
$dirty = $this->getDirty(); //修改之后的值
//是否有更新
if(empty($dirty)){
return 0;
}
//判斷更新的值是否存在
$diff = array_diff(array_keys($dirty), array_keys($this->original));
throw_if(!empty($diff), \Exception::class, 'key ['.implode(',', $diff).'] not exists when cas!');
//攔截更新事件
if ($this->fireModelEvent('casing') === false) {
return 0;
}
$query = $this->newModelQuery()->where($this->getKeyName(), $this->getKey()); //不帶 delete or query
foreach ($dirty as $key => $value) {
$query = $query->where($key, $this->getOriginal($key));
}
$row = $query->update($dirty);
if ($row > 0) {
$this->syncChanges(); //同步 changes
$this->fireModelEvent('cased', false);
$this->syncOriginal(); //同步數據庫
}
return $row;
}
/**
* Register a casing model event with the dispatcher.
*
* @param Closure|string $callback
* @return void
*/
public static function casing($callback)
{
static::registerModelEvent('casing', $callback);
}
/**
* Register a cased model event with the dispatcher.
*
* @param Closure|string $callback
* @return void
*/
public static function cased($callback)
{
static::registerModelEvent('cased', $callback);
}
}
